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EZNEC User Manual

1. 164 Viewing OpenPF files 128 Operating System cceeee 8 EE 8 155 OPONS eege 132 KEE at testes tae Staaten ts testes aces 46 Other Wire Considerations 57 OUTDO UNS tte eoticueciens 137 P Parallel Connected Loads Polarity ipa E 160 Parallel HBC 90 Parallel Type RLC Loads 90 Parallel Wues 65 Patches 150 181 Perfect Ground 102 pf Format Files 164 Conversion to Graphics Format REEL 144 Translating from ENT format 128 Phased Arrays nnnnnnnenan 72 86 Placing Insertion Objects On Segments see secsctageeetiveltecias 76 188 Placing Loads At Wire Junctions 88 Placing Sources At Wire Junctions aere 85 Placing Sources On Segments 84 Plane Wave Excitation 80 Interpreting results 82 Gpechfhving 81 With a Ground Plane 81 Se EE 138 Orientation cc 147 149 Step size 138 Translating file format 128 Viewing 128 Plot Data Fonts Ze 132 Plot File Types 2 000 142 Plot Line Wb 132 Plot EIER 132 162 Plot Type 138 eine ln Te DEE 138 Plot lee e EE 141 Polarization Age 102 lo DIE EE 11 112 Shown in 2D display 147 Power Level 132 Power Level selection 132 PowerDesSk ssssssssssssesseeeeereeeee10e 158 Prtiatal meop 162 Preserve Connections 49 PrintedOffsetAxisWidth 162 PrinterMargin unn 162 Printing The
2. Now let s tap wire 6 along the horizontal wire represented in the model by 5 wires In the Mouse Operation frame choose Move Wire Ends The next step is to select the top end of wire 6 and not the left end of connected wire 5 It s pretty easy here but can be a little trickier for more complex models The main requirement is to move the cursor to a point closer to wire 6 than wire 5 and closer to the desired wire end than any other wire end In this case this is satisfied by any point along or near the top half of wire 6 You can also pause the cursor over the wire near the end and look at the pop up window The wire and end numbers it shows are the ones which will be selected Selection can be made however at greater distances from the junction than required for the pop up window to appear With the cursor in the correct position momentarily left click the mouse If you successfully selected the top end of wire 6 you ll see this briefly before you move the mouse 42 Test Drive DN View Antenna Back yard dipole File Edit View Options Reset Center Ant Image Mouse Operation Normal iewing C Add Conn Wires Ze Move Wire Ends Preserve Connections If you see a different segment highlighted press lt Esc gt and try again In addition to the red square of the Add Conn Wires operation the segment of wire 6 nearest the junction is highlighted to show which wire was chosen for moving As before you ll se
3. 84 Building The Model Use standard non split sources whenever possible and use split sources only when it s necessary to put a source at a wire junction Placing Sources At Wire Junctions Conventional EZNEC sources have to be placed on a segment so simulating a source at a wire junction requires special techniques The preferred method is to use EZNEC s split sources which are intended for just this purpose When you specify a split source EZNEC actually creates two sources and places them on adjacent segments closest to the position you specified Split sources are shown in the View Antenna display as two sources but appear everywhere else as a single source Split sources are positioned just like conventional sources except that the position chosen by EZNEC will be the closest segment junction or wire end rather than the closest segment center to the position you specify When using split sources make sure that any load placed on the segment containing one source has a corresponding load on the segment containing the other and avoid putting transmission lines on segments with split sources Split sources can t be placed at a multiple wire junction and shouldn t be placed where the segment length or wire diameter is different for one source than the other Split sources also can t be placed on an open wire end because one of the actual sources making up the split source would be off the wire altogether The N4PCLoop ez and BYV
4. EZNEC is a registered trademark of Roy W Lewallen All rights are reserved Introduction Acknowledgements This program would not be possible without the help of the people who tested the program during its development stages These testers have provided invaluable suggestions for new features and improvement of existing ones ways to make the user interface easier to use and scrutiny of the manual And of course they ve found and reported many bugs and actively helped in tracking them down This has occurred for every version of EZNEC and its predecessor ELNEC Since each version has built upon the previous ones the people who have helped with any version have made a very substantial contribution to the present one am grateful and indebted to all hasten to add however that shortcomings of the program and remaining bugs are entirely my responsibility and not at all theirs It s impossible to express how much help was provided by Dan Maguire AC6LA in the development of EZNEC v 6 0 It would hardly have been possible at all without his extensive and expert help His feedback bug finding and chasing insightful suggestions and careful proofreading over a lengthy period were immeasurably helpful EZNEC v 6 0 is a much better product and is available much sooner than it would have been without his help Thanks Dan Rudy Severns N6LF gave the new Extended Accuracy ground a good workout and uncovered several bugs in the proces
5. 60 74 Modeling Wies sseseeeeeeseeeene 46 Modeling With EZNEC 45 lee EE 45 Very TANG EE 155 MOVING Wires sxtvescrazceeseestees nari 49 Multiband Antennas aaaaaneaaa 71 Multiple Insiances 157 Multiply Length By e 54 TEEN 112 N NAPCL oop ez 85 Near Field EE 137 el E 137 Near Field Analysis 103 112 123 Near Field Table 112 Near Field Table Format 132 NEG ee 150 Differences from EZNEC pro 150 IER 152 NEC ge 152 NEC Format Files 152 NEE e 152 Reading and writing 152 Working wf 152 NEC Radial Model 73 106 108 NEC reflection coefficient Ground SE 103 NEC Sommerfeld Ground 103 NEC E l 132 EZNEC User Manual NEG ee ee Ee 132 156 Double precision calculating GU 156 External Program s es 8 NEC 4 Notices nacione 177 NEC 4 2 n 8 150 152 177 GN3 Ground 103 155 Ee EE 132 NEG Tomat les 6 46 Decimal separator n1111 n 6 Opening and saving 46 lee TEE 162 NEetWOTrkS NEE 155 L Networks socne 98 Y Parameter Networks 101 NF Tab 140 Norton Antivirus cc eee 158 Notes For International Users 6 0 lee eugugugegugcgeeugg 132 142 144 View Antenna Display132 142 144 Observation Height 122 138 On The Race Course 29 Ee EE 140 Open Description sssnnnneeeeeeen 131 Opening The Description File 46 OpenPF Plot File Format
6. This choice is enabled only when one or more traces have been added to the basic display and a Desc Options choice has been made to plot multiple polarizations for example Vert Horiz Total Only one polarization can be shown when the display has multiple traces This menu selection allows choosing which of the polarizations to show Show 2D Plot 8D only Turns the 2D Plot Display on and off This allows viewing and detailed analysis of any 2D slice of the 3D plot Show Controls Turns the Control section of the display on and off NOTE This isn t available for the 2D display unless a 3D display is on with a slice of the 3D plot being shown on the 2D display Show Data 2D SWR only Turns the Data section of the display on and off Show Data Lines 2D only When on checked lines are added to the 2D display showing the directions of the pattern maximum 3 dB points and sidelobe as reported in the data box This option is available only if the Show Data option is checked Colors for these lines can be chosen in the Options menu Show Objects View Antenna only Allows you to select which of various objects is displayed in the plot section of the display such as currents segment dots etc These are detailed in the View Antenna Display Objects section 143 EZNEC User Manual Options Colors Allows you to choose the colors for objects displayed in the plot section of the display NOTE Choices will per
7. 0000 174 Legal dE 175 vi Table of Contents Legal DISCIAIMGN TE 175 License Agreement EE 176 SINGLE USE SOFTWARE LICENSE AGPREEMENT 176 Copyright and Trademark Notce 177 NEG 4 de le 177 Third Party Software Legal Notces AEN 177 VOACCEIGI AION Ae Ae Eeer ee See ee Aen eebe eer dee 177 WAZ Pa seca see ocr te A Ae a ne et Re a eat Ah aaa 178 e UE 179 S PPO eee ee rer ee ee ere eee ee ter ee 181 Updates Maintenance Releases ee 181 Reporting UgS EE 181 How to Contact EE 182 NIE X ne a a a iaai 183 vii Welcome Welcome to EZNEC version 6 0 This manual has been written to cover all EZNEC program types both standard and professional Sections which don t apply to all program types are identified otherwise all references in the manual to EZNEC apply equally to EZNEC and EZNEC Pro programs EZNEC Pro 2 and EZNEC Pro 4 It s assumed that you know basic Windows operation such as clicking dragging and selecting and references will occasionally be made to common Windows tools such as Notepad or the Windows Explorer Please consult your Windows documentation if you re not familiar with basic Windows techniques Comments about this manual are always welcome and will be read although a prompt personal reply might not always be practical Please send comments and suggestions to w7el eznec com Manual updates are included in the EZNEC maintenance releases which are available as they re developed Please see Updates for details
8. EZNEC User Manual plot See Displayable Objects 2D Pattern in Using The View Antenna Display for details An elevation plot is always viewed from ground level looking from the direction of the chosen azimuth angle The same plot will be shown but reversed in direction if viewed from the opposite direction that is an azimuth angle 180 degrees from the original When initially viewing a 2D slice of a 3D pattern EZNEC will choose the initial orientation based on the pattern maximum so the viewing angle might not be immediately obvious Likewise when switching between azimuth and elevation slices an apparent reversal of viewing angle may occur If you have trouble visualizing the pattern orientation adding the 2D plot to the View Antenna display as described above is helpful Navigation and Advanced Features EZNEC has a number of features to help you analyze 2D antenna patterns If you ve chosen to display multiple polarizations for example Horiz Vert Total via the Desc Options choice in the Control Center you can move the cursor from one polarization trace to another simply by clicking its name in the key list at the left of the 2D plot window The Data Window see below reports the field strength as gain relative to isotropic of that polarization component If you add traces you can switch the cursor to any trace by clicking the corresponding file name in the key list at the left of the 2D plot window When this is done and ad
9. Sergio Monesi Keith Owens George Petrov Greg Roelofs Kai Uwe Rommel Steve Salisbury Dave Smith Christian Spieler Antoine Verheijen Paul von Behren Rich Wales Mike White This software is provided as is without warranty of any kind express or implied In no event shall Info ZIP or its contributors be held liable for any 178 Legal Notices direct indirect incidental special or consequential damages arising out of the use of or inability to use this software Permission is granted to anyone to use this software for any purpose including commercial applications and to alter it and redistribute it freely subject to the following restrictions 1 Redistributions of source code must retain the above copyright notice definition disclaimer and this list of conditions 2 Redistributions in binary form compiled executables must reproduce the above copyright notice definition disclaimer and this list of conditions in documentation and or other materials provided with the distribution The sole exception to this condition is redistribution of a standard UnZipSFX binary including SFXWiz as part of a self extracting archive that is permitted without inclusion of this license as long as the normal SFX banner has not been removed from the binary or disabled 3 Altered versions including but not limited to ports to new operating systems existing ports with new graphical interfaces and dynamic shared or static libra
10. Sources are insertion objects which represent places where power is applied to an antenna Every EZNEC model must contain at least one source unless EZNEC Pro only plane wave excitation is being used Source voltages and currents are like all other EZNEC voltages and currents RMS NEC is notoriously sensitive to source placement and careless placement can lead to subtle errors in calculation results Please read the following section carefully so you ll avoid these problems Like other insertion objects sources are connected in an imaginary break in a wire They are connected in parallel with all other insertion objects in the same segment except for series connected conventional loads Technically a source is distributed over the entire segment at which it s connected you can envision it as being inserted at the center of the segment The positive terminal of the source always points to end 2 of the wire so a source with zero phase angle will produce current which flows from end 1 to end 2 of the wire These connections are dictated by the structure of NEC The restriction of source placement to segment centers prevents placing a source at a wire junction Junction placement is sometimes desirable for example in a vee type antenna EZNEC includes special source types to allow you effectively place sources at wire junctions when required If you want to keep the total power into the antenna constant you can select Power Level from the Co
11. WITHOUT LIMITATION CLAIMS THAT THE LEVEL OF SUCH EMISSIONS IS UNSAFE LICENSEE RELEASES LICENSOR FROM ANY CLAIMS RELATING TO THE INABILITY OF THIS SOFTWARE TO DETERMINE WHETHER LEVELS OF ELECTROMAGNETIC ENERGY COMING FROM LICENSEE S ANTENNA ARE HAZARDOUS OR UNSAFE TO ANY HUMAN BEINGS 175 EZNEC User Manual License Agreement SINGLE USE SOFTWARE LICENSE AGREEMENT By using the software the user agrees to the following terms and conditions Ownership All ownership of this software is reserved to Roy W Lewallen Licensor No title to or ownership of any software or any parts thereof is transferred by any delivery of this software The use of the software enclosed with this License Agreement conclusively establishes Licensee s agreement with all the terms and conditions hereof Limitation of Liability Licensor s liability under this Agreement shall be limited to a refund of the price paid by Licensee for the use of such program Licensor will not be liable for any property damage personal injury loss of use interruption of business or other special incidental or consequential damages however caused whether for breach of warranty contract tort including negligence strict liability or otherwise Exclusion of Warranties Licensor excludes all warranties express or implied including without limitation warranty of fitness for a particular purpose Licensor s sole warrantee is as follows For a period of ninety 90 days fol
12. is a registered trademark of Roy W Lewallen All rights are reserved NEC 4 Notices EZNEC Pro 4 may use a modified version of NEC 4 2 for calculations The following warning and notice apply to the portion of that program derived from NEC 4 2 Read the following important messages before using kkkkkkkkkkk WARNING kkkkkkkkkk The NEC 4 2 code is subject to export restrictions under Department of Commerce regulations EAR99 15 CFR Parts 730 774 kkkkkkkkkkk NOTICE kkkkkkkkkk The NEC 4 2 computer code material was prepared as an account of work sponsored by an agency of the United States Government Neither the United States Government nor the University of California nor any of their employees makes any warranty express or implied or assumes any legal liability or responsibility for the accuracy completeness or usefulness of any information apparatus product or process disclosed or represents that its use would not infringe privately owned rights Third Party Software Legal Notices vbAccelerator All EZNEC program types beginning with v 4 0 9 incorporate code generously provided free of charge by vbAccelerator The following information constitutes the license agreement for use of that software vbAccelerator code and binaries are provided for your reuse in any of your projects whether proprietary commercial or open source This document details voAccelerator s Open Source software licence vbAccelerator Software License Vers
13. performance of a beam antenna The stepped diameter correction used by EZNEC is not accurate for typical linear loaded elements and will not be applied to them Log Periodic Antennas An integral part of log periodic antennas is the transmission line connecting the elements This must be included in the model since no valid assumptions can be made about the relative voltages and currents at the element centers Transmission line segments between elements can be included as either wire models or as transmission line models If wire models are used it can be difficult or impossible to place the source in a way that fulfills all the requirements for source placement on a wire of at least 0 02 wavelength and three or more segments as described in Source Placement Precautions Results should be tested by changing the number of source wire segments source wire diameter and other parameters near the source to see if the answer remains relatively stable The Average Gain feature should also be checked and it can be used to correct the indicated gain to some extent See the LogPer ez example file and associated Antenna Notes file for more information Here s a tip for reducing the number of segments required to model a log periodic antenna Set the frequency to the lowest frequency of interest then use automatic segmentation to segment the model Note the number of segments in the longest element Then resegment the other elements to each have the s
14. series parallel or as a trap configuration as shown below R can optionally be made frequency dependent R L C Series RLC Values of R L and C are entered in the appropriate columns EZNEC will calculate and use the impedance of the RLC combination as required See Load Types for information about other types of loads and changing the load type Config Column The rightmost column is used to select the type of RLC circuit Series Parallel or Trap This selection can be made by entering S or Ser for Series type P or Par for Parallel type or T or Trap for Trap type Or you can click the cell to activate the drop down list arrow click the arrow to open the list then make the selection R L C Columns Series Configuration RLC Loads The R L and C are connected in series Any of the three components can be replaced by a short circuit by entering 0 the number zero S or Short as the value or by leaving the grid cell empty Note that there is no way to 90 Building The Model specify a zero capacitance open circuit in a Series type RLC load an entry of zero will be interpreted as a short circuit The resistance of typical wire and tubing increases as the square root of frequency so the resistance can be made to vary in this way for the Series RLC type See R Freq Column below Parallel Configuration RLC Loads The R L and C are connected in parallel Any of the three components can be replace
15. 1 will connect on both wires toward the wires end 1 and conductor 2 toward the wires end 2 Specifying a reverse connection reverses the connection to one of the wires reversing the phase of the voltage and current from the transmission line Specifying Loss Transmission line loss is entered as loss in dB per 100 ft or 100 m depending on the description Units setting If you want to enter the loss in dB 100 m when the choice is dB 100 ft simply change the Units to Feet or Inches enter the loss then change back Similarly change to a metric Units value to allow loss entry in dB 100 m The Loss Freq is the frequency at which the specified loss will be applied to the transmission line At frequencies above or below this the loss will be adjusted to mimic the approximate change in attenuation with frequency of a real transmission line over the HF UHF frequency range If the Loss Freq is set to zero the specified loss will be applied at all frequencies Be sure to read Transmission Line Loss to learn about some of the limitations of this model Selecting Adding Deleting Copying Modifying and Moving Transmission Lines See Using Insertion Objects Windows Transmission Line Loss Loss can be added to the transmission line models if desired in the Transmission Lines Window Loss is specified in dB 100 ft if model Units are Feet or Inches or in dB 100 m if Units are Meters or Millimeters If Units are Wavelengths dB 100 ft will be use
16. 10 4912 9 9822 38 1 Normally the wire specifications would be written to be easier to read The above format was chosen to illustrate the flexibility available in choosing field delimiters Complete Rules for Wire Files Used for Importing with the first format type General No distinction is made between upper and lower case letters A semicolon and anything to its right on a line will be ignored Blank lines will be ignored Spaces tabs or combination may be used as delimiters Commas may be used in regions such as the U S where a comma is not the decimal separator There are two types of specifications wires and optional units Units specification line optional must precede all wire specifications Text fields only can be surrounded by quotation marks These are coordinate units diameter units wire diameter specified as wire gauge and M specifying minimum segmentation Quotation marks are not required for any field The user will be given the choice of adding the wires to the existing description or replacing the existing description with the wires Units Specifications Zero one or two unit specifiers may be included Unit specifiers must precede all wire specifications If two specifiers are given they must appear on the same line and be separated by a valid delimiter The first unit specifier is the coordinate unit specification It will modify the EZNEC UNITS selection and wire coordinate
17. 2 just anywhere along wire 1 because wires can connect only at ends What we need are wire ends that we can connect to That s easily done with the new Split Wires feature In the Wires Window open the Wire menu and select Split Wires In the dialog that opens enter 1 in the Last wire to split box so that both first and last are 1 Let s split the wire into 5 so enter 5 in Number to split each into then click Ok Wire 1 is now replaced by wires 1 to 5 and former wire 2 is now wire 6 Let s look at the model straight on to make the next steps a little easier It s not necessary but a good place to point out another new feature Note that the X axis goes off to the right behind the antenna To maintain the same relationship between front and back we ll look at the antenna from the direction of the X axis that is from the front as we re currently viewing it Click anywhere on the View Antenna display window to give it the focus Then hold down lt Shift gt and press the X on your keyboard to rotate the view Try just X to see what happens now you see it from the direction of the X axis The Y and Z keys work the same for their respective axes When you re finished experimenting return to the X axis view with lt Shift gt X to look like this 41 EZNEC User Manual DN View Antenna Back yard dipole File Edit View Options Reset Center Ant Image Mouse Operation Normal Viewing C Add Conn Wires C Move Wire Ends
18. 7 42 0 Comments can be added to individual lines if desired by delimiting with an exclamation point Anything following an exclamation point on any line will be ignored Please note Partial translation of NEC files or defective NEC files might cause a program crash because many of EZNEC Pro s cross checks aren t done when reading NEC files If you encounter a crash when EZNEC Pro reads or executes what you believe to be a valid NEC file please notify the EZNEC Pro developer 154 Reference Very Large Models Several factors should be considered when working with models of several thousand segments The following information is provided to help you optimize the analysis of these very large models Calculation Time There are two major time consuming portions of the calculation impedance calculation matrix fill and current calculation matrix factor The first increases as about the square of the number of segments while the second increases approximately as the cube So for very large models the second process usually dominates Another part of the current calculation solve can become extremely long if the model contains a large number of transmission lines Adding ground to a free space model will also slow calculations substantially and use of Extended Accuracy NEC 4 2 GN3 ground available only when using an NEC 4 calculating engine can cause dramatic slowing Specially compiled fast calculating code is used f
19. Buttons and is included because some users have reported that the text doesn t fit when EZNEC is run at some resolutions on some systems The default font size is 8 so suggest you try a size slightly smaller than this if you experience this problem recommend setting the ButtonFontName to Arial if you use this option Arial permits setting font size to any value including fractional values The default font MS Sans Serif allows only whole even point sizes CalcProgReduction where is a number from O to 3 other values ignored Use when the program is slowed by an anti virus or anti malware program See Software Incompatibilities Limits how often the calculation progress indicator is updated during calculation A value of zero results in normal operation Higher values up to 3 reduce the update frequency speeding operation but making the calculation progress indication less smooth CursorBorder None Turns off the outline around the outer border of the cursor in the 2D 3D and SWR plots This is to avoid a problem seen in Windows 2000 with the ATI Xtra 128 video board where the cursor border is the same color as the cursor and gets left behind when the cursor is moved DotMult where is a number from 0 5 to 5 Increases or decreases the size of the grid dots on the 2D Display grid It modifies the value of the line width selected by the Control Center Options Plot Printing Printed Plot Line Width option only when printing
20. Display The stepped diameter correction display shows you exactly what substitutions EZNEC has made to correct for connected wires of different diameter One of its most important uses is to make sure that all the elements of a Yagi or similar antenna are being corrected The stepped diameter correction display is shown by first opening the Wires Window then choosing Show Stepped Dia Correction from the Other menu One of two indications will be shown for each wire If coordinates and diameter are shown for the wire that wire is being corrected and the coordinates and diameter are those of the wire being substituted by EZNEC Notice that the diameter of all substituted wires in an element are the same and that the element length has been modified slightly These are the consequence of the substitution process and will give accurate results The other possible indication is a message spread out over several columns briefly telling why the group of connected wires hasn t been corrected All the elements in a Yagi for example should be corrected So if any elements show as not being corrected you should return to the ordinary Wires Window display by selecting Show Stepped Dia Correction from the Other menu to turn it off fixing the problem and checking again until all wires are being corrected Some Special Cases Acute Angles NEC has some difficulty in accurately modeling multiple wires joining at a very acute angle such as wit
21. EE 46 Temporary Directory 2 138 Available Space ceeee 138 Test Drive 20 25 29 32 38 A Lap Around Track 5 32 Along The Straightaway 20 Introduction 02eeeeeeeeeeeee 20 On The Race Course 29 190 Taking Car 6 For A Spin 38 Through The Curves 00 25 Test Drive Introduction 20 The Calculation Progress Window EE 159 The Laplace Loads Window 91 The NEC Radial Model 108 The R j X Loads Window 90 The RLC Loads Window 90 Third Party Software Legal Notices E RTE Men Een ee 177 Thousands separaior 6 Through The Curves 25 SITS secs turds tence ieee cased aed nds tata edt ous 138 Hee LEES 132 Ground ie 132 Touchstone Format Files 160 162 Traces eee eee ee CEN 142 Adding to the 2D Display 142 Removing from the 2D Display ee 142 SAVING EE 142 VIGWING scccs et cniict inate eteat acne 128 TraceView 128 138 WANS Lines EEN 138 Transformers eebe reueg 32 96 Transformers Window 97 138 ipentng 2 derieeegigeieek iee dee r 138 Tue WE 97 Transmission Line Model 92 Transmission Line Models 70 Transmission Lines70 71 86 92 93 96 138 144 PDO EE 92 Actual distance between ends 93 Coaxial cable 96 Dielectric insulated 93 Electrical enoth 93 RGSS eebe 95 Physical lengthen 93 Showing in the
22. Free space analysis is also useful when working with a line of sight antenna having a downward tilting pattern When any ground is specified EZNEC will always report zero signal level at any elevation angle below the horizon So 102 Building The Model either free space or near field analysis has to be used to determine how much signal is being directed downward Perfect Perfect ground is useful to simulate the highly conductive ground seen in some antenna test chambers and ranges It s can also be used for comparing results with textbook patterns that make the assumption of perfect ground I ve often used it to educate people about the effect of finite ground conductivity on antenna patterns by comparing perfect ground results with real ground results Yet another use is when evaluating source placement with the Average Gain feature To use Average Gain for evaluating source placement errors loss must be reduced to zero Ground loss can be reduced to zero by temporarily changing the ground type to Perfect Wires can be connected directly to perfect ground and the connections have zero resistance The one thing you shouldn t use the perfect ground type for is simulating real Earth ground Real The Real ground types are used for simulating actual Earth ground Unfortunately none of the models are faultless otherwise there would be only one Real ground model type instead of two or for EZNEC Pro 4 three It s important to know w
23. Highlighting a 2D 0000 149 How to Contact Me 182 How to Do It cece 49 79 I If You Downloaded EZNEC 16 Impedance Display 149 Importing Wire Coordinates From ASCII File 49 57 131 File Format 171 INAUCHOF EE 90 MOdGlING DEE 90 detailer e EENEG 88 Information Window 129 138 ui te GEN 2 177 Inno Setup EE 2 177 Insertion Objects 75 77 129 144 Placement 76 126 129 NStANCE EE 157 Insulated Wie 56 Interpreting Plane Wave Results 82 Introduction WEEN 144 Introduction to Modeling 45 Inverted Vee Antenna 25 IONCAP Files ocen 124 J jpeg BE 144 L LNeiworkz 32 98 Limitations EE 100 L Networks Window 100 138 IESEL 138 ln e DEE 100 Lap Around Track bh 32 Laplace Load Type 87 89 Laplace Loads Window 91 Laplace Type Loads 00 91 Large Modelen 155 Last File Opened or Saved 138 LastZ s1p Files 160 162 aere egen 6 118 127 160 Last AXE EE 160 LaetZeorted tt 160 LDbfranslatton 162 Legal Disclaimers 175 177 t 0 D 54 144 Geoment 49 144 le EE 49 144 changing EE 54 License Agreement 176 Limitations of Real Ground Models Ee 105 Linear dB Plot Gcale 132 Linear Loaded Antennas 70 75 Kee EE 111 Connection 0000000 86 87 160 Impedance A 111 KEE 111 Parallel Connected 86 160 POWET EE 111 Volta
24. Pro source of 0 707 volts Similarly the currents reported by EZNEC Pro will reflect RMS values The power reported by EZNEC Pro is the same as that reported by NEC EZNEC Pro 4 communicates to the NEC 4 calculating engine via standard NEC input and output files If you view the NEC input file created by EZNEC Pro 4 and the output file created by the NEC 4 calculating engine you ll see the translation in value that takes place 150 Reference Data input Instead of editing an ASCII file descriptions are entered via a spreadsheet like entry system This allows very easy modification and the ability to immediately see the result on the antenna structure Note however that EZNEC Pro can read and write NEC format files and can import wire descriptions from a simple format ASCII file NEC features Not all NEC features are implemented in EZNEC Pro Those not implemented include symmetry patches and non air primary medium EZNEC Pro is chiefly oriented toward the analysis of wire antennas Files Although EZNEC Pro can read and write NEC format description files some functionality may be lost if this format is used exclusively Full features are available only with EZNEC format EZ files The binary format of these files is available on request Angles EZNEC Pro uses elevation angle in place of zenith angle Elevation angle is measured upward from the horizon XY plane EZNEC Pro also permits an alternate method of displaying azimuth
25. REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS IN NO EVENT SHALL NEIL HODGSON BE LIABLE FOR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE DATA OR PROFITS WHETHER IN AN ACTION OF CONTRACT NEGLIGENCE OR OTHER TORTIOUS ACTION 179 EZNEC User Manual ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE 180 Support Updates Maintenance Releases Updates to EZNEC and EZNEC but not EZNEC Pro programs EZNEC Pro 2 and EZNECPro 4 and the manual are posted at http eznec com ez60updates as they re developed EZNEC Pro users will find the update URL on the CD label Please check the appropriate URL periodically to keep your program up to date These aren t upgrades to new versions but include fixes for bugs as they re found and improvements to the manual Up to date information about your program will be posted there or elsewhere at http eznec com Reporting bugs Have you checked lately for updates A bug might have already been found and fixed Please see the Updates section for information Although EZNEC has been extensively tested there are bound to be bugs remaining If you encounter one and report it I ll fix the bug as quickly as possible and send you a replacement program However Windows is a complex environment and it can sometimes be very difficult to determine the exact sequence of events leadi
26. Siemens meter and the dielectric constant relative permittivity can be entered directly in the corresponding columns if desired Right clicking either of these columns opens a dialog box giving you a choice of a wide variety of typical ground types The selection of ground conductivity makes little difference for horizontal wires of moderate height but it can be very important for vertically polarized antennas When a medium is first created its initial conductivity and dielectric constant values are determined by the Control Center Options menu selection Default Ground Const Adding A Second Medium To add a second medium click Add in the Medium menu or simply enter the values in the add row at the bottom of the grid Empty cells or newly created media will use the conductivity and dielectric constant values specified by the Control Center Options menu selection Default Ground Const Please review Using Two Ground Media before using a second medium Completing the Specification Enter the second medium height and boundary in the remaining two columns These values are fixed and can t be altered for the first medium To change 106 Building The Model the boundary type between the media select Boundary Type in the Medium menu Adding an NEC Radial Model See The NEC Radial Model Using Two Ground Media The ground may be broken into two media each having its own conductivity and dielectric constant relative permittivity The sec
27. Spaced Wires for precautions Using Transformers Transformers Transformers are insertion objects which are specified via the Transformers Window opened by clicking the Transformers line in the Control Center 96 Building The Model The ideal transformer model object is intended to simulate real transformers or impedance transforming networks Like any other model however they have a number of limitations and peculiarities and come with some cautions The chief limitation is probably the fact that real transformers often don t behave like ideal ones so be sure to carefully read note 1 below As a two port network a transformer shares much in common with the transmission line model Each port or winding must be connected to a wire or virtual seqment which it effectively cuts at the insertion point Wires to which it connects can be any physical distance apart Like transmission lines transformers are connected in parallel with a source transmission line network parallel connected load or other transformer connected to the same segment They re in series with series connected conventional loads connected to the same segment At each port the current into one terminal exactly equals the current coming out of the other so there is no common mode current or radiation The turns ratio is the square root of the ratio of specified port impedances which should be chosen to be in the ballpark of the impedances to which they re c
28. The minimum segment length should be made equal to the height of the radial system The default maximum is adequate In the Minimum Segment Length box enter the height of the radial system above ground When placed on such a short wire the source must be surrounded by equal length segments After tapering combine the source wire and the one above into a single wire with 3 segments then move the source to the center of this wire If for example the original vertical wire was wire 1 with end 1 at the bottom as in example file ElevRad1 ez first taper all wires Then select any coordinate of end 2 of wire 1 and enter W2E2 to make its coordinates the same as end 2 of wire 2 Change the number of segments of wire 1 to 3 Then delete wire 2 Finally move the source to the center of wire 1 The result should look like ElevRad2 ez don t know of any good experimental measurements of the sky wave field strength from verticals with elevated radial systems There are a few ground wave measurements NEC 2 and NEC 4 both show ground wave field strengths for elevated systems which are stronger than some measurements seem to indicate particularly at frequencies of 3 MHz and below so there may be some doubt about the accuracy of the signal strengths reported by EZNEC for elevated radial systems End Fed Antennas A frequently asked question is how to model an end fed antenna This often comes after putting a source at the end of a wire representing
29. USING BEE 144 Wire number 132 View Menu 138 Virtual BAM 155 159 Virtual Segment 75 129 144 VOACAP Files a0aannaaeaanaaenn 124 WwW Wavelengoth 138 W GICOIM eege 1 What Was New in v A0 13 What Was New In v b 11 What s New in V n 8 WINGOWS EE 1 Basic operation cccceeeee 1 WINSMITH WEE 158 EEN 54 Diameter maximum 46 Graphical Modifications 53 Length changing EN 54 displaying eeee 49 144 ROtating ccccceeeeeeeeeeeees 49 54 Scaling eegeetegegdtegegedeggegd eee 49 SPINO EE 49 Wire Coordinate tie 171 Wire Coordinate Shortcuts 54 Wire Coordinates 49 54 137 171 ASCII File Format 0 171 Importing from ASCII file49 57 131 171 RIESS es 49 137 Wire Diameter 49 Gpechfving e 49 Wire Grid Creation 60 74 126 And Segmentation Check Warnings EE 60 126 Wire Grid Modeling 60 74 Wire Information 49 144 Wire Insulation 56 Wire loss 55 116 138 Evaluating with Average Gain116 Gpechfving eeen 138 Wire Number 132 144 Default settings 132 162 Wire Spacing seseessseeseeeeeeeeee 65 Wires46 49 57 64 103 107 131 138 144 EE 49 Connecting ssssssseeeeeeeeeeeeenne 46 191 EZNEC User Manual Connecting to ground103 107 108 COPYING EE 49 CROSSING KE 46 Deleting en 49 DANG le ee 46 Importing from ASCII file 131 Info
30. a Smith chart program that interactively aids in designing matching networks Additional Advanced Wire Features EZNEC EZNEC Pro only New powerful features have been added to make multiple copies of wires with each copy rotated and or translated from the previous one if desired generate a cylindrical structure and reflect wires in one of the principal planes See Making Multiple Offset and or Rotated Copies of Wires Making a Cylindrical Structure and Reflecting Wires in a Plane in Using The Wires Window These are replacements of the former EZNEC Pro only feature of direct NEC card entry but are more versatile and easy to use Getting Started IONCAP VOACAP file writing EZNEC EZNEC Pro only EZNEC can write tyoe 13 IONCAP VOACAP files after running a 3D plot These files contain gain data at every degree of azimuth and elevation in a defined format Increased frequency sweep steps EZNEC EZNEC Pro only Standard EZNEC allows up to 1 000 frequency steps for SWR and frequency sweeps 10 000 are now permitted for EZNEC and 100 000 for EZNEC Pro Y Parameter Networks EZNEC Pro only Y Parameter Networks can be used to simulate nearly any kind of two port network at a single frequency by defining the port characteristics with y parameters Familiarity with y parameters is required for use however This is a direct implementation of the NEC network Plane Wave Excitation EZNEC Pro only The model can be excited by a pl
31. a current flowing toward end 2 An ambiguity can arise when placing a split source at a wire junction because the polarity can depend on which wire the source belongs to and which way 85 EZNEC User Manual this wire is facing A split source placed on a junction of two wires belongs to the wire specified as its desired position Therefore it will be placed with the positive terminal facing end 2 of the specified wire Ambiguity can be avoided by making the wires face the same direction by connecting them end 1 to end 2 Whenever you use multiple sources in any antenna other than simple parallel wires it s highly recommended that you look at the currents in the wires and make sure they re really flowing in the direction you thought See Interpreting The Results Phased Arrays EZNEC allows you to model phased array feed systems provided that they re made exclusively of transmission lines and networks and provided that the transmission lines don t interact with the antenna as wires EZNEC doesn t model coupling to transmission line objects Example description files CardTL ez and 4SqTL ez are examples of this To investigate various possible patterns instead of modeling transmission lines place a current source at each element s feedpoint and vary the element currents by changing the source magnitudes and phases A very valuable capability of EZNEC is to tell you what the element feedpoint impedances are when an array is correctly
32. angle This corresponds to compass bearing and is measured clockwise from the y axis The choice is made in the Control Center Options menu Power In NEC all voltage sources are absolute EZNEC Pro permits you to specify a particular power level If this is done all voltage and current sources will be adjusted in proportion to obtain the specified total power This is useful for determining for example voltage stress on or power dissipation of loading components under actual operating conditions or of near field strength resulting from a specific power input The power level is specified in the Control Center Options menu Average Gain EZNEC Pro reports an average gain of 1 0 0 dB whenever the integrated total radiated power equals the power supplied from the sources whether or not ground is specified The NEC value of average gain varies with the region specified for the radiation pattern and equals 2 when radiated and input powers are equal and ground is specified Networks When a double precision calculating engine is used EZNEC Pro sends network parameters to the NEC calculating engine as double precision data NEC even when compiled for double precision has no equivalent way to input double precision data This can cause differences between double precision_EZNEC Pro_and NEC results when networks have been specified particularly when NEC networks are derived from EZNEC Pro L networks Plane wave excitation NEC 4 allows excitati
33. be open or short circuited Remember though that it s not capable of radiating so this stub model can be used only in those situations where a real stub wouldn t radiate More detail about use of the Transmission Lines Window and its features can be found in the Using The Transmission Lines Window topic Using The Transmission Lines Window EZNEC Pro uses NEC transmission line models There are several very important differences between these and real life transmission lines which are discussed in About Transmission Lines If you aren t familiar with the use and limitations of NEC transmission line models please acquaint yourself with these differences before using them Transmission lines have two ends unless they re specified to be an open or short circuited stub Stubs have only one end Transmission end positions are specified in the same way as for other insertion objects Like all others both ends ports of all transmission lines 93 EZNEC User Manual have to be placed on real or virtual segments See Placing Insertion Objects on Seqments for details Specifying Connections Like other insertion objects all transmission line ends ports except stub ends have to be placed on real or virtual segments See Placing Insertion Objects on Segments for details Specifying a stub A stub is specified by declaring one end to be either open or short circuited You can simply enter O or S in the Wire column or you can
34. be superimposed on the representation of the antenna More information about these features can be found in The 2D Display and The 3D Display sections of the Reference chapter Because the far field sky wave from a horizontally polarized source is zero at a zero elevation angle for any ground type and a vertically polarized source produces zero sky wave for any finite conductivity ground attempts to calculate a 2D pattern without the ground wave component under these conditions will result in an error message The 2D Data box activated via the 2D Display View Show Data selection shows a summary of key pattern characteristics such as beamwidth and front back ratio EZNEC offers an alternate azimuth coordinate choice compass bearing This presents azimuth angles in degrees clockwise from the y axis straight up on the 2D plot to correspond to compass bearing The choice is made in the Control Center Options Menu as Angle Convention No change to any plot orientation occurs when changing between standard and bearing representations only reported angles change Various options for far field display can be selected in the Control Center window and the Control Center Desc Options selection 113 EZNEC User Manual EZNEC Pro only f using plane wave excitation see Interpreting Plane Wave Results for additional information Antenna Efficiency Antenna efficiency is defined as the fraction of the applied power which is radiated Th
35. best quality of saved or pasted graphic display see the Edit section of the Graphics Windows Menus topic Note that pf format files saved as trace files are not graphics files They are binary files which contain only numerical field strength data and no information about how to plot or display it Using The View Antenna Display The View Antenna display is one of EZNEC s most useful displays With it you can see what the antenna looks like and see changes as they re made look at the currents on each wire see how the pattern is oriented relative to the antenna and much more You ll find it useful to leave this display open most of the time Several model modifications can be done graphically in this display described separately in Graphical Wire Operations The display window shows to scale what the antenna looks like Various objects can optionally be shown on this view in addition to the antenna as described below The Menus The menus are detailed in Graphics Windows Menus The Controls The Control Window to the left of the display can be turned on and off via the Show Controls selection in the View menu It has controls enabling you to zoom center and move the image and zoom the displayed currents after 144 Reference running a calculation Moving or zooming the display have no effect on the antenna model They only change the way you re looking at it Note that you can also move and zoom the display but not the cur
36. block length a word Block types 0 through 127 are standard and reserved Programs may use types 128 through 255 for special purposes but block length must always follow block type so that file parsers can skip over the block Blocks may appear in any order The following standard blocks are defined NOP Block Block type byte 0 Block length word 166 Reference Rest of block Block type 0 is a no operation block Its purpose is to provide a standard ignore me block Normally this block isn t used but it may be convenient when patching a file Block length is the total length of the block in bytes Block lengths less than 3 are invalid Relative Far Field Blocks Block type byte 1 16 Block length word Title length byte Environment length byte Notes length word Frequency FP Plane byte Plane angle FP Symmetry byte Number of points word First angle FP Angular increment FP Data points each FP Title ASCII Environment ASCII Notes ASCII Block types 1 16 contain planar cuts of relative far field data as follows Block Data Units 1 Total magnitude dBi 2 Horizontal magnitude dBi 3 Vertical magnitude dBi 4 Right circular magnitude dBic 5 Left circular magnitude dBic 6 Major axis magnitude dBi 7 Minor axis magnitude dBi 8 Ellipticity dB 9 Total phase degrees 10 Horizontal phase degrees 11 Vertical phase degrees 12 Right circular phase degrees 13 Left circular phase degrees 14 Major axis phase degrees 15 Minor a
37. calculation The function of each button is detailed in the Control Center Action Buttons section Menus The menus contain a wide variety of items most of which are program related An exception is the selections in the Plot menu which are saved with the antenna description Each selection in each menu is described in the Control Center Menus section 130 Reference The Control Center Menus Control Center Menus Introduction It s important to note the unique function of the Plot Setups and Options menus The Setups menu is unlike the other Control Center menus in that choices made in this menu are saved with the antenna description file just like the Information Window items They will be restored each time you open that description file The Options menu contains items which apply to all antenna descriptions until EZNEC is ended at which time your choices are discarded unless you ve selected Save As Default Whenever you choose Save As Default the last selection in the Options menu all Options menu selections are permanently saved and will be restored each time you start EZNEC Each selection of each of the menus is detailed in the sections which follow File Open Description Allows you to select an existing antenna description model EZNEC Pro only To open an NEC format file include the extension NEC with the file name Save Description As Allows you to save the current antenna description model as
38. characteristics complex characteristic impedance and complex propagation constant are known Before becoming too concerned about the accuracy of the loss model try changing the specified loss and see how much this changes the overall result If the overall result doesn t change much with specified loss then the accuracy of the loss model isn t critical Modeling Coaxial Cable A non radiating coaxial cable is electrically identical to a non radiating two wire line so an ordinary transmission line model can be used for modeling a non radiating coaxial line A radiating coaxial cable can be modeled quite well with a combination of transmission line model and a wire The transmission line model represents the inside of the coax and the wire represents the outside of the shield The wire is the diameter of the shield and connected where the shield of the actual cable is It should follow the same physical path as the real coaxial cable One of the example files DipTL ez shows how this is done See its Antenna Notes file for more information If the coax cable doesn t radiate the current on the additional wire will be zero and the additional wire contributes nothing to the analysis so can be removed There s no way to use the transmission line model to accurately model a radiating two wire transmission line one with common mode current present If it s necessary to do this the line will have to be modeled as two parallel wires See Closely
39. click the arrow on the right side of the cell and select open or short circuit from the pull down list Specifying Length Transmission line length can be specified in three different ways physical length electrical length and physical distance between ends If you specify physical length in current length units the model acts like a line with that physical length If specified in degrees electrical length the line acts like a line of that electrical length Note The electrical length of a line specified in degrees doesn t change with frequency like a real line would This type of length specification is recommended only for single frequency analysis Any of these three specifications can easily be made by right clicking the cell in the Length column choosing the specification type and entering a value if required Described below are shortcuts for the three methods Physical Length To specify physical length simply enter the length in current units or right click the Length column The physical length of the model doesn t have to bear any relationship to the distance between its ends See About Transmission Lines for further explanation Electrical Length Enter the length followed by d for degrees in the Length column Actual Distance Enter a in the Length column This will make the line length the straight line distance between the ends This choice isn t available if one end is shorted or open that is the
40. dB from the reported gain in dBi to find the gain relative to a dipole However over ground the only way the comparison can be made is to model a dipole at the same height as the antenna and compare its gain to that of the antenna Likewise to find the scattering cross section of an object over ground it s necessary to compare the field strength in dBsw or V m to that of a similarly placed object of known scattering cross section Interpreting Plane Wave Results The same tabular and graphical outputs are available with plane wave excitation as with standard voltage current voltage source excitation with a few differences First note that the Options menu Power Level specification makes no difference when using plane wave excitation since there can be no specific total power associated with the plane wave For the same reason Average Power isn t shown when plane wave excitation is chosen In the Control Center Options menu Far Field Table Units you can see that the non ground wave far field values will be reported in either mV m X dist or dBsw The first of these is the product of the field strength and distance from the origin The field strength at any distance is simply the reported value divided by the distance from the origin in meters provided that the observation location is in the far field and that the distance is large compared to any antenna dimension The field is of course caused by scattering or the current induced on th
41. description file ez extension The Antenna Notes file is kept in the same directory as the description files Antenna Notes files can be edited with any text editor or from within EZNEC To create view or edit an Antenna Notes file for the current description select Edit Current Antenna Notes from the Control Center File menu This opens the file in the EZNEC Editor When you re finished select File Save within the Editor then close it When you save an antenna description you might see a dialog box asking you what to do with the corresponding Antenna Notes file Both the Antenna Notes file associated with the current description and the one associated with the saved file name are shown to help you decide This dialog box won t appear if the text in the two files is identical or if you re saving the file with the same name as when it was opened EZNEC Pro only You can also use Antenna Notes with NEC format files Operation is similar to operation with ez files except that you ll see a temporary file name when you open the EZNEC Editor With NEC format files Antenna Notes are saved as a series of CM comment cards When you open the Antenna Notes for editing EZNEC copies the CM card comments to a text file and opens that instead Because there is no separate permanent Antenna Notes file changes you make aren t permanent until they re written into the NEC format file This isn t done until you save the description So be sure to save
42. different because of radiation and or physical length When this occurs the EZNEC load model which has equal currents at the two terminals does a poor job of representing the coil and considerable inaccuracy can result Whenever possible a helix rather than a load should be used to model a loading coil Coils frequently have a significant amount of loss which should be included in the model Measurement is the best way of determining the loss but even a guess may be adequate Air wound inductors typically have Q s in the range of 200 400 or so This means that you can estimate the equivalent series R as about 1 200 to 1 400 the reactance If using this range of values impacts your result you might want to make a measurement or better estimate of the Q 88 Building The Model Traps A trap has a primary resonance at only one frequency but still represents a significant impedance at other frequencies and on other bands So a trap model has to be reasonably accurate over the entire range of antenna operating frequencies Or at least over the range being modeled The only way to accurately model a trap is either by measuring its impedance at each frequency of interest or by knowing the equivalent L C and R components and how R varies with frequency These in turn must be measured unless you can talk the manufacturer out of this information or have constructed the trap yourself out of Known components Traps frequently will cause a cou
43. dipole pattern but still has slightly lower maximum gain This shouldn t be surprising if you investigate the patterns in more detail The inverted vee has more radiation off the end reducing the gain from the side But as you can see the gain difference between the dipole and inverted vee is less than one dB providing the centers of current are at the same height This concludes the Through The Curves exercise If you d like to learn some additional techniques try taking EZNEC On The Race Course You can continue directly from here or you can exit EZNEC and do it later On The Race Course This section takes you through some of EZNEC s more advanced features Open the back yard dipole model included with EZNEC Click the Control Center Open action button and select and open the example file BYDipole ez Let s look at the full 3D pattern Click the Plot Type line in the Control Center information window Select 3 Dimensional then Ok You ll see a notice that EZNEC is reducing the plot resolution to 5 degrees per step The minimum step size for 3D plots is 2 degrees although this is too dense for general use One degree resolution is a good choice for 2D plotting and the example file was set to this value Click Ok to close the message box Click the FF Plot action button to start the calculation When the calculation finishes you ll see a full three dimensional 3D display of the dipole pattern You ll note that it doesn t look much l
44. for wire number simply enter the letter V followed by a number you wish to assign to the virtual segment for example V10 Specify the same virtual segment number for any other insertion objects you want to connect in parallel with it This will result in the objects being connected in parallel Any type of insertion object can be connected to a virtual segment except split sources or series connected conventional loads Unlike all other insertion objects series connected loads are connected in series rather than parallel with other objects on the same segment The parallel connected load is provided for use whenever a load is to be connected in parallel with other objects on a real or virtual segment Virtual segment numbers can be any integer from 1 to 999 and don t have to be used in order or follow any other sequence or pattern A list of the virtual segments and the insertion objects connected to them can be seen by opening the View Antenna Display then selecting Show Virtual Seg Conn in the View menu See Virtual Segment Connection Display for more information When a model containing virtual segments is saved and opened with an older EZNEC program version the virtual segments are converted to real segments on a distant wire Likewise they appear as real segments on a distant wire when the model is saved in NEC format EZNEC Pro programs only The Control Center Control Center Introduction The Control Center is as its na
45. from the View menu and won t appear if the Data Window isn t being shown Control Window The Control Window is opened from the View menu However it s not accessible unless the 3D plot is also open since the controls are used primarily to select slices for display When open the controls in the Control 148 Reference Window are the same as those in the 3D Control window and the two sets of controls track Whether to show the frequency on the plot can be chosen in the Control Center Options menu Using The 3D Display The 3D Display opens automatically after running a far field pattern calculation when the Plot Type is 3 Dimensional It shows a full pattern plot To make the plot easier to visualize you can highlight any azimuth or elevation slice and easily see its shape and where it fits into the overall pattern The highlighted slice can optionally be shown in the 2D Display or superimposed on the View Antenna display Many menu operations are common among all the graphics displays so they re covered in the common section Graphics Windows Menus Orientation The 3D plot is always oriented in the same direction as the antenna in the View Antenna display after releasing the mouse button following a 3D Plot or View Antenna rotation This helps in visualizing the orientation of the pattern relative to the antenna Rotating the 3D pattern The 3D pattern is rotated in the same way as the View Antenna display by holding down t
46. gain several dB greater than this amount Alt SWR ZO Various displays show or output SWR assuming a 50 ohm system and a second impedance of your choice This is where you choose the second impedance A typical use would be an antenna fed with 50 ohm line through a 4 1 impedance step down transformer If you set the Alt SWR ZO to 12 5 ohms the indicated SWR is what you would see on that 50 ohm line Desc Options This selection allows selection of several properties which are saved with the description file Under the General tab you can choose to have the Geometry Check ignore the situation where the center of a segment is within another wire This sometimes can t easily be avoided and while it sometimes causes erroneous results it often doesn t See the Geometry Check topic for additional information Under the Plot tab are a number of 2D plot choices including linear and EZNEC and EZNEC Pro only circular polarizations to show on the 2D plot Gnd Wave Dist EZNEC Pro only Shows the horizontal distance to the ground wave analysis observation point Clicking it allows you to select the distance and to turn ground wave analysis on and off Action Buttons Several of these actions are explained in more detail in the Interpreting The Results chapter Open Click this to open a different antenna description file Note All unsaved information in the existing file will be lost Save your existing description if you want to prese
47. ground plane in your back yard and for many wavelengths in all directions you ll want to do the analysis over real ground Click on the Ground Type line and select Real The height of the antenna will determine which ground model we use If you have a fast computer you can always choose High Accuracy analysis unless you need to make a connection to ground Let s choose MININEC type ground for now That model is good with horizontal wires which are at least 0 2 wavelength high and it s fast Choose MININEC then Ok Finally we need to specify the ground characteristics Click on the Ground Descrip line This opens the Media Window Note that the Ground Descrip selection isn t visible unless Ground Type is Real The Media Window is where specification of Real ground is done One or two ground media can be specified but we ll only need one for this model When we changed the ground type to Real one ground medium was created The conductivity and dielectric constant of newly created grounds can be set for your local ground conditions by means of the Control Center Options menu Default Ground Const selection The values initially used by EZNEC are those of average or good ground conductivity of 0 005 S m dielectric constant of 13 These are the values you should see in the Media Window at this point unless you ve changed the default ground constants For this exercise let s suppose your back yard has the characteristics
48. highlighted To select additional objects hold lt Ctrl gt down when clicking the button To select a group of objects select the first object then hold lt Shift gt while clicking the last object in the group Deleting Objects The current object or selected objects can be deleted by pressing the lt Delete gt key Alternatively a sequential group of objects can be deleted by selecting object Delete and specifying which to delete Copying and Moving Objects To copy or move objects in the list first select the objects as described above Then select lt object gt Copy or lt object gt Move lt object gt s in List where lt object gt is the name of the object e g Source L Network etc You ll be asked for the location in the list for them to be put You can also select lt object gt Copy or lt object gt Move lt object gt s in List before selecting objects in which case you ll be asked for a range of object numbers to copy or move Modifying Objects 77 EZNEC User Manual Objects can be modified individually or if desired a group of objects can be modified at the same time using the Group Modify feature The procedure is the same for both cases except that to modify a group of objects Group Modify must first be activated Basic modification of one parameter is done simply by entering the new value in the cell then pressing lt Enter gt or clicking on acell in another grid row Using Sources About Sources
49. horizontal wires depends on several factors but results should be good down to at least 0 005 wavelength or about 6 inches 15 cm at 10 MHz or several wire diameters whichever is higher When High Accuracy ground is used a Sommerfeld Norton interpolation table is calculated Although this calculation is quite fast with modern computers the resulting table is saved on the disk If future runs require a table with similar values an already 104 Building The Model calculated table is read and used instead of repeating the calculations The key parameter which determines whether an existing table is close enough is the ground s complex permittivity which is a function of the frequency and the ground conductivity and permittivity If a table is found for a magnitude within a user specified tolerance of the required magnitude it will be used You can change this tolerance if desired from the Control Center Options menu A tolerance value of a percent or so is adequate where horizontal wires aren t extremely close to the ground In situations requiring high accurac or where there are low horizontal wires a much smaller tolerance perhaps 0 05 or even 0 is recommended Direct connection of wires to High Accuracy type ground shouldn t be made See Connecting Wires To Ground The High Accuracy ground type should be used any time the model contains low horizontal wires and this or Extended Accuracy ground is required for modeling bu
50. in v 6 0 Although I ve listed a call sign beside most of the testers names several of them are also professionals actively involved in antenna design Speaking of which This manual will be read by both professional and amateur users so I ll like to emphasize one point Although amateur radio callsigns are listed for most of the fine people acknowledged below many in fact most of them are highly experienced and regarded professionals in addition to being licensed amateurs Please take a look at Amateur or Professional for a little more about this topic A special thank you to Dick Green WC1M for his extensive and valuable help in tracking down a very elusive bug which affected only a few systems and couldn t be duplicated here Version 3 0 Version 4 0 began as 3 0 and four people patiently reviewed the more than 30 alpha versions of EZNEC v 3 0 as features were activated and debugged They are Gary Breed K9AY L B Cebik W4RNL sk Ed Farmer P E AA6ZM Roger Steyaert K7RXV These gentlemen continued on to provide help and encouragement during the extended beta testing phase and were joined by the following people John Devoldere ON4UN Linley Gumm P E K7HFD Rus Healy K2UA Prof Dr Gerd Janzen DF6SUJ Dick Kiefer P E KODK Dean Straw N6BV and C H Buck Walter Many others offered to help test the program and thank them but was regrettably unable to constructively process the input f
51. information about the segment field Wires having zero length or diameter will be rejected Coordinates are interpreted as being in the units specified by the first unit specifier If no unit specifiers are given they will be interpreted as being in meters not in the units currently being used by the program Diameters are interpreted as being in the units specified by the second unit specifier If no second unit specifier is present they will be interpreted as being in the same units as the end coordinates The diameter of any wire may be given as AWG wire size using n where n is an integer gt 0 n can have more than one digit The optional segmentation field can contain the number of segments for the wire or the letter M M will result in minimum recommended count automatic segmentation for the wire If the segmentation field is blank or contains any other non numeric value zero or a negative number the wire will be automatically segmented using conservative criteria Fields beyond the eighth will be ignored SECOND FORMAT TYPE EZNEC EZNEC PRO ONLY This format is provided to allow easy importing of wire coordinates from an NEC input file Only GW lines are read EZNEC will assume this format if it finds any line in the file beginning with GW The standard NEC format is required GW followed by the tag ignored number of segments end coordinates and radius not diameter No fields are optional and U S format is requi
52. insertion point For example the voltage across an insulator can be measured by making the wire continuous and placing the zero ampere current source in the wire at the insulator location The current or voltage being measured appears in the Source Data display Source Types Four conventional source types are available with EZNEC voltage current split voltage and split current NEC has additional types which aren t implemented In addition plane wave excitation is available in EZNEC pro programs When you specify a split source EZNEC actually creates two sources and places them on adjacent segments closest to the position you specified Split sources are shown in the View Antenna display as two sources but appear everywhere else as a single source Split sources are included so you can place sources at wire junctions such as on an inverted vee antenna See Placing Sources At Wire Junctions for more information about using split sources and Placing Sources On Segments for more information about using conventional sources If the antenna contains only one source a split source is counted as one source it makes no difference whether a current source or voltage source is used unless you have a need to know the field strength when a specific voltage or current is applied to the antenna However the choice can make a profound difference if multiple sources are used Voltage sources will always maintain the specified voltages and there
53. is that relatively complex combinations of components that is R L and C can be modeled The impedance of a Laplace load varies with frequency although the resistance can t be made to vary with frequency as in the RLC load type More detailed information about specifying the various load types can be found in Using The Loads Window chapter Load Connections There are two ways of connecting loads when sharing a segment with other insertion objects series and parallel external connection As the names imply series connected loads are placed in series with other insertion objects 87 EZNEC User Manual sharing the same segment This connection might be used for such things as a series loading coil or a resistance representing ground loss at the base of a vertical antenna Parallel connected loads are used when a lumped impedance has to be connected in parallel with another insertion object A typical use for these would be to represent a hairpin matching wire connected in parallel with a source or transmission line at an antenna feedpoint The choice of connection type is made with the other load characteristics Choice of connection for each load is made in the rightmost column of the Loads Window labeled Ext Conn Enter S or select Ser in the drop down list for series connection or enter P or select Par in the drop down list for parallel connection Series connected loads are shown in the View Antenna display as empty hollow squar
54. line in the Control Center In the add row at the bottom in End 1 column X Y or Z enter W1E2 without the quotes then lt Enter gt Then enter the same thing in End 2 column X Y or Z and lt Enter gt The Wire 2 line should show Zero Len in the Conn columns Now change only End 2 Z to zero and lt Enter gt This puts the bottom of the new wire directly under wire 1 end 2 Because the Z coordinate of wire 2 is zero it s connected to ground which can only be done with Perfect or MININEC type ground The ground type for this model is MININEC so direct connection is allowed and will result in a zero resistance connection as though a perfect ground plane were underneath Another possibility would be a slightly elevated radial system over High Accuracy or with EZNEC Pro 4 Extended Accuracy ground see Connecting Wires to Ground for more about this topic To finish the initial single wire fed antenna move the source to the bottom of wire 2 by clicking the Sources line in the Control center display In the Sources Window that opens change the Specified Pos Wire to 2 and the From E1 to 100 and press lt Enter gt Your model should look like this 40 Test Drive DN View Antenna Back yard dipole File Edit View Options Reset EZNEC Center Ant Image Mouse Operation Normal Viewing C Add Conn Wires C Move Wire Ends You can close the Sources Window if you d like We can t connect the top end of wire
55. manual to the appropriate section Please notify me if you see the menu opening to the wrong place Finally enjoy using EZNEC guarantee you ll learn from it as continue to do Roy Lewallen What s New in v 6 0 This topic describes the differences between v 6 0 and the previous version 5 0 If you re upgrading directly from an earlier version please also see the appropriate What Was New topics New tutorial topic Taking Car 6 For A Spin will get you acquainted with the major new features of EZNEC v 6 0 It s intended for users who are already familiar with basic EZNEC operation File Locations Previous versions of EZNEC conformed to an earlier Windows standard of installing programs under the Program Files directory and having them write primarily to their own directory Many later operating Getting Started systems however have restricted permissions for Program Files and its subdirectories making EZNEC unable to write into its own directory On those systems where it s permitted written files are diverted to a virtual store which is buried deep within the file structure and difficult to locate To solve these problems EZNEC v 6 0 conforms to the most current Windows standards for file locations See File Locations for details If you have an earlier version of EZNEC installed on your system EZNEC v 6 0 will copy your description EZ and IONCAP files to the new locations the first time it runs The original fi
56. many wavelengths from the origin The cause is some slight changes in internal constants The calculation of the phase at many wavelengths is sensitive to very small changes in these values However the important thing is the relative phases of the components which remain very close to the same as in previous versions NEC Format Files EZNEC Pro only EZNEC Pro v 4 0 can read GH helix and IS wire insulation cards EZNEC Pro will accept a file if it contains at least one GW GH or GA card in addition to a source New Special Option choice LD5Translation First will cause EZNEC Pro to apply the wire loss parameters of the first LD5 card read as global Wire Loss and ignore additional LD5 cards If You Downloaded EZNEC If you downloaded EZNEC it came in the form of one file Please back this up Major changes to your computer system might necessitate a reinstallation of the program and you ll need this file to do it see Reinstalling or Copying EZNEC for important information And a virus or hard drive crash can corrupt or delete the file If you aren t able to back up the file please contact me to purchase the CD The cost is nominal for people who have purchased the download Updates maintenance releases will be available from time to time and you should also keep the most recently downloaded update See Updates for details You will not be able to reinstall EZNEC or copy it to another machine by copying the files cre
57. matching networks along with realistic effects from transmission line loss can now be part of the model For the first time the performance of the entire system can be seen New tutorial topic A Lap Around Track 5 covers use of virtual segments L networks and transformers It s intended for users who are already familiar with basic EZNEC operation Insertion Objects Not a new feature but a new designation for the objects which can be inserted into a wire These include the sources loads and transmission lines of previous versions plus the new transformers L networks and Y parameter networks described below They share a number of properties besides being inserted in wires hence the new collective name of Insertion Objects Program Names EZNEC User Manual EZNEC Pro programs EZNEC M and EZNEC 4 have been renamed EZNEC Pro 2 and EZNEC Pro 4 respectively As before the sole difference is the availability in EZNEC Pro 4 of NEC 4 calculating engines Transformers Ideal transformers can now be connected between wires between a transmission line and a source or wire or in other places in a model L Networks L Networks are powerful new objects which can be used to simulate a wide variety of networks including phase shift and impedance matching networks They can be cascaded to form pi tee and other more complex networks Parallel Connected Loads A common problem in modeling with EZNEC has been the connection of a load in
58. of segments in the add row then press lt Enter gt or click on another row of the grid Any cells left blank will be filled with duplicates of the values for the last wire Entering End Coordinates Coordinates are entered in the appropriate columns of the grid Coordinates can also be modified by means of editing shortcuts International users Numbers must use the decimal separator defined by your Windows regional setting Entering Wire Diameter Diameter can be entered as a number or as American wire gauge AWG The units used for numerical diameter are shown near the top of the grid column To enter diameter as a wire gauge prefix it with For example AWG 12 wire is specified as 12 Note that wires specified as gauge aren t scaled if frequency scaling is done but can be scaled with the Scale Wires feature See About Wires for diameter limitations Entering The Number of Seqments The number of segments is entered in the Segs column Choosing the correct number of segments is something of an art and skill See Overview for more information Defining Wire Insulation Please refer to Wire Insulation for a full description of this feature Selecting Wires Deleting copying and moving wires require first selecting which ones are to be operated on In addition wires can be selected before starting Group Modify To select a wire click on the button on the left side of the appropriate row The selected wire will be highlighted To
59. parallel with a source or transmission line because a load unlike other insertion objects is connected in series with any other insertion object in the same segment EZNEC v 5 0 introduces the parallel connected load which as the name implies is connected in parallel rather than series with other insertion objects Transmission Line Loss Loss can now be included in transmission line objects If desired the amount of loss can be made to automatically vary with frequency at approximately the same rate as a real transmission line in the HF UHF range Wire Scaling You can now easily scale wires or a group of wires and optionally their diameters by a constant See Scale Wires in Using The Wires Window New 2D Plot Grid Style A new grid style is offered for the 2D pattern plot An advantage of the new style is a half circle display when ground is specified allowing larger plots The traditional style is still available if preferred The choice appears in the Control Center Options menu 2D Plot Grid Style selection When using the new style grid with a linear plot scale you can also select the value represented by the center of the plot Additional Impedance Displays EZNEC EZNEC Pro only There are several new ways to display the impedances from an SWR sweep besides the traditional SWR plot reflection coefficient magnitude return loss and Smith chart Note that the Smith chart is an impedance display only and not a substitute for
60. point out about the new wire wire 2 Notice that it s the same diameter as wire 1 and has the same number of segments By default EZNEC gives a new wire the same diameter and number of segments as the preceding wire It will of course use other values you specify if you do specify them In the View Antenna display you can see the new wire you ve created although it might not be too obvious It extends from one end of the horizontal wire wire 1 to the origin right along the z axis If you don t see the numbers beside the wires select Objects from the View Antenna display View menu and check the Wire Numbers box then Ok End 2 of the new wire is at the default coordinates of 0 0 0 When a ground is specified as it is here a z coordinate of zero automatically means a connection to ground This shows in the Wires Window Wire 2 End 2 Connection column as Ground Now it s time to fix end 2 of wire 2 Change the wire 2 end 2 coordinates to 0 16 715 30 and press lt Enter gt Notice in the View Antenna display the effect this change has on the antenna Wire 2 now looks like an extension to wire 1 We could have reversed the ends of wire 2 with no effect on the overall result The choice of which end to call end 1 and which to call end 2 is pretty much arbitrary One thing to keep in mind however is that reversing the ends Causes a reversal in the direction of current which EZNEC reports So when multiple sources are used or where
61. principal planes by choosing Reflect Wires in the Wire menu Note that the direction of reflected wires might appear reversed from the originals depending on their orientation and the reflection plane Therefore the phase angle of copied sources might have to be changed by 180 degrees to achieve the expected result Modifying Wires Wires can be modified individually or if desired a group of wires can be modified at the same time using the Group Modify feature The procedure is the same for both cases except that to modify a group of wires Group Modify must first be activated 51 EZNEC User Manual Basic modification of one parameter is done simply by entering the new value in the cell then pressing lt Enter gt or clicking on a cell in another grid row But EZNEC also has a number of shortcut features that make it easy to modify wires These shortcuts are described in a separate section A wire end optionally including connecting wires can be moved to another existing wire end directly in the View Antenna display See Graphical Wire Operations for details Modifying A Group of Wires Group Modify See Group Modify for information about this feature Changing the Antenna Height To change the height of the entire antenna or any group of wires select Wire Change Height By and enter the amount by which you want to change the height This simply modifies the z coordinate of both ends of all wires by the specified amount Chang
62. select additional wires hold lt Ctrl gt down when clicking the button To select a group of wires select the first wire then hold lt Shift gt while clicking the last wire in the group Deleting Wires The current wire or selected wires can be deleted by pressing the lt Delete gt key Alternatively a sequential group of wires can be deleted by selecting Wire Delete and specifying which to delete Changing the Position of Wires in the List 50 Building The Model To move wires in the list first select the wires as described above Then Move Wire s in List from the Wire menu You ll be asked for the location in the list for them to be put You can also select Wire Copy or Wire Move Wire s in List before selecting wires in which case you ll be asked for a range of wire numbers to copy or move Copying Moving and Rotating Wires To copy move or rotate wires in the model first select the wires as described above Then open the Wire menu and select Copy Wires Move Wires XYZ Rotate Wires or Stack The individual dialog boxes offer additional choices for the action you ve chosen You can also choose the action from the Wire menu before selecting wires in which case you ll be asked for a range of wire numbers to copy or move The Rotate Wires feature can be useful in changing the orientation of wire structures which are otherwise fixed For example the Create Radials feature creates a horizontal radial structure which can be re
63. such as Temp don t use Last it s used by EZNEC for the description present when the program ends then click Save Open the Wires Window by clicking on the Wires line in the Control Center information window With the mouse cursor over the X Y or Z coordinate cell of Wire 1 End 2 click the right mouse button Remember the mouse cursor has to be over the right cell regardless of where the text insertion point is This opens the shortcut list Select Elevation Rotate End Enter the value 45 and click Ok This rotates end 2 of wire 1 downward 45 degrees without changing end 1 In the View Antenna display you should now see wire 1 drooping downward 45 degrees Rotate the View Antenna display if desired by clicking in the display window and dragging with the mouse If you don t see this you should return to the dipole by either re entering the wire end coordinates or by reopening the file you saved a moment ago by clicking the Open action button and selecting the file Then try the rotation feature again The 2D plot disappeared as soon as you modified the antenna wire This is intended operation EZNEC removes any displays that are no longer valid As soon as you modified the wire the display no longer represented the pattern of the current antenna so it was closed Now repeat the rotation for the second wire With the mouse cursor over the X Y or Z coordinate cell of Wire 2 End 2 click the right mouse button Select Elevation
64. t appear at the lower right when the results of a frequency sweep are being shown Default 3D Step Size EZNEC s minimum step size of one degree is too fine to show detail when doing general purpose 3D plotting This menu selection allows you to set the default step size when a 3D plot type is initially chosen View Antenna Wire Numbers Selects whether the wire numbers are shown when you first start the View Antenna display and whether they appear centered on the wires or offset You can change these choices in the View Antenna Display but that setting cannot be made permanent while this setting can Initially On Wire numbers are on when you first start View Antenna Initially Off Wire numbers are off when you first start View Antenna Use this setting if you frequently work with complex models where the wire numbers overlap and become unreadable Initial Position Selects whether the wire numbers are initially centered over the wires or are offset Save As Default Clicking this choice makes all the values selected in the Options menu permanent Unless it is clicked any changes made will be discarded when EZNEC ends Any changes made after it is clicked will likewise be discarded at the end of the session unless it is clicked again to save the changes Outputs Geom and Seg Check Runs both the Geometry and Segmentation checks see below Segmentation Check Runs the Segmentation Check which checks the model for v
65. the bits may be set simultaneously Bits 3 7 are reserved Number of A B or C points These fields specify the number of points for each coordinate 0 is invalid The total number of data points is the product of A B and C For rectangular coordinates the field is computed over a point line rectangular surface or rectangular volume For spherical coordinates the field is computed over a point line circle disc spherical surface spheroid or portion thereof For cylindrical coordinates the field is computed over a point line circle disc cylindrical surface cylindrical volume or portion thereof First A B and C These fields specify the starting values of each coordinate A B and C Increments These fields define the sign and magnitude of the difference between successive coordinate values Data Points Points are ordered as follows A cycles from first to last then B and finally C The coordinate values of successive data samples differ by the A B or C increments Title Environment and Notes Strings These fields are the same as for relative far field blocks 170 Reference Input File Formats Frequency Sweep Input File The frequency sweep input file contains a list of frequencies to be used for the frequency sweep Its name is specified in the Control Center Setups menu Frequency Sweep selection Frequencies are in megahertz MHz and consist only of numbers They may be in any order and do n
66. the currents are of interest it s wise to be systematic in assigning the end numbers For example in an array of phased 26 Test Drive vertical antennas you should face all end 1s the same way so all element currents will be defined as flowing in the same direction For this antenna though the choice of end 1 makes no practical difference Our new antenna has twice as many segments as the back yard dipole This is fine unless you re using the EZNEC demo program which is limited to 20 segments If you are using the demo change the number of segments on both wires to 10 before proceeding Close the Wires Window You can see in the View Antenna display that the source represented by the circle is still on wire 1 To make a dipole or inverted vee from the two wires the source has to be at the junction of the two wires However the NEC calculating engine used by EZNEC spreads the source excitation over a whole segment or conceptually places it at a segment center We don t have a segment center at the center of the antenna so what should we do One solution to this problem is to insert a third wire between the two and put the source on it However this can be trickier than it seems because of NEC s general fussiness about source placement The best solution is to make use of EZNEC s split sources which can be placed at a wire junction Please click the link for more information about them Open the Sources Window b
67. the graph the SWR looks lowest at around 14 42 MHz or so What we ll do is change the frequency to 14 42 about where it s resonant Then we have a resonant antenna but at the wrong frequency We ll then rescale that resonant antenna to the right frequency In the Control Center information window click the Frequency line Enter the value 14 42 then Ok Click the Frequency line again Enter the value 14 1 But this time check the Rescale box before clicking Ok Open the View Antenna display by clicking the View Ant action button Right click on the wire in the View Antenna display You can see that EZNEC has lengthened the wire to about 34 2 feet It was originally 33 43 feet Close the View Antenna display Click the Control Center Src Data action button The source impedance still has a slight negative reactance about 4 ohms indicating that the antenna is still a little short The SWR rescaling process could be repeated or the antenna length changed in the Wires Window to fine tune it Let s run another SWR sweep to see how close we got to the target of 14 1 MHz Close the Source Data display Click the SWR action button Enter 13 9 and 14 4 for the Start and Stop Frequencies then click Run From the result you can see that we got pretty close to 14 1 There are a couple of reasons we didn t hit it exactly One is that we guessed at the initial resonant frequency Another SWR sweep with a finer step would have been more precise The se
68. the midpoint of a tower Reliable results were obtained only by spacing the end of the guy wire from the tower by about a segment length With slightly closer spacings reasonable results were obtained by making sure the segment lengths of both wires were the same and the junctions were directly across from each other as viewed through the bisector of the angle they formed EZNEC Pro 4 with an NEC 4 calculating engine may not be as sensitive but use care with this wire arrangement and make sure it isn t highly sensitive to the number of segments Advanced Wire Features Advanced Wire Features Introduction Advanced wire features are available for easily creating and modifying antenna structures Some features are available only for some program types refer to the following topics to see which program types have which features Structure creation features are accessed via the Wires Window Create menu Others are accessed via the Wire menu See Using The Wires Window for discussion of additional features Catenary Creation This feature is available only in EZNEC and EZNEC Pro programs It s located in the Create menu of the Wires Window A wire suspended between two supports doesn t form a straight line but if uniform in material and diameter forms a type of sagging curve called a catenary EZNEC can create an approximation to a catenary curve with a series of short straight one segment wires Even a moderate amount of sag can alter
69. the primary trace file is in ELNEC or EZNEC v 1 format ENT or F extension it can be saved as a PF file by selecting Save Trace As in the 2D display File menu This choice won t be available if the primary trace file is already in PF format 128 Reference Ending TraceView You can end TraceView by ending EZNEC or you can change to the normal mode by clicking TraceView in the Control Center View menu Undo Redo EZNEC has unlimited undo redo capability This applies to all choices saved with the antenna description but not to program level changes like the selections in the main window Options menu Undo redo is done via the Edit menu in the Control Center and other windows which can be used interchangeably Undo is reset when a new description is opened If the previous description has been changed you ll see a prompt asking you if you want to save it before proceeding This prompt can be turned off via Control Center Options menu selection Messages On Off Virtual Segments A Lap Around Track 5 in the Test Drive tutorial will be help you learn how to use virtual segments NEC requires that all insertion objects be connected to inserted in a wire segment There are many occasions where you want to connect two insertion objects for example a source and one end of a transmission line in parallel but not to any wire in the model For this purpose EZNEC provides virtual segments In the normal insertion object specification
70. the reading of this chapter Modeling With EZNEC All antenna models are made from EZNEC components wires insertion objects and ground media The accuracy of the model depends on how accurately the actual antenna and its environment can be represented by the model made from these components Some physical objects like a physical wire or metallic tube are easily modeled with high accuracy Some like a round loop or small flat metal plate must be approximated And some like a close helically wound dipole antenna can t be modeled accurately at all with the available components But a very wide variety of objects can be successfully modeled with EZNEC All EZNEC operations are accessed via the Control Center This is the form which opens when you start EZNEC and stays open while EZNEC is running The following sections will lead you through the steps of building a model You can get additional information by clicking on the links 45 EZNEC User Manual Opening The Description File EZNEC doesn t have a provision for starting with a blank description it always begins with the last antenna you ve analyzed So it s helpful to accumulate a collection of template antennas which are similar to the types you commonly model These make fast and easy starting points for developing your new model A description file is opened by clicking the Control Center Open action button or clicking the Open selection in the Control Center File menu I
71. this manual the term wires refers to the EZNEC component of that name Real physical wires are called physical wires The distinction is important because EZNEC wires are idealized models of the real thing much like a resistance is an idealized model of a resistor EZNEC wires are also used to model other physical objects such as cars or other structures Connected as a grid or screen they can be used to model flat conductive surfaces EZNEC models every antenna as a collection of straight wires Straight should be emphasized a round loop for example must be modeled as a polygon of straight wires The diameter of each wire can be freely chosen and the program will give accurate results with diameters from arbitrarily small up to at least 0 02 wavelength With some imagination nearly any type of conducting structure can be modeled as wires although not always practically or with great accuracy For example a metal wall can be modeled as a grid of wires with a mesh on the order of 0 1 wavelength or less You tell EZNEC where the wires are placed in space by giving their x y and z coordinates relative to a universal origin or 0 0 0 point You re free to decide where the origin is except that ground is always assumed to be at the height 46 Building The Model of the origin z 0 There are also some additional considerations involving the origin choice when two ground media are included in the model EZNEC has several features
72. to make entry within the coordinate system as easy as possible they re described in the Wire Coordinate Shortcuts section Wires are connected whenever an end of both have the same coordinates actually if the ends are within about 0 001 segment length of each other Wires can be connected only at their ends EZNEC automatically connects wire ends which have very nearly identical coordinates The actual criterion used by EZNEC is that wire ends have to be within about 1 1000 of a segment length to be connected When the Auto Coordinate Match option is on the default the coordinates of any wire ends which are close enough to be considered connected will be modified as necessary by EZNEC to make them identical If a ground is used a wire is connected to ground if its z coordinate is within about 1 1000 segment length of zero When Auto Coordinate Match is on the z coordinates of ground connected wires are modified by EZNEC to be exactly zero NOTE For High Accuracy ground the connection will be unpredictably lossy resistive See Real Ground Types Serious errors will occur if wires cross or occupy the same space Because wires can be connected only at their ends simply crossing wires won t connect them and would cause severe calculation errors if not for EZNEC s Geometry Check feature which prevents calculation when this error is present The calculating engine won t object to wires crossing at segment junctions and will consider them conne
73. types to display in outputs is made the same as for conventional sources via the Desc Options choice in the Control Center Source Placement Source Placement Precautions If modeling an end fed antenna please see End Fed Antennas NEC is very sensitive to source placement and subtle errors can result if sources are placed incorrectly Whenever possible you should try to follow these rules 1 The source shouldn t be placed on a wire which is shorter than about 0 02 wavelength particularly if adjacent wires connect at an angle 2 The segments adjacent to the source segment should be the same length and diameter as the source segment If placing it on a short wire it s good practice to give the wire three segments to insure this condition 3 Segments beyond the adjacent segments shouldn t be drastically different in length and diameter from the source segment and segments adjacent to the source segment 4 Sources shouldn t be put on a wire which is part of a small loop 5 It s usually better to use a split source at wire junctions than to insert a short wire containing the source Rules 1 and 2 can be broken when a short wire is used only for connecting a source to a transmission line In this case a very short one segment wire is generally adequate It s often not possible to follow all these rules and still accurately model the antenna so compromises sometimes have to be made One of the most powerful tools for evaluating sou
74. used to develop the help file The conversion process may have some imperfections so the resulting format isn t flawless However because the on line help system is intended to be the primary manual for EZNEC and any formatting changes would have to be repeated each time the manual is updated comprehensive editing and correction of minor formatting flaws in the printable manual won t be undertaken After some deliberation it was decided to furnish the manual in Adobe Acrobat pdf format The free Adobe Reader available from Adobe is readily available via the web An increasing number of other applications can also directly display and print these files The printable manual comes in two versions formatted for U S 8 5 X 11 inches and A4 210 X 297 mm letter size paper The integral manual help file is updated from time to time the revised manual being part of program updates When this occurs the printable manuals at the web site are also updated Program Version Compatibility A great deal of effort has been made to keep programs and description files compatible in both forward and reverse directions This has been largely successful ELNEC EZNEC s predecessor of 25 years ago can read and use today s EZNEC files although source and load placement will require adjustment and most insertion objects which didn t exist in ELNEC will be ignored Similarly the earliest ELNEC files can be opened and read by the current version of
75. you need If fail to communicate the fault is mine and I d like very much to hear where failed With today s tools it s not difficult to modify the manual and your input will help improve it and make it more useful to others So please let me know when you run across problems with the manual apologize in advance for not always being able to respond personally and promptly But your comments will be read and they will be acted upon Please send your comments to w7el eznec com I m sometimes asked if there are any restrictions on professional use of the standard program No there are none at all and in fact it s widely used for a wide variety of professional purposes The distinction between program types is only in price and features not in how they re used The other side of that coin is that people wanting to use the professional version for strictly amateur purposes pay the same price for the professional version as everyone else The only use restriction on any program is that only one person can use the program at one time unless corresponding additional copies are purchased Like many many EZNEC and EZNEC Pro users also wear two hats so welcome to both amateur and professional customers l m one of you both 73 Roy Lewallen P E W7EL Notes For International Users Although EZNEC is currently offered only in an English language version a very sizeable fraction of its users are outside the U S or even English speaking cou
76. your desktop The precise wording might vary slightly from one operating system to the other Right click the Start button at the lower left of your Windows desktop From the menu chose Explore to open Windows Explorer Navigate to the EZNEC program file directory folder If you selected the default directory during installation this will be C Program Files EZW or C Program Files x86 EZW on 64 bit systems Otherwise it will be whatever you specified at installation time In the EZNEC program file directory locate the file EZW exe standard or plus program EZWpro exe pro programs or EZWDemo60 exe demo program You might not see the exe part depending on how you have Windows Explorer set up Right click the appropriate exe file and select Send To from the menu From the next menu select Desktop create shortcut You ll probably see a message telling you that sure enough Windows is going to do what you asked it to When you click Ok the shortcut will be placed on your desktop You can rename it if you like Double clicking it will start EZNEC The program will open with a description file of your choice if you put its name on the command line in the shortcut properties or when starting EZNEC from Windows Start Run Note that the path EZW pro demo exe combination has to be enclosed with quotation marks if it contains a space You can also start EZNEC by dragging an EZNEC description EZ file to the shortcut and d
77. 0 126 After creating wire grid 60 126 Segments 48 49 66 71 138 Length displaying eee 49 144 Maximum number of 8 48 Specifying number of 48 49 Total number in current model EE 138 Ee 49 Selecting Wires 00000000000 49 144 Selection buttons 129 Selections na se 138 Series RLC seiciverorcntvndisntoadndts 90 Series Type RLC Loads 90 Se tUPS iiia 118 123 137 Frequency ween 118 Near field analysis 123 le TE EE 17 Desktop for starting EZNEC 17 Shortcuts 49 54 Wire coordinate entry 49 54 Show Calculation Time 138 Show Description 137 Show Freq on 2D Plot 132 Show Ground Info 138 Show Memory Info 065 138 Show Temp Dir Space 138 Gidelobe 147 Signed Files E 117 SiMSMiIth sca aici itn wanders arcane 158 SINGLE USE SOFTWARE LICENSE AGREEMENT 176 Slow Calculations snnneaeeenn 158 Small MOODS eeneg 72 Smith Chart Display 0002 149 Smith Chart Program selection 118 Smith Chart Programs 158 lut Tt BEE 158 Software Incompatibilities 158 Sommerfeld Norton ssseaaan 103 lte 25 85 111 132 Absolute vs relative value 132 Impedance An 111 Power 111 Egeter 25 85 Using to measure V and l 78 Voltage and Current 111 Source Data 111 Source Placement66 71 78 83 84 85 116 A
78. Ant 157 EZNEC User Manual IONCAP VOACAP Files Documents Folder EZNEC 6 0 IONCAP C Users lt user name gt My Documents EZNEC 6 0 IONCAP Temporary Files Temporary Files Folder EZNEC 6 0 C Users lt user name gt AppData Local Temp EZNEC 6 0 Temporary files written and read by the main EZNEC program This directory and its contents are deleted when EZNEC ends Application Data Files Local App Data Folder EZNEC 6 0 C Users lt user name gt AppData Local EZNEC 6 0 Files written and read by EZNEC and the calculating engines for communication between them and for diagnostic and temporary use This is a hidden directory and its contents are not intended to be modified by the user Ground Data Files Local App Data Folder EZNEC 6 0 Ground C Users lt user name gt AppData Local EZNEC 6 0 Ground Real High and Extended Accuracy ground data files This is a hidden directory and its contents are not intended to be modified by the user Program Data Files Program Data Folder EZNEC 6 0 C Program Data EZNEC 6 0 Storage of files containing data used by EZNEC This is a hidden directory and not intended to be modified by the user AutoEZ AutoEZ is an application which automates EZNEC and allows you to use variables to control and sweep multiple parameters It also has optimization capabilities Although EZNEC is configured to work with AutoEZ AutoEZ is a separate program developed sold and supported by Dan Maguire A
79. Antenna Description DE EG 137 Printing The Manual 18 Printing Wire Coordinates 49 137 Program Version Compatibility 18 R R j X Load Type 87 89 90 R j X Loads Window 90 R Freq Column 90 Radial Creaton 60 Hadals 60 66 73 108 Buried simulating DE 73 E le DEE 60 Modelmg 73 108 STEE a aa 155 159 Virtualni 155 159 Read Frequencies From File 118 Real Ground Models 102 105 Limitations EE 105 Real Ground Tvpes 103 Ref Level 138 Reflecting Wires in a Plane 49 Reflection Coefficient 149 160 162 Reflection Coefficient 11 152 Reinstalling EZNEC n se 160 Reporting Bugs 181 E EE 29 FROSCOMING GE 125 Resistance 000000 72 90 111 Frequency dependent 90 Negative cesses 72 111 Return Lopes 2veedeeedreedeeedredeeeg 149 FEW NOM DE 93 Reverse Connection ssss 93 RLC Load Type 87 89 90 RLC Loads Wimdow 90 Rotating wires 49 54 S EE 140 Save As Default ee 132 Save Description As 131 Saving A Trace 142 Scaling To a New Frequency 125 Scaling Wires ves eee ee 49 Scintilla steen ze etbgee eet gees 2 177 Segment Dots nnneeeeeeeeeeeeeee 144 Segment Length48 64 65 71 115 144 Segment Length Tapering64 66 125 Segmentation 48 65 66 115 126 Log periodic antenna 71 Segmentation Check46 115 126 132 137 Segmentation Check Warnings 6
80. Because the NEC 4 engines are relatively free from the stepped diameter problem Stepped Diameter Correction is disabled when one of these engines is selected Always off Stepped Diameter Correction is always disabled This setting may lead to inaccurate results for some types of antennas most notably Yagis having elements made from telescoping tubing Always on Stepped Diameter Correction is always on This would not generally be chosen unless it was desired to see its effect in NEC 4 IONCAP VOACAP File Zero Angle EZNEC and EZNEC Pro only Sets the reference for zero degrees when generating IONCAP VOACAP files See Writing IONCAP VOACAP Files for details EZNEC Geometry Check NEC allows wires to cross at segment junctions While it s discouraged for EZNEC models primarily because the connection will be broken if segmentation is changed no error will occur if this situation exists Some models originally designed to run under NEC 2 or 4 have numerous segment junction crossings This menu selection allows you to 135 EZNEC User Manual prevent warnings of this situation from appearing in the Geometry Check output Pre Calc Geometry Check EZNEC Pro 4 only Allows you to choose whether EZNEC runs its own geometry check uses the NEC 4 SEGCHK check or both EZNEC s check catches some errors which SEGCHK misses and it s faster so this selection should normally be left in the default condition EZNEC geometry check unl
81. C6LA For more information about AutoEZ see http ac6la com autoez html SimSmith EZNEC programs through v 5 0 created input files for one or two external Smith chart programs for aiding in designing impedance matching networks Those programs are now obsolete so support has been discontinued A very capable program is currently available that can directly use EZNEC s LastZ txt file for input This program is SimSmith by Ward Harriman AE6TY See http ae6ty com Smith Charte bim for information Software Incompatibilities Antivirus and Anti malware adware or spyware Programs When set to constantly check for virus like activity some programs cause a very significant slowing of the calculations It appears to be due to interception and analysis of the messages sent from the calculating engine to the main program in order to show calculation progress Slowing in terms of a fraction of total calculation time will be greatest for simple models since this is when the time spent sending calculation progress messages is the greatest fraction of total calculation time Total slowing will be most noticeable when doing a frequency or SWR sweep of a relatively simple model If the slowing is objectionable it can be alleviated either by turning off the feature in the antivirus or anti malware program or by directing EZNEC to update the calculation progress display less frequently The latter is done by setting Special Option CalcProgReduct
82. EC Pro will ignore requests to print major minor axis gains or do field normalization directive gain or gain averaging Please see additional GD GN RP comments below If no RP card is present default values will be entered TL Shunt loads will be ignored XQ Any value other than 2 is interpreted as being 1 since EZNEC Pro can t do simultaneous plots All other cards are ignored Translation of the input file will terminate after the first EN or NX card is read Additional GD GN RP comments Due to the complex interaction of ground specifications among GD GN and RP cards EZNEC Pro may not interpret the ground specification in the same way as NEC does Be sure and check the ground type and specification after reading an NEC file This is especially true when using the NEC buried radial radial ground screen model When EZNEC Pro is forced to interpret a card in a different way than NEC it will add a notice to the display shown at the end of the translation EZNEC Pro disregards the positions of data on the line Fields are delimited by spaces tabs or commas Any number of spaces or tabs may be used A field is considered blank or zero if it is surrounded by commas For example 3 51 4 is interpreted as four fields of value 3 0 51 and 4 Spaces and tabs adjacent to commas are ignored spaces and tabs elsewhere are interpreted as delimiters For example 3 15 7 42 will be interpreted as having fields of value 3 15 0
83. EZNEC All versions between are similarly compatible However because earlier versions can t be aware of the features which follow a file created with a later version of EZNEC won t necessarily be 18 Getting Started complete when opened with an earlier version In some cases it s been possible to adapt new features to retain full compatibility with older versions For example virtual segments didn t exist prior to EZNEC v 5 0 But when a description file is saved the virtual segments are converted to real segments on a distant wire so that earlier EZNEC versions can properly process the model But there s simply no equivalent to most new features Transformers and L networks for example were introduced in EZNEC v 5 0 There is no equivalent in earlier versions so if a file containing these objects is opened with an earlier version those objects will simply be missing And there is likely no way any substitute can be devised so it won t be possible to analyze the model with the earlier version You can be assured that a new version will never be introduced which won t be able to read and analyze the description files you ve saved with earlier versions 19 Test Drive Test Drive Introduction The best way to get familiar with EZNEC is to take it for a spin Let s analyze a 20 meter dipole hung 30 feet up in the back yard If you ve started EZNEC you should see the Control Center The file Dipole1 ez is included with the program
84. EZNEC User Manual Table of Contents WY GICO RIG EE 1 WEE 2 Acknowledgements AEN 2 Acknowledgement and Special Thanks Jordan Russell and Inno Setup 4 Acknowledgement vbAcellerator Goftware 4 Acknowledgement Info Zip Software ssnseeseeeeeesennnnnneeeeeernnnnnnnneseerenne 4 Acknowledgement Scintilla Goftware 4 A Few Words About Copy Protection Ae 4 EZNEG and Te 4 EZNEG PO KEE 5 ET eir ak Aar can cous E E A mavscins Misaline O AO 5 EEGEN 5 Notes For International lees eege ees ee ee EES 6 Getting SIAM CG sca ot ah Dotnet tebe oneal bares lB aban detent eege 8 A Few ESS E 8 WTS ING Wy WANG O EE 8 What Was New in V 5 0 EE 11 e ei Ree a aa Rt Re REE Be ASA daa aE GRE anan EEEE tae 11 Reeg 12 lee 12 Parallel Connected Loacde 12 Transmission Line LOSS ee eher EEN 12 Y Parameter Networks EZNEC Pro on 13 What Was New iN V 40 EE 13 reet e DEE 13 Control Center Menus nrnna nanamn nnmnnn ennenen 13 SOCAN ee 13 Segmentation Check formerly Guideline Check 13 Geometry GH GCK Ee 14 Wires Window Features nrnna 14 View Antenna Display EE 14 Circular Polarization EZNEC and EZNEC Pro only 14 ALENE DIE SEE AEE E E EE EE 14 Calculating REIDEN 15 Wire Insulation EEN 15 frt ee Ve H lun DEE 15 Easy Import of Wire Coordinates from NEC Files EZNEC EZNEC Pro COTY ss E Sa ats Oh i ea i ale ST 15 Multiple Instances EZNEC Pro only ceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeneeeeeeeees 15 RMIT So vias cies vases EE ee 15 If You Down
85. EZNEC has not been able to accurately model trapped or loaded Yagis or certain other antennas of varying diameter EZNEC v 6 0 applies advanced correction methods that make reasonably accurate modeling of loaded and trapped Yagis possible for the first time without needing NEC 4 Because of the many variables involved no specific guarantee of accuracy can be made but tests have shown significantly improved accuracy compared to earlier EZNEC versions which couldn t correct these antennas at all See Stepped Diameter Correction Overview for more information Graphical Wire Modification Some modifications to the model can be done graphically in the View Antenna display Selected wires can be deleted wire ends can be moved to other existing wire ends and new wires can be created which connect other existing wire ends See Graphical Wire Operations View Antenna Display Enhancements In the View Antenna display pressing the X Y or Z keyboard keys positions the display to be viewed from the X Y or Z axis Pressing lt Shift gt at the same time positions the view from the negative axis The Wire Information pop up window now shows the magnitude of current at the closest wire end if it has been calculated EZNEC User Manual Segment Limits EZNEC now has 2000 segment capability increased from the previous 1500 The EZNEC Pro limit has been increased from 20 000 to 45 000 Standard and Demo programs remain unchanged at 500 and 20 resp
86. File Opens the file shown in the File Name box for editing in the EZNEC Editor If no file name has been selected opens a dialog box allowing you to choose one Field Field To Calculate Selects whether EZNEC will run a far field or near field analysis for the frequency sweep If Near Field is chosen pattern plot output and pattern analysis data are not available and field strength table data will be near field Output Selects what data will be calculated and saved during the frequency sweep There are three general categories of output listed below For each category the output file name is specified by clicking the Select button and the choice is shown in the corresponding text window Pattern Plots If this is checked 2D pattern plots will be saved and shown when the frequency sweep is completed This selection is disabled if Near Field is chosen as the Field To Calculate Select this option when you want to see or save 2D plots for all the sweep frequencies These plot trace files aren t automatically erased when the sweep ends so they can be treated later like any other trace files It s recommended that you use a name like temp for files you won t want to view at a later date and use this same name each time you want to see frequency sweep plots but don t need to keep them The extension P is added to the file name you specify with being 1 for 119 EZNEC User Manual the first frequency 2 for the second e
87. NEC Pro have had separate manuals Besides the obvious difference of EZNEC Pro s additional features the manuals were written with a bit different orientation with an eye toward the most likely level of technical expertise of their respective users Since then the manuals have been combined Because maintaining two or more separate manuals involves a great deal of extra time combining them frees that time to be put to use in improving the program itself Even the standard EZNEC program has an extremely diverse user base It s purchased and used by amateurs who have very little technical background in electrical fundamentals let alone electromagnetics or antenna design It s also used by the U S and foreign military services aerospace companies defense contractors international broadcasters universities and so forth Add to that EZNEC User Manual the EZNEC Pro users and you have an idea of the enormous range of background knowledge represented by the readers of this manual So please for those of you who are more knowledgeable don t be insulted if some concepts are explained more simply than you re accustomed to And for those with less experience don t think for a minute that an effort is being made to snow you The sole objective here is to communicate and give you the information you need to get the most from EZNEC whichever program type you re using The only relevant question is whether you get from this manual the information
88. Rotate End Enter the value 45 and click Ok You should see the completed inverted vee in the View Antenna display If the inverted vee looks ok close the Wires Window Click the FF Plot action button to generate a 2D plot The plot should resemble the dipole plot To see how the pattern compares to the dipole s Open the 2D Plot display File menu and select Add Trace Locate the Back Yard Dipole file you saved at the end of the Along The Straightaway exercise and click Open Note that when automatic outer ring scaling is selected it s scaled for the largest of all the plots being displayed It can be shown that the center of current for a sinusoidal distribution is 1 3 of the way from the current loop This means that the effective radiation strength from the inner 1 3 of the inverted vee equals that from the outer 2 3 since the current is heavier 28 Test Drive toward the center If we raise the inverted vee by 3 94 feet it will place this current center at 30 feet which was the height of the dipole s center of current Let s try it and see what happens Open the Wires Window Open the Wire menu and select Change Height by Enter 3 94 in the bottom text box and click Ok or press lt Enter gt Again the 2D plot is closed as soon as the model is changed Close the Wires Window if desired then click the FF Plot action button Add the Back Yard Dipole trace to the 2D display as you did before The higher inverted vee is closer to the
89. SS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL VBACCELERATOR OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE Info ZIP All EZNEC program types beginning with v 4 0 14 make use of unzip32 dll and zip32 dll beginning with v 5 0 0 both generously provided free of charge by Info ZIP The following information constitutes the license agreement for use of that software This is version 2004 May 22 of the Info ZIP copyright and license The definitive version of this document should be available at ftp ftp info zip org pub infozip license html indefinitely Copyright c 1990 2004 Info ZIP All rights reserved For the purposes of this copyright and license Info ZIP is defined as the following set of individuals Mark Adler John Bush Karl Davis Harald Denker Jean Michel Dubois Jean loup Gailly Hunter Goatley lan Gorman Chris Herborth Dirk Haase Greg Hartwig Robert Heath Jonathan Hudson Paul Kienitz David Kirschbaum Johnny Lee Onno van der Linden Igor Mandrichenko Steve P Miller
90. Stepped Diameter Correction EE 62 Stepped Diameter Correction OvervieW sssssssrsesssesrrrrrnnrrnsserrrrne 62 Using the Stepped Diameter Correction Display 64 Some Special Cases AE 64 PCUIG PGI GS ee 64 GEIER 65 Closely Spaced TEE 65 EE EENEG 66 Elevated Radial Systems cccccecceceeeeeeeeeeeeeeeeeeeeneeeeeeeeeeeeeeeeeaees 66 End Fed EE 67 Feedlines and Baluns AEN 70 Linear Loaded E EE 70 Log Periodic DEI 71 Phased E 72 Ree Ee 72 Stacked DEES Aeren eege eebe een 72 Vertical Antennas And Buried Radials oooesneneeeeeeeeeeenrnnnrreeseereene 73 WV ire Ee he En e E 74 Keelen 75 Insertion Objects EE 75 About Insertion CObiects AAA 75 Placing Insertion Objects On Segments sssseeesseseenerrnneeserrrrrenrneeeee 76 EZNEC User Manual Using Insertion Objects Windows ssssssssseeeneeeeseerrrnnrreesserrrrrnnnneeenne 77 le Eeer 78 eeler 78 Ee 79 Using The Sources Wmdow EEN 79 Plane Wave Eeer 80 Plane Wave Overview EZNEC Pro only eeeeeeeeeeeeeeeeeeeeeeeeeeenees 80 Specifying Plane Wave Excitation ceeeeeeceeeeeeeeeeeeeeeeeeeeeeneeeeeeees 81 Plane Wave Excitation With a Ground Hlane 81 Interpreting Plane Wave Hesuhts ENEE 82 Source Placement EE 83 Source Placement Precautions ccccceeeeeeeeeeeceeeeeeeeeeeeeeeeneneeeeeeeees 83 Placing Sources On Geoments EE 84 Placing Sources At Wire Junctions ssessseeeeeessesssrerrreeseerrrrrnnnnnseee 85 Connect
91. View Antenna Ne 144 Gpechfving e 93 te E 93 Total number in current model VE 138 Velocity Tacho 93 Transmission Lines Window93 138 OPENING eieiei 138 ND SUI EE 93 HR NEE 75 89 90 Modelmg AAA 90 Trap Type RLC Loads 90 Ee 89 Twinlead 0 02 cece eee cceceeceeeeeeeeeeeeeees 93 U Undo edo 129 Eltere ege 132 138 Far field Goble 132 Gpechfhving neee 138 Te 181 Updates Maintenance Releases Geet 181 Using Multiple Sources 85 Using The 2D Display 147 Using The 3D Display 149 Using The L Networks Window 100 Using The Media Window 106 Using The Sources Window 79 Using The Stepped Diameter Correction Display 64 Using The SWR Display 77 149 Using The Transformers Window97 Using The View Antenna Display Se 144 Using The Wires Window 49 Using The Y Parameter Networks WINKOW nossen 101 Using Two Ground Media 107 EEN 138 vV VAObjTextSizePct 144 162 vbAccelerator eceecnaen 2 177 Velocity EE 93 Version Numbers saeeaceeeaean 138 Vert RE 73 Vertical Antennae 73 Vertical Antennas And Buried GE al EE 73 Very Large Models 155 TEE EEN 140 View Antenna Display132 140 142 144 Adding And Moving Wies 53 En CN 142 Mouse Operation 0000 53 Objects cecceeeeeeees 142 144 DEED Ae ics tice See 140 Rotating E 144 Selecting wires cccceeees 144
92. WR on a transmission line but is the SWR which would be on a line if the line were connected between the source and antenna Several other displays are available in the EZNEC and EZNEC Pro program types described below 149 EZNEC User Manual If you turn on the Control Window via the View menu you ll have a choice of the SWR for two values of line characteristic impedance SWR One impedance is 50 ohms The other can be changed to a value of your choice by clicking on the Alt SWR ZO line in the Control Center Information Window Also in the Control Window is a selector allowing you to choose the source for which to display the SWR in the event your model has more than one source Additional information appears in the Data Window below the plot The Data Window is turned on or off from the View menu In this window you can see the impedance and reflection coefficient as well as the SWR The cursor can be moved by clicking on the display window or by dragging with the mouse You can also use the arrow keys after clicking once on the display window with the mouse to make sure the display window has the focus EZNEC EZNEC Pro only These program types have an additional Display Type selection in the View menu This allows selection of the data display as either SWR reflection coefficient magnitude return loss or Smith Chart When Smith chart is chosen additional selection Data Markers is enabled As with the standard program s SWR plo
93. WindoW sessssssseenneeessserrrrrrrresserrrrrnnnnnnnserrrrrnnnnn 106 Using Two Ground Media WEE 107 Connecting Wires to GrounG DEEN 107 Connecting to High Accuracy Ground ccceeeeeeeeeeeeeeteeeeeeeeeeeeeeeees 108 The NEC Radial Model size cnisccccsttesteet petites eege 108 Interpreting The Hesuhte EEN 110 COUNT OUTINGS ee 110 RE 111 S rc Datarea ca ees y cas E a a peers ean E 111 Far Field EE 112 Near Ee 112 Far Field EEN 113 AEI A AETA E E E E Caccssiwisucctuedts 114 EE 115 EEGEN 115 Alternative 2D Pl t Grid ee 115 euer 115 Automatic Segmentation EE 115 Average Gaim E 116 Combining Antenna Descrnptons 117 EZNEG ABBE EE 117 Tee e 118 Frequency SWeCDes As hea CA AANA ANAS N AA MA ANA Aa eas 118 Geomety EE 120 Ground Wave Analysis seanna nni a E a a a Eea 122 Eat terena a EA 123 Near Ee 123 Writing IONCAP VOACAP Files EZNEC EZNEC Pro onlly 124 lee 124 RescalinNg EE 125 Segment Length Tapering sssssesssesesssnernrreessserrnrrnnrnnsserrrnnnnnnnnneerennne 125 Segmentation Check AAA 126 Stepped Diameter Correction EE 127 DOV GAN EE 127 EE 128 Starting Trace ew 128 R nning TRACE IEN eege eer 128 Ending Be 129 Undo REdO EE 129 a a Ee e EE 129 DEE Cente Ee 129 el teller geet DEE 129 The Control Center Menus EE 131 Control Center Menus Introduction EE 131 EE 131 GE 132 OPIONS ee 132 Re eege 137 MOSES EE 137 EZNEC User Manual IEN Eeer ee ee 138 EE 138 ele PEPE A Cee a er
94. a file EZNEC Pro only To save a file in NEC format include the extension NEC with the file name Add Description Allows you to select an antenna description model to add to the current model See Combining Antenna Descriptions for more information Restore Default Folder EZNEC remembers the last folder you used for opening or saving a description so the next time you open or save a description the last folder you used is listed as the initial choice This selection resets the initial choice to the description file folder specified in the Folders section of the Options menu Import Wires From ASCII File This choice allows you to select an ASCII file containing wire coordinates which will be imported into EZNEC See Importing Wire Coordinates for more information and Wire Coordinate File for the file format Add to Existing Wires The wires in the ASCII file will be added to the current model Replace Existing Wires The wires in the ASCII file will replace the wires in the current model Edit Current Antenna Notes Opens the antenna notes file for the current model in the EZNEC Editor Edit Antenna Notes Allows you to select an antenna notes file to edit View File Prompts you for the name of a text file to view with the EZNEC Editor Although you can modify the text in the editor you won t be allowed to save the file under the same name so the original file content is protected from modification The defa
95. a file name If you don t specify an extension for your file name EZNEC will use 13 However you can specify any extension you d like You can of course navigate to another directory before saving See Options below for how to change the default directory for saving IONCAP VOACAP files Depending on the options you ve set see below you might have a choice for the orientation of the data in the file After making your selection click Ok to write the file Consistent with IONCAP VOACAP standards the azimuth angles in the files represent a clockwise progression from the zero degree entry regardless of whether you ve chosen a conventional CCW angle or compass bearing display for your other EZNEC outputs There are two choices for the zero reference explained below Options Default directory folder You can change the directory which appears in the file saving dialog box either for just the current EZNEC session or permanently via the Control Center Options menu Folders selection You should set this to the location where your IONCAP type program expects antenna files to be Zero degree reference Basic IONCAP VOACAP programs expect the data for zero degrees azimuth to correspond to the antenna pattern maximum However some variations prefer or accept an absolute azimuth angle So EZNEC allows you three choices 1 Zero degree data in the plot always represent the gain in the direction of North or zero compass bearing up on th
96. a new title and save the description Vertical Antennas And Buried Radials The effect of radials and other buried ground systems is widely misunderstood In a typical quarter wavelength high vertical antenna the ground has two distinct and somewhat independent effects One is that the current flowing into the base of the antenna is matched by an equal current flowing from the ground to the other feedline conductor This current flows through the ground and incurs loss in the process The primary purpose of a buried ground system is to reduce this loss by increasing the conductivity of the ground near the antenna The effect of a poor ground system is to reduce the antenna efficiency This reduces the strength of the radiated field but doesn t change the antenna pattern The second effect is less widely appreciated but is often of much greater importance The elevation pattern of any antenna is created by a combination of a field travelling directly from the antenna to a point in space above the horizon and the field reaching the same point after being reflected from the ground The relative strength and phase of these two fields are what make the lobes and nulls of the vertical pattern As it turns out vertically polarized waves are affected differently by the ground reflection than horizontally polarized waves While horizontally polarized waves reflect nearly perfectly from even relatively poor ground except at high angles vertically polariz
97. acing Allows you to specify the spacing between wires the width of the holes The default value of 0 1 wavelength can be easily selected by checking the box Wire Diameter Allows you to specify the wire diameter The default value of spacing pi which results in wire area equal to modeled surface area can be selected by checking the box Create Box If checked an enclosed box will be created Box Parameters Define additional characteristics of the enclosed box Visible only when Create Box is checked 61 EZNEC User Manual Meander Line Creation This feature is available only in EZNEC Pro programs EZNEC Pro 2 and EZNEC Pro 4 It creates a flat meander zig zag line useful for planar loading It s located in the Wires Window Create menu Side wires refers to wires in the long direction of the meander width wires are wires crosswise to the meander i e the width of the meander is the length of a width wire Only full cycles of meander are created Wires can be deleted after creation if partial cycles are needed Parameters are self explanatory Some experimentation should quickly clear up any questions Stepped Diameter Correction Stepped Diameter Correction Overview The following information applies only to the NEC 2 calculating engine s which are the only choices for all EZNEC program types except EZNEC Pro 4 This problem described here doesn t occur when using NEC 4 with EZNEC Pro 4 for calculations un
98. ad types the short circuit can also be created by entering S or Short and the open with O or Open R Freg Column all configurations The R Freq column is the frequency at which the resistance has the value specified in the R column H any value other than zero is specified as the R Frequency the resistance will vary with frequency as described above Series resistance Series and Trap types changes in proportion to the square root of frequency Parallel resistance Parallel type changes in inverse proportion to the frequency Enter zero in this column to keep the resistance fixed with frequency The current frequency can be conveniently entered by clicking the cell to activate the drop down list arrow clicking the arrow then clicking the highlighted frequency value which appears Ext Conn Column all configurations See Load Connections for information about choosing the load connection The Laplace Loads Window Laplace type loads are impedances which are defined as Laplace coefficients This load type is most useful for representing complex combinations which can t be represented by other load types Any combination of R L and C up to fifth order can be represented with Laplace type loads Because Laplace type loads represent R L and C components rather than fixed impedances the impedance varies with frequency as appropriate for the components comprising the load However R cannot be made to vary with frequenc
99. adequate for a completely accurate calculation of cable characteristics However these multiple factors are often unknown so EZNEC uses an approximation which is reasonably good over a wide frequency range The single transmission line loss specification in dB 100 ft or m is used to calculate a complex characteristic impedance and complex propagation constant for the line EZNEC bases these calculations on an idealized transmission line model which has only resistive conductor skin effect loss and no dielectric loss This approximation is reasonably good throughout the HF and UHF range for most common transmission line types but not at the lower end of MF and below or at microwave frequencies and above Outside the MF through UHF range the assumption that loss is proportional to the square root of frequency becomes invalid and at microwave frequencies and above the calculation of characteristic impedance also becomes inaccurate The inaccuracy of the square root of frequency assumption can be minimized by only specifying a loss frequency which is close to the analysis frequency The error of the characteristic impedance calculation can be minimized only by having relatively low loss cables in the model and ones which are reasonably well matched to their loads Users of the professional programs EZNEC Pro 2 and EZNEC Pro 4 can use a Y parameter network to accurately represent any transmission line at a single frequency providing that the cable
100. ainted with EZNEC 14 gif PIGS cates cata AeA ate hss 144 GN RT 152 Gnd Wave Diet 122 Graphical Wire Operations 53 Graphics Fiesta 144 CHEATING BEE 144 Graphics Windows 142 Ee 142 Graphics Windows Overview 141 142 Graphics Windows Sections 141 Grid Spacing nos Sota cet cies toe 60 Ground craic 73 85 103 107 138 Connecting Sources 85 Connecting Wires 103 107 108 Information onooonannnnoeaeaeaaaann 138 Z Coordnate 102 Ground characteristics 103 106 Ground Consiants 132 DSTA ic tederssecestiresceesicesceeses 132 Ground Data bles 8 Ground Descrip 103 138 Ground File Tolerance 132 Ground loss nnannaaaaaaaannn 102 116 Evaluating with Average Gain116 Ground e ER 107 USING tWO 0 0 ceeeeeeeeeeeeeeeeeteeees 107 Ground Tvpe 102 138 DS PECIVING D 138 Ground Types soosenneen 102 103 Extended Accuracy103 105 108 132 155 162 Free Space 2 2 eeeeeeeeeeeees 102 Perfect grond 102 Real ground 102 103 Reflection coefficient 11 152 Ground Wave Analysis 122 138 Distance EE 138 Observation height 138 Group BGI eee vee us 123 Group Modify ee 49 123 Guarantee eege egeieeeeeg 5 H Ph Se KEE 112 123 186 EE enee 49 Antenna CHANGING DEE 49 Helix Creation EEGEN 59 el EE 138 Context sensitive 0 8 17 Help Menu ee 138 High Accuracy Ground65 73 103 107 108
101. ally be set to Extended if set to High Accuracy no change will be made when a file is opened This option defaults to High Accuracy because of the substantial calculation speed penalty exacted by use of Extended Accuracy ground This should be considered before changing the setting to Extended Accuracy See Real Ground Types for more information Segmentation Check This determines when the Segmentation Check utility will be run Auto Show All Automatically runs when a new description is opened wires are imported from an ASCII file or the frequency is changed Auto Minimum Warnings Only Automatically runs as above but doesn t warn of violations of Conservative guidelines unless run manually Manual Runs only when selected from the Control Center Outputs menu 134 Reference Plot Printing Printed Plot Line Width Allows you to adjust the width of the lines in the printed plots This affects only the Plot section of the Graphics Windows and only when printed It has no effect on the screen display When the width is set to a value greater than one lines normally shown broken separate 2D polarizations and View Antenna axes when offset from the origin and current polarization markers will be printed as solid Broken lines can be forced to be printed with a width of one however causing them to be printed as broken by means of the PrintedOffsetAxisWidth Special Option Printed Plot Data Font Selects the font
102. am is always single precision with the exception of L network transformer and Y parameter network EZNEC Pro only parameters Consequently wire coordinates for example are passed along to the calculating engine as single precision numbers and single precision arithmetic is used to determine wire connections within the interface Also some functions done by the interface such as wire height modification are done in single precision Marginal conditions of wire connection where wire ends are not the same but are very close to 0 001 segment apart should be avoided Both EZNEC and the calculating engine modify coordinates slightly to force a match when wire ends are extremely close but it could be possible for one to force or assume a connection and the other not under marginal conditions So while unlikely this situation should be avoided When using an NEC 4 engine EZNEC Pro 4 only the output of the interface portion of the program is an NEC 4 input file which is passed to the calculating engine The precision of all NEC 4 calculations is determined by the calculating engine choice See Options for information on selecting double precision operation L Network Limitations has information about the impact of double precision operation when the model contains L networks 156 Reference Multiple Instances Multiple instance operation is available only with EZNEC Pro programs EZNEC Pro 2 and EZNEC Pro 4 An instance of the program i
103. ame number of segments as the longest element Alternatively you can use the highest frequency and the shortest element to determine the number of segments the result should be about the same in either case The principle being used here is that at a given frequency only a few elements have significant current The segmentation of the other elements is less important since they contribute little to the overall field Using the method of using the same number of segments on each element assures proper segmentation of the active elements without using an unnecessarily overlarge number of segments on the other elements Multiband Antennas EZNEC is well suited for modeling multiband antennas Keep in mind the segment length however Remember that as you increase the frequency the segment length increases in terms of wavelength In general you should double the number of segments each time you double the frequency A bare minimum number of segments for a square loop is about four per quarter wavelength This means four segments per side at the frequency at which the loop is a full wavelength in circumference eight per side at twice the frequency etc Run Segmentation Check from time to time if you have doubts about the segment length Some commercial multiband antennas have a transformer at the feedpoint This will typically be so far from ideal in its operation over multiple bands that EZNEC s ideal transformer object won t adequately imitate i
104. an one which isn t Please try to begin exactly as you did and follow as closely as possible the sequence of operations you performed and see if you can make it happen again If so please record the sequence Note that some errors depend on which windows are open and sometimes even which windows are overlapping so this information can be important also 181 EZNEC User Manual 4 Does it happen only with a particular antenna description or descriptions If so please attach the EZ file to an email message and send it to me 5 If there was anything new different or unusual you were doing Please see How to Contact Me for information about where and how to send your report Thanks for your help How to Contact Me The best method of contacting me is email but other means might be better for you Email w7el eznec com Phone 503 646 2885 Fax 503 671 9046 Mail Roy Lewallen P O Box 6658 Beaverton OR 97007 U S A 182 2 E 29 147 149 2D Display 29 132 142 147 Grid Style i ccccdenc cessed ccs 132 MENUS ten 142 Plot Orientation 0000 147 Showing frequency on 132 elt eege 147 2D PASI EEN 29 144 Showing in the View Antenna Display sarea e 144 2D Plot Z re 132 RE Te 149 3 3 dB beamwidth ssnnneeeeeeenn 147 3D Display 29 142 149 MOTUS een EE 142 ODrientaton 149 USING istic leet atte teste te 149 4 CESTo i 2 ee ee ee eee 86 A A Few Wo
105. and dielectric constant so a file might already exist for a combination which is just slightly different than the current conditions If the difference is small the file data can be used with a negligible degradation of accuracy and the time required to recalculate the data is saved The initial default value of one percent is adequate for most use If you encounter periodic jumps in a frequency or SWR sweep the tolerance might be too high Also if you re trying to resolve very small differences in patterns particularly involving vertically polarized antennas where the ground characteristics are more important you might want to set the tolerance to a smaller value perhaps 0 1 For extremely sensitive calculations a setting of zero will force EZNEC to recalculate the data unless conditions match to within about five decimal places Messages On Off Allows you to suppress the Description has changed message when you open a new description and the tooltips that appear when you pause the cursor over some controls NEC Output File Format EZNEC Pro 4 only Sets the format used when saving files in NEC format See Working With NEC Format Files for more information about these options Default NEC 4 Ground Type EZNEC Pro 4 only This option sets the program behavior when opening files saved by program versions or types where Extended Accuracy ground isn t available If set to Extended Accuracy the ground type in those files will automatic
106. and should be installed at the proper location so we ll start with that antenna and modify it as necessary Notes lt Enter gt means the Enter key lt ESC gt is the Escape key You can type any entry in uppercase lowercase or any combination When text to be typed is surrounded by single or double quotation marks don t type the quotation marks themselves The Test Drive begins with Along The Straightaway Along The Straightaway This exercise leads you through the creation of a simple dipole and illustrates some of the basic steps in creating an EZNEC model Most of the steps could be done in any order The order of steps in this exercise is pretty much arbitrary If you d like to take a break before finishing the tutorial you can simply end EZNEC by selecting Exit from the Control Center File menu and the next time you start EZNEC it will resume where you left off Or you can save the description by selecting Save Description As from the File menu or by clicking the Save As action button and giving the file a name Then you can open the description by selecting Open from the File menu or clicking the Open action button and specifying the name you used for saving In the Control Center locate the Open action button and click it This will open a file selection dialog box Select Dipole1 ez or enter dipole1 in the File name text box and click Open Click here if you have trouble The bar at the top of the Control Center informa
107. ane wave from a distant source instead of being excited by conventional sources This allows finding the scattering cross section and directly finding the output of a receiving antenna What Was New in v 4 0 This topic describes the differences between v 4 0 and the previous Windows version 3 0 If you re upgrading from v 4 0 and are familiar with it you can skip this section and go next to What Was New in v 5 0 Undo Redo EZNEC v 4 0 has unlimited undo redo capability Control Center Menus The Plot menu no longer exists Its functions have been moved to the Desc Options line in the Control Center Information Window The Information Window now contains all the choices which are saved with the description file except for the near field and frequency sweep setups which remain in the Control Center Setups menu Segments The new EZNEC program type permits 1500 segments The EZNEC Pro program types EZNEC Pro 2 and EZNEC Pro 4 now allow 20 000 Note however that files as large as 6 GB can be written for the largest possible pro models at double precision and calculation times can run to more than a day with 2 GHz machines Segmentation Check formerly Guideline Check The EZNEC 3 0 Guideline Check has been renamed Segmentation Check to reduce confusion with the new Geometry Check below As before the Segmentation Check is only run when opening a file and under a few other conditions and its results won t inhibit ca
108. angle results in counterclockwise rotation negative in clockwise rotation When elevation rotation is done the azimuth angle of the wire is unchanged A vertical or near vertical wire can t be rotated in elevation because the azimuth angle is undefined When azimuth rotation is done the elevation angle of the wire is unchanged The text abbreviation for these shortcuts are RE and RA for elevation and azimuth rotation respectively where is the angle to rotate in degrees Additional operations and more detailed information can be found in The Wires Window chapter in the Reference section Wire Loss Realistic wire loss can be included in the model In the vast majority of typical antennas wire loss doesn t cause enough difference to be of concern but it can be important particularly with electrically small antennas Currently only one type of metal or one amount of resistivity and permeability can be specified for the entire antenna model However only one part of the model or another typically dominates the loss and choosing its characteristic will produce good results If the metal is plated the plating material should be specified unless the plating is exceptionally thin or the frequency low EZNEC 55 EZNEC User Manual assumes that the specified material is at least several skin depths thick at the analysis frequency Copper clad steel wire consisting of a thick layer of copper over steel will have the loss characteristics of
109. antage of the Combine feature and the ability to rescale a model Rescaling of a whole model can most easily be done by changing the frequency with the Rescaling option selected Don t forget to save your description before you take each step in case a mistake is made A group modify error can be very time consuming to recover from if you haven t made a backup copy Always remember that wires must contact and connect only at their ends so you shouldn t cross wires in the grid or elsewhere 74 Building The Model Yagi Antennas The following remarks don t apply to EZNEC Pro 4 when using an NEC 4 calculating engine NEC 4 is relatively free of the NEC 2 problem with stepped wire diameters NEC 2 is used by all other program types so this information applies to them Yagi antennas with full size near half wavelength unloaded and untrapped elements can be accurately modeled with EZNEC When made from telescoping tubing or other materials where the element doesn t have a constant diameter over its whole length EZNEC corrects for NEC 2 s stepped wire diameter problem However correction is less certain for elements which aren t nearly a half wavelength long i e elements which contain loading coils or traps or which are linearly loaded As detailed in the Stepped Diameter Correction Overview topic advanced correction methods are applied to these cases but the accuracy depends on many factors which haven t been fully determined EZNEC ca
110. antenna characteristics very significantly For example example model BYDipole EZ shows an impedance of about 79 2 j45 1 ohms Replacing the wire with a catenary extending between the same end points but with a five foot sag results in an impedance of 97 9 j46 8 The amount of sag of a physical wire depends on a number of factors including the weight and flexibility of the wire the tension and the height difference between ends EZNEC requires you to specify the amount of sag in any one of five ways Use whichever is most convenient In the Create Catenary dialog there are two basic ways to define the wire to be represented by the catenary One way is to uncheck the Replace wire with catenary box and enter the catenary end coordinates diameter and number of segments one wire per segment in the boxes below Specify the amount 58 Building The Model of sag and click Ok The catenary will be created at the specified location and the added wires placed at the end of the wire list An easier way is to create a conventional straight wire before opening the Create Catenary dialog and give it the characteristics of the desired catenary diameter number of segments and if desired insulation Place a source or other insertion objects on it as needed Open the Create Catenary dialog check the Replace wire with catenary box and enter the number of the wire to be converted to a catenary When you click Ok the specified wire will be re
111. anual Specifying Y11 Y12 and Y22 The real and imaginary parts of each impedance are entered in the appropriate cells in the grid Y11 is the admittance looking into port 1 with port 2 short circuited Y22 the admittance looking into port 2 with port 1 short circuited and Y12 is the short circuit current at port 2 divided by the voltage at port 1 or the short circuit current at port 1 divided by the voltage at port 2 See Y Parameter Networks for additional information Selecting Adding Deleting Copying Modifying and Moving Y Parameter Networks See Using Insertion Objects Windows Modeling Ground About Ground Models Ground has a profound effect on the antenna pattern and sometimes on its efficiency and feedpoint impedance EZNEC provides several choices for modeling these effects The three basic ground types selected via the Control Center Information Window Ground Type line are Free Space Perfect and Real Free Space is no ground at all Perfect is a perfectly conducting ground plane which is completely flat and infinite in extent The Real ground type is further subdivided into several models discussed in Real Ground Types Real ground is also flat and infinite in extent and depth although one downward step from the flat surface is permitted see Using Two Ground Media When anything but Free Space is specified ground always begins at Z 0 and occupies everything below that Except for Free Space or EZNEC Pro 4 when
112. applied Beginning with EZNEC v 6 0 additional correction methods are applied when some of the above conditions aren t met Tests with several loaded Yagis have shown much better correction than the basic Leeson substitution and very much better than no correction at all However testing has been limited and there are undoubtedly configurations which won t be corrected well So be cautious in accepting the accuracy of any model having stepped diameters and which don t meet the criteria above A poorly corrected Yagi model will generally exhibit inaccurate front back ratio and to a lesser degree a shift in resonant frequency A bright notice will appear on the EZNEC screen during calculation when the stepped diameter correction is being used for one or more groups of wires You can see exactly what the substitutions are from the Wires Window by selecting Other Show Stepped Dia Correction See Using The Stepped Diameter Correction Display The correction can be disabled from the Options Menu if desired but this isn t recommended In situations where wires of different diameters are connected but EZNEC s stepped diameter correction doesn t apply a technique can be used to minimize the error This is to use the minimum number of segments possible that is make the segments as long as possible and do not use segment length tapering Exception wires very near ground See Elevated Radial Systems The accuracy of NEC 2 is worst in the presence
113. ard read as global Wire Loss and ignore additional LD5 cards The following three options are used for controlling Windows RAM use when running very large models See Controlling Memory Use for more information MaxAbsRAMUsedkK MaxAbsRAMUsedPct MaxQualRAMUsedPct MaxCMWidth where is an integer EZNEC Pro only EZNEC Pro saves Antenna Notes as CM cards in the NEC input file This sets the maximum width of these lines in number of characters OpenPF Plot File Format EZNEC saves 2D and 3D plot trace files using the OpenPF standard Files using this standard are commonly given the extension PF and EZNEC uses this for ordinary 2D plot files However plots generated by the frequency sweep are given extension P where represents the frequency step 3D plot files are given the extension PF3 All these conform to the following standard The standard is included here for those who want to develop compatible software or who have a need to directly read the data in these files 164 Reference Important Note Although the plot files written by EZNEC conform to the OpenPF standard and EZNEC is able to read some 2D plot files produced by users or other programs EZNEC isn t generally able to import or correctly read OpenPF files created by users or other programs OpenPF Plot File Standard Version 1 0 June 1 1995 The following standard was developed by Brian Beezley and Roy Lewallen as a common format for sharing da
114. ate Although any extension can be specified for the file name by first choosing All files in the Files of type window of the file name selection dialog box it s recommended that you let EZNEC add a txt extension by leaving Text files as the Files of type choice This cues Windows to the fact that the result is a plain ASCII text file Geometry Check This powerful feature which runs automatically before each calculation checks the model for errors such as wires crossing at other than a wire end or segment junction wires occupying the same space or overlapping or wires coming too close to each other Calculation isn t allowed to proceed if geometry errors are found Wire crossings and connection at segment junctions are permitted by NEC and although not generally recommended for EZNEC operation due to disconnection occurring when segmentation is changed no errors will occur if wires cross at a segment junction However NEC files created by external programs and imported into EZNEC Pro often contain segment junction connections By default the Geometry Check will show a warning if wires cross at segment junctions If you commonly use files originally intended for NEC use which contain wires crossing at segment junctions you can suppress these messages via the EZNEC Geometry Check selection in the Control Center Options menu There s also an option in the new Desc Options dialog opened by clicking Desc Options in the white pane
115. ate a 2D plot Then save it by opening the File menu 2D Plot Window then selecting Save Trace As Enter the name Cardioid TL ARRL Example and click Save You now have a pattern which can be used to verify that the following steps produce an equally good result The first thing we ll do is replace Wire 3 with a virtual segment Prior to EZNEC v 5 0 it was necessary to create a short wire any time you wanted to connect sources or transmission lines in parallel Virtual segments are now available to make this unnecessary The source and both transmission lines connect to Wire 3 so we need to change all three connections Close the 2D Plot Window to reduce clutter Open the Sources Window by clicking on the Sources line in the Control Center In the Specified Pos Wire column replace 3 with V3 and press lt Enter gt The source is now connected to Virtual Segment 3 The number 3 was chosen simply because it s the number of the wire it replaces Any number from 1 999 could have been chosen 33 EZNEC User Manual Close the Sources Window and open the Transmission Lines Window In the End 1 Specified Pos Wire column replace 3 with V3 in both rows then press lt Enter gt Close the Transmission Lines Window The source and transmission lines are now still connected together as before but on Virtual Segment 3 rather than Wire 3 Wire 3 is no longer needed so it can be deleted Open the Wires Window Select Wire 3 by clicking on the box at
116. ated by the installation process You need the file you downloaded Getting Started Getting Acquainted with EZNEC The fastest way to get acquainted with EZNEC is to take the Test Drive This leads you through some of the basic operations After the Test Drive you ll be ready to model simple antennas Then as you progress and want to learn more begin reading the Building The Model chapter For detailed information about a window or menu look in the Reference chapter And as you use EZNEC press the F1 key when you have a question about a particular menu control or display It s not possible to cover all menus controls and displays but many of the important ones or ones particularly needing explanation do have links If a link isn t present the manual will open to an introductory section The EZNEC manual might seem long and complex This isn t because EZNEC is hard to use or learn but because it has a rich set of features and every effort has been made to explain them as thoroughly as possible The combination of hyperlinks detailed index and comprehensive search capability make it easy to find information about any topic of interest I m sure you ll find EZNEC to be a valuable and educational tool Making a Desktop Shortcut When you install EZNEC on your machine you ll get the option of creating a desktop shortcut If you decline you can still make one manually at any later time Here s how to make a shortcut to EZNEC on
117. ated radial creation feature Above ground radials will show resonant effects more sharply than buried radials but will provide a reasonable approximation of a buried radial system The NEC Radial Model If you would like to use the NEC buried ground radial model please first read this section very carefully It deals only with the NEC ground radial model available in the Media Window Other menu not the Create Radials feature in the Wires Window or radials modeled as wires The NEC buried ground radial model is similar to the model used in ELNEC and MININEC It is not actually a model of buried wires and it does not model the effect of ground radials on antenna impedance current loss or efficiency H does approximately model the effect of ground radials on the pattern an effect which is generally slight unless ground radials are very long See Vertical Antennas And Buried Radials for more information The effect of the NEC buried ground radial model on feedpoint impedance is different than the effect of a real radial system on a real antenna The presence of any NEC radials at all even one very short radial will change the NEC calculated ground connection resistance to zero but only at the point x y z 0 0 0 Experiments have shown this to not always be true when using the NEC 2 engine and wires connecting to ground at a sloping angle The resistance of connections to ground at other points will have an unpredictable r
118. ation anyway Open the Wires Window by clicking on the Wires line in the Control Center In the Wires Window click the box to the left of wire 23 to highlight that line Scroll down to wire 55 with the scroll bar at left Then hold down the lt Shift gt key and click the box to the left of wire 55 Wires 23 through 55 should now be highlighted Confirm that you ve selected the right wires by looking at the View Antenna display and seeing that the directors have been highlighted Disregard cyan colored segments that s how EZNEC shows which is end 1 All or half of a wire can be this color if it has only one or two segments With the wires selected open the Wire menu in the Wires Window and select Scale Wires No wire range selection is shown because the wires have been selected before opening Scale Wires Let s increase the lengths of the elements by 10 so enter 1 10 for the Scale Factor We don t want to change the element spacing which is the separation in the X direction so uncheck the X box in the Axes frame This model is all at Z 0 so checking or unchecking the Z axis box will have no effect For an antenna above ground we d check it if we wanted to scale the antenna height and uncheck it if not Scale Center allows you to set the point from which scaling takes place That would be important if we needed a particular part of the model to stay put and the rest to expand or contract relative to that point We re scaling only in the Y direc
119. btracting the Average Gain in dB from them The procedure for using Average Gain to evaluate source placement is detailed in the Source Placement Precautions section To use Average Gain to assess wire or ground loss you should first confirm that the Average Gain is near unity when all loss has been removed from the model When lossy factors have been restored the Average Gain indicates the loss incurred by these factors so comparison of the loss and no loss Average Gains can be used to evaluate efficiency The Source Placement Precautions section details how to set losses to zero The message Model Contains Loss appears at the bottom of the Control Center adjacent to the Average Gain if loss is present in the model to alert you to the fact that the Average Gain should not be expected to be equal or nearly equal to one zero dB 116 Reference If it s not possible to reduce the Average Gain to nearly unity zero dB the gain can be corrected with fair accuracy by subtracting the Average Gain in dB from the reported field strength in dBi For example if the reported gain is 2 dBi and the Average Gain is 3 dB the actual gain is 2 3 1 dBi If there is only one source the feedpoint resistance can also be corrected by multiplying the reported feedpoint resistance by the plain numerical not dB Average Gain Unfortunately the reactance error isn t predictable so can t be corrected by this method and the feedpoint resistance correction w
120. can be added to the basic View Antenna display These objects can be turned on or off via the Objects selection in the View menu Following is a description of each choice you see when you make this selection All items are on shown when its corresponding box is checked Axes Selects the axes Currents Adds currents to the display Current magnitude is indicated by distance of the current indicator from the corresponding wire This is a very useful feature in determining which parts of the model are contributing to the pattern Currents aren t shown until a calculation has been done Current Phase Modifies the current display to show phase by rotating the current lines around the wires This is sometimes useful in conjunction with the Current Phase Markers particularly when looking at phased arrays but it often only obscures the current magnitude information Current Phase Markers Added markers which can be selected if Current Phase is on These markers show a sold line in the direction of zero phase and a dashed line in the direction of 90 degrees These help show the current phase when Current Phase is being shown Segment Dots Turns segment and wire junction dots on or off Wire Numbers These are very useful when building modifying and troubleshooting a model However with a complex unzoomed model they become an indistinguishable mass The setting of the wire numbers is remembered until you quit EZNEC The state o
121. ce where only one source is used is positive indication of operation of EZNEC beyond its capabilities Very small loops particularly ones containing a source are often the cause of this condition The SWR shown is the SWR which would be present on a transmission line connected in place of the source Values are given for 50 ohm and user specified feedline impedances The user specified impedance is selected with choice Alt SWR ZO the Control Center Information Window The SWR is directly calculated from the source impedance If a source is connected to a transmission line model and you want to know the SWR on the transmission line the SWR reference impedance must match the characteristic impedance of the transmission line Negative Input Resistance Occasionally a negative resistance might be shown at one or more sources If a single source is being used this is a positive indication of a numerical error since it represents an antenna which is producing rather than accepting power The most common cause is a source placed in a very small loop See 111 EZNEC User Manual Small Loops When multiple sources are used a negative input resistance can be a valid result This actually occurs in some arrays and represents an element which is delivering power back to the feed system It gets this power from the other elements via mutual coupling The 4Square example description illustrates this characteristic There s more information in the A
122. ces and slice types and moving the cursor You can move the cursor in the 2D display by clicking in the 2D plot window After clicking in the 2D plot window the cursor can also be moved with the arrow keys and lt Page Up gt and lt Page Down gt keys And when the 2D control box is being shown you can move the cursor with the appropriate scroll bar Various information about the 2D pattern is shown in the 2D display data box under the plot One entry on the right side is the gain given as dBmax This is the gain relative to the maximum value anywhere in the 3D pattern Open the View Antenna display by clicking the Control Center View Ant action button In the View Antenna display open the View menu and select Objects Check the 2D Pattern box and click Ok The 2D slice now appears on the View Antenna display This shows how the slice is oriented relative to the antenna Notice that as you change the selected slice with either the 2D or 3D controls the View Antenna display changes accordingly Also notice that as you rotate either the 3D or View Antenna display the other changes position to match They don t track moment to moment but synchronize when the mouse or keyboard key is released One last point to mention before leaving the 3D display You can save a 3D plot from this display File Save 3D Plot but you can t open one from the 3D 30 Test Drive display or superimpose 3D plots You can specify any azimuth or ele
123. cial considerations which need to be taken when modeling several common configurations Additional and more detailed information about the Wires Window and View Antenna display can be found in the Reference section Segmentation Each wire is divided into segments for analysis purposes The NEC calculating engine assumes that the current has an essentially sinusoidal shape over the length of a segment and that the currents of adjacent segments match at their junctions and some distance beyond This makes the problem one of finding a finite number of impedances currents and field strength contributions Some of the skill in modeling is in choosing the number of segments EZNEC will choose for you with its automatic segmentation feature if you wish but its choice will often not be best Although accuracy generally improves when more segments are specified computation time increases approximately as the square of the number of segments A useful rule of thumb is 10 segments per half wavelength for pattern gain analysis and perhaps twice that number if really accurate impedance values are required Wires joining at very acute angles may require more segments see Acute Angles If in doubt a straightforward way of telling whether you ve specified enough is to increase the number and see how much the results 48 Building The Model change You should also develop the habit of looking at the currents on the wires Abrupt current changes might
124. cond reason is that when an antenna is 31 EZNEC User Manual scaled the wire diameter isn t changed if it s specified as an AWG gauge The diameter of our antenna wire is specified as 12 so it wasn t changed with the scaling Exact scaling requires changing the wire diameter in the same proportion as the antenna length EZNEC doesn t do this when wire diameter is specified as a gauge because it would usually result in a diameter which doesn t correspond to any standard wire size Ground conductivity also doesn t scale linearly with frequency This will generally make a noticeable difference only with the patterns of vertically polarized antennas however You might want to feed the antenna with 75 ohm line instead of 50 ohm line An alternate ZO is available for analysis It s set in the Control Center information window as Alt SWR ZO Since we didn t change it its value is 75 ohms which was the value in the DIPOLE1 description we started with To see what the SWR would be on a 75 ohm feedline Select the Alt option in the SWR display control box ZO section 75 ohm feedline feeding this antenna would have a lower SWR than 50 ohm line However the SWR is low enough that it s unlikely to make any difference in performance unless the feedline is exceptionally long or lossy If analyzing an antenna with more than one source such as the example antenna 4Square you can select which source to view using the up down control in the SWR display
125. connected to the antenna I m going to put antenna in quotes from here on to emphasize that the end fed wire isn t the whole antenna Let s look first at a single wire connected directly to the hot terminal of a transmitter coaxial antenna connector The other ground terminal of the connector is its inside surface the current flowing on that inner surface has to equal the current on the center hot conductor Current from the hot terminal can only flow to the single wire antenna But the current from the ground terminal can flow from the inside of the connector over the edge to the outside and from there over the chassis If the chassis is completely isolated from the Earth and any large or long conductors the other half of the antenna will be the chassis itself Like the EZNEC model with a source a half segment from the end of a wire the transmitter will see a high impedance and there will be very little current flowing to the antenna In practice there will also be some capacitive coupling to the Earth and probably other nearby wiring which will increase the current somewhat If the chassis is coupling to other wiring that wiring is carrying antenna current and is a part of the actual antenna or radiating system If you connect a ground wire a wire to the Earth the mains ground system or just a long wire to nowhere to the transmitter chassis you ve provided another path for current from the transmitter ground t
126. control box This concludes On The Race Course and the Test Drive Now you ve taken EZNEC for a good run The Building The Model chapter gives tips for creating models and interpreting results The Reference chapter contains complete information about each menu and its features The Stacked Yagis section contains an additional step by step tutorial that illustrates additional EZNEC features You might want to go through it now or at a later time A Lap Around Track 5 is an additional tutorial covering the use of transformers L networks and virtual segments However it s recommended that you get more familiar with basic EZNEC operation before going through it A Lap Around Track 5 This section of the Test Drive tutorial will acquaint you with using the transformer and L network insertion objects and virtual segments These features were introduced in EZNEC v 5 0 It s assumed that you re already familiar with basic EZNEC operation The examples involve modeling L network type feed systems for phased arrays The design of the feed systems of the two examples used here are described in Chapter 8 of the 21st Edition of the ARRL Antenna Book which became available at just about the same time as EZNEC v 5 0 The first example is a two element cardioid array fed with an L network feed system 32 Test Drive Leading Lagging element element Wire 1 Wire 2 Of course transmission lines TL1 and TL2 each have two conductors an
127. copper so that metal should be specified If you re not sure whether a plating is several skin depths thick run a calculation with the resistivity of the plating metal then with the underlying metal The actual antenna performance will be somewhere between these limits In some special circumstances it can theoretically be a bit outside the limits but not enough to be likely to alter any conclusions about antenna performance Wire loss is specified by clicking the Wire Loss line in the Control Center Information Window This opens a dialog box which allows you to choose from a number of common metals or enter the resistivity and permeability Please note The value used by EZNEC is the bulk resistivity of the metal not the DC or RF resistance per unit length of the wire The bulk resistivity doesn t change with wire diameter it s a function only of the metal of the wire or the outer layer of the wire if plated assuming as EZNEC does that the outer layer is at least several skin depths thick EZNEC calculates the skin depth from the bulk resistivity and frequency and uses that and the diameter of the wire to determine how much resistance each wire has If you know the resistance per unit length of a solid non plated or layered wire you can calculate the bulk resistivity of the metal from Rp H A where R is the bulk resistivity in ohm meters R is the wire s resistivity in ohms per meter length and A is the cross sectional diameter of
128. create and modify even very complex models without having to enter hardly any wire end coordinates The Wires Window is opened by clicking on the Wires line in the Control Center Information Window Open the Wires Window by clicking on the Control Center Wires line or the button to its left 49 EZNEC User Manual Wires are defined by specifying their end coordinates in the appropriate grid cells However several structures such as loops and helices can be created without specifying any end coordinates Also wires and groups of wires can be easily modified and copied so you can almost always begin with very simple geometries and then modify the wires to reflect the actual design Several wire modifications can be made graphically in the View Antenna Display See Graphical Wire Operations for information Menus and selections in the following paragraphs refer to the Wires Window Unless otherwise noted a sequence like Wire Add refers to first the menu then the selection s For example Wire Add means the Add selection in the Wires menu in the Wires Window Adding Wires To add any number of wires select Wire Add Enter the number of wires in the upper box If the lower box is left unchanged the new wire s will be added below the existing wires If desired you can specify other locations for the new wire s by entering the position in the lower box To add a single wire you can also simply type the coordinates diameter and number
129. creation form are self explanatory In the Turns Spacing Length frame you must choose any two measures for the length the third will be calculated and entered automatically If you check the Extend ends to helix axis an extra wire will be created on each end of the helix extending to the helix axis Turn spacing should be at least two wire diameters and ideally several wire diameters A few experiments making use of the Undo feature will quickly get you acquainted with the various features EZNEC Pro only If the Make Spiral box is checked diameters of the two ends can be separately specified and a linearly varying spiral will be created A flat spiral will result if length is zero and one end diameter is zero Loop Creation To create a loop open the Create menu in the Wires Window and select Loop Although the dialog box might appear complex it s actually quite simple to use Most items are self explanatory The wire diameter can be entered either as a value or as a wire gauge just like wires in the main wire entry grid In the Loop Size frame you can define the loop size in any one of three ways by circumference side length or the approximate diameter the diameter of the circumscribed circle As you enter a value the remaining two 59 EZNEC User Manual are calculated for you You can position the loop anywhere and can orient it with its axis in any of the three principal directions Loop Resizing You can use the loop
130. crement This field defines the sign and magnitude of the angular difference between successive data points Data Points The data set begins at the first angle The angles of successive data samples differ by the angular increment Title Environment and Notes Strings When string length is nonzero the string overrides the corresponding header string for this block When zero the header string applies for this block and no string space is allocated Absolute Near and Far Field Blocks Block type byte 64 81 amp 96 101 Block length word Title length byte Environment length byte Notes length word Frequency FP Power FP 168 Reference Coordinate system byte Symmetry byte Number of A points word First A FP A increment FP Number of B points word First B FP B increment FP Number of C points word First C FP C increment FP Data points each FP Title ASCII Environment ASCII Notes ASCII Block types 64 81 contain absolute fields Block types 67 81 are field components resolved in rectangular coordinates These blocks are defined as follows Block Data Units 64 Power density watts square meter 65 Peak E magnitude volts meter 66 Peak H magnitude amps meter 67 Px Poynting vector watts square meter 68 Py Poynting vector watts square meter 69 Pz Poynting vector watts square meter 70 Ex magnitude volts meter 71 Ey magnitude volts meter 72 Ez magnitude volts meter 73 Hx magnitude amps meter 74 Hy magnit
131. cted However these connections won t be recognized by the interface portion of EZNEC so errors can easily be made Also any change in wire length orientation or number of segments will break the connections Therefore attempting to make connections at segment junctions other than wire ends is strongly discouraged As an example modeling an X shaped structure with the recommended restrictions requires four wires if the cross members are connected at the center of the X Modeling the following wire grid 15 14 13 requires 24 wires Each side of each square is a separate wire A common problem involves wire spacing When wires are to be close but not connected users frequently space them very close sometimes a fraction of 47 EZNEC User Manual an inch or centimeter when the wavelength is tens of meters This isn t good practice and can lead to numerical problems It s difficult for any program to deal with wires which are 40 meters long but spaced 0001 meter apart Always use realistic spacing If you re analyzing a 3 MHz antenna you probably can space wires six inches 15 cm without materially affecting the antenna operation If you can do so If you can t make sure the results aren t unduly sensitive to the spacing or number of segments If they are numerical problems might be occurring More information about closely spaced wires and wires intersecting at an acute angle is given in the sections below Wires are di
132. d Az Ang rows above for explanations of the spherical coordinates Total Steps This shows the total number of locations at which the field will be calculated You can update this window by pressing lt Enter gt when the cursor is in any of the position entry boxes Writing IONCAP VOACAP Files EZNEC EZNEC Pro only EZNEC and EZNEC Pro can write type 13 input files for IONCAP VOACAP and related programs This file contains field strength data for each degree of azimuth and elevation in a defined format The files generated by EZNEC are directly readable by IONCAP type programs To generate an IONCAP VOACAFP file first you must have a model with some type of ground specified this feature isn t available with free space models In the Control Center set the Plot Type to 3 Dimensional and the Step Size to 1 degree Then calculate a 3D far field pattern by clicking FF Plot or FF Tab After the calculation is finished there are three places where you can initiate the file writing action If you chose the plot option open the File menu in the 3D Plot Window and select Write IONCAP VOACAP File If you chose the table option you can click the Write IONCAP VOACAP File button at the lower left of the formatting dialog box which opens when the calculation is complete or you can choose a format and use the option to write the IONCAP VOACAP file in the File menu of the tabular data display After clicking any of these you ll be prompted for
133. d and modified via the Loads Window Operation varies some with the load type chosen and detailed information about specifying each type of load is given in Using the Loads Window chapter Load placement is identical to placement of sources as explained in Placing Sources On Segments 86 Building The Model In critical applications the same restrictions should be applied to loads as to sources regarding placement See Source Placement Precautions don t know of any way to assess load placement problems with the Average Gain feature as is done with sources so the only way to spot problems is to modify placement and observe how much the result changes Like all other insertion objects EZNEC loads do not radiate except that the segment the load is placed on does radiate like any other segment Series connected loads are shown in the View Antenna display as empty hollow squares Parallel connected loads are shown as empty hollow diamonds Load Types Three different load types are available R jX resistance and reactance RLC and Laplace Each has its advantages as outlined below Note that all loads in a model must be the same type so a compromise sometimes has to be made in choosing which type to use R jX This load type is the fastest and simplest to use You just specify the resistance and reactance Because the impedance of an R jX load doesn t change with frequency while a real load if it contains reactive compone
134. d by an open circuit by entering 0 the number zero O the letter O or Open as the value or by leaving the grid cell empty Note that there is no way to specify a zero resistance or inductance short circuit in a Parallel type RLC load an entry of zero will be interpreted as an open circuit The parallel model is frequently used for relatively high impedance loads where dielectric loss often dominates Consequently the frequency dependence of R is that of typical dielectrics that is it decreases in inverse proportion to frequency See R Freq Column below Trap Configuration RLC Loads This load type can be used to represent objects other than traps For example it can be used to model an inductor accounting for the frequency dependent conductor resistance and shunt capacitance It was called a Trap type simply because this is one of the common applications The Trap type RLC load consists of a resistance R and inductance L in series The series combination is in parallel with a capacitance The series RL circuit is a reasonable model of a real inductor and the shunt capacitance can represent stray inductor capacitance a physical capacitor or a combination of the two The frequency dependence of R is the same as for the Series type RLC load In this load type entry of zero for R or L results in that element being replaced with a short circuit Entry of zero for C results in replacement with an open circuit As for the other RLC lo
135. d evenly spaced Make it a habit to look for these symmetries and you ll spot problems before bad results lead you astray Another thing to look for is abrupt and unexplained current changes instead of a smooth change from one segment to the next This usually is due to not having enough segments but might be due to some other factor causing EZNEC to be operating beyond its limits Sudden current reversals may be no cause for concern as they might be due to the way the wires have been defined Positive current flow always is defined as being from end 1 to end 2 so if two end 1 s or two end 2 s are connected together a 180 degree shift in current direction will be indicated at the junction of the wires provided View Antenna phase information is on or you re looking at the currents in tabular form The current actually is continuous as it should be but the definition of direction changes from one wire to the other There s nothing wrong with connecting wires in this fashion but don t be confused by the currents EZNEC shows as a result Watch for this also when using multiple sources see Using Multiple Sources Current phase information can be included on the View Antenna display but it frequently conceals important information about what s happening to the magnitude of the currents See The View Antenna Display for more information about this feature The importance of currents is underscored by the fact that the field generated by a wire is pr
136. d in series with the coax wire the wire simulating the outside of the coax at the point where a balun would be placed A good balun will have an impedance of the order of 500 1000 ohms and may be resistive reactive or a combination depending on construction Accurate modeling requires knowledge of the balun impedance at the frequency of interest The balun reduces the current in the coax wire which means that the current on the outside of the actual coax feedline is reduced It sometimes is necessary to insert more than one balun quarter wavelength spacing is typical to reduce feedline outside current to a low level Coaxial feedlines connected to unbalanced antennas like ground plane antennas aren t immune to induction of current either as you can confirm with EZNEC Linear Loaded Antennas EZNEC Pro 4 gives accurate results for these antennas when using the NEC 4 calculating engines so the following doesn t apply to EZNEC Pro 4 with an NEC 4 engine Linear loaded antennas generally Yagis are physically shortened by attaching to the elements wires which are parallel to and spaced close to the elements EZNEC will not give accurate results for this type of antenna unless all the wires of a given element are the same diameter This is due to NEC 2 s inaccuracies when dealing with connected wires of different diameters and the fact that even small parasitic element errors have a major effect on the 70 Building The Model
137. d only if Inches is chosen for diameter units The 100 ft or 100 m figure refers to the physical length of the transmission line If the alternate specification is desired the Units can be temporarily changed the loss entry made then the Units changed back A second option is the loss frequency entered in the Loss Freq column This value is used as follows If the Loss Freq 0 the specified loss in dB 100 ft or dB 100 m will be applied at all frequencies If the Loss Freq is any other value the specified loss will be applied to the transmission line at the specified frequency At other frequencies dB loss proportional to the square root of the frequency will by applied For example if the loss is specified as 1 0 dB 100 m and the loss frequency is specified as 10 MHz the line loss used by EZNEC will be 1 0 dB 100 m at 10 MHz 1 414 dB 100 m at 20 MHz 2 0 dB at 40 MHz 0 707 dB 100 m at 5 MHz and so forth This is evaluated each time a calculation is made including at each frequency of a frequency sweep calculation Important Notes The loss of real cables particularly coaxial cables is determined by many factors Besides the obvious conductor and dielectric losses conductor plating braided shield roughness roughness of a stranded center conductor and other effects can contribute noticeably to the total loss These vary in 95 EZNEC User Manual complex ways with frequency So a single loss specification is less than
138. d the models have two sets of two terminals just like the L network object Net The second conductor is omitted from the diagram for simplicity The ARRL Antenna Book example design shows that the value of the series inductor in the L network needs to be 1 815 uH and the shunt capacitor 199 7 pF to achieve the correct element current ratios with transmission lines TL1 and TL2 being quarter wavelength 75 ohm lines With an EZNEC model you ll be able to not only verify that the design is correct but also to check the pattern and impedance over a range of frequencies We ll begin with a model of a two element array using the simplest feed system a feed system using only two transmission lines whose lengths are calculated with a special program for the purpose It looks just like the diagram above except that there s no L network and TL1 and TL2 have particular unequal lengths The chief advantage of the L network feed over the simplest system is its adjustability In the Control Center locate the Open action button and click it This will open a file selection dialog box Select Cardioid TL ARRL Example ez The bar at the top of the Control Center information window should now read Cardioid with feed system Open the View Antenna display where you can see that the two transmission lines are connected from the two elements to a short connection wire Wire 3 The source is also connected at that wire Click the FF Plot Action Button to gener
139. diameters of the of the elements close to the boom Methods for determining the amount of correction can be found in Leeson Physical Design of Yagi Antennas ARRL 1992 The book also covers corrections for various types of clamps Information about modeling stacked Yagis can be found in the Stacked Yaqis section Insertion Objects About Insertion Objects networks and EZNEC Pro only Y parameter networks These are objects which are inserted into wires or virtual segments All insertion objects have some important common properties which are 1 Insertion objects have one or two ports often referred to as the ends of transmission line objects Sources loads and transmission line 75 EZNEC User Manual stubs have a single port which is inserted into a wire or except for series connected loads a virtual segment The others have two ports which must be connected to two separate real or virtual segments The two ports of the transformer object correspond to the two windings of an L network the input and output and the ends of a transmission line object Each port has two terminals 2 An insertion object effectively cuts the wire into which it s inserted placing itself or its port in the wire The current into one terminal of a port always exactly equals the current out of the other terminal of the same port therefore insertion objects do not radiate or electromagnetically couple to wires or other objects 3 When multi
140. ditional line of data appears in the right column of the Data Window showing the gain of that trace relative to the primary calculated trace at the cursor s angle This makes quantitative pattern comparisons simple Data Window The Data Window shows useful information about the 2D plot maximum gain front back or front side ratio 3 dB beamwidth and other parameters The items on the right side of the window show the values at the cursor so change as the cursor is moved The cursor is moved by clicking anywhere on the Plot Window and the plot cursor will move to a point on the direct line between the placed clicked and the center of the plot graph You can drag the cursor around the plot by holding the mouse button down as you move the mouse The mouse has to be on the Plot Window when initially clicked but can leave the window afterward if the button is held down The cursor is always present when the Data Window is open and never present when it s closed The up and down keyboard arrow keys can be used to move the cursor in small steps and the lt PageUp gt and lt PageDown gt keys to move it in larger steps It s first necessary for the Plot Window to have the focus It can be given focus by clicking anywhere on it with the mouse The Data Lines show the angles at which EZNEC has determined the maximum forward gain 3dB points and sidelobe occur The sidelobe is the lobe with second highest gain Data Lines can be turned on and off
141. ductor is truly open circuited But if you connected your ground wire to the hot terminal with the antenna on the ground terminal you d get essentially the same results as with the two reversed assuming no other current paths from the chassis Finally let s consider the common end fed or Zepp antenna One conductor of a feed line is connected to the antenna and the other is left unconnected Wire 1 is the antenna and wires 2 and 3 are the feed line The source is at the bottom of the feed line connected between wires 1 and 2 Although there is no current at the top of wire 2 the left feed line wire there is current at the bottom And in fact it s equal in magnitude and opposite in phase to the current at the bottom of wire 3 This will always be the case for wires connected to the two terminals of a source The source isn t connected to an open circuit as it would be if placed at the end of the antenna wire 69 EZNEC User Manual The current at the end of the antenna is not zero and it s equal and opposite to the common mode current flowing on wires 2 and 3 Common mode current is the difference between the two individual conductor currents and it results in radiation just as though there were a single current of that value flowing on a single conductor That is the feed line radiates just as the antenna does That s why the two terms have been placed in quotation marks In this case the length of the feed lin
142. e is about the same as the length of the antenna and the feed line common mode current is about the same as the antenna current so the feed line radiates about as much as the antenna So both the feed line and antenna have to be included in the model in order for either the impedance or the pattern to be correct In a real installation there will also be some path from the source the transmitter to the Earth or at least some additional connected conductors If so the common mode current from the feed line will travel along these conductors and they will radiate also and must be included in the model Feedlines and Baluns The radiation properties of a coaxial feedline can be modeled by connecting a wire of the coax shield s diameter to the point on the antenna where the shield connects The wire is then routed using additional wires to simulate bends to ground along the path taken by the actual feedline The ground path from the transmitter receiver should be included with wires of appropriate size This can be done whether or not an EZNEC transmission line model is used to model the inside of the feedline See the Using Transmission Lines chapter for more information about using transmission line models The Modeling Coaxial Cable topic also has additional information The job of a current balun or choke balun is to insert an impedance in the path formed by the outside of the shield To model a balun insert a loa
143. e sources which must be added from within EZNEC Example file for EZNEC wire importing four square array ONLY FOR REGIONS WITH COMMA DECIMAL SEPARATOR NOTE that wire import files don t contain sources or information other than wires To actually make a 4 square array with the information from this file requires specification of sources frequency ground type etc The first non comment line is the units specifier This will cause Program UNITS to be changed to METERS Wire coordinates to be interpreted as being in meters Wire diameter to be interpreted as being in millimeters mmm Next are the wire specifiers Only spaces or tabs are used in this example 172 Reference as delimiters to separate fields Commas are not allowed as field delimiters in regions where a comma is used as the decimal separator As this file is written these wires will be automatically segmented using conservative density If desired an additional field could be added to any line to cause minimum recommended density or a specific number of segments The first three numbers are the end 1 coordinates in meters because of the first unit specifier above The next three are the end 2 coordinates meters The seventh number is the diameter in mm because of the second unit specifier 00000 9 9822 38 1 0 10 4912 0 0 10 4912 9 9822 38 1 10 4912 00 10 4912 0 9 9822 38 1 10 4912 10 4912 0 10 4912
144. e 2D display in the direction of the Y axis 124 Reference 2 Zero degree data in the plot always represent the gain in the direction of the pattern maximum defined by EZNEC as the azimuth direction at which the pattern gain is at its highest for all azimuth and elevation angles 3 EZNEC will prompt you for a choice between the above two whenever the pattern maximum is not at zero degrees azimuth Increasing angles in the file represent field strength at increasing compass bearings i e in a clockwise direction regardless of the zero angle choice You make your choice in the Control Center Options menu IONCAP VOACAP Zero Angle choice Be sure to open the Options menu again and choose Save As Default if you want the choice to persist after the current EZNEC session Rescaling An antenna can easily be rescaled for a new frequency by clicking the Frequency line or button in the Control Center Information Window then checking the Rescale box The items which will be rescaled are wire end coordinates wire diameter if not specified as wire gauge wire insulation diameter second medium height second medium boundary ground wave distance and observation height EZNEC Pro only and transmission line lengths if not specified in degrees Transmission line ZO isn t modified even if it was initially entered as wire diameter and spacing The above items will be modified even if Wavelengths is the chosen unit of measure Note that resu
145. e Preserve Connections box in the View Antenna display which appears when moving wires is not linked to the Wires Window Preserve Connections box each affects only operations in its own window A number of other features are described in the Features chapter of the Reference section Tip Turn on the View Antenna display when entering or modifying values in the Wires Window This allows you to immediately see the changes you ve made Graphical Wire Operations Several modifications can be made to a model directly in the View Antenna Display All changes made in the View Antenna Display can be undone like all other model modifications Selecting Wires To select a single wire double click it To select additional wires hold down the lt Ctrl gt key and click This will also deselect a previously selected wire Wires selected in the View Antenna Display are also selected in the Wires Window where various operations can be performed on them The selected wires can also be deleted in the View Antenna Display as described below Delete Wires To delete wires select as described above then press the lt Delete gt key on your keyboard Add Connecting Wires This feature allows you to add a wire between any two existing wire ends In the Mouse Operation frame at the left of the View Antenna Display select Add Conn Wires The New Wires frame opens below to allow you to choose the diameter and number of segments of the new wire If Copy Conn Wi
146. e SE ce 144 Azimuth Ange 138 Azimuth Rotate End 54 B Back Yard Dipole ssseeseeenneeee 20 Backup CGopies 160 Balti NEEN 70 96 bmp d E 144 BUQS bins duhsiehsicheexhdehsiebechees 8 181 Heportmng e 8 181 Buried Radials 000 65 73 Buried Wires a 65 107 DButtontonthame 162 ButtonFontSize 0 162 BvVeeez E 85 C CalcProgReduction 162 Calculating Engine 132 CHOOSING EE 132 Calculating Engine Type 159 Calculation Progress 159 Calculation Time 8 138 155 Catena e E 58 Creating senai iiiter 58 Center of wire x end segment within wire xy 120 Change Coordinate By 54 Change Height Dy 49 EZNEC User Manual Change Length Dy 54 Change Length To 54 Change WINS ois geieeteegetgedegeeteerteg 49 Retain Numbers 000000000aaaa 49 Changing Folder Locations 132 Characteristic Impedance 93 Transmission Ime 93 Circular Polarization 11 112 138 Circeumierence 72 Loop MINIMUM WE 72 Closely Spaced Wies 65 Ee 115 162 Coaxial Cable cgi iaei tec dieticeclasctcl 96 MOGGIING DE 96 COlOIS iesiicisd slain 142 Selecting eegene 142 Combining Antenna Descriptions Ee 117 131 Comma delimited files 6 Command Lime 17 Common Features 0000000000000 142 Compass Bearing eeeeeeeen 132 Compatibility among versions 18 Component Version Numbers 138 CONGUCUVITY EE 106 Connect End To 54 Co
147. e a red line to the proposed new connection point and the process is finished by right clicking If the Preserve Connections box is checked all wire ends connected to the selected end are moved In this example moving the left end of wire 5 would result in overlapping wires so Preserve Connections should be unchecked Remember though that you can easily undo any change Select Normal Viewing in the Mouse Operation frame to restore mouse operation to normal Now for a brief look at the new wire scaling enhancements Open example file 20m5elYa EZ and open the View Antenna display Suppose we want to try increasing the lengths of the three directors elements with positive X coordinates without changing the element spacing But we want to change all the various diameter sections in the same proportion not just the end sections The first thing we have to do is select the wires for scaling In the View Antenna display zoom the display by moving the mouse with both keys held 43 EZNEC User Manual down and move the display by moving the mouse with the right key down until you can easily see the wires of the two directors You should see that the directors consist of wires 23 through 55 When fewer wires need to be modified it s convenient to select them directly in the View Antenna display see Using The View Antenna Display for details For this project it s easier to use the Wires Window and we ll have to use it for the scaling oper
148. e antenna conductors by the incident field Reported values don t include the incident field from the plane wave source The dBsw notation you ll see in the 2D Plot Window data box and in the Far Field Table means GB relative to one square wavelength scattering cross section for an object in free space An object in free space having a scattering cross section of one square wavelength in a given direction will produce a field of 0 dBsw and objects with greater and lesser Cross sections will produce correspondingly greater or lesser fields Caution This isn t true when over a ground plane See Plane Wave Excitation With a Ground Plane regarding use of plane wave excitation and a ground plane Because the scattering cross section is an area the dB is calculated using the same rule as for power e g approximately 3 dBsw will result from a scattering cross section of two square wavelengths in free space If you re familiar with NEC 2 or 4 the values reported as dBsw by EZNEC Pro are the same as those shown as GB or dBi by NEC when plane wave excitation is used Be sure to remember though that the plane wave amplitude is peak value in NEC and RMS in EZNEC Pro Note that the polarization of the scattered field is often different from that of 82 Building The Model the incident wave The polarization of the incident wave is that of the plane wave source when in free space but not necessarily so over a ground plane The choice of polarization
149. e can t be used as the prototype More complex radial structures can be made by specifying a group of wires as the prototype radial to be copied A prototype group of wires has to be sequentially numbered that is you can t use wires 1 2 and 4 as the prototype group for example and must be connected end 1 to end 2 This group of wires will then be duplicated centered around end 1 of the first wire in the prototype group The first wire in the group can t be vertical since this would result in the first wire of the copies all occupying the same space Radial wire structures in orientations other than the horizontal plane can be made by first creating the radials then using the Rotate Wire feature to rotate the structure to the desired orientation Wire Grid Creation The automated wire grid creation feature is available only in EZNEC Pro programs EZNEC Pro 2 and EZNEC Pro 4 For information about manually creating wire grid structures see Wire Grid Modeling This feature also allows creating a closed wire grid box A wire grid is a good way to simulate a flat solid conductive surface such as a metal roof or car top or an enclosed box A wire grid looks like a screen with each side of each screen hole made from a wire See the diagram in the About Wires section In general the best implementation is for each side of each hole to be a single one segment wire Although wire grid modeling is an art in itself a few general rules have evo
150. e change is significant segment alignment is important In all cases wire spacing should be at least several wire diameters Crossed Dipoles To model two dipoles fed at a common point sometimes called crossed dipoles see figure below feed by inserting a wire between the pairs of dipole halves and place the source on the wire The wire length should be a minimum of 0 02 wavelength and have three segments See Source Placement Precautions EZNEC Elevated Radial Systems A number of people have showed an interest in modeling systems of radial wires placed at very low heights above ground A system of very low wires can be used to simulate the performance of buried radials Experiments were done comparing various modeling codes resulting in the following guidelines 66 Building The Model 1 The minimum recommended height for modeling ground radial systems is 0 0001 wavelength or the diameter of the vertical wire whichever is greater 2 No special techniques are required if the radials are at a height of at least 0 001 wavelength and at least the diameter of the vertical wire Ordinary segmentation can be used Even stepped diameters don t require special attention with the NEC 2 engine in this situation This height is recommended for simulating buried radials with NEC 2 or radials placed on the surface of the ground 3 If the radials are between 0 001 and 0 0001 wavelength high seqment length tapering should be used
151. e remainder of the applied power is lost as heat in lossy parts of the antenna structure System efficiency can also include the effect of ground feedline and matching network loss EZNEC allows you to set all losses to zero resulting in a 100 efficient antenna or antenna system You can determine efficiency by comparing the gain from this perfect system with one having realistic losses To set losses to zero and create a 100 efficient lossless antenna 1 In the Control Center set the Wire Loss to Zero 2 EZNEC Pro only In the Wires Window set any insulation loss to zero 3 If the antenna contains any loads L networks or EZNEC Pro only Y parameter networks set their resistances to zero or delete them 4 lf there are any transmission lines in the antenna set the line loss to zero If any kind of Real ground is specified and you want to include the ground loss in the efficiency calculation change the Ground Type to Perfect If you want to include feedline and matching network losses in the efficiency calculation do steps 3 and 4 above for feedlines and matching network components as well as for antenna components If there are only a few items to change it s easiest to switch between the lossy and lossless models by using the Undo Redo feature Otherwise it might be easier to save the different configurations with different file names If the pattern of the antenna with loss is nearly the same as the pattern of the lossless ante
152. e text abbreviation for this shortcut is to increase or to decrease the coordinate by For example to decrease the Wire 4 End 2 y coordinate by 3 you can enter 3 in the appropriate cell Change Length By This shortcut changes the length of a wire by the specified amount The current end is modified while the other end is fixed Wire direction is unchanged The text abbreviation for this shortcut is L to increase the length by or L to decrease it by The length of a zero length wire can t be changed because the direction isn t defined Change Length To Use this shortcut to make the wire a particular length without changing the wire direction The current end is modified and the other end is fixed The text abbreviation for this shortcut is L to change the length to The length of a zero length wire can t be changed because the wire direction isn t defined Multiply Length By Divide Length By These function like Change Length By above except they multiply or divide the length by the specified amount rather than adding or subtracting a fixed amount The text abbreviation for this shortcut is L to multiply and L to divide Elevation Rotate End Azimuth Rotate End This shortcut rotates the current end of the wire leaving the length and other end fixed The rotation amount is specified in degrees For elevation rotation a positive angle causes rotation upward negative downward For azimuth rotation a positive
153. e that the Preserve Connections box is independent of the Preserve Connections box in the Wires Window Each affects operations only in its own window Wire Coordinate Shortcuts EZNEC includes many features to help you modify wires without having to determine coordinates For example you can easily change the length of a wire or rotate it about one end Shortcuts can be applied to either individual wires or in Group Edit mode to groups of wires Wire coordinate shortcuts can be applied in two ways both in the Wires Window One is to right click any coordinate cell in the Wires Window grid The other is to enter a special shortcut abbreviation for the desired action into a coordinate cell Shortcut text abbreviations aren t case sensitive Each of the selections below appears in the popup menu you get if you right click one of the coordinate cells For example to use the first method to change the coordinates of wire 4 end 1 so that it connects to wire 3 end 2 you right click the X Y or Z column in the End 1 group of the Wire 4 row This opens the shortcut popup menu Select Connect End To In the dialog box enter 3 in the Wire to connect to box and 2 in the End to connect to box then click Ok or press lt Enter gt To use the second method enter W3E2 in the X Y or Z column in the End 1 group of the Wire 4 row then press lt Enter gt or move the mouse cursor to another cell Unless otherwise noted the shortcut is applied only to t
154. e the wire the length we want Assuming our back yard dipole was designed using 468 f MHz to determine the length the length is 33 43 feet EZNEC doesn t require any symmetry and we re free to choose where in space we put the origin except that it has to be at z 0 if a ground is used so for convenience we ll put one end of the wire at x y 0 0 and the other at x y 0 33 43 Placing it along the y axis makes the maximum lobes in the direction of the x axis Ground is always defined as being at z 0 for the innermost medium Since the antenna is horizontal and up 30 feet the z coordinate of both ends is 30 To enter the coordinates Click on the Wires Window cell for Wire No 1 End 1 Y where the current value is 0 82 and change the value to 0 Notice that the mark on the button at the left has changed to a pencil This indicates that the row wire has been edited Note also that the number you ve entered is shown in red This indicates an edited value The edited value won t be accepted by EZNEC until you click on another row of the grid move the insertion point off the row with the lt Tab gt or arrow keys or press lt Enter gt You can undo an edited value but only before it has been accepted by pressing lt Esc gt Pressing lt Esc gt again will undo all edited values in the row Move to the next cell End 1 Z with the mouse or lt Tab gt key and enter 30 The coordinates of End 1 are now 0 0 30 Simila
155. early parallel wires which are closely spaced it can be very important to align the segment junctions That is they should be directly across from each other This is particularly true if the segment length is greater than the line spacing As the segment length gets shorter compared to the wire spacing this requirement becomes less important When segment junctions are misaligned but need to be aligned results can change dramatically as segmentation is changed The easiest way to assure that aligned parallel wires have aligned segment junctions is to give the wires identical lengths and numbers of segments If the wires are staggered or different lengths break them into more wires Make the portions of the wires which are directly across from each other into separate wires of equal length and number of segments An example of this technique is shown below where the long wire of a J pole antenna was broken into two wires Wire 4 is made the same length and given the same number of segments as parallel wire 6 The upper wire is segmented to make its segment length approximately equal to the segment length on wire 4 This is a close up view some of the long wire and its number aren t shown 65 EZNEC User Manual EZNEC If it s necessary to test whether alignment is necessary in a particular situation change the segmentation of one of the wires so that the segment junction alignment changes and note the change in results If th
156. econd medium is defined on both cards the last card read will dominate A radial ground screen will be ignored if only one medium is defined if two are defined and the boundary is radial the ground screen perimeter will be set equal to the boundary between the media Please see additional GD GN RP comments below GE The l1 specification will be ignored EZNEC Pro automatically sets the equivalent value to 0 when no ground plane is present 1 if a ground plane is present and no wires extend below the ground and 1 if any wires do extend below a ground plane Calculation for the latter case will be permitted only if EZNEC Pro 4 is being used with an NEC 4 calculating engine and Real High Accuracy ground has been selected GH Although not documented in the NEC 2 manual some versions of NEC 2 include GH but with a different parameter format than NEC 4 EZNEC Pro automatically determines which format is being used and places a message in the translation information window Parameters causing tapered turn spacing or wire diameter are ignored except the sign see the following information only constant spacing constant wire diameter helices are created In some NEC 2 implementations the length parameter is positive for a right hand helix negative for a left hand helix In others the sign of the turn spacing parameter determines the handedness So If either parameter is negative a left hand helix is constructed otherwise the helix is
157. ectively Split Wires Feature New feature splits a wire into multiple wires See Using The Wires Window Wire Scaling Enhancements You can now restrict scaling to one or two axes and choose the point about which the scaling takes place Described in Using The Wires Window Insertion Object Placement Check Inaccurate sometimes highly inaccurate results can sometimes occur if insertion objects are incorrectly placed The segmentation check now gives warnings if the recommended placement guidelines are violated See Placing Insertion Objects on Seqments Segmentation Check Option You can now suppress warnings of Conservative level segmentation guideline warnings via the Control Center Options menu Segmentation Check selection Discontinued Features External Smith chart programs View Antenna display data window EZNEC Pro 4 only External NEC 4 calculating engine EZNEC Demo Only EZNEC ARRL Capability 500 segment capability with specially signed files from the ARRL Antenna Book CD See EZNEC ARRL EZNEC Only More Segments EZNEC now allows a maximum of 2000 segments EZNEC and EZNEC Pro Only Catenary Creation Automatically creates a catenary wire Optionally replaces an existing straight wire with a catenary This realistically represents the sag in a real wire which can have a significant effect on impedance Touchstone sip Format Files In addition to LastZ txt EZNEC and EZNEC Pro now ge
158. ed waves do not and are affected most when reflecting at a low angle The net effect is that the pattern of a vertically polarized antenna is profoundly modified by the ground reflection With real ground there is very significant loss of the low angle field This can be illustrated by running the Vert ez example model saving the 2D trace of the elevation pattern changing the ground type to Perfect and running again Adding the previously saved trace to the one created with Perfect ground shows this effect graphically Note that Verti uses the MININEC type ground model which includes no conductive loss the first effect described above only the ground reflection effects The ground reflections which cause the low angle pattern reflections take place farther from the antenna than most common radial ground systems extend so ground radial systems have little or no _effect_on the ground reflection phenomenon Please keep these two effects in mind while reading the following discussion Buried radials can be directly modeled only with EZNEC Pro 4 using an NEC 4 calculating engine see Buried Wires With EZNEC EZNEC and EZNEC Pro 2 they have to be simulated There are three ways to simulate buried radials One is to use the NEC radial model This isn t generally a good approach because it only modifies the effect of the ground conductivity on the pattern due to ground reflection the second effect described above and not the conduction lo
159. ed if this option is available Before it can be used with the standard or EZNEC program types the NEC buried radial model feature must be enabled by means of an addition to the EZNEC INI file To make this modification open the Control Center Utility menu and select Edit INI File In the Special Options section add the following line NECRadials On Save the file and close it then end EZNEC Wait a few seconds for the disk cache to dump then restart EZNEC NEC radials and the Other menu selection in the Media Window will now be enabled This addition to the EZNEC INI file isn t required with EZNEC Pro Once this feature is enabled radials can be entered and modified via the Other menu in the Media Window This selection will be unavailable grayed out unless all the following conditions are met 1 Except for EZNEC Pro the feature must be enabled with the added EZNEC INI line described above 2 Ground type must be Real MININEC type 3 There must be two media 4 The media boundary type must be radial not linear When the boundary is radial the upper heading of the rightmost Media Window column is R Coordinate not X Coordinate You can change it via the Media menu 5 EZNEC Pro only Ground Wave analysis must be turned off When all these conditions are met the choice will be available and you can select the number and diameter of the radials The radial length is always the diameter of the first medium so to c
160. ee ez example files illustrate the use of split sources Another way to put a source at a wire junction is to insert an additional short wire at the junction and place the source on it This technique would be used for multiple dipoles with a common feedpoint for example But care has to be taken if this method is used Be sure to review Source Placement Precautions before doing this Sometimes it s helpful to taper the segment lengths away from the junction using EZNEC s Segment Length Tapering feature Connecting Sources to Ground A common question is how to connect one end of a source to ground The answer is to connect a wire to ground by giving one end a zero z coordinate and place the source in the bottom wire segment Example description file Vert1 ez illustrates this method Wires should only be connected to Perfect or Real MININEC type grounds See Connecting Wires to Ground for more information Multiple Sources Using Multiple Sources You have to take some precautions when using multiple sources in an antenna to avoid currents which are 180 degrees from what you intended In phased arrays of parallel wires make sure that end 1 of the wires are all facing the same direction for example all wire end 1 s of a vertical array connected to ground Reversing a wire will reverse the effective polarity of all sources in that wire because positive current from a source is always directed toward end 2 and positive current is defined
161. electromagnetic exposure Licensor therefore makes no warranties that this software provides any information regarding human safety or whether exposure hazardous to humans may result from use of Licensee s antenna Licensee acknowledges he or she is not relying on this software to determine whether User s antenna is safe or subjects any persons to hazardous or potentially hazardous exposures of electromagnetic energy LICENSOR HEREBY DISCLAIMS ANY AND ALL WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE LICENSOR S LIABILITY UNDER OR FOR BREACH OF THIS AGREEMENT SHALL BE LIMITED TO REFUNDING THE LICENSE FEE PAID BY LICENSEE IN NO EVENT SHALL LICENSOR BE LIABLE FOR SPECIAL CONSEQUENTIAL OR INCIDENTAL DAMAGES HOWEVER CAUSED WHETHER FOR BREACH OF WARRANTY NEGLIGENCE CONTRACT TORT INCLUDING STRICT LIABILITY OR OTHERWISE OR FOR PERSONAL INJURY OR FOR PROPERTY DAMAGE BY USE OF THIS SOFTWARE LICENSEE HEREBY ACKNOWLEDGES AND AGREES THAT HE OR SHE WILL BE SOLELY RESPONSIBLE FOR ANY INJURIES ARISING OUT OF OR RELATING TO ELECTROMAGNETIC ENERGY EMITTING FROM USER S RADIO ANTENNA USER WILL INDEPENDENTLY SATISFY HIMSELF HERSELF THAT USER S RADIO ANTENNA DOES NOT EXPOSE ANY PERSONS TO HAZARDOUS LEVELS OF ELECTROMAGNETIC ENERGY AND DOES NOT SUBJECT ANY PERSONS TO UNSAFE CONDITIONS USER WILL DEFEND INDEMNIFY AND HOLD LICENSOR HARMLESS FROM ANY AND ALL CLAIMS RELATING TO ELECTROMAGNETIC ENERGY EMITTED FROM USER S ANTENNA INCLUDING
162. eleting or modifying loads Trans Lines Shows the number of transmission lines in the model Clicking opens the Transmission Lines Window for adding deleting or modifying transmission lines Transformers Shows the number of transformers in the model Clicking opens the Transformers Window for adding deleting or modifying transmission lines L Networks Shows the number of L networks in the model Clicking opens the L Networks Window for adding deleting or modifying transmission lines Y Param Networks EZNEC Pro only Shows the number of Y parameter networks in the model Clicking opens the Y Parameter Networks Window for adding deleting or modifying transmission lines Ground Type Shows the type of ground model chosen Clicking it allows you to choose the ground type Ground Descrip This entry appears only when one of the Real ground type models is chosen It shows how many ground media 1 or 2 have been defined and their conductivities and dielectric constants Shows NEC radials if specified Clicking opens the Media Window for modifying ground characteristics and NEC radials Wire Loss Shows which wire loss characteristic has been chosen Clicking opens a dialog box allowing you to specify a wire loss characteristic Units Shows which primary unit of length you ve chosen Clicking opens a dialog box allowing you to choose the primary units of measure Plot Type Shows which plot type azimu
163. en using an NEC 4 calculating engine so this message won t appear in that case Disk Use As Virtual RAM If the calculating engine can t find enough available RAM it uses the disk as virtual RAM Although Windows will do this on its own the routines built into NEC are much more efficient for the purposes of doing the necessary calculations You won t see this message with the standard EZNEC program due to its segment limitation and only with large models when running other EZNEC programs Calculation Progress Several progress bars appear in the window as the calculation runs Which bars appear is determined by the calculations being done A ground file calculation bar appears only when using Real High or Extended Accuracy ground and then only if EZNEC failed to find a file containing suitable data from a previous calculation Progress as shown on the bars doesn t necessarily proceed at a constant rate so you shouldn t be concerned if it seems to speed up slow down or occasionally pause as calculations proceed In EZNEC Pro programs the current calculation is split into two parts Factor and Solve if any current sources or transmission lines are present in the model The solve portion tracks the progress of combining the main matrix with networks which can take considerable time with very large models See Very Large Models You ll also see a Geometry Check bar showing the progress of EZNEC s geometry check Cancel Click
164. en you change the load type all existing loads are converted to the new type if possible Most conversions are not reversible so if you change back to the original load type loads are likely to be different than the originals For example if you specify a parallel RLC type load and change to the R j X load type the impedance of the load will be calculated and entered as the R j X impedance If you change back to the RLC load type the R j X impedance will be converted to a series RL or RC circuit Changes can of course be completely reversed with the undo feature Selecting Adding Deleting Copying Modifying and Moving Transformers See Using Insertion Objects Windows 89 EZNEC User Manual The R j X Loads Window R j X type loads are expressed as a series combination of resistance R and reactance X The impedance of R j X loads does not change with frequency The load number column and specified and actual position columns function the same as for the Sources Window The impedance of each load is entered as resistance R and reactance X in the appropriate columns The value of R cannot be negative See Load Types for information about other types of loads and changing the load type and Load Connections for information about specifying the connection type The RLC Loads Window RLC loads are defined as a combination of R L and C components They can be connected in any of three different configurations
165. ent errors Caution Segmentation Check does not find all possible description errors only the ones listed above EZNEC Pro only Wire grids created using the EZNEC Pro wire grid creation feature Wires Window with default spacing will show violation of conservative guidelines This is normal and not of concern EZNEC Pro 4 only Velocity factor is taken into account when evaluating the segmentation of buried wires This often generates warnings when segments are physically quite short To see the velocity factor being used click Ground Info in the Control Center Utilities menu Ground loss is usually so high that coarse segmentation is adequate so you shouldn t be overly concerned about messages warning of too short segments on buried wires Stepped Diameter Correction A method used by EZNEC to correct for an NEC 2 inaccuracy when modeling connected wires of different diameters It s most accurate only under a limited number of conditions most notably full sized Yagis made from telescoping tubing but will correct other models reasonably well Stepped diameter correction isn t necessary for EZNEC Pro 4 using an NEC 4 calculating engine See Stepped Diameter Correction Overview for more detailed information SWR Graph The SWR sweep is run by first clicking the SWR action button in the Control Center If a sweep has recently been run and the model not changed since you ll be asked whether to view the existing data If you choose No o
166. entering data only to find that you re not using the units you intended For example you might be entering data intended to be in meters into a grid where the units are feet This option in the Other menu lets you recover without having to re enter the coordinates It will change the units but leave the numbers you entered and all others in the grid intact e Coord Entry Mode This check box is just above the data entry grid When checked all columns except the wire coordinate columns are skipped This allows faster entry of a large number of wire coordinates If you find yourself using this feature frequently it might mean you 52 Building The Model haven t learned how to use some of the time and effort saving features described above e Preserve Connections This can be very useful but must be used with caution It s a good idea to use the View Antenna display while this feature is enabled When Preserve Connections is on and you modify a wire end all wires connected to that end are also modified so their connections to it are preserved This can be used with Group Modify to preserve the connections of all modified wires If selected wires are both modified and connected to each other unpredictable results can occur So be sure to verify that each operation did what you intended before doing the next modification and use the undo feature when necessary Preserve Connections is turned off each time you close the Wires Window Th
167. entified by the asterisk on the button to its left In this step you ll also learn how to use one of EZNEC s powerful editing shortcuts Position the mouse cursor over any of the cells of End 1 of the add row and click the right mouse button This opens the list of shortcuts Select Connect End to In the dialog box enter the value 1 in each of the two boxes This tells EZNEC that you want to connect this end end 1 of the current wire the new wire to end 1 of wire 1 Click Ok or press lt Enter gt There should now be two wires shown in the grid numbered 1 and 2 The coordinates of end 1 of wire 2 are the same as the coordinates of end 1 of wire 1 as a result of the last step Take a look at the column labeled Conn Connections in the End 1 group This shows which wire and end is connected to an end In the wire 1 end 1 Connections column you should see W2E1 This tells you that wire 1 end 1 is connected to wire 2 end 1 Likewise the entry in the wire 2 end 1 column shows the connection to wire 1 end 1 as W1E1 In this example the connection is pretty obvious since the coordinates of the two ends are right above and below each other But you ll find this feature handy with more complex antennas If more than one wire is connected to an end only one connection will be shown in the Connections column but by following the connections you can identify all the wires connected together There are a couple of other things to
168. epresent azimuth angles in either of two ways Changing from one way to the other has no effect on the model antenna view or the graphics plots The only effect is in the angles reported in various tables and data outputs Compass Bearing Zero is in the direction of the y axis at the top of the 2D azimuth plot display Angles increase as you go clockwise from zero CCW From X Axis Zero is in the direction of the x axis to the right of the 2D azimuth plot display Angles increase as you go counterclockwise from zero This is the convention commonly used in mathematics and physics AutoComplete AutoSuggest Note This selection doesn t appear on Windows 95 98 or NT systems since these systems don t have the AutoComplete or AutoSuggest features In the file selection dialog boxes two automatic features can come into play on some Windows operating systems when certain Internet Explorer options have been chosen One of these AutoSuggest appears as a drop down list of files beginning with the same letters as any you have entered in the file name text box The other AutoComplete automatically enters in the text box one of the selections from the list Unfortunately there s no way to limit the suggestions or autocompletion to files with extensions appropriate for the purpose at hand So there s no way to guarantee that either the suggested or autocompleted file names are acceptable AutoComplete in particular can be a nuisance if i
169. erm eRe ype eee a er eran 138 Information Window and Action Buttons 138 Control Center Selections ENEE 138 elei Riede 140 The Graphics Windows AEN 141 Graphics Windows OvervieW ee 141 Graphics Windows e EE 141 Graphics Windows ET 142 GE 142 Een e a a 143 EE 143 Elle 144 Reset 2D 3D View Antenna only 144 Creating Graphics Files EEN 144 Using The View Antenna Diepl y AEN 144 Using The 2D Display EE 147 Using ReRe DADIE E A E ENEE 149 Using The ee 149 EZNEC Pro lnformatiON ieia aaa ee araia aat 150 EZNEG PIG And NEE 150 Working With NEC Format Files 0 cceecceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 152 Very Large E 155 Double Precision Operation EEN 156 M ltiple e EE e 157 Additional Informatio M ee 157 elle LE 157 EEN 158 ellen DEE 158 Software Incompatibilities EN 158 The Calculation Progress Wimdow 159 Reinstalling or Copying EZNEL 160 LastZ txt and LastZ s p files EE 160 Parallel Connected Loads Polarity en 160 Polarity Differences Between Series and Parallel Connected Loads 160 Special e lei E 162 OpenP F Plot Ee Formatie 164 EIER eege Ee 165 Data ee 166 NOI EE 166 el ele 167 Relative Far Field BlOCKS eegstegeegeegeegeteg eege sbgegageegeg 167 Absolute Near and Far Field Blocks 168 IPE Fil dEr 171 Frequency Sweep Input Eileen 171 Wire Coordinate TEE 171 First Format Type All program types ccceeeeeeeeeeeeeeeneeeeeeeees 171 Second Format Type EZNEC EZNEC Pro onlly 2
170. erminal It now flows from the inside of the connector to the outside over the chassis and down the wire The wire current consists of current induced by mutual coupling with the antenna and if there s a path to the Earth current conducted from the Earth which was induced into it by the antenna The real antenna is now the antenna wire and the ground wire Both are carrying current equal amounts at the transmitter and both are radiating Calling one ground doesn t change its properties it s just as much a part of the antenna as the intended antenna This is why adding a ground wire to a receiver often makes a marked improvement in reception when its antenna 68 Building The Model consists of a single wire If you want a model to tell you what the real antenna system will do you have to include the whole antenna system which includes the outside of the coaxial feed line and any other conductors connected to the transmitter chassis in the model What would happen if you connected the single wire antenna to the transmitter connector shell that is to the transmitter case rather than the hot terminal You d end up with an open circuited transmitter a very high load impedance and very small current This isn t because one terminal is hotter than the other it s simply because there s no alternate path from the center conductor terminal to the outside as there was for the ground terminal The center con
171. ermits the columnar data in these files to be properly aligned Some fonts such as FixedSys are screen fonts only and can t be printed If this happens either Windows or EZNEC will substitute another font during printing If Windows substitutes a variable width printer font for a fixed width screen font the columns in certain outputs won t line up properly If this happens select a printable fixed width font The Editor will remember the last fixed width font you chose and will continue to use it in the future until you change it again You can use the EZNEC Editor to view or edit any file not just EZNEC files by selecting View File or Edit File from the Control Center File menu The only difference between these two is that if you open a file with the View File selection you won t be allowed to save it under the same name That is it protects the original file from being changed by the editing process Frequency Sweep EZNEC s frequency sweep capability can be a very valuable tool in evaluating antenna performance over a range of frequencies However operation is somewhat different in the frequency sweep mode so it s important to understand the operation in order to get the most from this feature Note that the frequency sweep is actually discrete steps These can be evenly spaced or if read from a file any frequencies in any order In non frequency sweep operation EZNEC calculates antenna impedances currents and pattern and keep
172. es Parallel connected loads are shown as empty hollow diamonds The internal model of the parallel connected load is more complex than a conventional load so conventional loads are recommended except where the parallel connection is needed Parallel connected loads can be placed on virtual segments series connected loads cannot There should be no significant difference in results when using one connection type or another unless some other object is connected to the same segment The phase angles of load voltages and currents reported in the Load Data display might be 180 degrees different however due to different definitions of polarity for the two object types For a detailed explanation of the reason for this see Parallel Connected Loads Polarity in the Reference section Placing Loads At Wire Junctions Like a source a load is distributed over a segment so conceptually can be regarded as being placed at a segment center Direct placement on a segment or wire junction isn t possible but it can be simulated with two loads To simulate a load at a wire junction split it into two equal loads of half the value and place each one on the adjacent segment When EZNEC spots identical loads on segments adjacent to a wire junction it shows voltages currents impedances and losses of the combination as well as the individual loads in the Load Data output Loading Coils The currents at the ends of real loading coils are often substantially
173. esistance as they do without the radials This means that the model radials won t accurately predict the input impedance of a grounded wire such as a vertical antenna The NEC buried ground radial 108 Building The Model model is used only for calculation of ground reflection coefficients for the far field patterns Even for this limited use the buried radial model isn t accurate unless there are many radials and the radial field Accuracy is also poor when the radial field diameter is only a fraction of a wavelength and or the antenna is relatively close to the radial field For typical vertical antenna radial fields a model with radial wires suspended just above the ground or below the ground with EZNEC Pro 4 results in much greater accuracy than using the NEC radial model The conductivity of the radials is peanut buttered over the entire ground area that the radials cover varying with distance from the origin and the result is simply paralleled with the ground conductivity in the region where the radials are placed Four radials simply look like thinner peanut butter than 120 do Once again the NEC model radials do not represent a true picture of the effect of real ground radials Other methods are generally preferred as outlined in Vertical Antennas And Buried Radials Ground radials can be modeled with reasonable accuracy using EZNEC Pro 4 with an NEC 4 calculating engine so the use of the radial model isn t generally recommend
174. esistances so that their impedances change with frequency like real components e Resistances can be made frequency dependent to mimic conductor or insulation loss Please refer to the Insertion Objects topic for some important characteristics of L networks 98 Building The Model L networks have two ports and contain two branches a series branch and a shunt branch The shunt branch is always connected across port 2 O Port 1 Shunt Branch Port 2 Co o Each branch contains the equivalent of an EZNEC load of either the RLC or R X type The Laplace load type isn t available for L networks Like loads all branches of all L networks have to be the same type although they don t have to be the same as the type chosen for EZNEC loads Like loads the components of an RLC branch can be connected in a series parallel or trap configuration which simulates a capacitor in parallel with a lossy inductor The following diagram summarizes the combinations Series or Shunt Branch um Series Configuration m Parallel Configuration _ e mm Trap Configuration RLC Type L Network or OR MHo R jX Type L Network Like EZNEC loads specifying a value of zero for a parallel connected RLC component means component missing rather than a literal value of zero For example a zero value in a series configuration means a short circuit in place of that component a zero value in a parallel configuration means an open circui
175. ess there s some special reason to change it Far Field Table Units Selects the units used in the Far Field Table These have no effect on any other outputs or displays EZNEC EZNEC only dBi or dBref Shows field strength in dBi or if a non zero dB reference is chosen see below in dB relative to that reference mV m for 1 kW at 1 mile Shows the field strength in mV m at a distance of one mile for an applied power of 1 kW Note When this option is selected the Power Level selection above is not used for the Far Field Table mV m for 1 kW_at_1 km Shows the field strength in mV m at a distance of one km for an applied power of 1 kW Note When this option is selected the Power Level selection above is not used for the Far Field Table EZNEC Pro only The units which are displayed depend on whether ground wave analysis is being done With ground wave analysis off the choices have the same effect as those above The choices for units with ground wave analysis and conventional sources are mV m Output in mV m at the distance specified as the Control Center Gnd Wave Dist If the power level has been specified using the Power Level selection above this power is used if not the power resulting from the absolute source voltages and currents is used dBi or dBref Same as the corresponding non ground wave choice Additional units available with a plane wave source are dBsw or dBref dB relative to one square wavele
176. exactly twice the specified value at ground level The same wave arriving over a ground of finite conductivity will have zero amplitude at ground level An intuitive feel for the effect can be gained by looking at the far field radiation pattern of a conventionally excited antenna placed over ground in the direction of the plane wave source If the field is for example zero in that direction the field from a plane wave coming from that direction will also be zero Unfortunately there is no direct way for EZNEC Pro or NEC 2 or 4 to directly report the field strength of the wave after ground reflection It can however be deduced by means of an 81 EZNEC User Manual electrically short model test antenna This difficulty doesn t occur in free space analysis where the field at the antenna is always as specified for the plane wave source In Interpreting the Results it s explained that the field strength can be presented as dB relative to the field produced by a free space object of one square wavelength cross section or dBsw When over a ground plane the field produced by an object with one square wavelength free space scattering cross section will generally be quite different from 0 dBsw This is because of the effect of the ground on the field scattered from the object It s exactly the same problem as determining the gain of an antenna relative to a dipole when the antenna is over ground in free space you can simply subtract 2 15
177. extreme cases such as very small loops beyond the point at which EZCalc will begin to have difficulty A difference between EZCalc and EZCalcD results generally indicates that EZCalc and perhaps also EZCalcD is encountering numerical difficulties EZCalcD requires about twice the memory and disk storage that EZCalc does This isn t a concern with modern machines and moderate sized models but with the very large models possible with EZNEC Pro this factor should be considered The double precision engine also allows a wider range of values to be used in L networks and in EZNEC Pro Y parameter networks EZCalc4 NEC 4 EZNEC Pro 4 only Internal single precision NEC 4 calculating engine This is recommended only when model size and RAM limitations make use of virtual RAM necessary with the double precision engine and not with the single precision engine EZCalc4D NEC 4D EZNEC Pro 4 only Internal double precision NEC 4 calculating engine recommended for general use with EZNEC Pro 4 This engine requires twice the memory and temporary disk storage as the EZCalc4 option and is slightly slower It will give more accurate results in some situations such as when very small loops or unusual geometry are involved and it allows a wider range of values to be used in L and Y parameter networks Default Ground Const Allows you to enter values of ground medium conductivity and dielectric constant which will be used when you create a new gro
178. f EZNEC isn t already running it can be started with the desired description file open by dragging the description EZ file to the EZNEC shortcut icon on your Windows desktop or if you chose to associate EZNEC with EZ files at installation time simply double clicking on the EZ file in Windows Explorer EZNEC Pro only To open an NEC format file follow the above procedure but include the extension NEC when you enter the file name Likewise to save a file in NEC format include the NEC extension Modeling The Antenna Structure Wires About Wires When modeling an antenna you ll generally soend most of your time working on the physical structure made up of the antenna s conductors That s the subject of this chapter It s important to realize that EZNEC doesn t know or care what you consider to be the antenna and what other conductors in the model might represent If you ve included conductors to represent towers rain gutters fences or other antennas they re just as much a part of the model and the calculation as the part of the model you consider to be the antenna The whole model is a single coupled system to EZNEC just as it is in the real world I ve often commented to amateurs seeing strange results from multiple antennas in a small area that they don t have several antennas they have one antenna with several feedpoints And this is just how EZNEC looks at it All antennas in an EZNEC model are made from wires In
179. f positive load current is away from end 2 of the wire toward end 1 Relative to the wire this is the reverse of the direction of positive current for the series connected load The difficulty arises when a parallel connected load is placed in series with the source This can t be done on the same segment as done with the series connected load but it could be say on the adjacent segment That situation looks like this End 2 Parallel Connected Load Source I Voltage or Current Source t Wire I End 1 Compare this to the first diagram with the series connected load and it s apparent that the definitions of polarity of both the load voltage and current are opposite for the two types of loads This has no impact on any results except for the phase angle of voltage and current shown in the Load Data display Whenever you directly replace one load type with the other you ll see a 180 degree change in both voltage and current The only way to avoid the reversal between types is to reverse the convention of one type of load or the other If the series connected load were reversed the load current would be shown as reversed in phase from the source current when the two are directly in series If the parallel connected load were reversed its voltage would be opposite in polarity from that of a parallel connected source So the conventions shown above were chosen These are also the conventions used by NEC so using them in EZNEC help
180. f the limitations of the transmission line loss model detailed in the Transmission Line Loss topic Connection is sensitive to wire direction If two vertical elements are defined with one having end 1 grounded and the other end 2 grounded transmission lines connected to their grounded ends from the same point would result in reversed signals to the two antennas Imagine each end of a transmission line having two terminals 1 and 2 A normally connected line will always be connected so that terminal 1 is closest to end 1 and 2 closest to end 2 of each wire regardless of the physical orientation of the wires Each transmission line can be reverse connected if desired which reverses this connection just like giving a physical line a half twist Two examples of phased array antennas using transmission line feed are included as example description files CardTL ez and 4SqTL ez Transmission lines are defined in the Transmission Lines Window Except for stub ends all transmission line ends ports have to be placed on real or virtual segments See Placing Insertion Objects on Segments for details There s no way to connect a transmission line end at a wire junction the best you can do is to insert a short wire between the wires and place the transmission line end on it Follow the same procedure and cautions as described at the end of the Placing Sources At Wire Junctions section A transmission line stub can be created by declaring one end to
181. f the wire numbers when you first start EZNEC can be set with the Control Center Options menu View Antenna Wire Numbers selection You might want to make the initial state be off if you commonly model complex antennas The wire numbers can be centered on the wires or offset Wire numbers can also be toggled on and off by pressing the N key when the View Antenna window is active The wire number size can be changed if desired via Special Option VAObjTextSizePct 2D Pattern once calculated a 2D pattern can be added to the display This is particularly useful in showing the orientation of the plot to the antenna If Semi Solid is chosen lines are added to give you a better idea of the real pattern shape and what it represents The 2D plot won t appear if a 3D plot has been run and no slice is highlighted See Using The 2D Display for more information about 2D plot orientation 2 Port Objects Shows two port insertion objects Object Symbols Symbols shown in the display are Hollow circle Source Hollow Series connected square load Hollow Parallel connected diamond load Square with Two port insertion letter object The letter in a two port insertion object box identifies the type of object T Transmission line X Transformer L L network Y Y parameter network EZNEC 146 Reference pro only A two port insertion object which is connected to two wire segments is drawn as a square box between the two segments Dashed connecting l
182. fed This information is required to design a feed system to produce the desired current ratio To determine the impedances insert current sources at the feedpoints with the currents being in correct ratio Clicking the Control Center Src Dat Source Data action button will tell you the feedpoint impedances 4Square ez and Cardioid ez are examples of phased arrays fed with multiple current sources Using Loads About Loads Loads are insertion objects which represent a lumped impedance that can be inserted into a wire Like sources these are easy to place with EZNEC and appear connected across an imaginary gap in the wire Like sources loads are actually distributed along the entire segment but conceptually can be regarded as being at the segment center Loads are characterized by type configuration and external connection Load impedances can be specified as one of three types as an impedance consisting of fixed resistance and reactance R jX type as an RLC combination RLC type or as a quotient of Laplace transform polynomials Laplace type These are explained in more detail in the following section The RLC type gives you three different choices or configurations for interconnection of the resistance capacitance and inductance There are two ways of connecting loads when sharing a segment with other insertion objects series and parallel connection This is explained in detail in the Load Connections topic Loads are entere
183. fferences Between Series and Parallel Connected Loads The polarity of voltage and current reported in the Load Data display will usually be opposite for series and parallel connected loads The polarity reversal will be evident as a 180 degree difference in phase of current and voltage This is caused by a difference in definition between the two load connections in the definitions of which terminal is considered to have positive voltage relative to the other and which direction is defined for positive current flow The conventions and the reason for the difference are explained below 160 Reference First consider a source and conventional series connected load connected to the same segment of a wire red The load as the connection type implies is connected in series with the source The wire is shown in red Defined voltage polarity is shown for the source and load and the positive direction of current flow for each object is shown with an arrow End 2 Conventional series connected Load Voltage or Current Source If the source is producing say 1 ampere at a phase angle of zero degrees the Load Data display will report 1 ampere at zero degrees because the directions of the source and load currents are defined the same that is the positive current arrows are pointing in the same direction away from end 1 of the wire and toward end 2 This is also the direction of the wire current One would expect the current throu
184. find the maximum available power which an antenna can extract from a wave first excite the antenna with a conventional voltage or current source and find the source impedance by 80 Building The Model clicking Src Dat Then place a load having the complex conjugate of that impedance in place of the source and change to plane wave excitation Load Dat will report the resulting maximum power To find the effective length of a receiving antenna in meters divide the open circuit voltage as described above by the incident plane wave amplitude in V m Note Be sure to read Using Plane Wave With a Ground Plane if using plane wave excitation with a ground plane Specifying Plane Wave Excitation Plane wave excitation is available in EZNEC Pro programs only To specify plane wave excitation open the Sources Window by clicking on the Sources line in the Control Center If conventional sources are shown the default open the Other menu in the Sources Window and choose Change Source Type The Sources Window grid then changes to allow specification of the plane wave source Most of the parameters are self explanatory Pol Ang is the orientation of the electric field when the source is linearly polarized and the orientation of the major axis when circularly polarized The angle represents the rotation counterclockwise of the E field from downward oriented in the plane normal to the direction to the source with rotation direction defined by lookin
185. fore the specified ratio of voltages regardless of the impedances they encounter Similarly current sources maintain the specified currents and current ratio One of the most common applications for multiple sources is in modeling phased arrays Most arrays are designed to work with a specified current ratio because the fields produced by the elements are proportional to their currents so current sources are generally used in this application See Using Multiple Sources and Phased Arrays for more information about using multiple sources and the Plane Wave Excitation chapter for information about using plane wave excitation Using The Sources Window Open the Sources Window by clicking on the Control Center Sources line or the button to its left Note In EZNEC Pro programs both conventional source and plane wave excitation are specified using this window To change from plane wave excitation to conventional sources in EZNEC Pro open the Other menu in the Sources Window The following applies to conventional sources only the Plane Wave Excitation chapter covers use of that feature Specifying the Source Position Like other insertion objects all loads have to be placed on real or virtual segments See Placing Insertion Objects on Segments for details Special considerations for sources are described in Placing Sources on Segments and Placing Sources At Wire Junctions Specifying the Amplitude and Phase 79 EZNEC User Manual Whe
186. format created by v 2 and later EZNEC family products PF3 3D trace files OQpenPF format created by v 2 and later EZNEC family products Remove Trace 2D only Removes traces added via the selection above Clicking this option opens a list of added traces Clicking on an item in the list will remove that trace This selection isn t available if no traces have been added Save Trace As 2D Save 3D Plot 3D Use this selection to save the 2D or 3D trace A 2D trace can be added to a later display for comparison Either a 2D or 3D trace file can be opened in TraceView mode as a primary trace The plot will be saved in OpenPF format with a PF 2D or PF3 3D extension Show Added Trace Info 2D only Shows additional information about added traces This selection is disabled if no traces have been added Restore Default Folder 2D 3D only When you save a 2D or 3D trace or add a 2D trace EZNEC remembers the last directory you chose and takes you there when you open the file choice dialog box If you ve navigated your way to some obscure directory and want to return to the directory where you normally store trace files click this selection before choosing Add Trace or Save Trace As This selection returns the initially displayed directory to the 142 Reference one chosen in the Control Center Options menu Folders Description EZ and Plot Files selection Edit Undo Allows you to undo any change you ve made to
187. g difficulty particularly in situations involving source placement A second use for Average Gain is to evaluate the amount of loss incurred by wire resistance or the reaction of the field with a finitely conducting Real ground The Average gain is the total power in the far field determined by integrating the far field in all directions divided by the power delivered to the antenna by the sources It s shown at the bottom of the Control Center after a 3D far field plot has been run It is not computed for Azimuth or Elevation plot types EZNEC s NEC calculating engine is very particular about the length of segments containing sources and nearby segments When placement isn t to its liking an error in the form of inaccurate gain and impedance will frequently occur Without an independent means of evaluating gain this error can go undetected A solution to the problem is to calculate the Average Gain Average Gain is meaningful for assessing the validity of results only when no loss mechanisms wire loss resistive loads or real ground are present in the model When the Average Gain is one with no loss present the program is producing correct results If it deviates significantly from this value results are in error and source placement should be altered if possible Every effort should be made to correct the problem But if this isn t possible the pattern and gain figures can be corrected by dividing them by the Average Gain or by su
188. g from the distant source toward the origin The axial ratio choice is available and used only when circular polarization is specified Note that the amplitude is in volts RMS per meter rather than peak volts per meter as used in NEC The polarization type dictates only the polarization of the source The choice of polarization types to display in outputs is made the same as for conventional sources via the Desc Options choice in the Control Center It s important to realize that when a ground plane is present the amplitude and polarization of the plane wave striking the antenna model might be different from the specified plane wave that is the one emanating from a distant source Be sure to read Plane Wave Excitation With a Ground Plane if a ground plane is present Plane Wave Excitation With a Ground Plane Because the plane wave apparently emanates from a source which is an infinite distance from the origin the plane wave interacts with the ground between its point of origin and the antenna Consequently the magnitude and polarization of the plane wave striking the antenna are generally different than the specified plane wave magnitude and polarization That is the specified values define the plane wave before striking the ground en route to the antenna which is likely to be different from the wave at the antenna As one simple example a vertically polarized plane wave arriving horizontally over a perfect ground will have an amplitude of
189. ge and current 111 toad Data eiiis 111 140 Load Placement 88 Load Types 86 87 89 90 91 ENT elle EE 89 Lee 87 91 Bee eege ees 87 90 EE 87 90 Loading Coils eeeeeeeeeeee 88 Loads EE 88 89 138 Placing at wire junctions 88 Total number of in current model bhi hae ote ee chins oh 138 Loads OVErvieW cccceeeeeeees 86 Loads Window ees 86 Loads Wmdows 89 138 len ee EE 138 Log Periodic Antennas 71 ele SE 71 Loop IESEL eseu eebe dese 72 Minimum circumference 72 ST UE 72 Loop Creation c cece 59 Loop Resizing ccceeeeeeeee 60 Be E 55 114 Setting to Zero 83 114 Transmission Line 95 Ur le 55 M Maintenance Releases 181 Making a Desktop Shortcut 17 DEEG eege nied 1 17 dl UE 18 NN dl ul Te EE 18 Matrox PowerDesk aaaaccsccaan 158 MaxAbsRAMUsedk 00 162 MaxAbsRAMUsedPct 162 MaxCMWicdth cccccceeeeeee 162 MaxMSFregs nnnnnnnnnnnnnnn 118 162 MaxQualRAMUsedPct 162 McAfee Antivirs 158 Meander Line Creation 62 Measuring Voltage and Current 78 Media Window seeencennenn 106 OpeniNG E 138 RT lte DE 106 Memory Information 0 0 a 138 MicroSMmith sanne 158 MININEC type ground 73 103 123 Model Contains Loss message 83 116 Modeling Coaxial Cable 96 Modeling Flat Surfaces
190. gh the load to be the same as the current from the source since both are in series and the chosen definitions of current direction cause them to be the same The voltage drop across the load has to be defined as shown so that the impedance will be equal to V I Next consider a parallel connected load in parallel with a source End 2 Parallel Maltaga ar Connected Load Current Source End 1 Here the voltage across the load is the same as the voltage across the source so we would expect the load voltage to be reported as being the same as the source voltage And the convention for defining the voltage polarity of the load has been chosen to make this so But notice that the convention for voltage polarity is opposite that for the series connected load the terminal of the parallel connected source is toward end 2 of the wire while the terminal of the series connected load was toward end 1 of the wire Without this different definition the load voltage would be reported as being the negative of the source voltage when the two are connected directly in parallel a situation sure to be confusing Once the voltage convention is determined the convention for positive current is also fixed in order to make the load impedance equal V I Like the series connected load the direction of positive 161 EZNEC User Manual current is into the load from the positive terminal But because of the voltage definition reversal the direction o
191. grid dots This affects only the 2D printed plot See PrintedOffsetAxisWidth below ForceGndCalc Yes forces a ground calculation to be done every time when Real High or Extended Accuracy ground is specified This prevents EZNEC from using data from any saved ground data file and ensures absolute repeatability of results NECRadials On Standard EZNEC and EZNEC only See The NEC Radial Model for use of this option PrDataLineSp where is a number from 1 to 2 This sets the line spacing for data from a Data Window printed under a plot It affects only printed output PrinterMargin where is a number from 0 to 3 or a number followed by the letter c either case from Oc to about 7 6c Sets the width of the margins around printed graphics plots 2D 3D SWR and View Antenna displays If the number is followed by c the number is interpreted as being in cm otherwise in inches For example 1 2 will produce margins of 1 2 inches 2 3c will produce margins of 2 3 cm VAObjTextSizePct where is a number Sets the size of wire numbers and numbers related to insertion objects in the View Antenna display Default value is 5 the equivalent value in versions prior to 5 0 13 was 8 75 163 EZNEC User Manual WirelnfoDist where is an integer from 1 to 20 If the value is zero or positive it defines the distance within which the cursor has to be before the Wire Information popup window appears If the value is 1 t
192. h rules won t change significantly when using wire insulation unless EZNEC Pro 4 only the insulation is on buried wires and is relatively thick When the insulation s dielectric constant is considerably lower than that of the medium possible only with buried conductors available only with EZNEC Pro 4 the velocity factor increases significantly so segments can be longer This is under consideration for a future modification of the Geometry Check feature The characteristics of PVC vary widely so the values are a rough average for the HF range The Custom windows can be used for any values you think are better EZNEC Pro only EZNEC Pro programs also permit you to specify insulation loss but you ll find that even a fairly gross loss tangent doesn t make a huge difference PTFE and PE are pretty constant over a wide range of frequencies so the fixed values should be adequate for nearly any use Loss tangent stays relatively constant with frequency while conductivity doesn t so loss tangent was chosen for loss specification For any reasonable loss tangent the loss tangent is for practical purposes equal to the dissipation or power factor So table values of DF or PF can be used directly The level of loss associated with normal wire insulation generally has only a small effect on overall performance so it will probably be most useful for unusual coatings Importing Wire Coordinates Wire coordinates can be imported from an ASCII file
193. h a fan antenna the difficulty being greater with NEC 2 than with NEC 4 The problem has a different cause than the MININEC problem of cutting corners and quads are modeled very well by EZNEC without special attention However when modeling very acutely intersecting wires evaluate the results carefully particularly if a source or load is at or near the junction It has been reported that EZNEC s segment length tapering feature originally developed for MININEC based ELNEC improves the accuracy in this situation provided that the wires all have similar diameters Segment length tapering is likely to degrade the accuracy with wires of greatly different diameter Exception wires very near ground See Elevated Radial Systems Another method which has been reported to work is to put a separate source on each wire rather than a single one near their junction One problem with wires intersecting at an acute angle is that it s often difficult to avoid the problem of the center of one segment lying within another wire This problem is most likely when segment length is short near the junction See the Other Wire Considerations and Geometry Check topics for additional information 64 Building The Model Buried Wires NEC 2 is not able to model buried wires or conductors so all conductors must be above ground unless using EZNEC Pro 4 with an NEC 4 calculating engine selected The remainder of this section applies only to EZNEC Pro 4 when u
194. hange the Specified Pos Wire from V3 to V1 Press lt Enter gt then close the window The L network feed system is complete Press the FF Plot Action Button to see the resulting pattern In the 2D Plot Window open the File menu select Add Trace and locate and double click Cardioid TL ARRL Example pf Notice that the added trace overlays the plot perfectly If it doesn t you might want to try going through the steps again The finished project is furnished as example file Cardioid L Network Feed ARRL Example ez This model can be used to investigate how the pattern and feedpoint impedance vary with frequency and with such things as ground resistance If desired realistic transmission line loss and L network component loss can also be included In the second example you ll use a transformer and series capacitor to improve the impedance match of an array 35 EZNEC User Manual Open example file 4 Square L Network Feed ARRL Example ez This is the 4 square L network feed system example from Chapter 8 of the 21st Edition ARRL Antenna Book It can be and in fact was developed from A Square TL ARRL Example ez using exactly the same process as used in the first example But the purpose here is to illustrate how a transformer and series Capacitor can be added to the model to improve the impedance match The changes we ll make will be made between the array common feedpoint and the source so it will have no impact at all on the ar
195. hange the length you change the boundary of the second medium If desired you can enter the wire diameter as wire gauge AWG by typing where represents the wire gauge Gauges of wires larger than 0 e 00 are not permitted After the entry is complete and the dialog box closed the number of radials will appear in the Control Center Information Window as part of the Ground Descrip entry 109 Interpreting The Results Currents The currents at each segment can be displayed with the View Antenna feature or seen in tabular form by clicking the Control Center Currents action button The currents give important information about antenna operation In addition they re invaluable in assessing whether the antenna is working as intended and in spotting conditions where EZNEC is being used beyond its capabilities Note that the View Antenna display is intended as a visual aid Although the overall display is correct it has been smoothed so that details about the current along a single segment or at the junction of two segments may not be precise If you need this level of detail refer to the tabular data One thing to look for is symmetry If the antenna is symmetrical the currents should be also If not some error has been made in wire definition source placement or some other area For example the current from the vertical part of a ground plane antenna should split evenly among the radials if the radials are the same length an
196. he end of the wire where the mouse cursor is located when the right mouse button is pressed This will be called the current end A change will be applied only to the current wire that is the wire number of the row where the mouse cursor is located when the mouse is right clicked unless in Group Edit mode If in Group Edit mode the change will be applied to all selected wires See Using The Wires Window for more information about Group Edit All shortcuts except Change Coordinate By will or can change all three of the end coordinates x y and z regardless of which of the three cells the mouse cursor is placed on or where the shortcut text abbreviation is entered International users please note Floating point numbers numbers with a fractional part must have the proper decimal separator NOTE Only the Connect End To shortcut is available in the Add Row the blank line at the bottom of the grid Connect End To 54 Building The Model This is a convenient way to connect a wire end to an end of another wire Simply specify the wire number and end to which you want the current end connected The text abbreviation for this shortcut is W E where are the number of the wire and end you want to connect to See the example above Change Coordinate By This shortcut adds or subtracts the specified amount to or from the current end coordinate Unlike all other shortcuts this affects only the particular coordinate where the entry is made Th
197. he left mouse button while you move the mouse Highlighting a slice To take full advantage of the 3D display turn on the Control Window from the View menu and select either Azimuth Slice or Elev Slice The 3D plot will dim and the highlighted slice will be shown in a distinctive color You can select the slice and move the cursor with the scroll bars Note that you can also drag the scroll bar slider bar Displaying a 2D slice If you check the Control Window Show 2D Plot box the 2D Display opens and shows the highlighted slice If the 2D Control Window is shown the 2D controls will track the 3D controls This combination of 2D and 3D plot combines detailed analysis with easy visualization If you open the View Antenna Display you can add the 2D slice to the display via the View Antenna View menu Objects selection It will move as you change the 3D slice Using The SWR Display The SWR Display is shown after running an SWR sweep This in turn is started by clicking the SWR action button in the Control Center then entering frequencies or an input file name and starting the sweep as described in the SWR Graph section This section describes use of the resulting display Many menu operations are common among all the graphics displays so they re covered in the common section Graphics Windows Menus The SWR Display shows the impedance seen by each source The most basic is a graph of SWR vs frequency The SWR is not necessarily the actual S
198. he pattern Click the FF Plot action button This tells EZNEC to compute and display the 2D far field pattern You ll briefly see the Calculation Progress Window while the calculation is running When it s finished you should see the plot and some text below it with information about the pattern If you don t see the text below the plot open the 2D Plot Window View menu and select Show Data The plot represents an elevation slice of the antenna pattern From the text in the data box you can see that the pattern is maximum at 34 degrees above the horizon and other information about the pattern You can see the antenna gain second row in the data box on the right at any elevation angle by moving the cursor This can be done by simply clicking on the 2D plot The cursor will move to a point on the plot which is on an imaginary line from the plot center to the mouse cursor location Note that the mouse cursor must be in the plot window when the button is initially pressed although it can be moved outside the window while being held down You can also press and hold the left mouse button and drag the cursor to the desired angle The cursor can also be moved with the arrow keys for fine steps or the lt Page Up gt and lt Page Down gt keys for coarser steps Before using the arrow keys you should click on the 2D plot window Otherwise they might adjust some other program parameter or control Click the Src Dat action button in the Contro
199. he popup window will appear only when the right mouse button is clicked while holding down the lt Ctrl gt key 2DGridLineWidth where is an integer from 1 to 10 Sets width of 2D plot grid lines or dots and analysis lines on screen Has no effect on printed plot Note All lines will be solid if this is set to any value other than 1 Note Program does not have to be restarted for changes to become effective although the 2D Plot Window must be redrawn 2DTraceLineWidth where is an integer from 1 to 10 Sets width of 2D plot trace and key lines on screen Has no effect on printed plot Note All lines will be solid if this is set to any value other than 1 Note Program does not have to be restarted for changes to become effective although the 2D Plot Window must be redrawn EZNEC EZNEC Pro only The following options affect the content of the LastZ_src s1p files SipFormat MA Magnitude Angle or RI Real Imaginary or Parameter type S only DB dB magnitude Angle default MA 1pParamParamType S reflection coefficient S11 or Z impedance Z11 default S S1pZ0 Alt changes the reference impedance to the Alt SWR ZO value EZNEC Pro only LD5Translation Off inhibits translation of LD5 wire loss cards in NEC description file See Working With NEC Format Files for more information about LD card translation LD5Translation First will cause EZNEC Pro to apply the wire loss parameters of the first LD5 c
200. hen you add saved traces to the display you can view only one field at a time selected via the Mult Trc Fld choice in the 2D plot window View menu There you can 14 Getting Started choose among the fields selected in the main window Desc Options dialog box for the normal 2D display If you add traces to the display clicking on the name of any added trace file at the left of the display will move the cursor to that trace and the data in the data window will reflect the value for that trace Also an extra line will appear in the right column of the data window giving the field strength of the selected trace relative to the primary trace at the cursor angle The minimum step size for the 3D plot is now 1 degree instead of 2 Calculating Engines There s now a fully double precision NEC 2 engine choice plus and pro only selected via the Control Center Options menu All calculating engines are faster than before most notably in the calculation of currents The amount of speed improvement depends on which engine you ve selected what portion of the total calculation time is needed for the calculation of currents and the type of CPU you have But it can be quite spectacular with the NEC 2 engines in particular In program types allowing a choice of more than one calculating engine the choice is shown just above the FF Plot button in the Control Center Wire Insulation EZNEC v 4 0 has the capability of including the effect of wire
201. hich to use in a given circumstance so please carefully study the sections about Real ground types and Limitations of Real Ground Models Real Ground Types EZNEC provides two or three different models for simulating real as opposed to perfect ground None do the job perfectly and one is generally the best for a given situation It s important to know which ground model to use and what the limitations of each are The Real ground models are MININEC type and High Accuracy EZNEC Pro 4 provides a third Extended Accuracy The choice is made via the Control Center Information Window Ground Type line Ground characteristics are defined in the Media Window which is opened by clicking the Ground Descrip line or button in the Control Center The Real ground models share these common characteristics e All are perfectly flat and infinite in extent e All are homogeneous to an infinite depth e All have user defined conductivity and relative permittivity dielectric constant e All allow a maximum of two media each with its own characteristics The second medium can be at a lower level than the first if desired The ground model consists of one or two media which are separated by a radial or linear boundary If the radial boundary is chosen the first medium is a disk with the second medium occupying the remainder of the infinite ground plane If the boundary is linear the first medium occupies the ground to the x side of a line para
202. his byte identifies the OpenPF version used to generate the file The version number consists of a major revision an integer and a minor revision an integer between 0 and 9 separated by a decimal point The upper nibble 4 bits contains the major revision and the lower nibble the minor Header Length This field is the total length of the header in bytes File parsers should use this length to advance past the header instead of assuming that data blocks begin immediately after the notes string Future OpenPF revisions may define additional fields after the notes string Header lengths less than 3 are invalid Source Title Environment and Notes Lengths These fields specify the lengths in bytes of the ASCII strings Zero is valid Source String This string identifies the data source This may be an antenna analysis program an antenna test range a laboratory etc No bytes are allocated for a zero length string Title Environment and Notes Strings The title string describes the antenna The environment string describes the antenna environment free space antenna height ground constants etc The notes string contains auxiliary information that might be displayed only upon request Data blocks that follow may contain strings that override these global strings No bytes are allocated for zero length strings Data Blocks Data following the header is organized into blocks Each data block begins with block type a byte followed by
203. his is that no more than two wires can be connected at any junction All wires must be connected to each other Both ends of the group must be open or one end open and one connected to ground The group must be nearly resonant within about 15 of half wave resonance if both ends are open or within about 15 of quarter wave resonance if one end is grounded Only one source is permitted in the group and it must be at the center if the ends are open or at the bottom segment if the group is grounded If the ends are open and the center of the group is a wire or segment 62 Building The Model junction the source must be a split source If the group is grounded the source must not be a split source The rules for loads are the same as for sources except that two equal loads must be used wherever a split source would be used A single transmission line can be connected to the group If the ends of the group are open the center of the group must be a segment center not segment or wire junction and the transmission line can be connected only to this segment If the group is grounded the transmission line can be connected only to the bottom segment These criteria apply to typical full size Yagi elements made from telescoping tubing one of the most demanding cases where the correction is needed but any loading other than at the center or the presence of any traps violate the conditions so the Leeson correction won t be
204. how Controls click Show Controls to turn the control box off Repeat for Show Data if it s also checked This turns off the control and data boxes which aren t needed now Next open the Wires Window by clicking on the Control Center Wires line or the selection button to its left Position the Wires and View Antenna Windows for convenient viewing You can resize the View Antenna Window if desired by dragging a side or corner It s ok to cover all or part of the Control Center for the time being The Wires Window is where the wires of the antenna are actually defined The position of each wire in space is specified by giving its x y and z coordinates These coordinates represent distances from the origin For example look at the numbers in the Wires Window for Dipole1 It consists of one wire which extends along the y axis The y coordinate of End 1 is about 0 82 feet and the y coordinate of End 2 is about 0 82 feet so the wire is about 1 64 feet long You can confirm this by moving the mouse cursor to the y axis line in the View Antenna display where the wire is it might be a little hard to see at the moment and leaving it still for a moment to open the Wire Information window Alternatively you can move put the mouse cursor over the selection button at the very left of Wire 1 in the Wires Window and right click it Dipole1 is a half wavelength long at about 300 MHz so it s much too short for our 20 meter dipole Let s mak
205. ht click the mouse to complete the operation and the new wire is in place You can use the undo feature to start over if the wire isn t where you intended The new wire has the same diameter number of segments and insulation as the wire connected to its first end wire 1 in this case If the Copy Conn Wire box was unchecked we could have specified the diameter and number of segments Any desired insulation would have to be added manually in the Wires Window after the new wire is created Now let s investigate a Windom type antenna a horizontal antenna fed with a single wire usually off center Our model will connect the single wire directly to ground To model a real installation the entire path to ground over the outside of the rig and maybe following the mains power system to the Earth 39 EZNEC User Manual would have to be included for good accuracy Nonetheless the simplified model can be instructive and might be a good representation of a portable setup For this example we ll build models to investigate the effect of moving the single wire feeder to various points along the horizontal wire Start with the BYDipole EZ example file Open it and open the View Antenna Display We ll create another wire from end 2 of the existing wire to ground Because one end of the new wire isn t connected to any existing wire end we can t use the Create Wire feature of the previous example Instead open the Wires Window by clicking the Wires
206. i2 and y22 The y parameter networks are reciprocal so y21 y12 Standard rules and definitions for two port networks and y parameters apply Currents are defined as positive flowing into the positive port terminals and i1 v1 y11 v2 y12 i2 v1 y12 v2 y22 from which it can be seen that y11 is the admittance looking into port 1 with port 2 short circuited v2 0 and y22 the admittance looking into port 2 with port 1 short circuited v1 0 Y12 is the short circuit current at port 2 divided by the voltage at port 1 or the short circuit current at port 1 divided by the voltage at port 2 Transmission lines transformers and L networks cover most of the common uses for networks and are simpler to use In addition L networks allow use of realistic components with frequency varying impedances But more complex networks can be devised if desired by using this feature Remember that the y network impedances don t change with frequency so in networks which aren t purely resistive the y parameters will usually have to be redefined for each analysis frequency Using the Y Parameter Networks Window Open the Y Parameter Networks Window by clicking on the Control Center Y Parameter Networks line or the button to its left Specifying Connections Like other insertion objects both ports of all Y parameter networks have to be placed on real or virtual segments See Placing Insertion Objects on Segments for details 101 EZNEC User M
207. id If you right click any of the insulation columns you ll get a dialog box for convenient entry Here s how the dialog box works The first three fixed choices PVC polyvinyl chloride PTFE Teflon and PE polyethylene or polythene will enter values for dielectric constant k or relative permittivity and pro only loss tangent into the grid but won t alter the 56 Building The Model thickness value already in the grid The None choice and the three custom choices will replace the thickness value Choices including custom values are saved permanently unless you close the dialog box with lt Esc gt or Cancel The intent of the custom values is to let you enter parameters appropriate for some specific wire you might be using for antenna construction To set insulation to zero enter a thickness of zero For convenience there s a None choice in the dialog box which will do this A dielectric constant of 1 and pro only loss of zero will result in no effect However calculations will be done any time the thickness isn t zero Insulation thickness is scaled when the antenna is scaled Insulation properties of added wires are copied from the wire just preceding as are the diameter and number of segments The Segmentation and Geometry checks and the stepped diameter correction don t take any notice of the insulation since its effect as a percentage of wire length is generally small typically on the order of 2 percent Segment lengt
208. ike the textbook pictures you may have seen This is because the textbook pictures usually show a dipole in free space or at most over a perfect ground This on the other hand is the model of a dipole over real ground You can move the 3D display around to view it from different angles Position the mouse cursor anywhere on the 3D plot window Press and hold the left mouse button down as you move the mouse The mouse cursor has to be in the 3D plot window when the button is initially pressed However once the button is down the mouse cursor can be moved anywhere on screen You can also do fine positioning with the arrow keys as long as you first click anywhere in the 3D plot window One of EZNEC s powerful features is the ability to view individual 2D slices of the 3D display To use this feature the 3D display control box must be activated If you see some controls to the left of the plot the control box is on If not you need to turn it on at this point by opening the 3D display View menu and selecting Show Controls 29 EZNEC User Manual In the control box Highlight section choose Elevation Slice The 3D plot will dim and an elevation slice will appear in a distinctive color You can modify these colors via the 3D display Options menu Colors selection The two control box scroll bars are now active and can be used to change the slice and to move the cursor Most of the scroll bars in EZNEC can be adjusted in several differen
209. in Note that end 1 of wire 1 is already at this point but we ll need to modify its length to be suitable for the new antenna To make the new inverted vee the same length as the original dipole each of the two wires should be 16 715 feet long So first we ll modify the existing wire to be this length Watch the View Antenna display when you press lt Enter gt in the following step Change the End 2 Y coordinate to 16 715 and press lt Enter gt to make EZNEC accept the new value If you watched the View Antenna display when you pressed lt Enter gt you saw that the wire appeared to change both its length and height above ground The height however didn t really change The reason for the apparent change is that EZNEC rescales the View Antenna display each time you change a wire making it as large as possible without going beyond the window boundaries Although the relative dimensions of everything on the display are correct you can t determine absolute values from this display Notice that in the display the height of the wire is a little less than twice its length which is the correct proportion The coordinates of Wire 1 should now be 0 0 30 end 1 and 0 16 715 30 end 2 If not manually correct them and press lt Enter gt 25 EZNEC User Manual Now we ll add the second wire A wire can be added at least two ways The simplest way to add a single wire is to simply type its coordinates and other parameters on the add row id
210. in a simple format either replacing or adding to the existing model This can be used to import coordinates from another program To import wire coordinates select Import Wires From ASCII file in the Wires Window Other menu or the Control Center File menu The file format is described in the Wire Coordinate File section Combining and importing are sometimes confused If you want to add an existing description to your present model see Combining Antenna Descriptions Other Wire Considerations Some NEC literature cautions against permitting the center of a segment to lie within the volume of another wire See the Geometry Check topic for an 57 EZNEC User Manual illustration of this condition It can occur when segments are short wires have large diameters and intersection angles are acute haven t been able to devise a test which shows any adverse effects from permitting this to happen so it should be allowed to happen only if erroneous results are likely to be recognized if they should occur The Geometry Check tests for this condition but the test can be disabled for the current description via the Control Center Desc Options selection This choice is saved with the description A case was found where EZNEC produced results which were very inaccurate and showed great sensitivity to the number of segments This case was where a wire approached the middle of another at an angle but wasn t connected like an insulated guy wire at
211. in faster calculation than High and Extended Accuracy ground and is satisfactory if the antenna doesn t contain any horizontal wires which are lower than about 0 2 wavelength or higher if the wire is much longer than a half wavelength or so However the speed difference is minor for models of the size permitted by EZNEC and standard EZNEC so High Accuracy ground is recommended for those programs unless direct connection to ground is needed MININEC type ground is needede when modeling grounded wires such as verticals When using MININEC type ground a load must be added to grounded wires at the grounded segment if ground system loss is to be simulated Do not use this ground type if the model contains horizontal wires lower than about 0 2 wavelength The minimum height increases for horizontal wires longer than about a half wavelength EZNEC Pro 4 only This ground type can t be used with buried wires in EZNEC Pro 4 Near field analysis is disabled when MININEC type ground is selected f near field results are needed for a grounded antenna model the ground system as slightly raised radial wires and High Accuracy ground With EZNEC Pro 4 you can model a buried ground system and also use Extended Accuracy ground High Accuracy The High Accuracy NEC Sommerfeld ground is required for antennas with low horizontal wires and is recommended for use unless a direct zero ohm connection to ground is required The minimum permissible height for
212. indicate an insufficient number of segments but note that apparently abrupt phase reversals at wire end connections may be due to internal conventions of assigning current direction see Interpreting The Results One place more segments aren t better is if wires of different diameters are connected in a configuration which EZNEC can t correct with its stepped diameter correction This isn t a problem with the NEC 4 engine in EZNEC Pro 4 See Stepped Diameter Determining a reasonable number of segments isn t as hard as it sounds You ll soon get a good feel for about how many you need to get the shape of a pattern or a feedpoint impedance with the accuracy you need Altering the number of segments is often part or all of a solution to a problem of poor average gain Refer to that topic for more information In looking at models created by EZNEC users it s apparent that many people use more segments than necessary This is usually no disadvantage in small models but it unnecessarily increases calculation time and often is the source of a perception that not enough segments are available One important thing to keep in mind is that if a wire carries little current it contributes little to the overall field since the field is proportional to the current Consequently wires that carry little current can often be given fewer segments than the minimum recommended number or even removed from the model altogether The exception to this is situati
213. ines are drawn from the two segments to the box Different colored lines are used to identify the ports The colors of the connecting lines can be chosen via the Colors selection in the View menu A two port insertion object which is connected between a wire segment and a virtual segment is shown as a square box at the wire segment a short dashed line of the color of the port connected to the virtual segment extends to one side of the box left for port 1 and right for port 2 At the end of the line is the virtual segment number to which the port is connected For example a transformer having port 1 connected to wire 1 and port 2 connected to virtual segment 4 would be shown as a box at the appropriate segment on wire 1 with a short line of the port 2 color extending to the right V4 would appear at the end of the line An open or short circuited transmission line stub is identified in the same way except with S for short and O for open in place of the virtual segment number Insertion objects which are connected only to virtual segments do not appear in the View Antenna display but can be found in the Virtual Segment List Open the View menu and select Show Virtual Seg Conn See Virtual Segment Connection Display for more information Using The 2D Display The 2D Display shows the result of a far field azimuth or elevation pattern calculation which is a slice of the actual full three dimensional antenna pattern It can also be used in con
214. information from this file requires specification of sources frequency ground type etc The first non comment line is the units specifier This will cause Program UNITS to be changed to FEET Wire coordinates to be interpreted as being in feet Wire diameter to be interpreted as being in inches ft in Next are the wire specifiers Spaces commas and tabs are used in this example as delimiters to illustrate the flexibility available As this file is written these wires will be automatically segmented using conservative density If desired an additional field could be added to any line to cause minimum recommended density or a specific number of segments The first three numbers are the end 1 coordinates in feet because of the first unit specifier above The next three are the end 2 coordinates ft The seventh number is the diameter in inches because of the second unit specifier 0 0 0 0 0 32 75 1 5 0 34 42 0 0 34 42 32 75 1 5 34 42 00 34 42 0 32 75 1 5 34 42 34 42 0 34 42 34 42 32 75 1 5 Normally the wire specifications would be written to be easier to read The above format was chosen to illustrate the flexibility available in choosing field delimiters Example 2 for regions having a comma as the decimal separator This is the wire configuration for the 4 square array of example description file 4SQUARE EZ Note that a complete antenna description must also includ
215. ing the same button again Segment junctions are shown as dots on the wire The benefit to specifying source load and transmission line positions in terms of percent from the wire end is that the wire length or number of segments can be changed without affecting the relative position of the source except as necessary to place it at a segment center 22 Test Drive The source type shown in the Type column is a current source The Sources Window also show the source amplitude and phase in this case one ampere at zero degrees When a model contains only a single source the magnitude phase or type have no effect on the pattern or source impedance So we ll leave these as they are for now Now restore the source to the correct position in the middle of the wire Change the value in the From End 1 column of the Specified Pos group from 25 to 50 then pressing lt Enter gt The source should now appear in the middle of the wire in the View Antenna display and the Actual Pos should now show as 50 percent on segment 6 The source could have been connected through a transmission line However this will affect only the impedance seen by the source It will have no effect on the antenna gain pattern or other characteristics No transmission line will be used in this example Close the Sources Window by clicking the close button in the upper right corner Now it s time to deal with the ground Presuming you don t have a perfect
216. ing Loop Size This feature is described in the Advanced Wire Features section Printing or Saving the Wire Coordinates To print the wire coordinates or save them to a file select Other Print Save Wire List This opens the EZNEC Editor with a formatted list of the wire coordinates You can save or print the data from this window For a similar display which includes other features of the model such as sources and loads see the Control Center Outputs menu Other Features In addition to the features in the Wires Window Wire menu EZNEC has a number of powerful features in the Create menu described in the Advanced Wire Features section e Wire Information wire segment length You can see the wire and segment length for any wire by right clicking the box at the left of the row e Importing Wires Wire end coordinates can be imported from a simple ASCII file This isn t intended to substitute for EZNEC s file format but primarily as a way to import wire end coordinates generated by another program Wires are imported by selecting Import Wires From ASCII File in the Other menu The file format is detailed in the Wire Coordinate File section You can add the imported wires to your existing description or you can replace the existing wires with the imported ones See Importing Wire Coordinates for additional information e Change Units Retain Numbers This option allows you to recover from an easy trap to fall into It s easy to begin
217. ing Sources Jo GaroUpgd 2deeeedeNEENEEeNENEEEEeE Eege 85 Multiple erger 85 Using Multiple Sources jsc2ncttnt siete etic tet cttictaletiy tatantietete lit estn tes 85 Phased RA 86 BT aa WE EE 86 eieiei d Ee 86 NK 87 Load EE 87 Placing Loads At Wire JUNCTIONS AEN 88 gading CONG Asana oath hea e aD anata ea che aa Nat 88 Be 89 Using The Loads Windows 2 e ccersce sxescen des teuat ng sctes hateeel kates heneet aaa 89 Load Types And The Loads Window sssssseessessssnnnnreesserrrrrnnnneeeee 89 The R j X Loads Wmdow EE 90 The RLC Loads NWINOOW ee 90 The Laplace Loads WindoW EE 91 Using Reeg BE 92 About Transmission Lines 92 Using The Transmission Lines Window c cceeeeeeeeeeeeeeeeeeeeeeeees 93 Transmission Line LOSS eege Eet deed Ee 95 Modeling Coaxial Cable EE 96 Using TAI ed 96 Transformers eege gege eege ebe 96 Using The Transformers Window ee 97 Using L Networks EE 98 E EE 98 Using the L Networks VWumdow sssssessssssssssnnnnrrnssserrrrnnnnnnnnssrrrrrrnnnn 100 L Network En Ee 100 Using Y Parameter Networks AAA 101 Y Parameter Networks EZNEC Pro on 101 Using the Y Parameter Networks Wumdow 101 Mod lng Ground BEE 102 e TE Bee EE 102 Real Ground TYPOS viccisscssescotechsaeeknpssasaraghiteesspeioeloshiepenneitbaindaonaephenias 103 MININEC jwpe 104 High PROC DEE 104 Table of Contents Limitations of Real Ground Models sssssssseeeeeeeeseerrrrnnnnrnrserrrrrrenn 105 Using The Media
218. ing said violation in addition to any damage suffered by Licensor The provisions of this section shall survive any termination of this agreement General Terms The prevailing party in any legal action brought under this Agreement shall be entitled to reimbursement for reasonable attorney s fees at trial on appeal and on any petition for review Miscellaneous This instrument contains the entire agreement between the parties respecting its subject matter and may only be modified in a writing signed by Licensor and Licensee This agreement is governed by the laws of Oregon Any legal action arising out of this Agreement shall be prosecuted in Oregon Licensee submits to the jurisdiction of the courts of Multnomah County Oregon No waiver by Licensor of any violation or nonperformance by 176 Legal Notices Licensee shall be deemed to be a waiver of any subsequent violation or nonperformance All waivers must be in writing In the event any of the provisions of this License Agreement are invalid under any applicable statute or rule of law those provisions or portions thereof are to that extent deemed to be omitted or shall be interpreted if possible to comply with such statute or rule of law Copyright and Trademark Notice All EZNEC program types including EZNEC demo EZNEC EZNEC EZNEC Pro 2 and EZNEC Pro 4 and their manuals both printed and on line help are copyright 2000 2015 by Roy W Lewallen All rights are reserved EZNEC
219. ing this button will stop calculations and return you to the interface part of the program To avoid unnecessarily slowing calculations the state of this key is tested only periodically so there might be a delay before the program responds to your cancellation request particularly in models containing a very large number of segments 159 EZNEC User Manual Reinstalling or Copying EZNEC To reinstall or copy EZNEC simply insert the CD you received when you purchased EZNEC and run the setup file If you downloaded the program copy the file you downloaded to the target machine and run it Saved description EZ and trace files aren t affected by installation and uninstallation processes so they have to be copied manually When EZNEC is installed entries are made in the system Registry and files are placed in locations other than the program directory These entries and files are essential to EZNEC operation Consequently a copy of the files in the EZNEC program directory after installation isn t sufficient to reinstall the program or to copy it to another machine For those purposes you need either the program CD you received or the file you downloaded when you purchased EZNEC Only those contain everything necessary to install EZNEC Please make backup copies of the CD or downloaded file in case reinstallation is needed in the future It s not uncommon for a CD to become defective with time so two copies are more secure than one You ca
220. insulation See the new Wire Insulation topic for more information Improved Printing If you chose other than the default printer in EZNEC v 3 0 your choice would become the system default printer Also many printer property choices were ignored by EZNEC v 3 0 These deficiencies have been corrected Easy Import of Wire Coordinates from NEC Files EZNEC EZNEC Pro only An additional format is allowed for importing wire coordinates from an ASCII file the NEC GW card format See the Wire Coordinate File topic for more information This is the second format discussed in that topic Multiple Instances EZNEC Pro only Multiple instances are permitted in the pro programs including doing simultaneous calculations The instance number is identified by a number in parentheses in the title bar of each window Other Multiple Instances EZNEC v 3 0 permitted multiple instances to be operating at the same time provided that calculations weren t run Because of the way certain new features were implemented the v 4 0 standard and plus program types don t allow more than one copy to run at once Ground The Real Fast reflection coefficient ground type is no longer available With today s machines the saving in calculation time over the High Accuracy Sommerfeld ground isn t significant and the Fast option is limited in accuracy with low antennas Description files with Fast ground specified are 15 EZNEC User Manual c
221. invert the transformer connection effectively reversing the two terminals of one port This is useful not only for effecting an intentional phase reversal but also to force the polarity to be the same when the ends of connected wires are physically reversed For example suppose you wanted to connect a transformer between the base of two grounded vertical wires such that the voltage and current were the same at both ends with respect to ground If end 1 of one wire was the ground end and end 2 of the other wire its ground end you d have to choose the reverse transformer connection to get the desired result This is because like any other insertion object the polarity of the connection is determined by the end 1 end 2 direction of the wire rather than some physical direction Selecting Adding Deleting Copying Modifying and Moving Transformers See Using Insertion Objects Windows Using L Networks L Networks L networks are a powerful type of insertion object which can be used to model impedance matching networks phase shift networks attenuation pads and many other network functions They can be cascaded to create tee pi and more complex types of ladder networks Unique features of the EZNEC L Network are e The two internal branches of the network can consist of more complex combinations of series parallel or trap connected components e Components making up the branches can be specified as inductances capacitances and r
222. iolation of several NEC guidelines Geometry Check Runs the Geometry Check which detects a number of conditions that aren t allowed such as wires overlapping or intersecting or crossing at other than a wire end or segment junction Show Description Shows a summary of the antenna description as plain ASCII text in the EZNEC Editor This includes wire coordinates source and load locations etc The displayed description can be printed or saved to a file A similar display with only the wires coordinates is available in the Wires Window Other menu Setups Frequency Sweep Opens the frequency sweep setup dialog to set up parameters for the frequency sweep Near Field Opens the near field setup dialog to set up parameters for near field analysis 137 EZNEC User Manual View TraceView Puts EZNEC into TraceView mode for viewing printing or comparing saved far field pattern plots traces without having to do any calculations Utilities Edit IN File A number of special options can be enabled by entering statements in the EZNEC INI file in the EZNEC output directory These are generally options which are seldom used or are used only for special purposes This selection opens the EZNEC INI file in the EZNEC Editor for easy modification Most changes made to the EZNEC INI file aren t effective until EZNEC is exited and re started If you edit the EZNEC INI file and want to apply the changes save the file ex
223. ion 158 Reference Anti malware or security programs occasionally block EZNEC s access to files or quarantines or deletes files needed by EZNEC This can sometimes be prevented by appropriately setting the interfering program s security level or instructing it to allow EZNEC to operate The Calculation Progress Window The Calculation Progress Window appears whenever EZNEC calls the calculating engine to do calculations It remains on the screen until calculations are finished and no other EZNEC operations can occur while it s being displayed It shows several important pieces of information plus it allows you to terminate calculations before they finish Calculating Engine Type The title bar shows which calculating engine is being used For the standard EZNEC program it will always show NEC 2 With the other programs it will show which of the available calculating engine options is being used Frequency The frequency is shown just below the title bar This is particularly useful when doing a frequency sweep Stepped Diameter Correction This message appears under the frequency if one or more groups of wires is being corrected with the stepped diameter correction feature Its appearance doesn t guarantee however that all elements of a Yagi for example are being corrected To determine this you have to use the Stepped Diameter Correction Display EZNEC Pro 4 only Stepped Diameter Correction will normally be disabled wh
224. ion 1 0 Copyright c 2002 vbAccelerator com Redistribution and use in source and binary forms with or without modification are permitted provided that the following conditions are met 1 Redistributions of source code must retain the above copyright notice this list of conditions and the following disclaimer 2 Redistributions in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the documentation and or other materials provided with the distribution 177 EZNEC User Manual 3 The end user documentation included with the redistribution if any must include the following acknowledgment This product includes software developed by vbAccelerator http voaccelerator com Alternately this acknowledgment may appear in the software itself if and wherever such third party acknowledgments normally appear 4 The names vbAccelerator and vbAccelerator com must not be used to endorse or promote products derived from this software without prior written permission For written permission please contact vbAccelerator through steve vbaccelerator com 5 Products derived from this software may not be called vbAccelerator nor may vbAccelerator appear in their name without prior written permission of vbAccelerator THIS SOFTWARE IS PROVIDED AS IS AND ANY EXPRESSED OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNE
225. is in modeling a Beverage antenna where a connection is needed for the termination resistor Another example is an inverted L antenna where the horizontal portion is lower than about 0 2 wavelength In these situations the best approach is to approximate a buried radial system by creating horizontal radials just above the ground and make the ground connection to the radials EZNEC Pro 4 only The best approach for this program is to directly model the actual usually buried ground system make the ground connection to it and disregard the remainder of this topic A height of between about 1 100 and 1 1000 of a wavelength is suitable but in any case no less than several wire diameters If a low impedance connection is required make the radials about a quarter wavelength or odd multiples long and avoid lengths approaching a half wavelength or multiples These aren t free space wavelengths however but wavelengths for a wire at the radial height A half wavelength for a wire very close to the ground will be less than in free space though You can determine the wavelength by modeling a dipole at the height of the radials and adjusting its length until it s resonant Be sure you re seeing the lowest series resonance which for very low wires will occur with a dipole length somewhat less than a free space half wavelength The best radial length will be about half the resonant dipole length Radials can easily be constructed using EZNEC s autom
226. it EZNEC allow a few seconds for the disk cache to write saved information on the disk and re start EZNEC Calculation Time Shows the times which were taken for various calculations No numbers will be shown until EZNEC completes a calculation Note When a frequency or SWR sweep is run only the time for the last frequency calculation is shown not the time for the entire sweep Ground Info Gives detailed information about ground characteristics when Real ground type is selected Memory Info Gives information about available computer memory This report is directly from the Windows system and might not agree with some other analysis tools Note that it s not uncommon for the available memory RAM to be at or near zero Windows routinely uses the disk as virtual memory and frees up RAM as needed Temp Dir Space This shows the approximate amount of temporary space which will be required by the calculating engine to run calculations for the current description and the amount available Component Version Numbers Shows the complete version numbers of each of the major components of EZNEC Show Folders Shows the folders being used by EZNEC for input and output files Show Running Instances EZNEC Pro only Shows instances that are running simultaneously The instance making the query is identified with an asterisk Help Contents Opens this help file and shows the contents About EZNEC Shows the program ver
227. itself to making a model of a current balun common mode choke A conventionally connected transformer model will however act as an ideal current balun with a transformation ratio of your choice An example of the use of a transformer model is in the A Lap Around Track 5 topic in the Test Drive tutorial Using The Transformers Window Open the Transformers Window by clicking on the Control Center Transformers line or the button to its left 97 EZNEC User Manual Like other insertion objects both ports of all transformers have to be placed on real or virtual segments See Placing Insertion Objects on Segments for details In addition to connection location you have to specify port impedances and a choice of normal and reverse connection Specifying Impedances The ratio of the two specified impedances will be the square of the turns ratio For example a transformer specified as having a port 1 impedance of 50 ohms and port 2 impedance of 200 ohms will provide an impedance transformation of 1 4 or a voltage step up of 1 2 from port 1 to port 2 Although specified impedances of 1 and 4 ohms will provide the same transformation as 50 and 200 you should specify impedances which are in the general ballpark of the impedances actually seen by the transformer The reason for this is explained in the Transformers topic This isn t highly critical Specifying Normal Reverse Connection The Normal Reverse connection column allows you to
228. junction with the 3D Display to show an elevation or azimuth slice of the 3D plot This display automatically opens when a 2D azimuth or elevation pattern calculation is requested with the Control Center FF Plot action button To use the 2D plot to show a slice of the 3D pattern open the 2D Display from the 3D Display View menu or check the Show 2D Plot box in the 3D Control Window Many of the menu items are the same as for the other graphics displays so they re covered in a separate section Graphics Windows Menus Be sure to look this section over because it explains how to do such things as add traces to the display This makes it easy to compare antennas and plots and see the results of changes The 2D plot can include Data Lines and a Cursor Neither of these is shown if the Data Window is turned off via the View menu Orientation An azimuth plot is always oriented as though looking down on the antenna The top of the display is in the direction of the Y axis so the X axis is to the right When using conventional mathematical angles Angle Convention selection CCW From X Axis in the Options Menu angles increase as you go counterclockwise zero degrees being to the right If you ve chose the Compass Bearing selection zero degrees is at the top and angles increase as you go Clockwise It s often helpful to add the 2D plot to the View Antenna display for a visual indication of the relative orientation of the antenna and 147
229. l Center This gives you information about the source The fact that the impedance of 79 16 j 45 11 ohms has a negative reactive part indicates that the antenna is operating below resonance and needs to be lengthened if resonance is important The formula of 468 f MHz feet is an approximation and the exact resonant length depends on the wire diameter and height above ground The Source Data display also shows that if a 50 ohm transmission line were connected to this antenna the SWR on the line would be about 2 3 1 If a 75 ohm line is used the SWR on the feedline would be about 1 8 1 Close the Source Data display by clicking the close box In the View Antenna display an additional line has appeared above the antenna wire This indicates by the distance of the line from the wire the magnitude of the current along the wire You can see that the current is maximum at the antenna center and tapers to zero at the ends The current 24 Test Drive indication appears only after calculations have been done and it can be removed from the display if desired In the 2D Plot Window open the File menu and select Save Trace As Enter the name Back Yard Dipole and click Save This saves the 2D plot trace in a file named Back Yard Dipole pf We ll use it in the next exercise Save the antenna description by clicking the Save As action button entering the name Back Yard Dipole then clicking Save This concludes the drive down the straigh
230. l Segment 5 and virtual segment numbers 5 and 6 have been used So we want the low impedance side of the transformer to go to the array common feedpoint Virtual Segment 5 and the high impedance side to connect to the source We ll create Virtual Segment 4 for that purpose The transformer requires specifying an impedance for the two ports or windings Their ratio will be the impedance transfer ratio As explained in the Transformers topic the values of impedances chosen should be in the general ballpark of the impedances connected to the windings So we ll use 50 and 12 5 ohms for the two windings which will give us the desired 4 1 impedance ratio Open the Transformers Window In the Port 1 Specified Wire column enter V4 to connect Port 1 of the transformer to Virtual Segment 4 Enter V5 in the Port 2 Specified Wire column to connect Port 2 to Virtual Segment 5 the array common feedpoint In the Port 1 Rel Z column enter 50 and enter 12 5 in the Port 2 Rel Z column The Rev Norm connection column will default to Normal but in this application it doesn t make any difference After entering the impedances press lt Enter gt 36 Test Drive That completes the transformer entry You can close the Transformers window All that s left is to move the source to new Virtual Segment 4 where the transformer primary is connected Open the Sources Window Change the V5 position entry to V4 Press lt Enter gt Click the Src Dat Action But
231. l box with the X mark Open the Sources Window by clicking on the Sources line in the Control Center information window or on the selection button to its left In the Sources Window grid you can see that there s one source source no 1 which is placed on wire 1 50 from end 1 This is where we want the source to be However this is a good time to practice a little with the Sources Window In the Sources Window locate the cell in the From E1 column in the Specified Pos group Change the value from 50 to 25 and press lt Enter gt This change had several effects First the value shown in the From E1 column in the Actual Pos group changed from 50 to 22 7273 When you specify a source or load or transmission line position EZNEC attempts to place it as close as it can to the specified position But it s restricted to placing the source in the center of a segment In reality the source excitation is spread over the whole segment but it s easier to visualize as being at a single point So EZNEC tells you in the Actual Pos group where the source is actually placed So the Actual Pos group columns show that the source is 22 7 percent from end 1 of the wire and it s on the third segment from end 1 You can see this placement in the View Antenna display You can maximize the display by clicking the maximize button the one with a square near the upper right corner for better viewing then return it to normal size by click
232. lculations It now takes into account the velocity factor when evaluating buried wires EZNEC Pro 4 only which can result in warnings in descriptions which didn t formerly generate any EZNEC User Manual Geometry Check EZNEC v 3 0 has a Guideline Check feature to check the model against modeling guidelines for segment length In EZNEC v 4 0 this has been renamed Segmentation Check and a new Geometry Check feature has been added This powerful feature run automatically before each calculation checks the model for errors such as wires crossing at other than a wire end or segment junction wires occupying the same space or overlapping or wires coming too close to each other Wires Window Features There are a number of new powerful features in the Wires Window Wire menu Rotate Wires Move Wires XYZ Stack Copy Wires which allows making offset copies and Change Loop Size These can be used with a group of selected wires or with a sequential group of wires selected after choosing the action to perform There s a new Create menu with the familiar Create Radials and for EZNEC Pro users Create Wire Grid Check out the two new additions Create Helix and Create Loop Create Loop and Change Loop Size should be of particular interest to quad designers although they re useful for many other applications The new Rotate Wires feature shouldn t be confused with the Elevation Rotate End and Azimuth Rotate End features accessed by right c
233. les are left intact but are not used by EZNEC v 6 0 If they are currently in a directory under C Program Files x86 this will be done without prompting and you will be notified of the change If those files are currently in some other location you ll have the opportunity to accept or reject the move The Control Center Utilities menu has a new selection that shows all folder locations Previous EZNEC versions permitted changing the locations of temporary and ground files v 6 0 does not Operating System Requirements All EZNEC v 6 0 program types require Windows XP Service Pack 3 SP3 or later 32 or 64 bit Earlier operating systems are no longer supported Faster Calculations EZNEC v 6 0 calculating engines are more highly optimized and make greater use of multiple processors so speed improvements of two or more times over v 5 0 are typical Much greater speed improvement is possible with very large models using EZNEC Pro on 64 bit systems described below Better Loaded Trapped Yagi Accuracy Note this doesn t apply to EZNEC Pro 4 when using an NEC 4 calculating engine which doesn t require the described correction Because of errors inherent in the NEC 2 code used for most EZNEC calculations it isn t able to accurately model sensitive antennas such as Yagis made with telescoping tubing or otherwise varying diameter EZNEC has been able to correct this very well but only when a Yagi isn t trapped or loaded NEC 2 based
234. less there are extreme differences in the diameters of connected wires In general if you have EZNEC Pro 4 you should use an NEC 4 calculating engine whenever wires of different diameters are connected NEC 2 is known to be inaccurate in modeling connected wires having different diameters such as Yagi antennas made with telescoping tubing Note This is sometimes called being tapered It shouldn t be confused with EZNEC s segment length tapering The problem gets worse as the segments near the junctions get shorter and as the diameter difference gets larger The error is small enough that it s not important for many applications such as evaluating a tower top loaded with a beam However if the stepped diameters are on a parasitic element or exceptionally high Q antenna the inaccuracy can cause significantly bad results EZNEC incorporates methods based on the one developed by Dave Leeson and described in his book Physical Design of Yagi Antennas ARRL 1992 for calculating an equivalent wire of constant diameter to replace a group of wires of different diameters The original Leeson method provides excellent results but only under a narrow range of conditions and EZNEC will apply it only under those circumstances The requirements are that There must be at least two wires in the group At least two of the wires must have different diameters All wires in the group must be collinear in a straight line A consequence of t
235. licking a wire end cell present in both v 3 0 and 4 0 The new feature allows rotating any group of wires around any axis around the end or center of any wire or around any point in space while the right click feature rotates a single wire around one of its ends View Antenna Display The display can now be moved by dragging while holding down the right mouse button and zoomed by dragging while holding down both buttons See Using The View Antenna Display Because of the new use of the right mouse button the Wire Information popup window appears when you pause the cursor over a wire This behavior can be changed via the WirelnfoDist Special Option Circular Polarization EZNEC and EZNEC Pro only There are several new 2D and 3D plot and Far Field Table display options right and left circular polarization and linear component along the major and minor axis of an elliptically polarized field These are selected via the new Desc Options line in the main Control Center window Click Desc Options then select the Plot tab then the Fields tab Note that the selection affects the 2D and 3D plots and the FF Table Plot Displays Major enhancements have been made to the 2D plot display When displaying multiple fields e g Total Vertical and Horizontal you can click on the field name in the list at the left of the display and the cursor will move to that field The data in the data window will reflect the values for that field W
236. llel with the y axis the remainder of the ground being the second medium The boundary is the radius of the disk radial type or the x value of the dividing line linear type When a new Real ground is created the initial values for its conductivity and dielectric constant are determined by the values entered in the Control Center Options menu Default Ground Const selection 103 EZNEC User Manual EZNEC EZNEC and EZNEC Pro 2 are not able to model buried wires EZNEC Pro 4 is able to model buried wires only when using the High Accuracy or Extended Accuracy ground model and an NEC 4 calculating engine The unique characteristics and uses of each Real ground type are outlined below MININEC type MININEC type ground is not recommended unless direct connection must be made to the ground for example in modeling a ground mounted vertical High Accuracy ground should be used in other cases Like the High and Extended Accuracy real ground models the MININEC type model takes ground conductivity and dielectric constant relative permittivity into consideration when it calculates the pattern and gain However it considers the ground to be perfect when calculating the impedances and currents The net effect is that a connection to MININEC type ground has zero resistance unlike the High and Extended Accuracy ground models so there s no ground conduction loss but the effect of ground on the pattern is included MININEC type ground results
237. loaded TEE 16 Getting Acquainted with EZNEC ccccceeeeeeeeeeeeeneeeeeeeeeeeeeeeeeeneeeeeeeees 17 Making a Desktop Shortcut ENEE 17 EZINEG e RE 18 Printing The Manual EE 18 Program Version Compatibility ccccceeeeeeeseeeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeteeee 18 Test EE 20 Test Drive Introduction cccccccccccccccccccccceececceceeececcceeceeeceeeeeseeeeeseeeseness 20 Table of Contents Along The Straightaway AEN 20 Through later 25 On The Race Course rset cre ca isc EE 29 A Lap Around Track eege 32 Taking Gar 6 For EE 38 B ilding The MOG EE 45 Introduction to Modeling 22 rdee regAdeehte ieren See e die Seier blend cn Aerer Aaen 45 Modeling With E 45 Opening The Description File see Ee 46 Modeling The Antenna Structure Wues EE 46 EENHEETEN 46 Segmentatio Cates ttc teed Aeren ee eege ere 48 Using The Wires leie EE 49 Graphical Wire el e CN 53 Ieren e DEE 54 WINGO EE 55 Wire JEE 56 Importing Wire CGoordmates AEN 57 Other Wire GONSIAGIAUONS oi ace ee Sse seccsycs cede tees naccasies ones tact emceagedencganed unos 57 Advanced Wire Features eege deeg 58 Advanced Wire Features Introduction ssseeeeeeseenenneeeeserernrnrrreeeee 58 Calenary Crean EE 58 Helix RSA iiss cect cece eile tree aaron ahead oad 59 een E 59 Loop FOS IZING ace tees ees toes does e ences ueavesicucdenescnvacguasves TE ARA 60 Radial EE nennen ena EEN EE EEGA 60 Wire Grid Grea tiOn EE 60 Meander Line Creaton EE 62
238. lowing delivery the Licensor will refund the full purchase price upon notification that the Licensee is not completely satisfied with the program and upon receipt by the Licensor of all hardware keys furnished with the program Except as stated in the previous sentence licensor does not warrant that the functions contained in the program will meet the licensee s requirements Licensor makes no other warranties of merchantability or fitness for a particular purpose Use of Licensed Software Licensor is licensing Licensee to use the software as a single user No use of this software may be made on a company or location basis including without limitation local area networks Modification Copies Licensee may make copies of the licensed program but no more than one copy per license may be used at any one time Any modification of this licensed software program by Licensee shall remain subject to all terms and conditions of this Agreement and shall remain the sole property of Licensor all derivative works shall remain the property of Licensor Protection During the term of this Agreement or thereafter in the event Licensee uses or conveys or attempts to use or convey the licensed program manual and or technical documentation or any duplication or modification thereof in a manner contrary to the terms of this Agreement Licensor shall be entitled to an injunction to be issued by any court of equity in joining and restraining Licensee from continu
239. lts might not be exactly the same after rescaling for several reasons One is that not all items are rescaled For example if you defined some wire diameters as wire gauge they won t be scaled so the final antenna won t have exactly the same proportionality as the original Another factor is ground and wire conductivity Neither of these is scaled yet the resistance of both changes with frequency as a consequence of the difference in skin depth So a scaled antenna will generally perform very closely to but not exactly like the same antenna before scaling Rescaling of any wire or group of wires optionally including wire diameter and insulation thickness can be done via the Scale Wires feature in the Wires Window This feature allows much more flexibility including the ability to restrict scaling to certain axes and to specify the scaling center Segment Length Tapering Note The process of making an element from telescoping tubing is called tapering by some authors and corrections for NEC 2 s inaccuracy in modeling these is sometimes called taper correction EZNEC uses the term segment length tapering or segment tapering to refer to the process of stepping or tapering segment lengths rather than diameters The process of correcting NEC 2 for steps in wire diameter is called stepped diameter correction Multiple wires joining at an acute angle sometimes require shorter segments than single straight wires or wires joining in a line par
240. lved which give good results for most situations One is that the size of the holes that is the wire spacing shouldn t 60 Building The Model exceed about 0 1 wavelength Some studies have indicated that a coarser structure is adequate far from the source where current is lower The same general rule should be followed here as for elsewhere in any model that segmentation needs to be finer when the current changes rapidly from one segment to another Another general practice is to make the surface area of the wires equal to the area of the surface being modeled This requires larger diameter wires than normally used diameter equal to the spacing divided by pi but usually produces the best results EZNEC provides an automated method which greatly simplifies the creation of wire grids Wire grid definition is done with a dialog box opened by selecting Create Wire Grid from the Wires Window Other menu It requires you to specify the coordinates of three corners of the grid then EZNEC will do the rest You can adjust the wire spacing and diameter if you wish But the default values which follow the rules described above are generally adequate The Wire Grid Creation dialog box is opened by choosing Other Create Wire Grid in the Wires Window In the dialog box note the rectangular area with GRID shown in the center and with Side A and Side B labeled This represents the physical grid Sets of text boxes labeled X Y and Z are
241. me implies the center and beginning point for all EZNEC operations It appears when EZNEC first starts and remains 129 EZNEC User Manual present until the program ends It contains several distinct areas shown below fS EZNEC beta v B3 0 Fie Options Qutpute Pit Setups View Utites Help Menu I LAST EZ requency 299 793 MHz Save As Grade Wavelength 1m ronn 1 Wire 11 segments 1 Source O Loads rans Lines 0 Lines round Type Free Space View Ant Zeto Meters Azimuth ODeg 1 Deg dBi FF Plot i H zA Selection buttons Action buttons Information window Information Window This window shows information about a number of important parameters of the antenna being modeled Any of the information in this window which can be changed is saved with the antenna description in the antenna description file Selection Buttons These buttons allow you to change the item shown on the corresponding line Buttons which don t have a gt mark or which have a dim mark can t be changed Selections can also be chosen by clicking anywhere on the corresponding line in the Information Window Most selections will open a dialog box or input grid These functions are detailed in the Selections section Note that the Title line above the Information Window is also one of the available selections Action Buttons These buttons start various common actions such as opening the View Antenna display or starting a pattern
242. memory if necessary See Calculation Time above for more information When virtual memory is in use more than 40 GB is required for temporary storage for the largest models and files of about 25 GB are written NEC 2 engines require several times the temporary storage space as NEC 4 engines due to a different calculation method EZNEC Pro will check your available disk space before beginning calculations and will refuse to run if not enough is available Networks The presence of networks can slow the solution a great deal particularly in very large models In one model with 9000 segments 100 networks nearly doubled the calculation time so reduction of the number of networks can make a striking difference One network is created for each current source and transmission line and two for each split current source Combining of the networks with the main large matrix shows in the calculation progress window as Calculating currents Solve During the time this 155 EZNEC User Manual progress bar is filling you might also see constant disk activity particularly if the disk is being used for virtual RAM Reducing the number of networks or the number of segments will shorten this portion of the calculation Bailing Out You can terminate the calculations by clicking the Cancel button in the Calculation Progress Window It might take some time to respond so please be patient the calculation will stop You ll also find that if you cove
243. must precede all wire definitions If absent wire coordinates and diameters are assumed to be in meters Wire definitions consist of end 1 coordinates end 2 coordinates and diameter If desired the number of segments can be added as an eighth field If the segment field isn t included the wire will be automatically segmented using the conservative criterion The file is case insensitive Blank lines and any text on a line following a semicolon will be ignored Blanks tabs or any combination can be used as delimiters separators between fields or individual specifications Commas can be used as delimiters only if your decimal separator is not a comma Number format must correspond to your Windows regional setting That is if you normally write one and one half 1 5 then it must be written that way in this file Imported wires can be used to add to or replace an existing definition 171 EZNEC User Manual Example 1 for the U S and other regions having a period as the decimal separator This is the wire configuration for the 4 square array of example description file 4SQUARE EZ Note that a complete antenna description must also include sources which must be added from within EZNEC Example file for EZNEC wire importing four square array ONLY FOR REGIONS WITH PERIOD DECIMAL SEPARATOR NOTE that wire import files don t contain sources or information other than wires To actually make a 4 square array with the
244. n NEC 4 engine with EZNEC Pro 4 See Stepped Diameter Correction Overview Segment length tapering isn t available the menu choice will be grayed out if more than one wire is selected or if you re in Group Modify mode To length taper segments 1 Save your antenna description Segment length tapering is permanent and can t be undone 2 In the Wires Window select Taper Segs in the Wire menu This opens a dialog box 3 Select the wire you want to taper and which end of the wire is to be the end with the shortest segment length The default maximum and minimum segment lengths are suitable for most purposes but you can modify these values if desired 4 The number of segments and wires which will be created by the process are shown in the dialog box If this is ok click Ok and the specified wire will be tapered The new collection of wires will be shown in the Wires Window with a distinctive color so you can easily keep track of which wires you ve tapered Tip To create a group of tapered radial wires create a single wire then use EZNEC s radial creation feature to make the remaining radials with it as a prototype Segmentation Check Segmentation Check detects some common violations of NEC modeling guidelines namely segments which are too long or short segment length diameter ratio out of bounds and insertion placement errors Unless automatic operation is disabled via the Control Center Options menu Segmentation Check is run
245. n a single source is used the amplitude and phase will make no difference to the pattern gain or impedance Only the source and load voltage current and power and absolute field strength in V m or A m will change If a power level has been specified even these won t change as you change the source amplitude and phase Amplitude and phase are most important when multiple sources are used in which case their relative values are what count See example files Cardioid ez and 4Square ez which illustrate the use of multiple sources Using sources as voltmeters or ammeters A zero volt voltage source can be used as an ideal current meter to measure the current at any point in a wire A zero ampere current source can be used to measure the voltage across a small gap For example the voltage across an insulator can be measured by making the wire continuous and placing the zero ampere current source at the insulator location It will effectively create a gap at that point The current or voltage being measured can be seen in the Source Data display Specifying the Source Type Move the cursor to the right most column Click on the arrow at the right of the cell to open the pull down list Choose the desired source type from the list or enter the appropriate letter or letters in the cell See Source Types for more information Selecting Adding Deleting Copying Modifying and Moving Sources See Using Insertion Objects Windows Plane Wave Excita
246. n copy EZNEC to any number of machines you d like The only restriction is that no more than one copy can be in use at any time The only exception is the clearly identified demo program which may be freely copied and distributed LastZ txt and LastZ sip files The LastZ txt file is created when a Frequency Sweep or SWR sweep is run It contains in comma delimited ASCII format the impedance and SWR at each source and frequency It remains in the EZNEC output directory after the program ends and can be used for other purposes if desired Text headers in the first line identify the field contents LastZsorted txt is a differently ordered variation of LastZ txt When the description has multiple sources LastZ txt lists data for each of the sources at the first frequency then at the second frequency etc LastZsorted txt lists all the frequencies for source 1 then all the frequencies for source 2 and so forth The two files contain the same data EZNEC and EZNEC Pro only The LastZ_src s1p files contain impedance Z11 or reflection coefficient S11 information for each source in Touchstone format The default parameter and format are reflection coefficient magnitude and angle S MA but others can be selected with Special Options The impedance reference is 50 ohms but a Special Option allows the Alt SWR ZO value to be used instead These files are written during each SWR and frequency sweep Parallel Connected Loads Polarity Polarity Di
247. n model shortened Yagis with known good accuracy only if their element diameters are constant The overall performance of shortened antennas with tapered diameter elements can still be determined but there may be a frequency shift in the results from the actual frequency where that performance will occur EZNEC v 6 0 uses advanced techniques to more accurately correct a wider range of Yagi variations but can t be fully tested for every possible situation When modeling a Yagi with near half wavelength elements it s important to follow the rules outlined in Stepped Diameter Correction Overview to allow EZNEC to apply the best correction EZNEC provides a method to show when a correction is being applied as it should This is the stepped diameter correction display and its use is described in Using The Stepped Diameter Correction Display You should consult this display each time you design or modify a Yagi model to make sure all elements are being corrected A conductive boom whether electrically connected to the elements or not can modify Yagi antenna operation in some cases However if an antenna is perfectly symmetrical and the boom is exactly along the center line of the elements EZNEC will no show any effect from it regardless of its diameter This is because a simplification made by NEC is to assume that all the current on a wire is concentrated along a line at the wires center A model can be modified to account for a boom by modifying the
248. nd Average Gan 116 At wire unchons 85 On Gegments 84 Source Placement Precautions 71 83 Source Tvpes 79 Sources 78 79 84 85 86 138 ele lr e cee Soe a 79 Connection to other EZNEC COMPONEMS eetep s iecretz eerg 78 Copying and moving 79 Deleting xicdeciicestscsiseiacntenedeceices 79 189 EZNEC User Manual End Fed Antennas 67 Modifying ceeeeeeeeeeeeeeeeetteees 79 Multiple taics extancrendicncrmedianss 85 86 SPCCHYING vscs ccd eee eects 79 SING i eier eet ege 78 Sources VWimdow 79 Opening 138 MUSING oes taser ra Ae tea 79 Special Opttons 138 162 Spiral Creation sssnnnneeeeeeeeeeenne 59 eeler 25 85 Splitting Wires ceeees 49 SiC DAH aac eege 111 140 Stacked vagie 72 Starting EZNEC ege 17 Step Size 0 eee 83 113 138 Stepped Dameier 62 Stepped Diameter Correction 62 64 70 75 125 127 132 159 Stepped Diameter Correction EE ege 64 TL e BE 64 Stepped Diameter Correction OVEIVICW ccccccceecececeeeeeeeeeees 62 Eege 93 Transmission line 000000000 93 rt 92 Support ee 181 182 How to contact me 182 Reporting bugs 181 e E 111 138 140 Setting alternate ZO0 138 SWR Display 29 127 142 149 ease geed ege deg 142 le DE 149 SWR Graph nnnnaaaaaaaaa 29 127 149 SWR Gweep 29 140 RUNNING egener 140 T Takeoff Ange 147 Taking Car 6 For A Spin 38 Taper Segs EE 125 Eu
249. nded to any file block File parsers that use block length to advance to the next block will skip over new fields OpenPF uses standard coordinate systems For rectangular coordinates X and Y are in the horizontal plane and Z is height For spherical coordinates R is radial distance phi is azimuth angle and theta is zenith angle For cylindrical coordinates rho is horizontal distance phi is azimuth angle and z is height Azimuth angle is 0 along the X axis and increases in the XY plane toward the Y axis counterclockwise Zenith angle is 0 along the Z axis and increases in the Z phi plane toward the phi ray Units are meters and degrees OpenPF files use the Intel processor little endian data convention least significant byte first for multibyte data Bit number 0 is the least significant bit Bits marked as reserved are undefined and should not be assumed to be 0 OpenPF files use the file extension PET In the descriptions that follow word means a 16 bit unsigned integer and FP means a 32 bit single precision floating point number that conforms to the IEEE 754 1985 standard ASCII means a character string that uses the extended ASCII PC 8 symbol set Header OpenPF files begin with a block of the following format 165 EZNEC User Manual Version byte Header length word Source length byte Title length byte Environment length byte Notes length word Source ASCII Title ASCII Environment ASCII Notes ASCII Version T
250. ndows All Graphics Windows can be sized by dragging an edge or corner or can be maximized or minimized by use of the controls in the upper right corner of the form Minimum sizes apply to some forms limiting the size adjustment range Graphics Windows Sections The Graphics Windows are divided into sections as shown below Not all Graphics Windows contain all three sections The Control Box section of the 2D Plot Display which is shown below is available only when the 3D Plot Display is also on The Data and Control sections can be turned on or off via the menu File selection im 40 meter four square array OF x File Edit View Options Reset m Highlight _ EZNEC 4 alpha Azimuth Slice Elev Slice 0 360 Plot Hi E 45 Slice Azimuth 180 Se Elevation Plot Cursor Eley 25 0 deg D Azimuth Angle 45 0 deg Gain 5 34 dBi as Outer Ring 5 34dBi DO dBmax aa zl 0 3D Max Gai 5 34 dBi Sei Slice 3a 5 34 dBi Elev Angle 25 0 deg Cursor Elev 39 4 deg 3dB 9 1 48 5 deg Sidelobe Gain 11 74 dBi Elev Angle 120 0 deg Front Sidelobe 17 08 dB Control Data Plot or Display The Plot or Display section contains the actual graphical information being displayed Data The Data section contains additional information about the plotted data Control 141 EZNEC User Manual The Control section contains controls to alter the Plot display Graphics Windows Menus Menus All Graphics Windows have all
251. nerate a Touchstone sip format file of reflection coefficient or impedance for input to RF design programs The files are created each time an SWR or frequency sweep is run EZNEC Pro Only Major Speed Improvement for Very Large Models Previous versions of EZNEC Pro could only access about 2 GB of RAM This made it necessary for EZNEC Pro to use the disk for virtual memory with models of roughly 10 000 15 000 or more segments which dramatically slowed calculations EZNEC Pro v 6 0 installs 64 bit calculating engines on 64 bit operating systems later than Windows XP which have access to a major fraction of installed RAM If sufficient RAM is installed virtual memory use is avoided and calculations are much faster Tests have shown speed improvements of ten times with some models needing virtual memory use with v 5 0 but not with v 6 0 Note that this level of improvement requires a 64 bit operating Getting Started system later than XP and sufficient installed RAM to avoid virtual memory use See Very Large Models for more information More Segments The maximum number of segments permitted by EZNEC Pro v 6 0 is 45 000 increased from the previous limit of 20 000 Wire Grid Creation Enhancements The wire grid creation feature has been expanded to allow creating a box End wires on any side of a wire grid can be omitted to facilitate connection to other structures Meander Line Creation EZNEC Pro automates the process of crea
252. ng on wire diameter this card will override the internal setting It has no effect when using an NEC 4 engine EN Terminates EZNEC Pro translation EX EZNEC Pro is able to read and write EX 1 2 and 3 cards when opening and saving descriptions in NEC format If both conventional EX 0 and plane wave EX 1 3 sources appear in an NEC format file EZNEC Pro will read both types However unlike NEC 4 EZNEC Pro won t use both types simultaneously you must choose which to use When saving a description in NEC format only the source type currently selected in EZNEC Pro will be saved to the NEC format file This is to prevent an NEC 4 program reading the file from using both source types and producing a different result than EZNEC Pro NEC type 4 and 5 sources will be converted to type 0 The magnitudes of all sources are divided by the square root of two to convert from NEC s peak convention to EZNEC Pro s RMS convention This is done so that powers reported by the programs will agree FR Frequency step data will be ignored Frequency stepping must be manually set in EZNEC Pro s Frequency Sweep Menu 152 Reference GA If more than one GA card have the same tag number sources loads etc applied to that tag number will only be placed on the arc defined by the first GA card with that tag number EZNEC Pro will assign individual wire numbers to each one segment wire making up each arc GD GN All parameters are translated If a s
253. ng to a crash or other problem so your help is essential The key to fixing a bug lies in being able to make it occur If can make it happen can fix it If can t make it happen it s usually virtually impossible to infer the cause In the Windows environment a problem can occur only when certain windows overlap in a particular way or in a particular order or only when certain windows are open So it s important to get as much detailed information as possible about the state of the program when the problem occurs The following information is very important so please include as much of it as you can in your report 1 Error messages Please record the exact wording of the error message and the title on the colored bar at the top The title helps determine what generated the message Often some or all of the program s windows remain on the screen while the error message is being displayed So this gives you an opportunity to record what forms windows are open their approximate sizes and where they re positioned Of course some bugs won t generate an error message If it doesn t that s useful information in itself so please include it 2 What you were doing in as great detail as you can remember when the error occurred This includes not only the very last action but as much as you can recall of the events which led up to it 3 Is it repeatable This is essential information A repeatable error is very much easier to find th
254. ngth scattering cross section mV m X dist Divide the reported value by the distance in meters to get field stregth in mV m at that distance Near Field Table Format Selects whether near field phase information is to be shown The narrow format output doesn t include phase information and may produce a more easily readable output when viewed or when printed to a portrait oriented page This setting affects the output saved in the frequency sweep output file as well as the single frequency near field output display 2D Plot Scale This allows you to choose between two types of scale for the 2D plot ARRL Type This scale is the standard scale used by the ARRL and in many amateur publications It s a logarithmic dB scale which shows the pattern maxima with greater detail at the expense of compressing minor lobes This scale is generally recommended for amateur use because the plots will be more easily compared to published ones Linear dB As the name implies this is a plain dB scale linear with respect to dB It extends 40 dB from the outer ring to the center of the 136 Reference scale Although the outer ring value in dBi is adjustable the range from the center to outside is not 2D Plot Grid Style Allows selecting the dot type 2D grid used by EZNEC v 4 0 and earlier Show Freq on 2D Plot When this option is on checked the frequency is shown at the lower right side of the 2D plot display Note that the frequency won
255. nna If two identical loads appear on identical adjacent segments EZNEC will also show you the data for the two loads together This is so you can simulate a load placed at a wire junction by splitting it in half and putting it on adjacent segments as described in Placing Loads At Wire Junctions Series and parallel connected loads might show a 180 degree phase difference in voltage and current See Parallel Connected Loads Polarity for an explanation Source Data The impedance SWR RMS voltage and RMS current at each source can be viewed or printed by clicking the Src Dat action button in the Control Center In addition a graph of the SWR vs frequency can be displayed by clicking the SWR action button If EZNEC reports a very low value of resistance at any source be careful this might indicate operation beyond EZNEC s limits If two elements are closely spaced and fed out of phase W8JK type antennas the low resistance is real but the real antenna might not work like EZNEC predicts unless you ve included wire loss a Control Center choice Losses become important when the resistance is low so be sure wire loss is included if a low resistance is indicated Negative resistances sometimes are reported for multi element arrays These actually can occur but are subject to the same cautions as low positive resistances The SWR for these sources will be reported as undefined and shown on the graph as infinite A negative source resistan
256. nna you can simply compare the gains of the two at the pattern maximum H they differ by for example 6 dB the efficiency is 25 1 4 If the patterns are different it will be necessary to use the Average Gain feature to find the efficiency It can also be used if the patterns are the same to simplify numerical calculations You simply divide the numerical Average Gain of the antenna with loss by the Average Gain of the lossless antenna For example if the Average Gain with loss is 0 25 6 dB and with no loss 1 0 dB the efficiency is 0 25 1 25 114 Reference Features Alternative 2D Plot Grid The Classic plot grid used in EZNEC prior to v 5 0 is available via the Options menu for those who prefer it When the V 5 style plot is chosen you can also set the linear plot scale range that applies if Linear dB is selected via the Options menu 2D Plot Scale selection The linear plot scale range setting is done via the Control Center main window Desc Options Plot 2D Misc choice Like all choices made in the main Control Center window the choice of linear plot scale range is saved with the model so it can be set to a value appropriate to the plot of the particular model s 2D pattern Antenna Notes Antenna Notes are a way to include notes with your antenna description An Antenna Notes file is an ordinary ASCII text file which has the same name as the associated antenna description file but with a txt extension in place of the
257. nnecting Sources to Ground 85 Connecting to High Accuracy Ground EE 108 Connecting Wires to Ground 103 107 Control BOX eg 141 Control Center129 131 132 138 140 Action buttons 140 Information Window 138 EE 131 Options menu 132 SECTIONS eedan 129 El 138 Control Window 141 144 149 Coord Entry Mode 49 Coordinate Sytem seeeeeeeeennne 46 Coordinates ccccccceeeeeeeeeees 49 Copy Protection 3 isciiceccieciiecsascsueds 4 Copying EZNEL 160 Copyright Nottce 177 Creating Graphics Files 144 Crossed Dpoles 66 184 Current balun 70 Current Phase 110 144 Current Phase Markers 144 Currents 86 110 140 144 Direction EE 110 Showing in the View Antenna Display E 144 Ee TE 110 Currents Table 110 EE 147 2D Displayen 147 CursorBorder osise 162 Cylindrical Structure 49 D Data Lines 142 147 Data Window 141 144 147 ABI Ae CREEL CRAP eR OREN TEN 112 132 dBre EEN 112 132 138 el 81 82 Decimal Separator 6 171 Frequency sweep input file 171 Default Ground Const 132 Deleting A Trace 142 Desc EEN Eeer 138 Description File 131 Changing Location 132 Combining adding 117 131 n UnL DE 131 EE 131 Desktop Shortcut 17 RI 49 Wire RIETSER wisenaetndicsdicndiensicetian 46 Spechfving eeen 49 Dielectric Constant 106 Di
258. ntenna Notes file for this example EZNEC Pro only The Source Data display isn t available when plane wave excitation is being used Far Field Table The Far Field Table is accessed by clicking the FF Tab action button in the Control Center It shows the field strength at each azimuth and or elevation angle If you ve selected a 3D plot type you ll be asked which data to display and how it s to be organized The Far Field Table data can be shown in several different formats as selected via the Control Center Options menu Far Field Table Units selection They are dBi or dBref Shows the same data as the 2D plot Values are relative to the reference value set by the Control Center Ref Level choice or in dBi if the reference level is zero mV m for 1 kW at 1 mile Gives the field strength in mV m at one mile assuming a supplied power of 1 kW Any setting of the Control Center Options Power Level is ignored mV m for 1 kW at 1 km Same as above but at a distance of 1 km EZNEC pro only Ground wave analysis choices dBi or dBref Same as for ordinary far field mV m Absolute value of the field at the distance and height specified in the Control Center Information Window You ll generally want to set the power level via the Control Center Options menu Power Level selection before using this option EZNEC pro only Additional choices when a plane wave source is used dBsw or dBref dB relative to one square wavelength
259. ntries A great deal of effort has been made to make EZNEC work correctly on computers set for the standards of other countries This means that if a comma is set as the decimal separator by the Windows Control Panel Regional Settings all numbers should be displayed with that convention and all numerical inputs are designed to accept that convention The decimal separator is automatically chosen according to your language preference However it can be changed to another character via the Regional Settings if desired You must use the separator chosen for the computer when entering numbers into EZNEC There are a few exceptions to this detailed below Dates should be displayed according to your standard All outputs should print correctly on A4 as well as U S sized paper and the program should otherwise operate normally in all respects If you encounter any operation at any time which requires you to enter or view data in a format other than the standard convention for your country please let me know Of course all details you provide will be helpful Exceptions EZNEC might be unable to correctly format numbers when run on some operating systems if both the decimal and thousands separators are set to Introduction characters which aren t standard for the region of operation If the setting causes a problem EZNEC will detect it and show an error message when the program starts A period is used as the decimal separator in all c
260. ntrol Center Options menu and specify the desired power When this option is used the specified source voltages and or currents of multiple sources will be maintained in the specified ratio but their absolute values will be adjusted by EZNEC to furnish the specified total power to the antenna If a single source is used its value will be adjusted as necessary to provide the specified power This feature is useful when absolute values of field strength near or far field voltages currents or power loss need to be known for a given power input There is no way to control the power sent to an individual source if the model contains more than one source other than manually adjusting the source voltage or current until the desired power is obtained I m not aware of any application for which this would be necessary or desirable A source is shown in the View Antenna display as an empty hollow circle Detailed information about specifying sources is in the Using The Sources Window topic Using sources as ammeters or voltmeters A zero volt voltage source can be used as an ideal current meter to measure the current at any point in a wire and a zero ampere current source can be 78 Building The Model used to measure the voltage across a small gap A zero volt voltage source is effectively a short circuit so can be placed in a wire without disturbing normal operation A zero ampere current source is an open circuit so it will create a gap at the
261. ntrol Center View menu Alternatively EZNEC can be started in the TraceView mode by entering lt path gt EZW TV in the Windows Start Run text box where lt path gt is the EZNEC program path If you use TraceView frequently you might want to set up a desktop shortcut to start EZNEC in TraceView mode Running TraceView When TraceView first starts you ll be prompted for a primary trace file This can be any current version 2D or 3D EZNEC plot trace file having the extension PF or P or files from ELNEC and EZNEC v 1 having extensions ENT or F which you ve previously saved If you haven t saved any plots from previous EZNEC calculations there won t be any to view with TraceView and TraceView can t be used The chosen plot can be viewed in the same manner as a regular EZNEC plot Additional traces can be added to the 2D plot or slice but only the primary trace field strength values can be shown in tabular form The primary trace also determines the initial value of the plot outer ring if automatic scaling is chosen and characteristics shown in the Control Center are those of the primary trace Menu selections and operation are the same in TraceView as for the standard mode except that many menu items are missing because TraceView is for viewing only and the Open selection prompts you for a primary trace file rather than a description file You can select a new primary trace at any time with the Open button or File menu item If
262. nts does the R jX load type is most useful for frequency independent loads e pure resistances or for analysis at a single frequency or a narrow range of frequencies RLC This load type is most convenient if you know the values of equivalent R L and C of the load you re trying to model Not all components have to be present so this type can also be used for modeling any combination of the three including a single R L or C A powerful feature of this model type is that the resistance can be made to vary with frequency to simulate skin effect loss such as an inductor exhibits or insulation loss Each load s resistance can be set independently so you can make some vary and some not if you wish You enter RLC loads directly as values of R L and C for this load type rather than as resistance and reactance The impedance of the combination varies realistically with frequency Three configurations of RLC type loads are available series parallel and trap series RL with parallel C The trap model is useful for modeling inductors as well as traps or other parallel resonant circuits Laplace This load type can be used only by people who understand how to calculate the Laplace polynomial quotient which represents a circuit Explanation of this is beyond the scope of this manual and interested readers should consult a text on circuit analysis for more information The advantage of this load type for those who are able to use it
263. o inches and another wire wire x is connected to it at a right angle as shown in the diagram below If the segments of wire x are shorter than two inches the center of the end segment of wire x will be inside wire y The message will appear with longer wire x segments and or smaller wire y diameter if the angle between the wires is acute Sometimes this condition causes serious computation errors and sometimes not If possible it should be avoided by decreasing the diameter of wire y lengthening the segments of wire x or both The Geometry Check report of this condition can be overridden for the current model allowing calculation to proceed via the Desc Options selection General tab in the Control Center main window Use caution if choosing to override An Average Gain check should be run although a good value isn t a guarantee that results will be valid 121 EZNEC User Manual 1 4 seg length 2 dia Center of segment is inside wire y Wire y Ground Wave Analysis This feature is available only in EZNEC Pro 2 and EZNEC Pro 4 Ground wave analysis is similar to far field analysis in that it uses approximations valid only in the far field but differs in that it includes the ground wave and reports the absolute field at a specified distance rather than a relative one at an arbitrary distance Ground wave analysis is enabled via the Gnd Wave Dist ground wave distance Control Center selection When Ground Wa
264. o the antenna wires the transmission line itself is somewhere else So unlike real transmission lines EZNEC transmission line objects don t interact with the antenna fields That is the currents in the model s two conductors are always equal and opposite so the line doesn t radiate or have current induced by coupling In many real life cases a transmission line does interact with the antenna fields and becomes a radiating part of the antenna This can be caused by coupling to the antenna due to non symmetrical placement of the feedline or by presenting the feedline with an unbalanced source or load EZNEC transmission line objects are suitable for modeling symmetrically placed balanced lines such as a log periodic feed distribution line or W8JK phasing line They aren t suitable for modeling for example a quarter wavelength phasing stub extending outward from a collinear antenna since the stub wires in a real collinear antenna have unbalanced currents and will radiate Coaxial lines laid on the ground such as in a vertical phased array feed system may carry current on the outside just like a ground radial wire In many cases this can be ignored and the EZNEC Pro model used A coaxial cable with field interaction that is with current flowing on the outside of the shield can be modeled with a combination of a wire and transmission line object as described in Modeling Coaxial Cable A two wire line which interacts with the antenna s fields ha
265. ocedure 1 Measure the antenna s feedpoint resistance If you can only measure impedance the resistance will be the impedance at resonance 2 Add a load to the model at the feedpoint and adjust its value until the feedpoint resistance matches the value you measured Wire Grid Modeling EZNEC Pro programs include a feature to automate the process of creating flat rectangular wire grids Even if you re creating wire grids manually you should read the information in the Wire Grid Creation section which also describes use of the EZNEC Pro feature This section gives general guidelines for wire spacing and diameter Before beginning a wire grid model you should estimate the number of segments which will be required The approximate number required based on 0 1 wavelength spacing is 220 A where A is the area in square wavelengths Some compromises might have to be made to avoid exceeding the standard program s segment limit You can see that the number of segments required for a given physical size of object depends on the wavelength at which the analysis will be done A car for example can be modeled as a pretty simple wire frame at HF But even just a roof will strain or exceed the ability of the standard EZNEC program at UHF Be sure to take advantage of EZNEC s Group Modify features for creating your wire grid You ll find that with a little practice wire grid creation can go pretty quickly You can also re use wire grids by taking adv
266. of very good ground Move the mouse cursor to either the Cond or Diel Const cell in the Medium No 1 row and click the right mouse button Note Make sure the mouse cursor not just the text insertion point is in the designated cell when you right click This will open the Ground Characteristics dialog box Select the Very Good option then click Ok The Media Window should show 0 0303 for the conductivity and 20 for the dielectric constant Close the Media Window by clicking the close box in the upper right hand corner 23 EZNEC User Manual This completes creation of the model itself We can now choose what to calculate and display Note that all the information in the Control Center information window is saved with the description when the description is saved to a file In addition frequency sweep and near field analysis setups and the selections in the Control Center Plot menu are saved in this file We know that the dipole s maximum lobe will be at zero degrees but at what angle above the horizon will it be maximum We ll run an elevation plot to find out 3D plotting is covered in On The Race Course in the last section of the Test Drive Click on the Plot Type row in the Control Center This opens the Plot Type dialog box Select Elevation then Ok The azimuth angle for the plot is zero degrees broadside to the antenna which is where we d like to look and all the other parameters look fine To plot t
267. of a segment the source is actually distributed over the entire segment If source placement is critical for example in a base fed half wave vertical or center fed full wavelength dipole if impedance is important the length of the segment containing the source can become important The shorter the source segment is made the more closely it imitates one connected at a single point A simple test can show if this is important Divide the wire containing the source into a reasonable number of segments remembering to follow the rules at the top of this section Run the program and note the results which are important to you such as gain or impedance Move the source over one segment and repeat If the results change more than you re willing to accept you ll need to minimize the length of the source segment One way to do this is to use segment length tapering NO Placing Sources On Segments Like other insertion objects all sources have to be placed on real or virtual segments See Placing Insertion Objects on Segments for details EZNEC s split sources mimic single sources placed at a wire or segment junction but they re really made from two conventional sources placed on the segments adjacent to the chosen junction as shown in the View Antenna display Connecting a source to a transmission line requires that a wire be created for both the source and transmission line to connect to No more than one source can be placed on a given segment
268. of stepped diameters when the segment length diameter ratio is small Especially when confronted with a large difference in diameters the best accuracy will be obtained if you use the automatic segmentation feature in the Wires Window and select M in recommended The accuracy is still not likely to be good enough for accurate modeling of parasitic elements if the built in correction can t be applied The inaccuracy of NEC 2 in the presence of large steps in diameter typically shows up as an incorrect reactance If you design an antenna with parasitic elements having connected wires with largely differing diameters EZNEC will give an accurate idea of the antenna performance However it will show the performance occurring at not quite the correct frequency When you actually build the antenna you can expect the predicted performance but may need to adjust parasitic element lengths slightly to achieve that performance at the desired frequency For example if EZNEC shows your X beam to have a gain of 6 dBi front back ratio of 20 dB and feedpoint SWR of 1 5 1 at 14 63 EZNEC User Manual MHz you might find when you build it that the front back ratio is much worse than predicted at 14 MHz but is very good at 14 5 In this case you would need to lengthen the parasitic element until you get the best front back ratio at 14 MHz The beam will then have very nearly 6 dBi of gain and 1 5 1 SWR at 14 MHz Using the Stepped Diameter Correction
269. of the main 120 Reference window General tab to allow calculations to proceed if the only errors found are that a segment center is within another wire see below This choice is saved with the description since the condition sometimes causes serious calculation errors and sometimes not but it s sometimes hard to avoid The selection affects both the EZNEC Geometry Check and in EZNEC Pro 4 SEGCHK if enabled For users familiar with NEC 4 the Geometry Check tests for the same kinds of errors as NEC 4 s SEGCHK However it s faster and a bit more conservative than SEGCHK and it catches some geometry errors which SEGCHK doesn t And it s present in all EZNEC program types and runs regardless of the calculating engine chosen EZNEC Pro 4 users have a Pre Calc Geometry Check selection in the Control Center Options menu to choose between the EZNEC and NEC 4 checks or both when running an NEC 4 calculating engine suggest keeping the EZNEC Geometry Check enabled unless you have some special need to use the NEC 4 check If you ever do see an error which SEGCHK catches that EZNEC s Geometry Check doesn t I d like very much to hear about it Center of wire x end segment within wire y is a message which brings frequent requests for explanation so a detailed description of its cause has been included here It occurs when two wires are connected at an angle Suppose for example that one wire let s call it wire y has a diameter of tw
270. omma delimited output files such as Lastz txt Comma delimited output files are intended to be used for importing data into spreadsheets and other such programs In this format fields are separated with commas so the period must be used for decimals It is also used for IONCAP VOACAP program files which expect this convention EZNEC Pro only NEC format files read and written by EZNEC Pro 2 and EZNEC Pro 4 use the U S standard because most compiled versions of NEC 2 and NEC 4 expect and produce files using this convention Please let me know if you have any information to the contrary or if you see any indication that EZNEC is not producing or interpreting these files with U S conventions Thousands separators are not used in EZNEC However certain settings of this option might cause a problem See the first paragraph in the Exceptions section Getting Started A Few Essentials First please make one or more backup copies of your program Read the Reinstalling or Copying EZNEC section for important information Next a story Once at the Dayton Hamvention a very skeptical and critical person was asking rapid fire pointed questions about EZNEC which made every effort to answer directly and honestly in spite of his combative nature This approach somewhat dampened the desired effect of intimidation so finally in desperation he nearly shouted Does your program have bugs To which immediately replied Yes In fact guarantee
271. on t work if there are multiple sources Combining Antenna Descriptions Antenna descriptions can be combined into a single model One typical use would be to separately analyze Yagi antennas for different bands then combine them to study interactions Or parasitic structures might be modeled separately then combined in various combinations in a single model To add an existing antenna description to the current model choose Add Description from the Control Center File menu Note Saved descriptions must always contain at least one source So if you want to save a model of a parasitic structure that is one which doesn t have a source you have to add a source to it This source can be deleted after combining it with an existing description which does have a source Combining and importing are sometimes confused If you want to add wires whose coordinates are in an ASCII file or want to replace your current model with wires from an ASCII file see Importing Wire Coordinates EZNEC ARRL EZNEC demo only EZNEC ARRL is a special feature of the EZNEC v 6 0 demo program which gives it extra capability when working with certain files This capability was previously restricted to special EZNEC ARRL programs included with the ARRL Antenna Book but is now built into the EZNEC v 6 0 demo as a standard feature The main purpose is to enable users to view and analyze examples of antennas discussed in the Antenna Book The ARAL Antenna Book CD con
272. on with a plane wave source at the same time as conventional voltage sources _EZNEC Pro does not only one type of excitation can be used at a time EZNEC Pro_also doesn t have provision for sweeping the plane wave source location Bugs EZNEC Pro has corrected several bugs found in NEC 2 and NEC 4 During development of the EZNEC Pro plane wave excitation feature it was discovered that NEC 2 does not ignore the axial ratio parameter on the EX card as it should when a linearly polarized plane wave is specified any value other than zero will improperly modify the results for a linearly polarized plane wave source In addition NEC 4 1 incorrectly calculates the dB scattering cross section when the plane wave source amplitude is other than the default of 1 V m peak or when the polarization is elliptical and the axial ratio is other than 1 Also the polarization sense right or left of an elliptically polarized plane wave source is reversed from the sense specified in the EX card These errors were reported and have been fixed in recent issues of 151 EZNEC User Manual NEC 4 2 but still exist in most copies of NEC 2 and in older copies of NEC 4 1 They don t occur in EZNEC Pro so EZNEC Pro results will differ from those of many versions of NEC 2 or NEC 4 whenever the above described conditions occur Working With NEC Format Files This section applies only to EZNEC Pro programs Writing files in NEC format is relatively straightforwa
273. ond medium can be at a different height but must be at the same level or below the first medium The media can be arranged in parallel slices or concentric rings One use of two media would be to model an antenna on a lake surrounded by land A very important thing to understand is that the second medium is used only for far field pattern calculations and is ignored for all other purposes Be careful when using two media and keep the following in mind 1 Even if you place the antenna over the second medium EZNEC will always use the ground constants and height z 0 of the first medium for calculation of the impedances and currents 2 The second medium is used only for far field calculations Near Field and Ground Wave calculations assume that the first medium is of infinite extent and ignores the second medium 3 The effect of the second medium is taken into account only in a very simplified way The vertical pattern is generated by tracing rays direct from the antenna and reflected from the ground When a second medium is used the ground reflection ray is determined by whichever medium it strikes the top of The ray does not penetrate either medium and diffraction or similar effects aren t considered Because of this a highly conductive inner medium and normally conductive outer medium is not a good model of a ground radial system and shouldn t be used for this purpose 4 Buried wires in EZNEC Pro 4 will always be treated as tho
274. one into developing just this version of this program and refining it to make it useful and easy for you to use and over two years for the first Windows version Other expenses like advertising aren t cheap either So please when someone asks you for a copy of the program realize that he or she is asking you to steal Politely say no but tell them where they can order a copy http eznec com It s a bargain at the price it ll save future users more nuisance and a higher price and it ll save the wear on your conscience wheel Thanks EZNEC Pro This software is protected by a hardware key Every effort has been made to make the protection system as reliable and easily usable as possible It not only protects the developer from theft of software which has taken literally thousands of hours to develop but also protects you the user from having to compete with those who might otherwise use the same tools without having paid for them All comments about this copy protection method both positive and negative are solicited and welcome Guarantee If you re not completely satisfied with EZNEC I ll promptly refund the full purchase price There is no time limit to this guarantee for the standard and plus programs and it s good for 90 days after the purchase of EZNEC Pro This is my only guarantee but honor it rigorously Please refer to the Legal Disclaimer for specifics Amateur or Professional Early versions of EZNEC and EZ
275. onnected For example in an application transforming about 50 to 200 ohms don t specify 0 5 and 2 or 5000 and 20000 ohms for the transformer impedances See item 2 below for the reason Here are some further notes and cautions 1 Remember that real transformers are far from ideal Real transformers seldom maintain the specified transformation ratio over a very wide frequency or impedance range In addition they commonly add a substantial amount of series and shunt impedance except within a fairly narrow frequency and impedance range In particular transformers or baluns used for multi band antennas typically depart dramatically from ideal behavior So don t expect the model transformers to act anything like a real transformer over a wide frequency range 2 The models are not quite ideal Because of the way they re implemented the transformer models actually have a small but usually insignificant resistance in series with each winding The value of this resistance is based on the specified port impedances such that if the specified impedances are in the ballpark of the impedances to which the ports are connected the resistance will be insignificant There s quite a bit of leeway here however so you don t have to be precise about it Please note The specified impedances aren t winding impedances and they aren t the values of the series resistances They should be chosen as explained 3 The method used to create these models doesn t lend
276. ons where deep nulls or high front back ratios have to be determined In those cases even the small fields from wires with little current can modify the results and should be undersegmented or removed with care When studying the effect of an undriven nearby antenna the model of the nearby antenna can frequently be undersegmented or simplified a great deal For example the elements of a 20 meter beam are far from being resonant on 15 meters so constant diameter somewhat undersegmented elements could be used for the 20 meter beam when analyzing its effect at 21 MHz The tip in the Log Periodic Antennas section for segmenting that type of antenna might give you some ideas for others See Some Special Cases in Modeling The Antenna Structure for some examples where the number of segments or segment length requires special consideration Also see the index under Segments or Segmentation for additional references EZNEC permits a maximum total of 500 segments and EZNEC 2000 EZNEC Pro programs EZNEC Pro 2 and EZNEC Pro 4 permit 45 000 Using The Wires Window Other than the Control Center the Wires Window is probably the part of the program you ll interact with most This is the place where the basic structure of the antenna is defined The antenna is made from straight wires The location diameter and interconnection of these wires are all defined in the Wires Window The Wires Window has many powerful features that allow you to quickly
277. onverted to High Accuracy when opening and will be saved with High Accuracy ground Loads When you convert from R jX to RLC type loads either directly or due to combining descriptions with different load types you now have the option of conversion to a parallel RL or RC equivalent Wire Connections Wire end coordinates will always be modified to be identical if the wire ends are deemed connected same coordinates within about 1 1000 segment length because NEC always does this It was formerly an option Options menu Auto Coord Match but no longer is LastZ txt EZNEC Pro only LastZ txt files for instances beyond the first will persist in the EZNEC output directory as LastZ_N txt where N is the instance number The file for the first instance will still be simply LastZ txt Messages The tooltips can now be turned off as well as the new message warning you if the description has changed before opening a new description via Messages On Off in the Options menu Crash Recovery A feature that hope won t see much use if you should ever encounter a program crash please report it the next time you start the program you ll get a prompt giving you the opportunity to recover to the model as it was just before the crash Ground Wave Analysis EZNEC Pro only Ground wave analysis can produce somewhat different phase angles for the polarization components than earlier versions particularly when the observation point is
278. oportional to the current flowing on it If one element of a multi element antenna shows a small current relative to the others it s not contributing much to the overall field It might however be generating just enough to deepen a null in the pattern If your model contains several nearby wires towers and other objects a look at the currents on them will quickly tell you whether they re having a significant effect on your antenna s performance If the current on an object is small relative to the current on your antenna you generally can remove it from the model without much impact on the result unless deep nulls are important even small fields can have a significant effect on nulls Shorter conductors require more current than long ones to have the same effect 110 Interpreting The Results If using plane wave excitation see Interpreting Plane Wave Results for additional information Load Data Load data are shown by clicking the Load Dat action button in the Control Center The RMS voltage across RMS current through impedance of and power loss of each load is shown In addition the total load loss is shown in watts and dB The loss figures are invaluable in determining the loss caused by traps loading coils and the like You can also determine the voltage across the load or current through it under actual operating conditions by entering via the Power Level selection in the Control Center Options menu the power to the ante
279. or most of the following Menu selections The selections function the same for all displays except for exceptions noted below File Print Plot Prints the Plot section of the window on the printer The plot is sized to print the page its size isn t adjustable The line width of the Plot section can be adjusted from the Control Center Options menu Print Plot and Data 2D SWR only Prints the Plot and Data sections of the window on the printer The Data text is printed below the plot The line width of the Plot section and the font used for the Data section can be adjusted from the Control Center Options menu Printer Setup Opens a dialog box allowing you to choose the printer and paper type and characteristics Add Trace 2D only Opens a dialog box allowing you to choose a trace to add to the existing display Information about added traces and gain comparison to the primary trace can be displayed in the Data Box if desired See Using the 2D Display for more information The colors of added traces can be selected via the 2D display Options Colors Recalled Traces selection described below Trace types which can be added are ENT 2D Trace files created by ELNEC and EZNEC family products prior to v 2 0 F 2D Trace files created by ELNEC and v 1 EZNEC family products frequency sweeps P 2D Trace files OpenPF format created by v 2 and later EZNEC family products frequency sweeps PF 2D trace files OpenPF
280. or the current calculation portion but only if the program isn t forced to use the disk for virtual memory Consequently a major speed reduction will occur if this mode becomes necessary 64 bit calculating engines are installed with EZNEC Pro on a 64 bit operating systems later than XP These have access to a very much larger amount of RAM than 32 bit engines so virtual memory operation isn t necessary if sufficient RAM is available on the system But a maximum size 45 000 segment model would require about 16 GB of available RAM if run in single precision and 32 GB for double precision No program can use all the system RAM so amounts greater than this would have to be installed to avoid virtual memory operation To avoid extremely slow calculations with very large models install EZNEC Pro on a 64 bit system with as much RAM as possible and reduce the number of segments as necessary to avoid virtual memory operation And don t use Extended Accuracy ground unless absolutely necessary Segments In my experience of viewing models created by EZNEC pro users many models use more segments than necessary Calculating time is approximately proportional to the square of the number of segments for small models and to the cube of the number of segments for large models so reducing the number of segments is always desirable The Seqmentation section contains tips for reducing segment use Virtual RAM Use EZNEC Pro will use the disk for virtual
281. order of several meters at the lower end of the HF range Real ground is likely to be stratified with widely varying conductivity and dielectric constant within this depth range Because NEC therefore EZNEC assumes a perfectly homogeneous ground of infinite depth the model may not accurately reflect the antenna s actual environment While NEC is believed to be accurate in its evaluation of the model it cannot accurately predict antenna performance if the model does not adequately represent the real situation Consequently EZNEC results for antennas with very low horizontal wires or EZNEC Pro 4 only with buried wires particularly at lower frequencies may be of limited usefulness in predicting actual antenna system performance EZNEC is not able to model ground as being composed of other 105 EZNEC User Manual than a single homogeneous material of infinite depth EZNEC EZNEC and EZNEC Pro 2 are not able to model buried wires Another factor limiting the ability to predict antenna performance when ground is a major factor is that actual ground conductivity appears to vary with frequency an effect not accommodated by EZNEC Consequently conductivity values for frequencies other than the frequency of use might not be accurate It s also important to be aware of your limited ability to make realistic connections to ground as outlined in Real Ground Types See Vertical Antennas and Buried Radials for more about the limitations of Real g
282. oriented using Rotate Wires Scaling Wires Lengths and optionally diameters of any selection of wires can be multiplied by a constant factor by selecting Scale Wires in the Wire menu The form which opens lets you choose the center of the scaling and in what directions along which axes scaling takes place Distances of all wire ends from the chosen center point in the chosen directions are scaled by the specified factor To change the lengths of wires while keeping one end fixed use the Change Length By or Change Length To shortcut instead Splitting Wires Any wire can be split into multiple equal length wires by selecting Split Wires in the Wire menu Making Multiple Offset and or Rotated Copies of Wires EZNEC EZNEC Pro only Multiple offset and or rotated copies of a wire or group of wires can be made with the Make Multiple Copies feature in the Wire menu Each copy is offset and or rotated from the previous one by the specified amount This feature can also be used to move a wire or group of wires without copying although this can be done more easily using other features Making a Cylindrical Structure EZNEC EZNEC Pro only The feature makes copies of the selected wires and places them in an evenly spaced circle around the Z axis Choose Make Cylindrical Struct in the Wire menu Reflecting Wires in a Plane EZNEC EZNEC pro only A copy of selected wires can be made which are positioned as though reflected in any of the three
283. oss the bottom to make a triangle Previously we would have had to enter the coordinates of the new wire into the Wires Window add row The coordinates could have been entered as W1E2 and W2E2 But with very large models where the wire numbers might have been turned off it s necessary to pause the mouse cursor over one end to identify it with the pop up wire information display to determine the wire number and end Here s how we can do it now In the Mouse Operation frame choose Add Conn Wires Move the mouse cursor to the lower end of wire 1 left click the mouse but don t hold the button 38 Test Drive down You ll see a large red square appear at the lower end of wire 1 Ina more complex model you might sometimes accidentally select the wrong wire If you do just press lt Esc gt to cancel the selection Next move the cursor to the existing wire end where you want to connect the second end of the new wire A red line will follow the cursor jumping to the nearest acceptable point like this DN View Antenna Back yard inverted vee File Edit View Options Reset EZNEC Iw Center Ant Image Mouse Operation C Normal Viewing Add Conn Wires C Move Wire Ends New Wires Segs 7 Dialin 12 Iw Copy Conn Wire In this case there s only one acceptable connection point the wire 1 wire 2 junction is excluded because a new wire to there would overlay wire 1 When the red line is in the desired position rig
284. ot have to be equally spaced They will be sorted in increasing order for display Frequencies must be separated by spaces carriage returns or a combination of these If your regional decimal separator is a period and not a comma a comma may also be used as a separator alone or in combination with spaces or carriage returns Any line not beginning with a number is considered to be a comment and ignored They may be entered anywhere in the list Entries of zero or empty fields are ignored A negative entry will terminate reading of the file so that only values preceding the negative entry will be used This is a convenient way to limit processing to only the first part of a lengthy list Wire Coordinate File The wire coordinate file is used for importing wire coordinates via the Wires Window or the Control Center by choosing Import Wire Coordinates from ASCII File in the File menu The plus and pro program types permit two different file formats the standard type permits only the first one described below FIRST FORMAT TYPE ALL PROGRAM TYPES The ASCII import file consists of an optional line defining the units to be used for coordinates and diameter followed by one line per wire giving the end coordinates diameter and optionally number of segments Comments may appear anywhere in the file Tabs spaces commas or any combination may be used as delimiters The optional units specification is done on one line and
285. ound Types topic The points in space where EZNEC will calculate the field strength are specified in the Near Field Setup dialog chosen in the Control Center Setups menu Near Field selection The entries in the dialog are described below Start Stop Step Columns These are the locations in space relative to the origin where EZNEC will calculate the field strength values EZNEC begins at the Start location and steps by increments in the Step column until the Stop location is reached X Y and Z or Dist Zen Ang and Az Ang rows The titles of the rows depend on the Coordinate System selection For Cartesian coordinates the rows represent the x y and z distances from the origin in current units For spherical coordinates they represent the radial distance from the origin in current units the zenith angle angle downward from the z axis in degrees and the azimuth angle angle counterclockwise from the x axis in degrees Field Either the E electric or H magnetic field can be calculated As distance from the antenna increases the ratio E H approaches 120 pi so at sufficient distances calculation of only one field is adequate because the other is then known This isn t true however when close to the antenna Coordinate System Stepping can be done either in Cartesian x y z or spherical coordinates but results are always shown in Cartesian coordinates 123 EZNEC User Manual See X Y and Z or Dist Zen Ang an
286. owing rules should be followed whenever possible Segments immediately adjacent to the insertion object should have the same length and diameter as the segment containing the insertion object and should be in a straight line If the insertion object is on the end segment of a wire only a single wire should connect to it An often convenient way to insure these conditions are met is to place the insertion object on a wire having at least three segments and not on one of the end segments The condition of segments being in a straight line is often violated when using a split source such as at the center of an inverted vee or the corner of a square element This however is usually a case where any error is minor and can be detected with an Average Gain test EZNEC s Segmentation Check shows violations of these guidelines Tip If you want to place an insertion object in the center of a wire give the wire an odd number of segments Using Insertion Objects Windows The following operations are common to all insertion object windows e g objects Window Transmission Lines Window etc Placing Objects on Segments See Placing Insertion Objects On Segments Selecting Objects Deleting copying and moving objects require first selecting which ones are to be operated on In addition objects can be selected before starting Group Modify To select an object click on the button on the left side of the appropriate row The selected object will be
287. ows in the L Networks Window grid The upper row of the Specified Pos and Actual Pos columns are the connection to Port 1 and the lower row for Port 2 For the remaining columns the upper row is for the series branch and the lower row for the shunt branch The meaning of each cell is indicated by the column heading Connect Port 1 to Virtual Segment 1 by entering V1 in the Port 1 Wire cell The is the upper cell of the leftmost two row column Under that entry in the lower column Port 2 Wire enter V2 In the upper Series Branch row of the L column enter the value in uH of the series inductor 1 815 In the lower Shunt Branch cell of the C column enter the value in pF of the shunt capacitor 199 7 Press lt Enter gt The configuration defaults to series connection and empty cells are set to zero which for a series connection means a short circuit So the series branch has only the inductor and the shunt branch has only a capacitor The first two rows of your L Networks Window grid should look like this L Networks Actual Pos Seg Seg Shunt Branch 1 Vi Short 1 815 Short 0 Ser Y2 Short Short 199 7 H Ser You might have to use the horizontal scroll bar to see some parts of it We haven t specified an R Freq because we re using an ideal inductor for this example If the L Networks Window display looks ok close the L Networks Window Only one step remains to move the source to Virtual Segment 1 Open the Sources Window C
288. ox Press lt Enter gt Notice that the R L and C values for the shunt branch bottom row all show Open as they should The final step is to move the source onto new Virtual Segment 3 Close the L Networks Window and open the Sources Window Change the position of the source from V4 to V3 and press lt Enter gt The impedance transforming system now looks like the figure above Click the Src Dat button to see the impedance It s now 43 45 j0 2612 the reactance is very nearly gone as we planned and the SWR is down to 1 151 1 The finished project is available as example file 4Square L Network Feed With Z Matching ez This completes the lap around Track 5 37 EZNEC User Manual Taking Car 6 For A Spin EZNEC v 6 0 allows you for the first time to make antenna modifications graphically rather than with the Wires Window Here are some examples showing how to take advantage of this capability We ll also see how the new Split Wires feature can be used to advantage Open the BYVee EZ example file and open the View Antenna display In View Antenna check the Center Ant Image box for better viewing It should look something like this View Antenna Back yard inverted vee File Edit View Options Reset Iw Center Ant Image Mouse Operation Ze Normal Viewing C Add Conn Wires C Move Wire Ends Let s suppose we have this antenna in the back yard and want to see the effect on pattern and impedance if we add a wire acr
289. p TE GZ a 96 Directories 132 Changing Locations 132 Disk Use As Virtual RAM 159 Display Window ssseseeeseeeeeeen 141 Divide Length Dy 54 DotMult EEN 162 Double Precision Operation 100 156 Download 16 160 E E Field EEN 112 123 Edit Men 132 CUEING E 131 Antenna Notes secen 131 EES eege ee 131 Ee tee 118 e LEE 118 EffICIency scc cevansieeacdiccesaededate 114 Elevated Radial Systems 66 Elevation Angle en 138 Elevation Rotate End 54 EIEVRAG eege 66 Elevbiad ez 66 End Coordinates eaaaeneeeeaennn 49 EnteriNg iain icttacrceuks 49 End Fed Antennae 67 Ending EZNEC eettecieer usgdegc 131 Entering and Modifying Ground E TE 106 Entering and Modifying Transmission Lines a00001 u 93 Exit Normal ss 131 Exit Without Saving 26 131 Extended Accuracy Ground8 103 155 EZCalc4D NEE 156 Ce 131 181 Ending EE 131 EXITING araa 131 Previous versions aa aaaeaa 18 Updates 181 EZNEC Components eeeaan 45 EZNEC Editor ccecce 118 EZNEC PIG eeen 150 Differences from NEC 2 and NEC A 150 EZNEC Pro And NEC 150 EZNEC Pro User 18 EZ NEG PrO 4 ccenn 156 Double precision NEC 4 engine EE 156 EZNEC INI cee 138 162 ge EE 11 EZNEC AbRL eee 117 EZNEC M ooesseenseeeenenernnnn 11 F Far Field Patterns 0 113 Far Field Table 112 Far Field Table Units 112 132 Fast Anal
290. placed by a catenary and insertion objects on the original wire will be placed in the same relative positions on the catenary When the Replace wire with catenary box is checked data cannot be entered in the direct entry boxes below but when a valid wire number is specified the characteristics of that wire are loaded into the direct entry boxes The data in the direct entry boxes can be modified only by unchecking the Replace wire with catenary box which disables the replacement feature If you want to replace a wire but with different diameter number of segments or end coordinates you must close the Create Catenary dialog and modify the wire then reopen Create Catenary and select the wire Tip Tto place a source at the center of a catenary when directly defining it and not replacing a wire specify an odd number of segments wires Then place the source on the middle wire For example if the catenary has 51 segments and comprises wire numbers 35 to 85 place the source on wire number 35 85 2 60 Helix Creation The helix creation dialog box opens when you select Helix from the Wires Window Create menu A helix should be used whenever possible to model a loading coil or any other coil where the current at one end can be different from the other due to radiation and or significant electrical length The assumption of equal currents at the ends of lumped loads make them unsuitable in those situations Most entries in the helix
291. placed close to the corners of the grid which their coordinates represent That is the coordinates on the upper left are for the upper left corner of the grid the junction of Side A and Side B and so forth Other options are IEW for Include End Wires and Create Box Unchecking IEW for any side will inhibit creation of the outside wires of the grid on that side This allows more convenient connection to other structures in some cases If Create Box is checked additional parameters appear at the bottom of the window to allow defining an enclosed box The approximate number of wires to be created is shown near the lower left If insufficient information has been entered to calculate the number of wires Data incomplete appears Note After creating a wire grid using the default wire spacing Segmentation Check will show that the segment length exceeds the conservative maximum This is normal and no reason for concern X Y Z three sets In these boxes enter the coordinates of three corners of the grid Note that it s possible to create a parallelogram as well as a rectangle by the appropriate choice of coordinates The units of the coordinates are the current units chosen for EZNEC which is shown below the lower left set of coordinates IEW If one of these boxes is unchecked the wires along that side will be left off This option is used when connecting two wire grids to avoid creating duplicate wires at their junction Grid Sp
292. ple insertion objects are placed on the same segment all are connected in parallel except conventional series connected loads which are placed in series with other objects on the same segment 4 The polarity of a port that is in which direction the and terminals are connected is determined by which terminal is closest to end 1 of the wire This varies some depending on the object and you ll find more information in some of the individual object topics However the two ports of all two port insertion objects are always phased the same relative to the end 1 end 2 directions of the wires into which they re inserted Insertion object windows e g Sources Window L Networks Window etc also have a number of common features See Placing Insertion Objects on Segments and Using Insertion Object Windows for more information If at least one port of an insertion object is placed on a wire the object is shown in the View Antenna Display See Using The View Antenna Display for a description of the symbols used Placing Insertion Objects On Segments All insertion objects have to be placed on real or virtual segments All insertion objects with the single exception of the series connected conventional load can be placed on a virtual segment For insertion objects with two ports the two ports must be connected to different real or virtual segments There will be two sets of input specifications for two port insertion objects
293. ple of dB loss at one frequency or another so failure to include loss resistance will lead to overly optimistic results The trap RLC model as its name implies is particularly useful for modeling traps If the trap is physically large or long enough that unequal currents can occur at the ends an EZNEC load can result in considerable error When possible a helix should be used to represent the coil A wire can be added along the center of the helix and a suitable capacitive load inserted in the wire to represent lumped trap capacitance Using The Loads Windows Load Types And The Loads Window The Loads Window is where impedances are placed on the wires in the model Open the Loads Window by clicking on the Control Center Loads line or the button to its left Like other insertion objects all loads have to be placed on real or virtual segments See Placing Insertion Objects on Segments for details Loads can be specified in three different ways as R j X RLC and Laplace types The types can t be mixed so all loads have to be of the same type The appearance and operation of the Loads Window depends on which load type you ve selected The load type is saved with the description file so when you first open the Loads Window from the Control Center it will reflect the type of load specified for the current description You can change the load type at any time from the Loads Window by selecting Change Load Type from the Other menu NOTE Wh
294. r any of the EZNEC Pro windows during a lengthy calculation there might be a delay before they redraw Both these delays are due to the fact that the calculating engine communicates with the main program only at discrete times and updates and button responses can only be serviced at these times Double Precision Operation EZNEC EZNEC Pro 2 and EZNEC Pro 4 include a double precision NEC 2 calculating engine in addition to the standard mixed precision engine EZNEC Pro 4 also includes a double precision NEC 4 2 calculating engine EZCalc4D as well as the standard single precision EZCalc4 engine The choice of calculating engine type affects the size of model at which virtual memory operation will take place it will happen with a smaller number of segments approximately 0 7 times as many when running double precision calculations than when running single precision In addition to the inherent slowing during virtual memory operation operation may also be slowed somewhat because of the increased sizes of arrays which must be written to and read from the disk during calculation Approximately twice as much memory and temporary disk space will be used for double precision operation The maximum number of segments and wires which EZNEC will accommodate is the same for both single and double precision See Very Large Models for more information about virtual memory use and techniques to minimize calculation time The interface portion of the progr
295. r if there s no existing valid data you ll see a dialog box which allows you to enter the start stop and step increment frequencies for the sweep These values 127 EZNEC User Manual are shared by the Frequency Sweep function Alternatively you can have EZNEC read a list of frequencies from an ASCII text file The requirements for this file are detailed in the Frequency Sweep Input File section After entering your selections click Run to begin the sweep At the conclusion of the sweep the SWR Display will open showing the results Use of this display is covered in the Using The SWR Display section of the Reference chapter After the sweep is finished a file named LastZ ixt is present in the EZNEC output directory This file contains impedance results from the sweep and persists after the program ends The data in this file can be used for analysis by other applications if desired TraceView TraceView mode is a way to look at compare or print previously saved traces far field pattern plots without having to run far field calculations TraceView mode is also capable of displaying some plot files in the OpenPF standard format generated by programs other than the EZNEC family but this operation isn t guaranteed TraceView can also be used to translate plot files to PF format from the ENT format of ELNEC and EZNEC v 1 Starting TraceView EZNEC can be put into the TraceView mode at any time by selecting TraceView from the Co
296. ray pattern or gain Only the impedance will be affected In the Control Center click the Open Action Button then locate and double click 4 Square L Network Feed ARRL Example ez Click the Src Dat Action Button and look at the reported impedance and SWR As you can see the impedance of 10 55 j3 832 ohms is too low for a good match to a 50 ohm feedline As is the SWR on a 50 ohm feedline which is what we ll use for this exercise connected to the common feedpoint would have an SWR of about 4 8 1 It appears that a 4 1 impedance ratio transformer would improve the impedance match considerably We ll insert this transformer between the source and its connection to the array feed system Before we begin we need to know two things the wire or virtual segment the source is connected to since that tells us where the common feedpoint is and what virtual segment numbers have been used so we can choose a new one for the source transformer connection We can get both bits of information from the Virtual Segment Connection display since interconnections in this model which don t need a wire connection use virtual segments Close the Source Data Window You don t have to close each window before opening another it just reduces clutter to close windows which aren t being used Open the View Antenna display In the View Antenna display open the View menu and click Show Virtual Seg Conn This display shows that the source Src1 is connected to Virtua
297. rce Load or Transmission Line menu and specifying the range of item numbers to be modified Alternatively the items can be selected before making the menu selection While Group Modify is active the selection is frozen and items can t be added to or removed from the selected group Any changes made to any of the items is applied to all items in the selected group Most changes which can be done on individual items including shortcuts can be done on a group of items using Group Modify To turn Group Modify off select Wire Source Load or Transmission Line Group Modify again Near Field Analysis As of this writing EZNEC and similar programs are accepted by the FCC and some counterpart bodies in other countries as permissible for calculating compliance with RF exposure requirements However EZNEC results should never be used in any judgements regarding human safety Please carefully read the Legal Disclaimer for further information Near field analysis as it applies to EZNEC is something of a misnomer because the complete field is actually calculated and reported So near field analysis results apply equally well in the far field EZNEC presents near field data only in tabular not graphical form Reported field strengths are RMS Near field analysis is run by clicking the NF Tab button in the Control Center Note This feature is disabled when MININEC type ground is selected For more information see MININEC type in the Real Gr
298. rce placement is EZNEC s Average Gain feature Whenever a 3D plot is calculated EZNEC calculates the average gain by integrating the total radiation pattern power and dividing it by the power furnished by the sources This is reported at the bottom of the Control Center form Source placement problems are often indicated when the average gain value of a lossless model is significantly different from one See the numbered list below for how to set loss to zero Source placement can then be modified to bring the average gain as close as possible to one in the lossless model after which the lossy objects can be restored to normal Note EZNEC Pro 4 only Average Gain can t be used to evaluate source placement if the model includes buried wires EZNEC s Segmentation Check detects and notifies you of some common placement errors To use Average Gain to test source placement 1 Save the current description optional you can use the undo feature to restore the original model if you prefer 2 In the Control Center choose Plot Type 3 Dimensional 3 If any Real ground type is specified change the Ground Type to Perfect 83 EZNEC User Manual 4 If any loads L networks or EZNEC Pro only Y parameter networks are specified set their resistances to zero or delete them Set all transmission line loss to zero In the Control Center set the Wire Loss to Zero Do a far field plot Note the average gain reported at the bottom of the Cont
299. rd To save a description in an NEC format file simply include the extension NEC when you specify the file name The remainder of this section deals with reading NEC format files To import an NEC format file into EZNEC Pro include NEC as the extension when you specify the file name A number of NEC features aren t implemented in EZNEC Pro so exact translation of all files can t be done However many files can be directly translated and most geometry cards which usually constitute the majority of complex files will be translated There are a few differences between NEC 2 and NEC 4 format files as follows RP requires ground medium information in NEC 2 and not in NEC 4 Phi and theta are reversed on NE and NH between NEC 4 and NEC 4 GN3 ground available only with NEC 4 2 NEC 2 and NEC 4 1 do not recognize this ground type EZNEC Pro 4 allows choosing among NEC 2 NEC 4 1 or NEC 4 2 formats via the Control Center Options menu Other program types write and interpret files according to NEC 2 standards Following are the card types read by EZNEC Pro The following cards are read but some with altered interpretation as detailed below CE CM CW EK EN EX FR GA GC GD GE GH GM GN GR GS GW GX IS LD NE NH NT NX RP TL WG XQ CE CM The first 30 letters of the first CE or CM card becomes the title EK When using the NEC 2 calculating engine EZNEC Pro normally sets the extended thin wire kernel automatically dependi
300. rds About Copy Protection iscsi A ee eds 4 ADOULUEZNEG veasciustienesastanentst 138 About Ground Models 102 About Insertion Objects 75 About LOGOS cicosc tocccetes neuen tescas 86 About Sources e 78 About Transmission Lines 92 About Wires nnnnnnnnnnnnnnnnnnnnne 46 Acknowledoememts 2 Action buttons 000000000 129 140 Setting font size and type 162 Acute Andgles Ae 64 Adding A Description 117 131 Adding A Trace aeeeennneeaeenn 142 Advanced Wire Features Introduction eeeeeeeeeeeeee 58 Along The Straightaway 20 Alt SWR Z0 EE 138 149 Alternative 2D Plot Grid 115 Amateur or Professional 5 Angle Conmventon 132 Antenna Efficiency eeeeean 114 Antenna Heoht 49 EI elle Le BEE 49 Antenna Notes 115 131 162 Editing octane nein Matera es 131 NEC file CH 162 Anti adware Programs 158 Anti spyware Programs 158 Antivirus Programs sseneeaa 158 ARRL Antenna Book 117 ARRL Type Plot Scale 132 TEE 132 Auto Coord Match 132 Auto Coordinate Match 46 Auto SEQ EE 126 Ee e EE 132 Autor omplete sssseeseeeeeeeee 132 te 158 Automated Radial Creation 60 Automatic Segmentation 48 115 Average Gain 71 83 116 Detecting source placement Droblems 83 WLC Dearne ere aren Aer re arena ner 49 PXOS e
301. re is checked the new wire will have the diameter and number of segments of the highest numbered wire connected to the beginning end point of the new wire To begin left click the point where you want the new wire to start A large square will appear at that point Press the lt Esc gt key to cancel the selection if you need to choose a different location After choosing the start point move the mouse cursor to the desired end point of the new wire and right click to finish the operation Any needed modification to the wire can be done in the Wires Window as it is for any wire Move Wire Ends 53 EZNEC User Manual With this feature you can move a wire end and optionally all connecting wires from its current location to the end of any other wire Select Move Wire Ends in the Mouse Operation frame at the left of the View Antenna Display If you want to move all the wires at a multiple wire junction Check the Preserve Connections box if you want to move only one wire end leave it unchecked Left click near the wire end you want to move A large square will appear at the selected junction and the closest segment of the wire to be moved will be highlighted Only one wire will be highlighted even if Preserve Connections is checked although all wires connecting to the same junction will move Press lt Esc gt to cancel the operation at any time before movement is finalized Right click at the desired new location to finalize the movement Not
302. red If any line is found beginning with GW the file is assumed as being GW format and all other lines in the file including dimension specifications are ignored and all values are assumed to be meters Comments can follow the data on the line by preceding the comment with an exclamation point This format enables importing wires only directly from an NEC file or from GW lines cut and pasted from one Note that EZNEC pro programs allow direct reading of NEC format files including most of the other card types so this method of input isn t usually necessary 174 Legal Notices Legal Disclaimer The licensee Licensee or User acknowledges that the reliability of any and all results produced by this software are not precise and are subject to significant levels of variability Licensee further acknowledges that the reliability of results can be affected by a multitude of factors including the type of antenna used whether it is used in an urban environment surrounding objects ground conductivity conditions and the experience and skill of Licensee in using computer modeling techniques Licensee specifically acknowledges that this software CANNOT BE USED TO tell User whether 1 the amount of electromagnetic energy being emitted from User s antenna is unsafe to User User s family User s neighbors or anyone else in proximity to User s antenna 2 Licensee s antenna subjects Licensee or any other persons to potentially hazardous
303. rent flowing into the other terminal of the source from the ground Now suppose you have a very very small battery powered transmitter Connect one of the transmitter terminals it doesn t matter which one to the end of a very high horizontal wire and leave the other end open circuited What happens You ve connected a load the antenna wire to one terminal but there s nothing connected to the other The source sees an open circuit and no current flows into the antenna wire or anywhere else An EZNEC source is distributed over the segment on which it s placed this is approximately equivalent to placing it at a point in the center of the segment Consequently it s not possible to put a source completely at the end of a wire the closest it can come is a half segment from the end But unless the segment length is very long what you ll see if you place a source on the open circuited end of a wire is a very high impedance typically consisting of a large Capacitive reactance and very low current This is because one terminal of the source is very nearly open circuited since it s effectively connected only to a very short piece of wire The small amount of current which does flow is due to the mutual coupling between the antenna wire connected to one source terminal and the half segment length wire connected to the other terminal So why does a real end fed antenna work The answer is that there s a path for current from the source terminal not
304. rents with the mouse See Mouse Operations below The Axes When an antenna is first viewed the intersection of the axes represents the coordinate system origin If you move the antenna with the controls or by clicking the Center Ant Image box in the Control Window the axes no longer represent the absolute coordinate system When this is true they become broken rather than solid The origin marker a dot surrounded by a circle continues to show the true position of the origin even when the display is moved or zoomed Special Key Functions N Turns wire numbers on or off X Y Z Positions display to view from the X Y or Z axis Hold down lt Shift gt with the key to view from the negative axis lt Delete gt Deletes selected wires See Selecting Wires below Mouse Operations Rotating To rotate the display position the mouse cursor anywhere on the display window Press and hold down the left mouse button You can then rotate the display in two directions by moving the mouse while the left button is held down Although the mouse cursor must be on the display window when the button is first pressed it can be moved outside the window if necessary while the button is down You can use the keyboard arrow keys for fine rotational positioning but only after clicking in the display window to give it the focus Moving To move the display position the mouse cursor anywhere on the display window Press and hold down the right mouse b
305. resizing feature Wires Window Wires menu Change Loop Size to change the size of any polygonal loop The first step is to specify the loop by selecting the wires in the Wires Window or View Antenna display Or you can click the selection before you select wires in which case you ll have to choose a set of wires in numerical sequence The selected wires have to be connected in a loop of course and no wires can be connected to the loop other than the wires comprising the loop If you ve recently created a loop its wires will be entered as an initial choice The buttons and text box at the bottom of the dialog box allow you to modify the size with any of three different operations on any of three loop size measurements Radial Creation EZNEC s automated radial creation feature is a convenient way to make a group of radial wires This feature is accessed from the Wires Window Create menu Create Radials selection When this selection is made a dialog box appears which prompts for a range of prototype wires To make a simple set of radials you should first create a single radial wire End 1 of the radial wire should be where you want the center of the radials to be Enter its number as both the first and last wires in the prototype group In the bottom box enter the total number of radials you want the finished structure to have then click Ok The radials will be created fanning out evenly around end 1 of the prototype wire A vertical wir
306. ried wires with EZNEC Pro 4 Extended Accuracy This ground model is available only with EZNEC Pro 4 when using an NEC 4 calculating engine It s the GN3 ground type introduced in NEC 4 2 and gives significantly improved accuracy in some situations including ones where the ground conductivity and or dielectric constant are outside the range normally encountered for Earth ground or water There can be however a high price to be paid for this improvement Extended Accuracy ground slows impedance calculation by approximately a factor of four This is the dominant time consuming part of the overall calculation with large models so Extended Accuracy ground should be used only when needed especially when the model is large Extended Accuracy ground shares the limitation of High Accuracy ground in that the ground is assumed to be homogeneous to an infinite depth Descriptions with High Accuracy ground saved with program types other than EZNEC Pro 4 or versions earlier than v 6 0 can have their ground type automatically changed to Extended Accuracy when opened with EZNEC Pro 4 v 6 0 via the Default NEC 4 Ground Type selection in the Options menu This should be done only with awareness of the speed penalty incurred with Extended Accuracy ground Limitations of Real Ground Models EZNEC s Real ground model might not be representative of some real ground situations At lower frequencies current penetration becomes deep with skin depth being on the
307. right handed GM Only entire wires will be operated on If a specified segment does not fall on a wire end the whole wire containing that segment will be included in the operation The tag increment number ITG1 is ignored and new wires assigned numbers in accordance with EZNEC Pro s method GN GN 0 reflection coefficient type ground will be converted to High Accuracy Sommerfeld ground type EZNEC doesn t support reflection coefficient type ground GR Tag increment number ITG1 is ignored and new wires assigned numbers in accordance with EZNEC Pro s method GS The coordinates and diameters of all wires which have been read prior to encountering the GS card will be multiplied by the third parameter on the line FSCALE GW Tag numbers are ignored Wires are sequentially numbered Sources loads and transmission lines will however be placed on the proper wires GX Tag increment number ITG1 will be ignored and new wires assigned numbers in accordance with EZNEC Pro s method IS NEC 4 convention is used for reading this Gard Only entire wires will be operated on If a specified segment does not fall on a wire end the whole wire containing that segment will be included in the operation LD LD type 1 reset loads isn t translated If some loads are R jX type 4 and others RLC types 0 3 or wire loss type 5 the EZNEC Pro load type is set to RLC and the R jX loads are converted to series RL or RC The impedances of
308. rly modify the End 2 coordinates to be 0 33 43 30 21 EZNEC User Manual Finally define the wire diameter We ll assume the antenna will be made from 12 gauge AWG wire In the Diameter column enter 12 EZNEC will also accept the diameter in inches or other appropriate units depending on the Control Center Units selection The last column is to define the number of segments for the wire 11 is a reasonable number for pattern analysis of a half wave antenna so we don t need to change it We do need an odd number of segments so we can put our source in the middle of the wire Then press lt Enter gt so EZNEC will accept the values Notice that the View Antenna display has changed to show what the new antenna looks like You should see a horizontal wire parallel to but above the y axis If you don t go back to the Wires Window and correct the coordinates End 1 coordinates should be x y z 0 0 30 and End 2 coordinates should be 0 33 43 30 Move the mouse cursor to the wire in the View Antenna display and leave it still for a moment to open the Wire Information window The length of the wire should be 33 43 feet If it isn t correct the coordinates in the Wires Window The next step is to define the source This is connected at the point where the power is applied to the real antenna in this case the center of the wire Close the Wires Window by clicking the close button in the upper right corner the smal
309. rmation WEE 144 Intersechng E 57 Intersecting at an acute angle 64 Lengte 144 Making multiple copies 49 Making offset or rotated copies49 Modifying DEE 49 Gelechmg iiinis 49 144 Total number in current model E 138 Wires Window s e 49 138 OPENIN EE 138 192 USING WEE 49 Working With NEC Format Files SA 152 Y Y Parameter Networks 101 Y Parameter Networks Window L nder e eer ee 101 138 ln UnL EE 138 WI SUNG se eee ee 101 Ee EE 62 75 127 Modeling ccceeeeeeeeeeeees 75 Stacked cesessssssessssssssesees 72 Yagi Antennas nnnnnnnneen 75 127 Z CN 138 Specifying alternate value for WV E 138
310. rol Center form If you see Model contains loss to the right of the average gain it means that all losses have not been removed so you should review the steps above and remove the remaining loss The average gain won t be meaningful for this purpose if there is any loss in the model indicated by the Model contains loss If the 3D pattern has very narrow lobes it might be necessary to reduce the step size for greater accuracy However 5 degrees is generally adequate The field strength and gain error is approximately equal to the deviation of the average gain from one zero dB That is if the reported average gain is 2 dB the gain and field strength reported by EZNEC is about 2 dB greater than reality Source placement should be modified to make the average gain as close to one zero dB as possible If full correction can t be made the average gain in dB should be subtracted from the field strength results This correction method might be considerably in error if the model contains multiple sources but should be reasonably accurate for a single source 8 Note the modifications you made to improve the source placement If modifications were extensive it s probably easiest to restore the loads wire loss and ground type to the lossless model If minor it might be easier to open the saved original file and apply the source placement modifications to it Even though sources appear in the View Antenna display to be placed in the center
311. rom a larger group Valuable help in discovering and tracking down bugs after product release has been provided by Leland Scott KC8LDO Thanks also to others who have reported bugs provided important information and when necessary have downloaded and run diagnostic programs to help me find and fix them The fundamental computation portion of this program is that of NEC 2 and or NEC 4 Many people have contributed to the development of these codes but in recent years the major contributors have been G J Burke and A J Poggio of Lawrence Livermore National Laboratory Without their monumental effort this program would not be possible Earlier versions and ELNEC Dr Dick Adler K3CXZ Dr Jack Belrose VE2CV Gary Breed K9AY Jim Bromley W5GYJ John Brosnahan WOUN Paul Carr P E N4PC Dr L B Cebik W4RNL Dr Al Christman K8LC Bill Clarke WA4BLC Tony DeBiasi K2SG Ed Farmer P E AA6ZM Dick Gardner N1AYW Ernie Guerri W6MGI Linley Gumm P E K7HFD Jerry Hall K1TD Ed Hanlon Bob EZNEC User Manual Haviland W4MB Wes Hayward W7ZOI Dick Kiefer P E KODK Doug McGarrett WA2SAY Bob Rullman K7MSH Jim Sanford WB4GCS Roger Steyaert K7RXV C H Buck Walter and Dean Straw N6BV want to give special acknowledgement to L B Cebik W4RNL sk who consistently provided a tremendous amount of help during the development and testing of several versions Thanks to all the EZNEC users who took the time to send in their s
312. ropping it Or if you chose to associate EZ files with EZNEC during installation simply by double clicking any EZ file in Windows Explorer EZNEC User Manual EZNEC Pro Users If you re acquainted with using NEC 2 or NEC 4 please review the EZNEC Pro And NEC section which outlines some of the differences between these programs You ll find other EZNEC Pro specific information in the EZNEC Pro Information chapter of the Reference section under Additional Information Printing The Manual Nearly all Windows software currently being sold uses a help system for a manual as EZNEC does personally disliked help systems for some time but after getting used to using them have come to greatly prefer them to printed manuals Among the advantages are the hyperlinks or jumps allowing instant movement between topics and extensive indexing However many requests have been received from EZNEC users for a printed or printable manual So a printable manual has been made available for those who want one If you purchased EZNEC on a CD you ll find the printable manual in the Printable Manual directory of the CD The Readme txt file in that directory contains information and instructions If you don t have a CD you can download the printable manual from http eznec com ez6Omanual htm Please respect the copyright The manual is for use only by EZNEC customers and EZNEC demo users The printed manual is generated from the help file by the software
313. rouble The bar at the top of the Control Center information window should now read Five element Yagi this is the title of the antenna description stored in file 20mbdelya ez In the Control Center information window click Units and change the units to Feet for convenience Click the View Ant action button to open the View Antenna Window and the Wires line in the Control Center information window to open the Wires Window In the Wires Window open the Wire menu and select Stack This opens the Stack dialog box Note that all wires number 1 to 55 have been entered into the first two boxes Those are the desired wires for this example If you had wanted to stack only some of the wires in the description you can enter the range of wires here You can also select the wires in the Wires Window before opening the Stack dialog box in which case the top two boxes won t appear The third box indicates where the new wires will appear in the Wires Window wire list 56 indicates that the new wires will be placed at the end of the list Let s put the second Yagi 40 feet above the original Enter 40 in the Stacking distance box and click Ok That s all there is to it This completes the stacking process If desired you can change the height of both Yagis by choosing Change Height By in the Wires Window Other menu 72 Building The Model making sure that the range of wires to change is 1 110 In the Control Center you can add a ground choose
314. round models EZNEC Pro 4 only The Real High Accuracy Sommerfeld ground model will produce erroneous results if the ground conductivity is specified to be much greater than that of salt water about 5 S m and an NEC 4 calculating engine is being used Extended Accuracy ground should be used if ground parameters are outside this range NEC 2 is more tolerant than NEC 4 of high conductivities when using High Accuracy ground Using The Media Window This window is available when Real ground type is selected and is opened by clicking on the Ground Descrip line or selection button in the Control Center The ground constants entered in this menu are used somewhat differently for two purposes When Real High Accuracy ground is chosen the constants of the first medium are used during determination of antenna impedance and currents The constants of both media are used during pattern calculation by modifying the strength and phase of the field reflected from the ground Exception Only the first medium is used when ground wave EZNEC Pro only or near field analysis is being done Ground constants are not used if Free Space or Perfect ground is specified and are used only for pattern calculation if Real MININEC type ground is being used Real MININEC type analysis assumes a perfect ground during impedance and current calculations See Real Ground Types for more information Selecting the Conductivity and Dielectric Constant The conductivity in
315. rve it EZNEC Pro only To open an NEC format file include the extension NEC with the file name Save As Click to save your current antenna description EZNEC Pro only To save a file in NEC format include the extension NEC with the file name Currents This opens the Currents output which shows the currents on the wires in tabular form running a calculation if necessary Src Dat Opens the Source Data output which shows the voltage current power impedance and SWR at each source running a calculation if necessary Load Dat Opens the Load Data output which shows the voltage current power and impedance of each load running a calculation if necessary FF Tab Opens the Far Field Table output which shows the far field strength in tabular form running a calculation if necessary NF Tab Opens the Near Field Table output which shows the near field strength in tabular form running a calculation if necessary 140 Reference SWR Opens a dialog box so you can define the sweep parameters for the SWR Graph View Ant Opens the View Antenna display which gives you a 3 dimensional view of the antenna FF Plot or Freq Swp Begins a far field pattern calculation or frequency SWEED The Graphics Windows Graphics Windows Overview The 2D Plot 3D Plot View Antenna and SWR displays have a number of common features so all are grouped together here They are collectively called the Graphics Wi
316. rview for a detailed description of the L network object Extreme differences between the impedances of the two branches should be avoided when using a single or mixed precision calculating engine See L Network Limitations for more information Selecting Adding Deleting Copying Modifying and Moving L Networks See Using Insertion Objects Windows L Network Limitations It s recommended that a double precision calculating engine be used if available when analyzing a description containing L networks for the reasons outlined below Double precision engines are available in the EZNEC and EZNEC Pro program types but users of the standard EZNEC program type should also read the following L networks are more affected by the limitations of single precision arithmetic than most other objects When the series and shunt branches have very different impedances for example if one is shorted or open and the other contains a component or components numerical truncation could cause large errors if the values were passed directly to a single precision calculating engine or the standard EZNEC mixed precision NEC 2 engine This problem is avoided in EZNEC by limiting the impedance ranges of the branches when using single or mixed precision calculations When necessary EZNEC modifies the values used for calculation by applying these limits Application of limits depends on the absolute and relative impedances specified for the branches and won t usuall
317. ry versions must be plainly marked as such and must not be misrepresented as being the original source Such altered versions also must not be misrepresented as being Info ZIP releases including but not limited to labeling of the altered versions with the names Info ZIP or any variation thereof including but not limited to different capitalizations Pocket UnZip WiZ or MacZip without the explicit permission of Info ZIP Such altered versions are further prohibited from misrepresentative use of the Zip Bugs or Info ZIP e mail addresses or of the Info ZIP URL s 4 Info ZIP retains the right to use the names Info ZIP Zip UnZip UnZipSFX WiZ Pocket UnZip Pocket Zip and MacZip for its own source and binary releases Scintilla All EZNEC program types beginning with v 5 0 26 make use of the Scintilla editor SciLexer dll generously provided free of charge by Neil Hodgson The following information constitutes the license agreement for use of that software License for Scintilla and SciTE Copyright 1998 2003 by Neil Hodgson lt neilh scintilla org gt All Rights Reserved Permission to use copy modify and distribute this software and its documentation for any purpose and without fee is hereby granted provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation NEIL HODGSON DISCLAIMS ALL WARRANTIES WITH
318. s Some of the following folders have subdirectories depending on usage Caution Earlier versions of EZNEC retain the same file locations as before v 6 0 locations are kept separately So if for any reason you run an earlier version of EZNEC after installing v 6 0 files you ve saved with one version may not be visible to the other unless file locations used by both old and new versions are set to the same folder Program Files Program Files Folder EZNEC 6 0 C Program Files EZNEC 6 0 Main executable file calculating engines and other files used for EZNEC functionality These files are essential to EZNEC operation EZNEC does not write or modify any files in this directory or subdirectories The directory where program files are placed can be chosen during the installation process but it is recommended that the default location be used Output Files Documents Folder EZNEC 6 0 C Users lt user name gt My Documents EZNEC 6 0 Output files and files commonly accessed by the user such as LastZ txt EZNEC INI LastRun log fEZNEC EZNEC Pro only LastZ_src sip EZNEC Pro 4 only NEC 4 input and output files EZ NEC and NEC OUT Note that the output file folder selection available in previous EZNEC versions changed only the default location of only a few files The option now affects all the files mentioned Description EZ and Plot Files Documents Folder EZNEC 6 0 Ant C Users lt user name gt My Documents EZNEC 6 0
319. s Jim Streible K4DLI and Roger Steyaert K7RXV helpfully reviewed EZNEC v 6 0 before its release EZNEC v 6 0 is built upon v 5 0 and it upon 4 0 and so forth So the help provided by beta testers for all previous versions was also essential to the development of v 6 0 Previous version testers were Version 5 0 Steve Best VE9SRB L B Cebik W4RNL sk Gerd Janzen DF6SJ Dan Maguire AC6LA Dan Richardson KEMHE Dean Straw N6BV Jim Streible K4DLI Roger Steyaert K7RXV Version 4 0 which underwent a great deal of development effort want to give very special thanks to four people who for a period of over a year tested and commented on over 30 alpha program revisions as features were added tested and modified Their effort was exceptional and neither version 4 0 nor 5 0 would not have been possible without them They are L B Cebik W4RNL sk Dan Maguire AC6LA Dan Richardson KEMHE Dean Straw N6BV A great heartfelt thank you to these wonderful folks And many many bugs were found reported and doggedly tracked down during the v 4 0 beta testing phase by the above people plus beta testers Introduction Vil Arafiles Steve Best VE9SRB Dave Rodman KN2M Jim Streible K4DLI Bert Barry VESQAA I m indebted to all these people for all their time trouble and valued comments criticisms and suggestions They deserve a great deal of credit for EZNEC v 4 0 s better features which you ll also enjoy
320. s in the import file will be interpreted as being in the specified units If the units specifier line is absent all coordinates and diameters will be interpreted as being in meters The second unit specifier optional is the diameter specification Wire diameters will be interpreted as being in these units The units used by the program for wire diameter may be different than and will not be determined or changed by this specification For example if both the coordinate and diameter units specifications are feet EZNEC will change its UNITS to feet If a diameter is given in the import file as 0 5 it will be interpreted by EZNEC as 173 EZNEC User Manual having a diameter of 0 5 feet However EZNEC shows diameters in inches when UNITS are feet so after importing the wire will show up in EZNEC as having a diameter of 6 inches If no diameter unit specifier is given wire diameters will be interpreted as being in the same units as the end coordinates Only the first two letters of each specifier is read They are interpreted as follows M or ME meters If M is used alone it must not be followed by any other character including a period MI or MM millimeters FT or FE feet IN inches WA or WL wavelengths Wire Specifications Wire specifications must have at least 7 fields Fields are end 1 x y z coordinates end 2 x y z coordinates diameter and optionally in an eighth field number of segments See below for more
321. s initiated by starting EZNEC Pro again when the program is already running Windows associated with instances after the first are identified with a parenthetical number e g 2 for the second instance This allows working on or running calculations for more than one problem at a time Some caution must be used when running multiple instances however because certain data are shared among all instances These include options selected in the Options Menu and saved as defaults Special Options in the EZNEC INI file and positions and sizes of windows when closed and re opened If the Wires Window of one instance is closed the next Wires Window of any instance which is opened will open with the size and position of the recently closed window And if any Options are saved as default they will be read and used by any newly starting instance Open instances can be closed in any order and new ones opened at any time Additional Information File Locations Following are the default locations of files read from and written to by EZNEC Ones marked with an asterisk can be changed via the Folders selection in the Control Center Options menu Substitute Program Files x86 for Program Flles below if the operating system is 64 bit Parenthetical paths are typical for Vista and later Windows systems but might differ Windows XP will have different paths My Documents sometimes shows in Windows Explorer or elsewhere as Documents or MyDocument
322. s the current and pattern information When changes are made to the antenna only necessary recalculations are done For example when the plot elevation angle is changed only the pattern is recalculated This is not the case with frequency sweep It s not practical to keep all the information for all frequencies so final calculation results are written into an ASCII file after each frequency step Data present in arrays are erased and EZNEC is reset before beginning calculations at the next frequency Therefore calculation results from a frequency sweep are available only in the form of the file containing the data and optionally a trace for each frequency The exception to this is that data from the last frequency in the sequence can be viewed The frequency sweep can be run only when the Control Center Plot Type selection is Azimuth or Elevation It can t be run when 3D plot type is selected One or two outputs are available from the frequency sweep data output is always available for selection 2D far field plots traces are available only when far field analysis EZNEC Pro with or without ground wave is chosen for frequency sweep You can choose to have EZNEC save any combination of these Additional impedance and SWR data are always saved in a separate file regardless of the outputs you choose to keep These data are 118 Reference used for the SWR Graph and reside in a comma delimited ASCII file named LastZ txt in the EZNEC outpu
323. s to be modeled as wires The second thing to realize about EZNEC s transmission line objects is that all ends which aren t specified as a shorted or open stub must be connected to wires or virtual segments If you want to connect a source directly to a transmission line that is connect the two terminals of a source in parallel with the two terminals of one end of a transmission line the easiest way is to specify the same virtual segment for both as the wire number The 92 Building The Model disadvantage to this method is that you don t have any visual representation of the transmission line in the View Antenna display An alternate method is to create a short one segment wire short so it doesn t interact appreciably with the antenna field not too far from the antenna and connect both source and transmission line to it Then you ll see the transmission line in the View Antenna display Remember the physical distance between the ends of the transmission line in your model don t have to be the same as the line length it can be either greater or less unless you specify Actual Distance for the transmission line length Third when a transmission line is connected to the same segment as another insertion object it s important to be aware of the way they re connected together A transmission line is connected in parallel with any other insertion object except a series connected load in the same segment Finally you should be aware o
324. s when making comparisons to NEC results Special Options A few choices are likely to be so seldom used that they don t justify being put into a menu However EZNEC still provides a way to enable or change these choices In the EZNEC output directory is a file named EZNEC INI EZNEC reads this file each time it starts so it can be used to communicate the values of special options The EZNEC INI file can be edited with any text editor or you can conveniently open it for editing with the EZNEC Editor by choosing Edit INI File in the Control Center Utilities menu The file must be saved with the new value s for them to take effect Options marked with an asterisk are checked each time the affected operation is done For example a change in 2DGridLineWidth becomes effective the next time the 2D plot grid is redrawn Do not include the 162 Reference asterisk in the EZNEC INI file entry Options not marked with an asterisk will not take effect until the next time the program is restarted All entries are case insensitive Spaces around the sign are optional All entries are put into the file in the Special Options section that is they go below that heading ButtonFontName fontname where fontname is the name of a valid font such as Arial This sets the font type for the Control Center Action Buttons Please see ButtonFontSize above ButtonFontSize where is a number This sets the font size for the Control Center Action
325. scattering cross section mV m X dist Divide the reported value by the distance in meters to get field stregth in mV m at that distance See the Options section of the Control Center Menus chapter in the Reference section for more details In EZNEC and the EZNEC pro programs you can also choose whether to show linear or circular components This is done with the Control Center Desc Options selection Plot Fields tabs EZNEC Pro only f using plane wave excitation see Interpreting Plane Wave Results for additional information Near Field Table Unlike far fields the near fields can be pointed in any direction They are broken into three components in the X Y and Z directions A total is also shown The total is generally all that will be used unless you have an interest in the orientation of the E or H field EZNEC also reports near the top of the list the largest field that was found Be careful that none of the steps falls inside a wire if it does the results for that step won t be meaningful and it 112 Interpreting The Results could be reported as the maximum value Near field analysis uses only the first ground medium If two ground media are defined the second will be ignored Because the ratio of E electric to H magnetic near field depends on the antenna type and the distance from it the two fields must be analyzed separately Note that Near Field analysis actually reports the total field so it s valid a
326. sing an NEC 4 calculating engine For information about simulating buried wires with other EZNEC program types see Vertical Antennas And Buried Radials and Connecting to High Accuracy Ground There are only a few restrictions on modeling buried wires as follow 1 The Real High Accuracy NEC Sommerfeld ground model must be used 2 Horizontal wires should be at least several wire diameters below the surface 3 Wires can penetrate the ground z 0 only at a segment junction It s recommended that penetration be done at a wire end That is have the above ground wire end at z 0 and make the portion below ground be a separate wire connecting to the above ground wire at z 0 This way the connection won t move and the requirement will be satisfied if you change the wire lengths or number of segments 4 The velocity factor under ground is often a fraction of the velocity factor in free space Consequently many more segments are required for the most accurate results EZNEC Pro 4 s Segmentation Check takes this into account and shows warnings or cautions if segments are too short On the other hand the loss associated with ground often permits coarser segmentation than general guidelines indicate This is one of those cases where some experimentation trying different numbers of segments to see where accuracy begins suffering is required if the segment count needs to be minimized Closely Spaced Wires When modeling parallel or n
327. sion number and copyright and trademark notice EZNEC Pro only Also shows if 64 bit calculating engines have been installed and are being used Information Window and Action Buttons Control Center Selections All selections in the Control Center Information Window are part of the antenna description and are saved with the antenna description EZ file Selections made in the Setups menu are also saved with this file 138 Reference Title This selection isn t marked except with a gt symbol It s the gray bar just above the white Information Window and contains the title of the description Clicking anywhere on this line opens a dialog box for you to enter a title for your antenna model File Shows the name of the last file saved or opened This is for information only and can t be changed Frequency Shows the current frequency or if Frequency Sweep is enabled Click this to change the frequency or rescale your model to another frequency Wavelength Shows the wavelength in current units This is for information only and can t be changed Wires Shows the number of wires and segments in the model Clicking opens the Wires Window for adding deleting or modifying the antenna structure Sources Shows the number of sources in the model Clicking opens the Sources Window for adding deleting or modifying sources Loads Shows the number of loads in the model Clicking opens the Loads Window for adding d
328. sist only until the program ends unless the Colors menu is re opened and Save As Default is clicked Also allows resetting choices to the saved default colors NOTE Background color choice is ignored when printing Reset 2D 3D View Antenna only Reset Cursor to Max 2D 3D only Resets the cursor to the point of maximum field strength In the 3D display this option isn t available unless highlighting is on and the highlighted slice is also returned to the one containing the maximum field strength Reset Position View Antenna 3D only Rotates display to the default position Reset All View Antenna 3D only Resets position and all other choices such as zoom but except colors to initial values Creating Graphics Files EZNEC does not directly create graphics files in common formats like omp gif or jpeg However it s still easy to do In any of the Graphics Windows open the Edit menu then select one of the Copy options This will copy the current display to the Windows Clipboard Open a graphics application such as Paint which is furnished with Windows and paste the Clipboard contents into it The graphic display can then be saved to a file in any of the formats available in the graphics program Of course it s not necessary to save or convert the graphic display in order to insert it into a word processor or other application It can simply be pasted there directly from the Windows Clipboard For tips to get the
329. so do the following steps for each of the two ports To place an insertion object port on a wire The insertion object port location is specified by wire number and location on the wire In the appropriate object input window e g Sources Window Transformers Window enter the wire number and the percentage of the way from end 1 For example to place a source on end 2 enter 100 for the percentage from end 1 A shortcut is available for end or center placement In either of the columns in the Specified Pos group you can enter W E where the two s represent the wire and end numbers for example W3E2 to place it at end 2 of wire 3 To place a source at the center of the wire you can enter W C EZNEC places the insertion object as close as it can to the specified position and tells you the placement location in the Actual Pos columns To place an insertion object on a virtual segment 76 Building The Model In the wire number column of the object input window grid enter the letter V followed by a number of your choice between 1 and 999 for example V23 Other insertion objects connected to this virtual segment will be placed in parallel with it The percent from end 1 column isn t used for virtual segment connections Insertion object placement for best accuracy EZNEC s NEC calculating engines can produce inaccurate results under some conditions of insertion object placement In some cases the error is minor in others major The foll
330. ss The NEC radial model can t be used to assess antenna efficiency and as mentioned above radials of reasonable length have little effect on the ground reflection And the NEC radial model tends to give an erroneous estimation of the effect of the radial field on ground reflection due to the simplistic way it evaluates reflections The second approach is to model buried radials by substituting radials just above the ground surface This does a moderately good job of predicting the 73 EZNEC User Manual ground system efficiency as well as whatever pattern modification typically minor results from the radial system With this approach the High Accuracy Real ground type must be used See Connecting to High Accuracy Ground for more information The third approach is to use MININEC type ground which models the ground reflection but not the conductive loss and simply add a resistive load at the feedpoint to simulate the radial system loss resistance The NEC radial model can be used in addition if desired Approximations for the amount of resistance for a given number of radials can be found in Chapter 8 of The ARRL Antenna Book This reference gives total resistance for a quarter wave vertical so subtract 36 from the values shown to use as the ground system resistance These are of course approximate Direct measurement is better yet If you have an antenna analyzer or similar way to measure your antenna s feedpoint resistance follow this pr
331. t 99 EZNEC User Manual L networks can be connected in tandem to make pi tee or ladder networks This is made easier with the virtual segment feature Extreme differences between the impedances of the two branches should be avoided when using a single or mixed precision calculating engine See L Network Limitations for more information Example files using an L network are 4Square L Network Feed ARRL Example ez Cardioid L Network Feed ARRL Example ez and 4Square L Network Feed With Z Matching ez Step by step development of the latter two is given in the A Lap Around Track 5 topic of the Test Drive tutorial Using the L Networks Window Open the L Networks Window by clicking on the Control Center L Networks line or the button to its left Each L network occupies two lines in the input grid The upper line contains port 1 wire connections and series branch components the lower line is port 2 wire connections and shunt branch components Specifying Connections Like other insertion objects both ports of all L networks have to be placed on real or virtual segments See Placing Insertion Objects on Segments for details Specifying Type Configuration and Values Each L network branch contains the equivalent of an EZNEC load so specification of the components in the branch is done in the same way as for loads The R jX Loads Window and The RLC Loads Window topics describe the process for the chosen branch type See L Networks Ove
332. t a cursor is present when the Show Data selection is checked in the View menu and the cursor position can be changed by clicking near the point of interest or by using the keyboard arrow keys after first clicking on the plot to make it the active window And like the standard SWR plot information about the selected frequency point is shown in the data window below the plot The vertical scale factor of the rectangular plot types is fixed as is the Smith chart scale The program remembers the last plot type choice and uses that plot type the next time an SWR sweep is run Note that the Smith chart display is a display only and not a substitute for a Smith chart program with interactively aids in the design of matching networks EZNEC Pro Information EZNEC Pro And NEC This section applies only to EZNEC Pro 2 and EZNEC Pro 4 There currently are two programs in the EZNEC Pro family EZNEC Pro 2 and EZNEC Pro 4 EZNEC Pro 4 can use an included enhanced NEC 2 calculating engine or an enhanced NEC 4 2 engine supplied with EZNEC Pro 4 EZNEC Pro 2 can use only the included enhanced NEC 2 calculating engine This is the only difference between the two programs However there are several significant differences between EZNEC Pro and NEC Voltages and currents NEC uses peak values for voltages and currents EZNEC Pro interprets and reports values in RMS An NEC input file having a 1 0 volt source when read by EZNEC Pro will result in an EZNEC
333. t any distance including far from the antenna It can also be used in the standard EZNEC program for evaluating the ground wave Field strengths are RMS values For more information see Near Field Analysis in the Reference section Remember that many factors affect the results from a modeling program EZNEC_ should not under any circumstances be used to determine whether the energy or field strength from an antenna presents a hazard or unsafe condition This applies to all results including both Far Field and Near Field EZNEC Pro only f using plane wave excitation see Interpreting Plane Wave Results for additional information Far Field Patterns Three choices of far field plot are available 2D Azimuth 2D Elevation and Three Dimensional 3D although only azimuth is available if the ground wave component is included EZNEC Pro only Any elevation angle can be chosen for azimuth plots and any azimuth angle for elevation plots 2D plot range can be restricted if desired The step size can be chosen a too coarse step size results in a jagged pattern and a very fine step size may produce more data than needed or desired Both the observation distance and height above ground can be freely chosen when the ground wave component is included EZNEC Pro only EZNEC includes a visualization aid for orienting the pattern relative to the antenna in the View Antenna display where the 2D pattern plot or a slice of the 3D plot can
334. t directory This file remains after the program ends and may be used for other purposes as desired Following is a detailed description of the features in the Frequency Sweep Setup dialog which is opened via the Control Center Setups menu Frequency Sweep selection Frequency Sweep Off On Turns frequency sweep off and on Frequency Selection Selects frequencies to be used for the sweep Frequencies can be specified in one of two ways If specified as start stop and step frequencies the frequency steps will be evenly spaced extending from the start frequency to the stop frequency If a frequency sweep input file is specified frequencies are read in order from the file and there are no restrictions on spacing or order Start Stop and Step Frequency MHz Specifies the range of frequencies to sweep and the step size Read Frequencies From Eile If this is checked Start Stop and Step Frequency entries will be disabled and a file name is required The file must contain a list of frequencies to be used in the sweep See Frequency Sweep Input File for details about the file format If unchecked File Name Select and Edit File are disabled File Name Shows the name of the input file you ve chosen if Read Frequencies From File is checked You can not enter a file name in the text box the file must be chosen by using the dialog box opened with Select Select Opens a dialog box to allow you to choose an input file Edit
335. t selects a file name having an unacceptable extension These features can be turned off and on in the Windows Internet Explorer Tools menu and the settings there apply to all Windows applications Please refer to your Windows or Internet Explorer documentation for details The AutoComplete AutoSuggest option in the EZNEC Options menu allows you to 132 Reference choose separate settings for AutoComplete and AutoSuggest to be used by EZNEC As with all other Options menu items these settings apply only until you end EZNEC unless you select Save As Default in the Options Menu after making your other selections Calculating Engine EZNEC and EZNEC Pro only Allows you to choose the engine used for calculations The calculating engine being used is shown just above the FF Plot button in the Control Center Double precision calculating engines are recommended for general use if available EZCalc NEC 2 Internal NEC 2 calculating engine This is a mixed precision engine doing some calculations in single precision and some in double In most cases its accuracy is equal to double precision EZCalcD and it s slightly faster In EZNEC Pro 4 this engine would normally be selected only if comparisons are to be made between NEC 2 and NEC 4 results EZCalcD NEC 2D EZNEC and EZNEC Pro only Internal double precision NEC 2 calculating engine In most cases its results will be the same as EZCalc However it will maintain accuracy in
336. t ways You can click on the arrow boxes at the ends to move the control a single step Holding the left mouse button down when on an end box moves the control rapidly If you click in the area between the adjustment bar and the end box the control will move in larger steps Or you can simply drag the adjustment bar to the desired position Finally the keyboard arrow keys will move the control if it has focus that is if it s the currently active control Now click the Show 2D Plot box at the bottom of the 3D display control box This turns on the 2D display where the currently highlighted slice of the 3D plot is shown Notice that as you change the 3D slice and the cursor position the 2D plot changes accordingly Turn on the 2D display control and data boxes as follows On the 2D plot open the View menu If Show Controls isn t checked select it Repeat for Show Data if it isn t checked The 2D display controls track the corresponding controls on the 3D display So once a 3D plot has been calculated various slices can be selected directly from the 2D display if desired When the Plot Type is 3D the only way to open the 2D display is from the 3D display either by checking the Show 2D Plot box in the control box or by selecting Show 2D Plot in the 3D display View menu If you close the 3D display and want to reopen it click the FF Plot action button in the Control Center Experiment with the 2D and 3D controls selecting different sli
337. ta files between programs Although we both contributed to the content the original proposal was Brian s and he is the author of the following standard and did the majority of the work We encourage others to adopt this standard OpenPF is an open nonproprietary standard for computer files that contain electromagnetic field data OpenPF is intended for files created by antenna analysis programs and for files containing measurements OpenPF files can be used to archive or transport data Programs can use the files to plot fields and radiation patterns on a screen printer or plotter The OpenPF file format is extensible Data is organized into blocks that begin with a block type identifier followed by block length This structure allows a file parser to skip and ignore blocks it s not designed to handle including block types defined in future revisions of OpenPF The blocks defined below provide for 2D relative far field data azimuth and elevation radiation patterns and 3D absolute near and far field data 3D radiation patterns can be represented by a set of 2D data blocks The file format enables a single file to contain near and far field data absolute and relative data azimuth and elevation data low and high resolution data partial and full data cuts data for multiple frequencies and unidentified data The file format provides for new fields in future OpenPF revisions without the overhead of reserved bytes New fields can be appe
338. tains a large number of EZNEC description EZ files whose names begin with ARRL_ These files are specially signed and when opened with the EZNEC v 6 0 demo program give the program the 500 segment capability of the full EZNEC standard program Signed files of 500 or fewer segments can be analyzed modified and saved However any file saved by the EZNEC demo or any other EZNEC program won t be signed So if reopened the EZNEC demo will operate normally with a 20 segment limit EZNEC ARRL 500 segment operation is identified by a pink colored File line in the Control Center main window You ll see this whenever you open a signed file Signed files are available only from the ARRL Antenna Book CD beginning with the 20th Edition Signed files are otherwise standard EZNEC description files that can be used with any EZNEC program type 117 EZNEC User Manual EZNEC Editor The EZNEC Editor is basically a copy of the Windows Notepad functionality It s used as a convenient way to edit text files from within EZNEC Controls menus and operation are very similar to Notepad although occasionally you ll see a difference The EZNEC editor is automatically opened to display a number of EZNEC files and outputs A few words about fonts When used for displaying tabular outputs like Currents Source Data Far Field Table and so forth the EZNEC Editor restricts your choices to fixed width fonts such as FixedSys and Courier New This p
339. taway If you d like to try your hand at a little more complex maneuvering try taking EZNEC Through The Curves You can continue directly from here or you can exit EZNEC and do the next exercise later Through The Curves If you haven t yet done so take EZNEC along the straightaway In this section you ll begin with the plot generated by the straightaway drive and get introduced to a few of EZNEC s more advanced features Ready to go Let s see how an inverted vee compares with our back yard dipole If you ve shut down EZNEC since doing the along the straightaway exercise you ll have to open the back yard dipole description after starting EZNEC This is done by clicking the Control Center Open action button entering the name Back Yard Dipole and clicking Open You should also open the View Antenna window by clicking the View Ant action button Open the Wires Window by clicking on the Wires line of the Control Center information window We ll make the inverted vee by beginning with a dipole then use one of EZNEC s powerful editing features to convert it into an inverted vee without having to calculate any additional wire end coordinates An inverted vee can t be made from just one wire since it s bent in the middle and all wires must be straight So we ll have to add another wire and use each of the two wires for half of the inverted vee Let s put the center of the antenna at x y Z 0 0 30 30 feet straight up from the orig
340. tc These are EZNEC OpenPF binary plot files and are not readable without specialized software To save far field plot data in readable ASCII form check Data File and Field Strength Table Data File Saves selected data in ASCII format in a text file The choices of data which can be saved in the dialog Data File Contents section are listed below Field Strength Table Saves a table of field strength values for each frequency either far field or near field as determined by the Field To Calculate choice The format of the data is the same as for the single frequency tabular far field FF Tab or near field NF Tab display The locations in space where near field strength is calculated are defined in the Near Field Setup dialog Source Data Incl SWR Saves source data impedance voltage current power and SWR in the same format as for the single frequency Source Data Src Dat display Load Data Saves load data impedance voltage current and power in the same format as for the single frequency Load Data Load Dat display Currents Saves wire currents in the same format as for the single frequency Currents display Pattern Analysis Saves information about the plot such as maximum value angle at which the maximum occurs front back or front side ratio etc essentially the same information that is presented in the 2D Display Data Window This choice is disabled when Near Field is selected as the Field To Calcul
341. ter the wavelength is shown as 137 562 ft at this frequency so a quarter electrical wavelength transmission line is 137 562 0 66 0 25 22 698 ft Enter this value into both rows of the length column and press lt Enter gt From the diagram above we see that Transmission Line 1 will be connected to Virtual Segment 1 and Transmission Line 2 to Virtual Segment 2 Change the Transmission Line 1 End 1 Specified Pos Wire value from V3 to V1 Change Transmission Line 2 End 1 from V3 to V2 Press lt Enter gt Close the Transmission Lines Window The source is connected to Virtual Segment 1 Open the Sources Window Change the wire connection from V3 to V1 and press lt Enter gt Close the Sources Window Now it s time to create the L Network Open the L Networks Window We want to specify the L network branch impedances as an L and C rather than fixed R and X So 34 Test Drive In the L Networks Window open the Other menu and click Change L Network Type In the dialog box which opens select the RLC button and click Ok The L Networks Window now has columns for R L and C We ll do the connections first then enter the L and C values In an L network model the shunt component is always at Port 2 Or to put it another way Port 2 is the port having the shunt component across it So from the diagram it s apparent that Port 1 is connected to Virtual Segment 1 V1 and Port 2 to Virtual Segment 2 V2 Each L network consists of two r
342. tery and resistor will do a poor job of predicting the current if the battery is old and the model doesn t include internal resistance Likewise a model for analyzing UHF circuits which doesn t include accurate inductive and capacitive effects won t produce accurate results So it s imperative that you learn the limitations of your modeling tools This manual will help you in that endeavor Skillfully used within its limitations EZNEC can do a remarkably accurate job of predicting antenna performance But remember it s analyzing a model of an antenna not an actual antenna So its accuracy is always limited by the accuracy of the representation of the real antenna and its environment by the model In some cases the tools simply are not available to make an accurate representation so approximate results are the best that can be obtained For example a parabolic reflector can be approximately modeled as a wire grid but the representation will not accurately predict low level lobes or characteristics sensitive to dish smoothness But for many antennas under a wide range of circumstances EZNEC will give you startlingly accurate results And for most antennas the results will be close enough for nearly any practical use Building a good model and interpreting the results requires considerable skill This manual is intended to help you acquire the skills necessary to get consistently good results You may want to take the Test Drive before or during
343. th elevation or 3 dimensional you ve chosen Clicking opens a dialog box allowing you to choose the plot type EZNEC Pro only When Ground Wave Analysis is active this option is fixed at Azimuth the only type allowed with ground wave analysis Elevation Angle Azimuth Angle or Bearing or Observation Height This selection isn t available when 3D Plot Type is specified When doing an azimuth plot it shows and allows you to choose the elevation angle for the 2D azimuth plot When doing elevation plot it allows you to choose the azimuth angle or compass bearing EZNEC Pro only When Ground Wave Analysis is active shows and allows you to choose the height of the observation point 139 EZNEC User Manual Step Size Shows and allows you to choose the angular increment for the 2D or 3D plot Minimum step size is 0 1 degree for 2D plots 1 degree for 3D plots Maximum for both is 90 degrees although such a large value would result in an unusable coarse display 2D step size must evenly divide into 180 degrees and 3D step size into 90 degrees error messages will appear if any of these conditions isn t met Ref Level All outputs showing field strength will be relative to the value shown here If you want for example to show gain relative to the gain of a dipole in free space set this value to 2 15 dBi This choice is meaningful only when doing free space analysis As shown in the Test Drive a dipole mounted over ground exhibits
344. that it has bugs and will always have bugs No matter how many are found and fixed some will always remain They will never all be found I m incapable of writing a program as complex as EZNEC which is entirely free of bugs and doubt that anyone else could do it either He got uncharacteristically quiet So said I do the next best thing Whenever a bug is found and reported fix it as quickly as can and issue an update This is uploaded to my web site where any user can download it to update his program to the latest revision at any time No one will have a program with any known bugs for any longer than it takes me to track down and fix the most recent one found At that point he faded back into the crowd I ve made every effort to eliminate program bugs and consider a bug to be unacceptable and something to be corrected as quickly as possible But as told the fellow there will always be some lurking It s unlikely that you ll ever encounter one but if you do please report it so it can be found and fixed Program crashes are not normal operation and if one happens it s not something you did wrong You should not be able to crash the program no matter what you do Please see Reporting Bugs and Updates for more information Third some users don t realize that EZNEC features context sensitive help Whenever you want more information about the current menu window or display press the F1 key From most locations this will open the
345. the antenna and seeing results which don t seem right Results from this model aren t right and the following will explain why An EZNEC source like a real transmitter signal generator or for that matter a battery has two terminals The current flowing out of one terminal must equal in both magnitude and phase and at every instant the current flowing into the other When a load is connected between the terminals an electrical circuit is formed and the amount of current flow conforms to Ohm s law If a load is connected to only one terminal the source sees an open circuit and no current flows to or from either terminal One terminal of real sources is often connected to a metallic board or chassis and called ground This nomenclature doesn t impart any special properties however it s still just a collection of conductors to which one of the two terminals is connected and which must obey the current equality rule When a source is connected to a dipole there is of course an open circuit at DC However mutual coupling between the dipole halves creates a displacement current through the intervening space providing a path for current between the source terminals Likewise a grounded vertical induces current in the ground which at the bottom of a source at its base exactly 67 EZNEC User Manual equals the current the source is putting into the antenna That is the current up into the antenna from the source exactly equals the cur
346. the description file after you edit the Antenna Notes Automatic Segmentation Automatic wire segmentation is available in the Wires Window Wire Auto Seg and in the Seqmentation Check display Segmentation menu enabled only if one or more wires produces a warning Two choices are offered Conservative and Minimum Recommended The Conservative choice is best for general use If computation time becomes too long or the total number of 115 EZNEC User Manual segments becomes excessive the Minimum Recommended choice can be used In any case don t blindly depend on the automatic segmentation to always choose the optimum number of segments There are many occasions such as several described in the chapter Some Special Cases in Modeling The Antenna Structure which require more segments In some other cases such as placement of a source or load on a short wire or when dealing with closely spaced parallel wires the segment length or alignment is important Automatic segmentation won t recognize these special circumstances so it will be up to you to determine how many segments are required Probably the best use of automatic segmentation is as a first segmentation of a new antenna description as an initial setting Segmentation Check has a related feature called Fix Segs which is described in the Segmentation Check topic Average Gain Average Gain is a valuable tool in detecting situations where EZNEC s calculating engine is havin
347. the description since opening it in reverse sequence to the order in which the change was made A change made anywhere in the program can be undone from any window having an undo selection Redo Allows you to redo changes which have been undone Copy Plot Copies the Plot section of the display to the Windows Clipboard as a bitmap This allows it to be pasted into any Windows application which can accept graphical objects Unlike the Print Plot selection above the plot is not redrawn to a larger scale the plot is copied exactly as it is If the copy is later enlarged quality will be poor because of the limited number of pixels in the original It s best to adjust the EZNEC plot size to the actual size desired for the copy before creating the copy Alternatively you can first maximize the plot by clicking the maximize button near the upper right corner of the window For best resolution turn off Controls and Data sections via the View menu if on Then do the copy The resulting copy will have the highest possible resolution and many applications will be able to reduce it to the desired size while retaining high quality Copy Plot and Data 2D SWR only Copies the Plot and Data sections of the display to the Windows Clipboard as a bitmap See the above comments regarding quality This selection isn t available if the Data section is turned off The Data section can be turned on via the View menu View Mult Trc Field 2D only
348. the left of the line which will highlight the line Then press the lt Del gt key on your keyboard Click Ok in the dialog box which appears Close the Wires Window The source and transmission lines are now gone from the View Antenna display since they connect to virtual segments whose location isn t specified To see all virtual segment connections Open the View menu in the View Antenna display and select Show Virt Seg Conn This shows what is connected to each of the virtual segments From it you can see that Source 1 Src1 End 1 of Transmission Line 1 TL1 1 and End 1 of Transmission Line 2 TL2 1 are connected to Virtual Segment 3 Close the Virtual Segment Connections display The model should work exactly as before To check the pattern Click the FF Plot Action Button In the 2D Plot Window open the File menu and select Add Trace Locate and double click Cardioid TL ARRL Example pf This superimposes the previously saved pattern over the current one As you can see the two plots overlay exactly as they should Close the 2D Plot Window Now we ll change the transmission lines to a quarter electrical wavelength each and add the L network Please refer to the diagram above as you do the next steps First let s change the transmission line lengths and connections Open the Transmission Lines window It shows that the velocity factor of the two transmission lines is 0 66 and we ll continue using the same type lines In the Control Cen
349. the wire in square meters Wire loss is especially important to include in a model showing low source resistance In these antennas wire loss can sometimes be substantial You can determine the amount of loss caused by the wire by calculating the pattern with zero wire loss and realistic wire loss and comparing the gain If feedpoint resistance is very low and your model has a single source you should temporarily remove the wire loss to insure that the source resistance isn t negative A negative source resistance with a single source model is an indication of numerical problems and it can sometimes be concealed by wire loss See Source Placement Precautions for more information Wire Insulation Important note The Wire Insulation feature is accurate only for a thin insulation layer and dielectric constants in the range of those of typical wire insulating materials Attempts to extend its use to purposes other than simulating the effect of wire insulation will produce inaccurate results EZNEC has the capability of including the effect of wire insulation Only the pro programs provide for lossy insulation but the loss of normal insulation coatings will have virtually no effect on antenna performance The loss feature is useful only for very unusual circumstances not typically encountered The parameter choices appear as new columns in the Wires Window grid These columns can be hidden for convenience if desired via the checkbox above the gr
350. these will vary with frequency unlike the original NEC R jX loads The EZNEC Pro load type will be set to R jX only if there are no RLC or wire loss loads in the NEC file Loads with per unit length specifications 153 EZNEC User Manual types 2 and 3 are calculated for the lengths of segments they re initially placed on But if segment lengths are subsequently changed in EZNEC Pro their values won t change Wire loss LD cards type 5 are converted to RL loads with a frequency variable R which varies in the same manner as wire loss The L won t change with frequency although this is generally a minor effect with wires Remember though that these are now EZNEC Pro loads not wire loss Their values will be correct for the wire diameter and segment length of their initial positions but won t change if diameter or segment length is subsequently changed Repeated loads are placed using the same convention as NEC Note LD5 card translation can be inhibited if desired See LD5Translation in the Special Options section NE NH Only the first NE or NH card will be read The information contained on the card will be entered in the EZNEC Pro Near Field Setup Menu Note The convention for phi and theta is reversed between NEC 2 and NEC 4 EZNEC Pro uses the NEC 4 convention A caution is shown in the translation window when these cards are encountered NT All parameters are translated NX Terminates EZNEC Pro translation RP EZN
351. ticularly when a source 125 EZNEC User Manual or load is near the junction This is seen with antennas such as multiple dipoles connected to a common feedpoint Another case is with very low elevated radial systems The straightforward solution in this situation is to increase the number of segments However doing so increases computation time The technique described here provides high accuracy with a smaller total number of segments Instead of making the entire wires out of short segments the segments can be made short near the junction gradually increasing or tapering to a greater length away from the junction EZNEC automates this process but it s useful to know how the procedure works so you can optimize it for your particular purpose The basic procedure is to replace the original wire with several wires of different lengths The new wire closest to the junction is made very short and with one segment The second wire is made twice the length of the first also with one segment This process is continued until the segment length becomes long enough say 1 20 wavelength and the remainder of the original wire is made up of a multiple segment wire of approximately this segment length In the automated process you can choose the minimum and maximum segment lengths or use the default values of 1 400 and 1 25 wavelength This technique shouldn t generally be used if connecting wires have different diameters unless perhaps when using a
352. ting a meander line for planar loading or other purposes Spiral Creation The helix creation feature now includes the option of making a linearly varying spiral including flat spirals Additional NEC Format Cards Read See Working With NEC Format Files for a complete list EZNEC Pro 4 Only NEC 4 2 Implementation NEC 4 2 introduces three major advancements from NEC 4 1 Allocatable arrays current sources and an advanced Sommerfeld ground model The first two have been features of all EZNEC program types from its inception and of its predecessor ELNEC since its introduction in 1990 The new Sommerfeld ground GN3 model is incorporated in EZNEC Pro v 6 0 as Extended Accuracy ground All other changes and improvements made in NEC 4 2 have been incorporated into EZNEC Pro v 6 0 What Was New in v 5 0 This topic describes the differences between v 5 0 and the previous version 4 0 If you re upgrading from v 5 0 and are already familiar with it go directly to What s New in v 6 0 If you re upgrading directly from an earlier version please also see What Was New in v 4 0 EZNEC v 5 0 marks the transition of EZNEC from an antenna analysis tool to an antenna system analysis tool The new Transformer and L Network objects in addition to the ability to include transmission line loss extend the modeling capability for the first time from the antenna all the way back to the transmitter Array phasing networks tuners impedance
353. tion Plane Wave Overview EZNEC Pro only EZNEC Pro allows excitation of the model with a single fixed plane wave source as well as with conventional voltage and or current sources The plane wave source cannot be used in combination with conventional sources The plane wave source generates a plane wave from a specified direction at an apparently infinite distance The user specifies the direction of the source and the polarization and magnitude of the wave The wave induces currents in the model s wires The program reports the fields which result from those currents with results being exactly the same as if those currents had been created by conventional voltage and or current sources However note that in general the current distribution on the wires is different when the antenna is excited by an impinging plane wave than when excited by voltage and or current sources This feature is useful in determining the scattering cross section of a model structure or in direct determination of feed point voltage or current of a receiving antenna for a given field strength For example open circuit antenna voltage resulting from an incident plane wave is easily determined by placing a high resistance load at the point of interest and clicking Load Dat to see the resulting voltage A zero ohm load can be placed to conveniently monitor short circuit current at a specific segment or the Currents button can be used to see the currents at all segments To
354. tion and the elements are centered along Y 0 so the origin is a suitable choice for symmetrical scaling relative to the element centers You probably wouldn t want to scale wire diameters on an antenna like this since it would result in non standard diameters for tubing Leave that box unchecked Now click Ok You can see the rescaling take place in the View Antenna display but it can be deceiving the display automatically rescales to insure that the whole model will be on screen when unzoomed and at any position So the director and driven element will seem to shrink as the others extend It should be apparent though that the directors have gotten longer relative to the other two elements The remaining new features are largely self explanatory Be sure to read What s New in v 6 0 and try them out Feel free to experiment remember you can always undo any number of changes you ve made 44 Building The Model Introduction to Modeling Modeling is the technique of evaluating the performance of one object or system by evaluating the performance of a substitute called a model Models can be physical objects like a reduced size scale model antenna sometimes used for evaluating HF antennas Models can also be purely mathematical like the equations you use in circuit analysis The accuracy of the results are never better than the accuracy with which the model matches the real object For example a model of a circuit consisting of a bat
355. tion window should now read Dipole in free space this is the title of the antenna description stored in file Dipole1 Let s enter a title for our back yard dipole Click anywhere on the information window title bar where the text Dipole in free space is and a dialog box will open for you to enter the new name Enter Back yard dipole then click Ok or press the lt Enter gt key Notice that the information window title bar now shows the new description name Now let s change the frequency to 14 MHz Click anywhere on the Frequency information window line or on the selection button to its left Enter 14 in the dialog text box and click Ok or press lt Enter gt Let s choose feet for a convenient unit of measure This isn t the most convenient for international users but please select feet for this example Click on the Units line or the selection button to its left then select Feet and Ok The ground type for model Dipole1 is Free Space and we ll want to model this antenna over ground This will be taken care of after we define the wires and sources 20 Test Drive Next we ll describe the antenna itself EZNEC gives you the ability to see the modifications you re making as you make them To take advantage of this powerful feature open the View Antenna window by clicking the View Ant action button in the Control Center In the View Antenna Window click to open the View menu If a checkmark appears next to S
356. to be used for printing the Data_section of the Graphics Windows It has no effect on the screen display or on the Plot section of the printed output Power Level If the Absolute V sources box is checked voltage and current sources will have the values declared in the Sources Window The total power applied to the antenna will then be determined by a combination of these values and the feedpoint impedances If you uncheck the box and enter a non zero value for the power level all sources will be adjusted in proportion to result in the specified power being applied to the antenna The specified power will be the total power from all sources and it won t vary with antenna impedance The values shown in the Sources Window will represent relative not absolute voltage and current values The actual voltages and currents can be seen in the Source Data display This is a powerful and useful feature for a number of applications Stepped Diameter Correction Determines when Stepped Diameter Correction will be used EZNEC EZNEC and EZNEC Pro 2 only On recommended EZNEC will use Stepped Diameter Correction when possible Off EZNEC will not use Stepped Diameter Correction This setting may lead to inaccurate results for some types of antennas most notably Yagis having elements made from telescoping tubing EZNEC Pro 4 only NEC 2 On NEC 4 Off rec Enables Stepped Diameter Correction when using the NEC 2 calculating engine only
357. ton The impedance seen by the source is now very close to four times what it was before It won t be exact because of program accuracy limitations and the small unavoidable transformer resistance The SWR for a 50 ohm transmission line is now 1 445 1 much improved from the previous value Although this SWR is acceptable for nearly all purposes let s see how much we can improve it by cancelling out the 15 24 ohms of inductive reactance with a series capacitor A quick calculation shows that 15 24 ohms of capacitive reactance requires a 1460 6 pF capacitor We want it to be between the source and transformer in series The final impedance matching system will look like this LNet2 Sim Src1 Vi V5 We ll need to create additional Virtual Segment 3 as a place to connect the source and input to the new L Network How do we make an L network with a missing shunt branch An easy way is to use a parallel RLC configuration and set all three component values to zero In a parallel configuration a specified value of zero means an open circuit so setting all three to zero results in a completely open circuit Close the Source Data Window and open the L Networks Window In the add row below the currently defined L Network 1 specify a connection to V3 for Port 1 and V4 for Port 2 In the top row of the new network enter 1460 6 in the C column This is the series branch In the bottom row of the Config column enter P or select Par from the drop down b
358. transmission line is a stub If Actual Distance is specified and one or both ends are connected to virtual segments an error message will appear when you attempt to do calculations Specifying Characteristic Impedance Z0 In the ZO column you can either enter the characteristic impedance in ohms or you can right click the cell to open a dialog box with more options The dialog box lets you choose from a list of common cable types or enter the wire diameter and spacing of parallel wires If you use the parallel wire entry EZNEC will assume air insulation unless you give a velocity factor If you enter a velocity factor EZNEC will infer an effective dielectric constant and calculate the impedance based on this dielectric constant So the parallel wire entry can be used for ladder line twinlead or other dielectric insulated lines as long as you know the velocity factor The results of its calculations are shown at the lower left of the dialog box Specifying Velocity Factor To specify velocity factor enter a positive number no greater than one in the VF column Alternatively you can right click the cell to open the same dialog box as described above Specifying Reverse or Normal Connection 94 Building The Model Connection orientation is selected in the Rev Norm column Normal connection means that the same conductor of both ends will face the same wire end number That is if one line conductor is labeled 1 and the other 2 conductor
359. ts characteristics Refer to the transformer chapter for additional information 71 EZNEC User Manual Phased Arrays Issues involved with phased arrays are discussed in the section also named Phased Arrays in the chapters about sources Small Loops NEC 2 is unable to accurately model small loop antennas If this is attempted a zero or negative feedpoint impedance and accompanying error message may result NEC 4 is more tolerant but problems might still be encountered with very small loops Double precision versions of both engines permit smaller loops than the standard or single precision versions Tests with a square loop in free space one segment per wire showed reasonably accurate results with loops down to the following minimum circumferences NEC 2 0 05 wavelength NEC 2D 0 0005 wavelength Available in EZNEC EZNECPro 2 and EZNEC Pro 4 only NEC 4 0 001 wavelength Available in EZNEC Pro 4 only NEC 4D 107 wavelength Available in EZNEC Pro 4 only These should be used as guidelines only as accuracy can depend on a number of factors Stacked Yagis Stacked Yagis or other antennas can be modeled easily with EZNEC by using the Stack feature A step by step example follows In this example we ll stack two of the Yagis of the example file 20m5elya ez In the Control Center locate the Open action button and click it This will open a file selection dialog box Select 20m5elya ez and click Open Click here if you have t
360. ual Acknowledgement Scintilla Software All EZNEC program types make use of Scintilla editor software which is generously provided free of charge by Neil Hodgson scintilla org The full license statement and disclaimer is in the Legal Notices section of this manual Third Party Software Legal Notices section of this manual A Few Words About Copy Protection EZNEC and EZNEC A friend of mine made the observation that a conscience is kind of like a little wheel with sharp teeth that spins and digs into you But each time it does he said the teeth wear down a little so the next time it s not quite as sharp Eventually if you use it enough there aren t any teeth left If the teeth on your Introduction wheel are worn all the way down what I m about to say won t reach you anyway so you may as well skip the rest of this section Copy protection is a big nuisance to both the user and the software developer It also can necessitate an increase in price That s a lousy deal more nuisance for a higher price That s why this software is not copy protected Yet copying it is easier than ripping off a Walkman from K Mart with zero chance of getting caught although it s just as illegal and dishonest So it s pretty risky to put the product out without copy protection I m well aware that sellers of similar programs have had to copy protect their programs to prevent such theft Theft You bet Over a year of virtually full time work have g
361. ude amps meter 75 Hz magnitude amps meter 76 Ex phase degrees 77 Ey phase degrees 78 Ez phase degrees 79 Hx phase degrees 80 Hy phase degrees 81 Hz phase degrees Block types 96 101 contain absolute electric field components resolved in spherical coordinates as follows Block Data Units 96 E R magnitude volts meter 97 E phi magnitude volts meter 98 E theta magnitude volts meter 99 E R phase degrees 100 E phi phase degrees 101 E theta phase degrees Use block type 65 for peak E magnitude 169 EZNEC User Manual Block Length String Lengths and Frequency These fields are the same as for relative far field blocks Power This field is antenna input power in watts Coordinate System This byte specifies the coordinate system used to locate data points it does not specify the coordinate system used to resolve field components The byte is O for rectangular coordinates 1 for spherical coordinates and 2 for cylindrical coordinates Other values are reserved Coordinates are defined as follows Coordinate System A B C 0 Rectangular X Y Z 1 Spherical R phi theta 2 Cylindrical rho phi z Symmetry The low order bits of this byte have the following meaning when set Bit Meaning 0 A coordinate symmetry 1 B coordinate symmetry 2 C coordinate symmetry Here symmetry means that the data has the same value when the coordinate is negated this definition is not the same as that for relative fields Any of
362. uggestions and those who have patiently waited for this version Finally but foremost thanks to my family for being understanding and supportive during the many many hours I ve spent away from them working on this program Acknowledgement and Special Thanks Jordan Russell and Inno Setup All variations of EZNEC version 4 0 31 and later use the open source Inno Setup installer created by Jordan Russell This is a tremendously rich and powerful but easy to use installer I m very grateful to the author and any other contributors who have obviously put in a tremendous amount of effort in developing this fine application and have made it available to be freely used at no charge It wasn t chosen for EZNEC because it s free it was chosen because it s simply the best installer available at any cost for the job Acknowledgement vbAcellerator Software This product includes software developed by vbAccelerator http vbaccelerator com thank vbAccelerator for generously making this high quality software available at no charge The full license statement and disclaimer is in the Legal Notices section of this manual Third Party Software Legal Notices Acknowledgement Info Zip Software All EZNEC program types make use of file compression and decompression software which is generously provided free of charge by Info ZIP A list of contributors to this project can be found in the Third Party Software Legal Notices section of this man
363. ugh they re immersed wholly in the first medium When a second ground medium is first created its conductivity and dielectric constant are set to the default values determined by the Control Center Options menu Default Ground Const selection Connecting Wires to Ground A Wire end is connected to ground by specifying a zero z coordinate EZNEC actually considers a wire end to be connected to ground if it is within about 1 1000 of a segment length of ground A good general practice is to space unconnected vertical or sloping wires at least several wire diameters above ground A wire with both ends within 1 1000 segment length of ground is not permitted and will produce an error message If you connect a wire to ground when using the High or Extended Accuracy real ground type the program makes the connection with an unpredictable series resistance EZNEC will warn you when this situation occurs Use the MININEC type ground when modeling antennas with vertical grounded wires if the ground system itself isn t part of the model Sometimes it s necessary to both make a ground connection and use High Accuracy ground A technique for doing this is described in Connecting to High Accuracy Ground 107 EZNEC User Manual Connecting to High Accuracy Ground This applies also to Extended Accuracy ground available only in EZNEC Pro 4 Sometimes it s necessary to make a ground connection and use High Accuracy ground An example of this situation
364. ult folder which appears when you first choose this option is the EZNEC output folder for convenient viewing of EZNEC output files However it can be used for viewing any text file 131 EZNEC User Manual Edit File Same as View File above except that the original file content isn t protected and you re allowed to save a modified text under the same file name Exit Without Saving EZNEC normally saves the current description in a file named Last EZ which it loads the next time it starts However if you select this choice the current description won t be saved This is useful if the current description is defective thereby preventing EZNEC from saving it or if you ve done a quick experiment but want EZNEC to start up the next time with the same description it started up with for the current session Clicking Yes to exit without saving ends the EZNEC session Exit Normal way to end EZNEC Saves the current description in Last EZ and ends the program Does the same thing as clicking the close box in the upper right corner of the Control Center Edit Undo Redo Allows you to undo changes made to the description since it was opened and to redo any changes that were undone Options All selections in this section remain effective until the program ends They can be made permanent that is they become the new default values by clicking Save As Default at the bottom of the list Angle Convention EZNEC allows you to r
365. und medium You might want to set these to reflect the properties of your local ground Folders Allows you to specify the default locations of various files used by EZNEC To select a folder double click your choice The folder name and path will appear under the white window and the folder icon will show that the folder is open Remember that your choice will be effective only until the program ends unless you re open the Options menu and select Save As Default at the bottom of the Options menu selection list Each of the following dialog boxes includes a Default Folder button This will return the selection back to the folder which has been saved as the default 133 EZNEC User Manual value It s useful when you ve selected a folder for temporary use and want to return to the normal default location Description EZ and Plot Files Default location of the description files and 2D and 3D plot files IONCAP VOACAP Files Default location of the IONCAP VOACAP files You should set this to the directory expected by your IONCAP type program Output Files Location of most files generated by EZNEC except the ones having their own folder options Ground File Tolerance When EZNEC does an analysis with Real High or Extended Accuracy ground it checks to see if the necessary ground data have already been calculated and saved as a ground data file Each file corresponds to a particular combination of frequency and ground conductivity
366. using an NEC 4 calculating engine no wires can have Z coordinates less than zero Whenever any ground type other than Free Space is specified no wire can have both ends at Z 0 that is at the ground surface with any program type EZNEC Pro 4 when using an NEC 4 calculating engine is able to model buried wires All other EZNEC program types are not Horizontal wires should not be placed exactly on the ground but should be at least 1 1000 wavelength above and in the case of EZNEC Pro 4 also below the ground See Elevated Radial Systems for more information about low horizontal wires Free Space Free space analysis is computationally the fastest It s useful for comparing antennas when the end operating environment isn t known or for comparing the pattern of a model antenna with published free space patterns of other antennas When antennas have similar vertical patterns in the main direction of interest the gain of the antennas when mounted over ground at the same height will differ by about the same amount as the free space gain A dipole and a Yagi of a few elements are in this category so the free space gain of a Yagi compared to that of a dipole is very nearly the same as the gain difference when both antennas are mounted at the same height This isn t true however for antennas with different polarizations such as a ground plane and dipole or for antennas with quite different vertical patterns such as a dipole and W8JK antenna
367. utton You can then move the display It will move in the direction of one of the axes the one most closely parallel to the mouse movement so you might have to rotate the display in order to achieve movement in the direction of a particular axis Zooming To zoom the display position the mouse cursor anywhere on the display window Press and hold down the both mouse buttons This does not zoom the currents that can be done only with the scroll bar Selecting Wires The wire closest to the mouse cursor will be selected when the left mouse button is double clicked Additional wires can be selected by pressing and holding the lt Ctrl gt key while clicking with the left mouse button lt Ctrl gt clicking a selected wire will deselect it Double clicking a wire will always deselect all other wires The View Antenna display and Wires Window are coordinated Whenever the Wires Window is on wires selected in the Wires Window will be automatically selected in the View Antenna display and vice versa Wire Information You can see information about any wire by pausing the mouse cursor over the wire One important use of this feature is identifying which end of the wire is which among the information shown are the coordinates of the wire end closest to the cursor and that end is identified in the display The behavior of the popup can be altered with Special Option WirelnfoDist Displayable Objects 145 EZNEC User Manual A number of objects
368. vation slice of a saved 3D plot to add to the 2D display Or you can recall and view the entire 3D plot with TraceView Close all the windows except the Control Center Now let s run an SWR plot of the antenna Click the SWR action button Enter 14 14 4 and 1 in the Start Frequency Stop Frequency and Frequency Step boxes respectively Then click Run This will run an SWR sweep with the results being shown when the sweep is finished Turn on the control and data boxes via the SWR display View menu if they re not already on You can move the cursor on the SWR graph to any position by clicking on the graph near the point where you want the cursor to go or by dragging the cursor You can also move the cursor with the arrow keys after first clicking anywhere on the SWR graph As the cursor moves you can see the SWR for that frequency in the data box below the graph The graph clearly shows that the antenna is too short if lowest SWR on 20 meters is a goal This is indicated by the fact that the SWR decreases clear across the band Let s make the antenna resonant at 14 1 MHz One way would be to adjust the lengths of the wires and find resonance by trial and error But we ll use another method First we find out just where the antenna is currently resonant We know it s at or above 14 4 MHz so Click the SWR action button Click No in the message box which appears Enter 14 3 and 14 8 in the Start and Stop frequency boxes and click Run From
369. ve analysis is enabled the Elevation Angle or Azimuth Angle selection changes to Observation Height which you can also specify Note that if an observation height greater than zero is chosen the ground wave distance is the horizontal distance from the origin to the observation point i e the projection of the actual distance on the XY plane The actual distance from the origin to the observation point is the square root of the sum of the squares of the ground wave distance and the observation height If ground wave analysis is enabled Plot Type is restricted to Azimuth Results can be presented as a dBi plot or in a table of dBi or absolute electric field values the choice being selected with the Control Center Options menu Far Field Table Units selection Ground wave analysis may be done with any ground type except free space Note If more than one medium is defined with Real ground the analysis will be done using only the constants of the first medium as though it extends to infinity the second medium if present will be ignored 122 Reference Group Modify Modifying A Group of Wires Sources Loads or Transmission Lines The Group Modify feature is common to all the Input Grid Windows except the Media Window It s a powerful feature for modifying a number of items at once Many of the normal editing features and shortcuts apply when Group Modify is activated Group Modify is activated by selecting Group Modify from the Wire Sou
370. vided into segments for computational purposes and good segmentation is essential to accurate results See the Seqmentation section for more information about this important topic Several NEC guidelines are checked by the automatic Segmentation Check It runs automatically when you open a file or change the wire description or you can run it manually at any time There are two sets of guidelines conservative and minimum recommended In general the conservative guidelines will result in more segments and better accuracy than the minimum recommended It s impossible to place an accuracy figure on either set of guidelines because the effect of small errors in current amplitude or distribution can vary greatly depending on the type of antenna and the role the wire plays As a general rule you should use more conservative guidelines when modeling antennas which have a narrow bandwidth or use parasitic elements such as a Yagi See Segmentation for more information More serious errors such as crossing or overlapping wires are detected by the Geometry Check which can be run manually at any time but always runs at the beginning of a calculation Unlike the segmentation check you can t choose to ignore these errors EZNEC will refuse to do the calculations if geometry errors exist Bear in mind that neither check can find all possible errors SO care and knowledge on the part of the user are still required The Some Special Cases section describes spe
371. whenever the program is started a new description is opened the frequency is changed or wires are imported from an ASCII file It can be run at any time from the Control Center Outputs menu 126 Reference There are two sets of guidelines conservative and minimum recommended In general you should keep your antenna within the minimum recommended guidelines and observe the conservative guidelines if the antenna is narrow band or critical Always be aware however that even this doesn t guarantee a sufficient number of segments See Segmentation for more information Segmentation Check output is shown with the EZNEC Editor so you can save or print the data if desired Display of conservative guideline warnings when run automatically can be suppressed with the Segmentation Check selection in the program Options menu If any errors are found an additional menu Seqmentation is shown in the Editor This allows you to have EZNEC automatically adjust the number of wire segments to conform to the NEC guidelines The choices in this menu are as follows Fix Segs Adjusts the number of segments only on wires which violate guidelines Auto Seg Adjusts the number of segments on all wires to the minimum number required to meet guidelines Each of these selections has two additional choices allowing you to adjust to conservative or minimum recommended guidelines explained above Neither however automatically corrects insertion object placem
372. wire offset dipole with a standard source This illustrates that you have a great deal of flexibility in modeling your antenna Click the Src Dat Control Center action button The indicated impedance is slightly different than it was for the original dipole Most of the difference is due to the fact that the new dipole has twice the number of segments But small differences in reported impedance are to be expected whenever a model is changed however slightly The differences are insignificant for any practical purpose If you d like to experiment a little open the Wires Window and change the number of segments on the wires keeping 27 EZNEC User Manual the number the same for both Then click Src Dat again to see the effect of this change on the source impedance Repeat for several different numbers of segments Close the Wires Window when you re finished to get it out of the way Close the Source Data display Now we ll make the dipole into an inverted vee At this point most other modeling programs would require you to do some trigonometry or carefully draw the inverted vee on graph paper to determine the coordinates of the wire ends But not with EZNEC We ll use EZNEC s Rotate feature to make it into an inverted vee with an included angle of 90 degrees Before proceeding it s a good idea to save the description This way an easy recovery can be made if an error is made Click the Control Center Save As action button Furnish a name
373. xis phase degrees 16 Polarization tilt degrees Ellipticity is the length of the minor axis of the polarization ellipse divided by the length of the major axis expressed in dB the IEEE 754 1985 floating point code for infinity is valid Polarization tilt is the counterclockwise angle between the major axis and the E theta direction Block Length 167 EZNEC User Manual This field is the total length of the block in bytes Block lengths less than 3 are invalid Title Environment and Notes Lengths These fields specify the lengths of the ASCII strings in bytes Zero is valid Frequency Frequency is in MHz Plane This byte is 0 for azimuth data constant zenith angle and 1 for elevation data constant azimuth angle Other values are reserved Plane Angle This field is the zenith angle for azimuth data and the azimuth angle for elevation data Symmetry The bits of this byte have the following meaning when set Bit Azimuth Data Elevation Data 0 X symmetry XY symmetry 1 Y symmetry Z symmetry Symmetry means that the data has the same value when reflected about the line or plane indicated For azimuth data bits 0 and 1 refer to the X and Y axes For elevation data they refer to the XY plane and the Z axis Both bits may be set simultaneously Bits 2 7 are reserved Number of Points This field is the number of data points that follow 0 is valid First Angle This field is the angle of the first data point Angular In
374. y as 91 EZNEC User Manual with RLC type loads Do not use this load type unless you are familiar with the use of Laplace transforms the explanation of which is beyond the scope of this manual Impedances are entered as Laplace coefficients with zero to fifth order from left to right and numerator on the top and denominator beneath At least one denominator coefficient must be non zero See Load Types for information about other types of loads and changing the load type See Load Connections for information on choosing the external connection type in the Ext Conn column Using Transmission Lines About Transmission Lines There are important differences between the NEC transmission line objects used by EZNEC and real life transmission lines so there are several things you have to be aware of in order to use them effectively The first characteristic is shared by all other two port insertion objects The only parts of the transmission line object which exist as far as the program is concerned are the ends Imagine the model as being two sets of portable terminals which can be placed in any two segments The current and voltage at one set of terminals relative to the other is just the same as though there were a transmission line connected between them But the transmission line can be any length you specify including longer or shorter than the physical distance between the terminals Although the terminals are accessible to connect t
375. y be apparent in the results The limitation is most 100 Building The Model likely to be noticed when EZNEC raises the impedance of a shorted branch In some cases the resulting impedance used for calculation can be as high as one ohm This won t usually cause any significant change in results but might be noticeable in some extreme cases These limitations can be avoided by using a double precision calculating engine available in EZNEC and EZNEC Pro program types only The increased resolution increases the allowable impedance ranges to the point where no applied limitation will cause a noticeable change in results Using Y Parameter Networks Y Parameter Networks EZNEC Pro only Y Parameter Networks are insertion objects which can be used to simulate most two port networks The network s admittance characteristics are defined as y parameters These admittances don t change with frequency so the model must be changed for each frequency if the network is intended to represent one which includes real reactive components This feature intended for engineering level users is the direct equivalent of the NEC network model Connection rules are the same as for other insertion objects Full discussion of y parameter network techniques is beyond the scope of this manual it s assumed that the user is familiar with the use of these networks Very briefly the Y Parameter Network object is a two port network defined by y parameters y11 y
376. y clicking the Sources line in the Control Center information window Click the cell in the Source 1 Type column As soon as you Click the cell a small button with an arrow appears in the cell This indicates that several distinct choices are available Clicking on the button opens a pull down list of choices Select GI Then move to the From E1 column in the Specified Pos group and change the value from 50 to 0 This will put a split current source at end 1 of wire 1 Press the lt Enter gt key On the View Antenna display you should now see two source circles one on each side of the wire 1 wire 2 junction You can rotate the display for better viewing by pressing the left mouse button while the cursor is in the display window then moving the mouse while holding the button down You can also resize the display by dragging any of the sides of the window At this point we have a dipole again but made from two wires instead of one Click the FF Plot action button to generate a 2D plot In the 2D Plot window open the File menu and select Add Trace If you saved the trace from the Along the Straightaway exercise you should see a file named Back Yard Dipole Click it then click Open This overlays the back yard dipole plot with the plot from the new dipole It should overlay exactly showing that the new dipole made with two wires and a split source and centered with respect to the x axis has the same pattern as the single
377. ysis Ground Type 11 Feedlines and Baluns 70 Feedpoint Resistance 72 73 111 Negative sees 72 111 SOS warn wane 72 EE EE 140 FF Tab WEE 112 140 Field E and H 0 112 123 E AATE EEN 131 138 164 el EE EEN 164 EQUI EE 131 Last opened or saved 138 Raeren EE 157 VIEWING e a ieiet tniii 131 File Lee 157 el 6 152 Comma delimited 0066 6 NEC format cee eee 152 PIX E 126 Flat Surface Modeling 60 74 Folderz 8 132 138 157 Changing Location 132 CHOOSING 22 ocd iat irnniretitectces dees 132 Used by EZNEC 8 132 138 157 GE 118 132 Control Center Action Buttons SOUING eieiei 162 Printed plot data 132 Printer VS screen 118 Substitution ceeeeeeee eee 118 Free Space ee Ee 102 Freq SW E 140 Frequency 29 125 132 138 KHMER eerste deeg 138 Rescaling EE 29 125 Selecting e 138 Showing on 2D Display 132 Frequency Sweep118 137 140 160 Data output file 118 Input 8 UE 118 Lastz txt file 160 Maximum steps in Smith chart program fleien 118 Eeer 118 R NNING EEN 140 SOUP ser nsn 118 137 Decimal separator 000 171 een EE 171 Frequency Sweep setup 118 137 Turning on and oft 118 Frequency dependent Resistance gedeelt 90 EZNEC User Manual Front Back Ratio eee 147 G Ga EE 147 Geometry Check 120 Geometry Check 120 Getting Acqu

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