What is TANT
Contents
1. Open Save As Ant Motes Cancel Currents Elevation Angle Range fi Full Range Organize Data As Load Dat C Elevation Slices f Azimuth Slices Vai rite View Ant IDNCAPWOACAP File NEC 20 Plot Type FF Plat Step Size 2 Deg Ref Level O dBi Alt SWR ZO 75 ohms Desc Options Average Gain 0 968 0 14 dB Afooe COIS AOSS Select option Azimuth Slices and check Full Range Press Ok button and EZNEC will generate a txt file containing the Far File data in a table 5 13 Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 The FF Tab file you just generated should look like this The content of the second line may vary of course as it is depending on your comments to the NEC file Valid for correct calculations by TANT is the Reference level of 0 dBi and the tables following the header See notes below on Decimal Separator P ef0713 Editor Datei Bearbeiten Formak Ansicht 7 EZNEC ver 5 0 13 el vagi by YUYEF 18 10 2008 FAR FIELD PATTERN DATA Frequency 144 35 MHZ Reference dBi Azimuth Pattern Eleyation angle 90 deg Deg wog H dB Tot dB 9 13 13 4 13 13 34 13 13 32 13 13 30 l 3 l 3 28 T 13 24 13 13 25 13 13 24 13 13 23 1 3 13 22 13 13 ee 2ER ee 21 14 13 20 14 13 14 14 13 19 142. Tpattern attenuated by the loss The information on ohmic losses is contained in the EZNEC Far Field Table It is the difference between 0 00 dBi and power gain averaged over all directions Average Gain The Average Gain is displayed on the Bottom Line of the EZNEC main window once you have run the 3D far field plot see EZNEC User Manual on Average Gain EZNEC v 5 0 File Edit Save As Ant Motes Currents Sre Dat Load Dat FF Tab NF Tab SWH Yew Ant MEC 2 FF Flot Qptens Outputs Setups View Wtiites Help gt YTUFEF s EF0213 as Plot Type Step Size es Ref Level o gt Alt SWR Z0 UVEF_ 144 13ele_ ong EZ 144 2 MHz 2079 01 mm 13 Wires 143 segments 1 Source U Loads U Transmission Lines 0 Transformers OL Networks Free Space Aluminum 6061 16 Milirneters 3D 2 Deg O dBi T5 ohms _ bestUptions O O Average Gan 0 970 0 13 dB AOGE COTAN Arex 9 13 Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 Antenna elevation The following picture shows the Far Field of the example yagi in 30 deg elevation Do not arrange wires i e antenna in EZNEC in that position your self since you would loose the maximum gain at 0 convention This picture is for demonstration only TANT does this virtually for you in the output in steps of 5 over a variation from O to 90 EZNEC 30 deg
3. 13 zA 14 rae e 1 4 14 13 17 15 13 17 15 13 17 15 13 1 6 I S Es Save this file using the 8 3 DOS filename convention In straight words use a name with 6 characters followed by a period dot and ending txt example ef0213 txt Important Note Decimal separator for the table values must be a period as TANT can not handle the e J comma that you might eventually get due to the regional settings your Windows Controls EZNEC does not provide the choice of what separator to use see EZNEC User Manual on Decimal Separator TANT will react on the comma separator with immediate shut down If you dislike manipulating your PC s Windows settings you may load the FF Tab file in some advanced Text Editor like MS Word or Open Office Writer and exchange commas with periods using the auto replace function on whole text Then save in txt format again Do not try this in MS Editor it will take ages to replace the average of 10 000 40 000 commas by periods 6 13 Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 How to run TANT Start TANT by double clicking the TANT exe file o C PROGRA 1 EZ7W Ant tant Tant exe lof xi Press any key and then press 1 to type in your FF Tab file name example ef0213 txt TANT 1 2 April 23 20665 by Sinisa YTiINT WESEA paupahan Antenna Temperature and G T Rat
4. Example YU7EF EF0213 13 element yagi for 144 MHz in EZNEC v 5 0 At an antenna elevation of 0 the Tpatten is always the average of Tsky and Teann for any antenna having a symmetrical pattern relative to the horizontal plane regardless of the actual pattern gain losses F B F S or sidelobe level see next 8 G T ratio as from VE7BQH G T simulation table descriptions G T ratio is a figure of merit used to determine the receive capability of the antenna G T Ga 2 15 10 log Ta dB Example using the EF0213 data G T 14 02 dBD 2 15 dB 10 log 223 9 K 16 22 dB i 10 log 223 9 K 16 22 dB 23 50 dB 7 28 dB Interpretation More positive i e less negative figures are better Antenna gain Ga is in dB vs dipole dBD The addition of 2 15 dB matches a figure vs isotropic radiator dBi Temperature is expressed in dB by conversion with 10 log 10 13 Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 What does that mean to terrestrial low signal communication Excursion by YT1NT edited by DG7YBN May we consider a general case of an antenna with a symmetrical elevation pattern i e equal top and bottom half spaces This is always the case with e Single Yagis e Multiple Horizontally Stacked Yagis e Multiple Vertically Stacked Yagis with symmetrical current distributions when all of these antennas are operated with an elevation o
5. Ta in DJ9BV s article It represents the sum of forward sidelobe and backward temperatures which is likely not the same as the sum of similar named values in YA 3 54 See Notes for additional information Please note that terms forward sidelobe and backward in DJ9BV s Article and like wise in YA 3 54 have nothing to do with your antenna s pattern They are just unfortunately chosen names for differential parts of the integration surface related to the 30 degrees elevation used and having no relation whatsoever to the actual antenna pattern Rainer DJ9BV had to give some name to those sections in which he split the integration paths of the complete pattern surface Please note that there is an error in DJ9BV s article In section 4 the integration surface is partitioned incorrectly to forward sidelobe and backward parts As stated there the partitioning is correct only for azimuth values of 0 and 180 degrees The noise temperature and G T treatment in YA 3 54 seems to be based on DJ9BV s article However with our antenna samples YA 3 54 results were in substantial agreement with TANT results although it is not clear whether it was so because the error was small in the samples tested or because YA 3 54 performed the integration correctly You can keep TANT running while you work in EZNEC When you re ready save the pattern file and select Compute in TANT Bear
6. g a g a g aTa i Pe ee im ii F E E E E E E E a E E E a Pao Pao Peo Px PA DA Pd Da Pao PS Pao Ba fo Ba Pat Ba E Th Ta p _ h r r r Th Ta r h Tr P r Th Ta pe r r Bol Da Doa Dl Dl Gal Goal Bo Pot Cl Cal Gl h pab peak fo E M en ens ee oo Med ated Doha Ratt Mate of pate oft ETO a Met Boil MS aT Met Bal ton pan any key to continue a ar ki WI ay Note the red line for 30 degree elevation angle for easier comparison with Yagi Analysis 3 54 YA 3 54 This became the standard angle since it was chosen by DJ9YBV as being a typical elevation angle of the antenna for EME applications But there is nothing magic about 30 degrees Depending on the application some other elevation angle may be of more use for you Values in this example are referring to the EF0213 yagi 8 13 Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 How to interpret results Tant Antenna temperature is computed in and displayed in 3 values Tpattern applies to a lossless antenna with exactly the same shape of the pattern as for Ttotal This is arrived at by compensating for the loss as calculated below Tpattern shows the directional qualities of the antenna pattern ignoring ohmic losses Ttotal applies to the antenna pattern exactly as supplied by EZNEC Tloss Ttotal
7. not matter on the issue of antenna temperature Of course we all know that sidelobes and F B ratio matter very much in real world terrestrial communication But this is not taken into account in the Tant definition Thus consequently Tant as it is defined can not express those valuable qualities of antennas for terrestrial communications lf we wanted to express the quality of the antenna s directional pattern we d have to define different Tearth values in different directions Until we do so both the assertions of Tant and TANT are of limited use for terrestrial work We may only deduce that a yagi with lower Tant than a referencing one at 30 elevation will be quieter in terrestrial work 11 13 Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 Additional notes from original readme txt as far as not mentioned above Antenna temperature and G T ratio are not parameters of the sole antenna itself Instead they are parameters of the entire antenna ambient system Total Toss T pattern attenuated by loss exactly as Ta in DJ9BV s article Whenever T pattem gt Tret 290K any antenna loss will LOWER the Tota i e it will DECREASE the total noise power towards the thermal noise power at Te Of course this can not be used to improve G T or S N ratios Based on the equations presented by DJ9BV the pattern temperature T pattem is exactly the same as
8. TANT V1 2 Illustrated add on to the original readme txt issued by Sinisa YT1NT VE3EA on April 23 2006 m How to build proper EZNEC files for TANT m How to run TANT m How to interpret results Written by Hartmut DG7YBN on Feb 07 2009 with kind help of YU7EF and supervision by YT1NT Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 What is TANT TANT is a program written by Sinisa YT1NT It computes Far Field table output originating from antenna radiation pattern that have been produced with EZNEC from version 3 to the actual version 5 0 onwards or any other exactly similar table format holding complete Far Field data TANT calculates Antenna Temperature and G T Ratio for antenna elevation angles from 0 to 90 degrees in steps of 5 degrees whilst assuming uniform sky and earth temperatures for the full sight of sky sphere z in radian respectively earth up to horizon 22 in radian for polar coordinates TANT is a DOS program that can be run from either MS DOS prompt or MS DOS Console when using Windows environment What is the actual version of TANT TANT 1 2 What is the calculation base of TANT s equations Common Base for calculating the antenna temperature is the integration of infinite slices of Temperature in observation direction multiplied with equal slice of antenna beam characteristic in that direction over the sight of noise temperature emitting
9. environment The well known article by Rainer Bertelsmeier DJ9BV Effective Noise Temperature of 4 Yagi Arrays for 432 Mhz EME presents the full set of equations and theory It is a good introduction to antenna temperature and G T ratio See Dubus magazin 4 87 or http www mrs bt co uk dubus 8 04 1 pdf file size 598 kB How to install TANT TANT does not need to be installed It consists of a single executable exe file Place it in the same folder as your EZNEC pattern files and run it from there Terminology TANT refers to the programs name Tant refers to Antenna Temperature in Kelvin K FF Far Field Picture on front page FF of 4 yagi bay of YU7EF s 7 ele yagis EF0207 made with 4nec2x 3D viewer extension 2 13 Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 How to generate a Far Field table suitable for TANT analysis First you must build a proper Far Field table of your antenna with EZNEC Building a Far Field Table lt FF Tab gt file that can be computed by TANT in three steps Step 1 Build your EZNEC model file in a way that X axis element position on boom Y axis element length Z axis height of element i e distance to ground Maximum gain must occur at elevation angle 0 degrees and azimuth angle 0 Set parameter Step Size for pattern calculation accuracy to 1 2 or at least 3 Degree Set parameter Ref Level t
10. f 0 degrees In other words this is almost always the case in terrestrial communication Under these conditions the antenna temperature does not depend at all on the radiation pattern and it is always Tant Tsky Teann 2 ignoring ohmic losses As TANT is assuming uniform sky and earth temperatures for the full sight 860 turn of sky sphere respectively earth up to horizon what you get is just the medium value between Tsk 200 K and Teann 1000 K Every per coordinate determined infinitesimal patch of environment in the sky has a complementary patch on the ground Since the antenna pattern is symmetric the gain per sky patch and complementary earth patch is equal Hence all the integration mechanism may be crossed out of the equation What is left may look as simple as this 200 K 1000K 2 600 K In straight words e Tant will stay the same as long as the elevation pattern is symmetrical e Tant will not depend on gain sidelobes F B or F R ratio etc Does this mean that Tant indicates absolutely nothing about antenna qualities for terrestrial communications Yes it indicates absolutely nothing if you take the Tant figure for 0 of antenna elevation angle as an objective This follows from the assumptions underlying the definition of antenna temperature Tant and specifically the assumption that Tearth is the same in all directions If Tearth is the same in all directions then sidelobes and F B ratio do
11. in mind that 0 1 K accuracy in Topattern OF Tiota would demand less than 0 002 dB error in pattern which can not be expected from NEC modelling Even the resolution of 0 01 dB in the EZNEC pattern file is far better than actual accuracy 12 13 Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 Disclaimer No guarantee whatsoever use TANT at your own risk This is freeware use TANT for any purpose you like Acknowledgements by Sinisa YT1NT To YU1CF for numerous suggestions testing and providing test samples and EZNEC patterns files To YT1NP for testing with EZNEC Demo versions To YU 7EF and YU XL for most stimulating discussion leading to the development of TANT My own thanks go to YU EF who helped me generously to get TANT running provided all the EZNEC screenshots and the fine 13 element yagi demonstration model as an advanced selection from his Low Temperature Antenna Gallery see www yu ef com for more vy 73 Hartmut DG7YBN 13 13
12. io or elevations from 4 to FA degrees in steps of 5 degrees Uniform Sky and Earth temperatures assumed gt Please Select Far Field Pattern file ef 8213 txt Sky Temperature K 246 48 Earth Temperature K 1666 44 Compute Help Quit Please select option 1 6 Then press Return Finally press 4 to compute your file The advanced user may vary Sky Temperature and Earth Temperature in similar manner Do not change these figures at the moment and do not change them if you like to compare your data with the well acknowledged standard in the VE7BQH Temperature and G T ratio Table which is based on these environment temperatures and 30 degrees of antenna elevation angle 7 13 Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 If TANT is running properly it shall look like this while computing EN PROGRA 11 E7WidAntitantilant exe ol xi Tat Far Reading 4 E 7 SLE 5126 elevation And this is what the output shall look like H 14 dBi gt temperature pattern loss 6660 6 K 7 2 476 6 H 7 2 1 ja y pon Du oe ee p hy m T w o D th h Or Oo eo eo ny a ee e H at E bo 00 Oo of E E E L E L BJ OM Mo GS I E 4 4 7 AOA J oo 5 Ha d pah jak fk D5 haf m BOBS BOBO Boo Bo D Po od a a F ak pek g q q a Ca q g rr Es ca q q
13. o 0 dBi See EZNEC main window underneath Wires window la x Wire Creabe Edit Other Coord Enty Mode Preserve Connections IY Show Wire Insulation Segs Diel C Thk mm l ro J im alea ajo co a rar tas ot owas Jo gt W es fon fo ats bma fo p m NEC 20 Plot Type FF Plot Ea Tr Step Size Ref Level Alt SWR ZO Desc Options p KA 1 Example file model YU7EF EF0213 13 ele yagi for 144 MHz in EZNEC v 5 0 The above design is the sole property of Ljubisa Popa YU7EF Distribution and publishing of these data and information is permited ONLY for radioamateur purposes and construction Use of these information and data for any commercial purposes is strictly prohibited without the written authorization of Ljubisa Popa 3 13 Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 Step 2 Select Options and set Parameter Angle Convention to CCW From X Axis lt EZNMEL Y 5 0 File Edit Options Outputs Setups View Utilities Angle Convention Undo Disk Space IONCAPVOACAP File zero Angle MEC 2D FF Flot EZNEC Geometry Check Far Field Table Units Mear Field Table Format zD Flot Scale b 2D Plot Grid Style d w Show Freg on 2D Plot Default 30 Step Size View Antenna Wire Numbers d Save 45 Default 4 13 Help Open SuboCompletelS
14. uggest w CCW From amp Axis save As Calculating Engine Ant Notes Default Ground Const Curente Folders Srce Dat Ground File Tolerance Load Dat Messages On Orr aaea FF Tab Segmentation Check p emission Lines NFTab Plot Printing p peformers __ WA Power Level eiei pace View Ant Smith Chart Program Stepped Diameter Correction um 6061 76 Next run Far Field Plot lt FF Plot gt with Plot Type 3D to create the Total Field radiation pattern Left This is what your 3D pattern should look like you do not need to highlight the azimuth slice as in this example Pattern must not necessarily be symmetrical since there are no shortcuts being taken in TANT s computing engine The entire pattern must be present and integration is always over the entire space Just make sure that all axis are in place and maximum gain occurs at elevation angle 0 deg and azimuth angle 0 deg Illustrated Add On to TANT 1 2 readme txt April 23 2006 by YT1NT Written by DG7YBN on Feb 07 2009 Step 3 How to generate the Far Field Table that TANT shall use to compute the antenna temperature and G T ratio Clicking the FF Tab button produces the 3D Far Field Table Form see below EZNEC 3D Far Field Table File Edit OF Select whether to organize the data in azimuth or elevation slices and what range of angles in each slice to include in the table
Download Pdf Manuals
Related Search