LDG AT-200Pro Automatic Antenna Tuner
Contents
1. fools your transmitter into behaving as though the antenna were resonant avoiding any damage that might otherwise be caused by high reflected power Your antenna should always be as close to resonance as practical Forward Power Watts 14 11 24 el a794 642 444 360 314 283 262 246 233 18 37 97 7 87 5 08 400 342 306 280 262 247 20 990 583 444 373 330 3 00 278 262 1292 674 494 407 355 321 296 277 24 17 94 7 87 551 444 383 3 42 314 292 26 _ 27 96 9 32 617 485 412 365 3 32 3 08 28 57 98 11 24 695 531 444 3 90 352 3 25 30 1393 7 87 5 83 479 416 373 3 42 32 _ 17 94 900 642 518 444 395 3 60 34 2463 10 40 7 09 560 475 419 3 80 36 T 3797 12 20 7 87 607 508 444 400 3a 7799 1460 880 66o 544 471 421 Reflected Power Watts e 9 99 47 94 1063 787 642 551 so T o do S do o T 2195 11 92 8 55 685 5 83 SWR Lookup Table Find SWR at intersection of 20 forward power column and reflected power row The LDG AT 200Pro In 1995 LDG pioneered a new type of automatic antenna tuner The LDG design uses banks of fixed capacitors and inductors switched in and out of the circuit by relays under microprocessor control A built in SWR sensor provides feedb2. verticals Yagis or virtually any coax fed antenna It will match an amazing range of antennas and impedances far greater than some other tuners you may have considered Also it consumes very little power making it suitable for battery powered operations While resembling earlier LDG tuners in overall layout and function the AT 200Pro represents a quantum leap in features and performance Enhanced tuning algorithms provide much faster precise and consistent tuning Automatic tuning is now available during transmission even SSB and many user settable options are accessible from the front panel The two large LED meters provide simultaneous readings of power and SWR and readouts of internal states and settings LDG pioneered the automatic wide range switched L tuner in 1995 From its laboratories near the nation s capitol LDG continues to define the state of the art in this field with innovative automatic tuners and related products for every amateur need Jumpstart or Real hams don t read manuals Ok but at least read this one section before you transmit Connect the antenna jack on your transceiver to the Tx jack on your AT 200Pro tuner using a 50 Ohm coaxial cable jumper of appropriate power handling capability Connect your 50 Ohm antenna coax lead to the Ant 1 jack on the back of your AT 200Pro Connect your AT 200Pro to a source of 11 16 volts DC 750mA via the 2 5 by 5 5 mm power jack on the back center posi
3. AT 200Pro has 16 000 3 D frequency memories 8 000 memories for each antenna port They store the tuning parameters for each frequency as you tune that s 2 000 memories for each of four different antennas on each of the two ports You can use a wide variety of antennas connecting them to the two antenna ports as needed Think of it you could be using a Yagi Quad Loop or Vee on the Ant A port and a Dipole Vertical Longwire or J Pole on the Ant B port connecting them as needed or switching them through an external coax switch and each of them will have 2 000 dedicated memories When you transmit on or near a memorized frequency again the tuner finds the best match for that port and antenna and resets those parameters in a fraction of a second much faster than a full tuning cycle This will work best if you always use a particular antenna on the same antenna port each time When you tune you can select between a Memory tune and a Full tune If you select Memory tune and there is no appropriate memory data the tuner will automatically begin a full tuning cycle Tuning parameters are stored in EEPROM memory and are retained indefinitely even if power is removed Full Tuning Cycle Long press Set your transmitter or transceiver to SSB AM FM CW or Packet mode and a power level of no more than 125 watts if your radio has a power rollback circuit If your radio lacks a rollback circuit see your owner s manual set the power level to
4. and accurate delivery of your repaired unit Include a full description of the problem along with your name address and a phone number or e mail address where we can reach you with any questions Repairs average about 3 to 6 weeks We will be glad to service your AT 200Pro after the warranty period has ended We will notify you of repair charges by phone or e mail and bill you after repairs are completed Firmware upgrades From time to time LDG may release upgraded firmware for the AT 200Pro refining operation and adding features Your AT 200Pro is not field programmable you will have to remove the present chip and replace it with the upgrade chip You will return the old processor chip to LDG upgrades will be sold by exchange only The processor chips are recycled and reprogrammed to 22 minimize future upgrade costs Upgrades are expected to cost about 10 20 with chip exchange and will be announced on our web site when available Feedback If you have an idea to improve our software or hardware please send us a description If we incorporate your idea in the AT 200Pro we ll send you a free upgrade as a thank you We encourage everyone who uses the AT 200Pro to contact us card letter or e mail preferred telling us how well it works for you We are also always looking for photographs of our products in use we frequently place such pictures on our Web site www ldgelectronics com 23
5. frequency On the other hand if your antenna SWR is relatively flat across the band of frequencies you re using retuning might not be necessary and semi automatic mode would be preferable 17 When to use Peak mode Any averaging wattmeter will read correctly only when excited by a steady unmodulated carrier Any modulation will cause the reading to vary Peak mode measures the peak power as the name indicates and is much steadier in the presence of modulated highs and lows You will generally want to use Peak mode when using SSB or AM and average mode when using FM RTTY or any other 100 duty cycle mode that provides a steady carrier to the wattmeter circuitry When to turn the LEDs off You can set the LEDs to remain off when transmitting This will help conserve power when operating from batteries Field Day for instance or when you don t want the distraction of the flashing LEDs RF Noise The processor in your AT 200Pro creates a certain about of RF noise which you may notice in your receiver while tuning only if you are using a separate receiver and not a transceiver or when information is being displayed in the LED display This will be most noticeable when operating CW with break in while using the Peak power display This should present no problem as the Peak mode is not very useful on CW The extremely short tuning cycle minimizes the impact of the noise the tuner creates no RF noise while not tuning MARS CAP cov
6. no more than 25 watts Press the PTT switch on the microphone close key on CW to transmit a carrier or simply begin talking on SSB or AM While transmitting press and hold the Tune button on the front of your AT 200Pro for at least 2 5 seconds 10 20 40 60 100 150 200 250 PWR SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over Long Press gt 2 5 Sec for Manual Tune 12 Release the Tune button an automatic tuning cycle will begin You will hear the relays in your AT 200Pro as they switch in and out seeking a match they make a buzzing noise The tuning cycle will end in a few seconds with the SWR LED meter indicating the final match At the end of a full tuning cycle the SWR LEDs will scan inward from both ends to indicate a successful tune to an SWR of less than 1 1 Unkey your transmitter or transceiver and reset to your desired power if you changed for tuning you re ready to operate The new tuning parameters are stored for the present operating frequency replacing any parameters that were previously stored for that frequency Memory Tuning Cycle Medium press If you are tuning near a frequency at which you have already completed a tuning cycle you can reset the tuner very quickly by using a Memory Tuning Cycle Key your transmitter as described above and press and hold the Tune button for 5 to 2 5 seconds then release The tuner will automatically check for a saved tuning setting and if present will restore that setting in
7. 239 socket Antenna connector 2 marked Ant 2 standard SO 239 socket DC power in 2 5 by 5 5 mm power jack marked Power center positive Stereo 1 8 jack marked Radio for connecting a control cable to a compatible transceiver e Ground connector wing nut j d 1x teat an g ry St Leonard Merasa L 10 556_9 20886 Ds z Radic we RS SO cE a a Foe Installation Your AT 200Pro tuner is intended for indoor use only it is not water resistant If you use it outdoors Field Day for example you must protect it from rain The AT 200Pro is designed for use with coax fed antennas If you wish to use it with longwires or antennas fed with a balanced transmission line e g ladder line an external balun is required either the LDG RBA 4 1 or RBA 1 1 is ideal depending on the antenna and transmission line used Always turn your radio off before plugging or unplugging anything Your radio may be damaged if you connect or disconnect a cable with the unit powered up Note that some radios do not power down the tuner even when the radio is turned off To be safe unplug the tuner s power connector before plugging or unplugging anything else Connect the HF antenna jack on your transmitter or transceiver to the Tx jack on the back of your AT 200Pro tuner using a coax jumper with standard PL 259 plugs not provided Properly soldered connectors will be far more satisfactory and reliable than crimp on or solderles
8. 50 m BWR oa n gt mm PWR SWR os SELH SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over 10 Auto Tune Threshold You can set the SWR at which an automatic tuning cycle will begin press and release the Func button Then press and release the L Dn button The SWR meter will show the new setting Repeat this sequence to cycle through the available values 1 1 3 5 The default value is 2 0 The example below shows the threshold set to 1 7 10 20 40 60 100 150 200 250 PWR SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over Auto Threshold Display High Low Impedance Toggle You can manually set your AT 200Pro for Hi Z or Lo Z antennas Press and release the Func button While this function is rarely used it is available for the more advanced user to temporarily set the tuner to an LC or CL configuration To toggle the Hi Lo Z setting press and release the Ant button The LEDs will show the following patterns to indicate low and high impedance This setting is relevant only when you are manually adjusting the match using the C and L buttons It is automatically set when you run any automatic tuning cycle 10 20 40 60 100150 200250 PWR 10 20 40 60 100150 200250 tr r BNR SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over Low Impedance High Impedance SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over Antenna Selection Press the Ant button to toggle between Ant 1 and Ant 2 the default is Ant 1 The LED display points tow
9. ARD and REVERSE power levels Once adjusted the forward and reverse power sensors produce a calibrated DC voltage proportional to the forward and reverse RF power levels These two voltages are read by the ADCs in the microprocessor Once in a digital format the they are used to calculate SWR in real time The relays operate from DC supplied by via the power input jack The total current drawn by the AT 200Pro depends primarily on the number of energized relays with the maximum current drain being approximately 750 mA but only during the few seconds a tuning cycle is running At all other times the tuner is in a deep sleep mode drawing only a few milliamps The last tuned setting is automatically reset on the next power up Although the microprocessor s oscillator runs at 20 MHz The main tuning routine takes about 75 cycles to make a tuner adjustment and take a new SWR measurement or 7 milliseconds per tuner adjustment If running at maximum speed the microprocessor can try all inductor capacitor combinations in under 3 seconds Unfortunately the mechanical relays can t react as quickly as the microprocessor and the tuning speed must be slowed down to compensate for relay settling time The tuning routine written in assembly language uses an algorithm to minimize the number of tuner adjustments The routine first de energizes the high low impedance relay if necessary then individually steps through the inductors to find a coarse
10. AT 200Pro Automatic Antenna Tuner Manual Version 1 0 ELECTRONICS LDG Electronics 1445 Parran Road PO Box 48 St Leonard MD 20685 2903 USA Phone 410 586 2177 Fax 410 586 8475 Idg ldgelectronics com www ldgelectronics com LDG AT 200Pro Automatic Antenna Tuner Introduction 4 Jumpstart or Real hams don t read manuals 3 Specifications 4 An important word about power levels 4 Getting To Know Your AT 200Pro 5 Installation 7 Operation 8 Basic operation 8 Tuning 11 Auto and Semi Auto Modes 12 Memory Tuning 12 Full Tuning Cycle Long press 12 Memory Tuning Cycle Medium press 13 Bypass mode Short press 13 Power and SWR Indication 14 Off Mode 14 Advanced Operation 14 Operation with an LDG radio interface 15 Application Notes 17 Mobile operation 17 When to use Auto mode 17 When to use Peak mode 18 When to turn the LEDs off 18 RF Noise 18 MARS CAP coverage 18 Error indications 18 Theory Of Operation 19 Some basic ideas about impedance 19 Transmitters transmission lines antennas and impedance 19 The LDG AT 200Pro 21 A word about tuning etiquette 22 Care and Maintenance 22 Technical Support 22 Warranty and Service 22 Firmware upgrades 22 Feedback 23 ELECTRONICS 2 Introduction Congratulations on selecting the LDG AT 200Pro tuner The AT 200Pro provides fully automatic any mode antenna tuning across the entire HF range plus 6 meters at power levels to 250 watts It will tune dipoles
11. G strongly recommends that you use a properly installed high quality lightning arrestor on all antenna cables Operation Basic operation All functions are controlled through the seven front panel buttons Each function is invoked when the key is released Some commands are indicated by the length of time you hold a button before releasing it There are three lengths of press short less than 0 5 seconds medium 0 5 2 5 seconds and long more than 2 5 seconds This sounds a lot more complicated than it actually is this interface will quickly become familiar and easy Setting Options All settings are retained in EEPROM memory indefinitely even if power is disconnected Separate settings are stored for each antenna except for Antenna selection Startup Options Your AT 200Pro has two startup commands invoked by holding down one or more keys while applying DC power to the unit usually by plugging in the coaxial power connector Version display Press and hold Func while powering up This will display the version number of the firmware in your tuner on the LED meters The first digit of the version number is displayed on the PWR meter the second on the SWR meter The LEDs use a one of eight display indicating 1 2 3 etc from right to left In the example below version 1 3 is displayed this is just an example your version number may be different 10 20 40 60 100 150 200 250 PWR SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over Ver
12. a small fraction of a second If no tuned setting is saved near the present frequency the tuner will begin a full tuning cycle saving the result when finished for future operation on that frequency In this way your AT 200Pro learns the longer you use it the more closely it adapts itself to the bands and frequencies you use You will probably use Memory Tuning most of the time it takes advantage of any stored tuning settings but automatically defaults to a Full Tuning cycle if no stored data is available Memory frequency step size varies with band Steps are very small on the 75 meter band to accommodate the expected higher Q of most antennas whereas the step size is somewhat larger on 10 meters where antenna Q is usually lower 10 20 40 60 100 150 200 250 PWR SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over Medium Press gt 5 Sec for Auto Tune Bypass mode Short press To place your AT 200Pro in bypass mode press the Tune button less than a half second The tuner will switch to bypass All LEDs will flash once to confirm bypass mode In bypass mode RF from your transmitter goes directly to the antenna with no matching A second short press toggles the tuner back to its last tuned setting the LEDs show which C and L relays are energized Bypass followed by Func Tune will clear the present memory Bypass mode is not saved when you power down On the next power up the tuner will reset the last tuned settings You can if you wis
13. ack the microprocessor searches the capacitor and inductor banks seeking the lowest possible SWR The tuner is a Switched L network consisting of series inductors and parallel capacitors LDG chose the L network for its minimum number of parts and its ability to tune unbalanced loads such as coax fed dipoles verticals Yagis in fact virtually any coax fed antenna The inductors are switched in and out of the circuit by relays controlled by the microprocessor An additional relay switches between high and low impedance ranges The capacitors are connected to ground with the seven inductor relays Another relay switches the entire capacitor bank to the input or output side of the inductor This switching allows the AT 200Pro to automatically handle loads that are greater than 50 ohms high setting and less than 50 low setting All of the relays are sized to handle over 300 watts continuously The SWR sensor is a variation of the Bruene circuit This SWR measuring technique is used in most dual meter and direct reading SWR meters Slight modifications were made to the circuit to provide voltages instead of currents for the analog to digital converters ADCs that provide signals proportional to the forward and reverse power levels The single lead primary through the center of the sensor transformer provides RF current sampling Diodes rectify the sample and provide a dc voltage proportional to RF power Variable resistors calibrate the FORW
14. ard the selected antenna connector as viewed from the front of the unit You cannot change antennas while transmitting the antenna selection function is disabled when RF is present When you change antennas the tuner references the last frequency used on that antenna and recalls tuning settings for that frequency if any 10 20 40 60 100 150 200 250 10 20 40 60 100150 200250 PWR Hor BAIR SWR Toa SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over 11 Tuning Auto and Semi Auto Modes In Auto mode see section on selection Auto or Semi mode the tuner will begin a tuning cycle whenever the SWR exceeds the value you set see section on setting autotune threshold In Semi mode a tuning cycle begins only when you start one by pressing the Tune button regardless of SWR You can also start a Semi tuning cycle while the tuner is in Auto mode Your personal operating practices will determine which mode is best for you The default mode is Auto Auto mode tuning works well while you are transmitting in SSB AM CW or any digital mode Recent advances in LDG s tuning algorithms allow your AT 200Pro to tune effectively even with a varying RF signal This means that as you change frequencies antennas or bands you don t have to make a separate tuning transmission just start talking and your AT 200Pro will match up in as little as 0 2 seconds Memory Tuning This is pretty amazing so lash yourself to the mast your
15. cate the present scale setting without changing it When done release all buttons Other status queries include Ant Presently selected antenna C Up Present PWR meter mode C Dn Present tune mode Auto or Semi L Up Present PWR meter scale L Dn Present Auto Tune threshold 14 Operation with an LDG radio interface Operation with an optional LDG radio interface is even simpler With the interface installed on an Alinco Icom or Kenwood radio as noted simply press the Tuner or AT button on the radio for Yaesu radios press the Tune button on the tuner to begin an automatic tuning cycle The radio will automatically transmit a 10 watt carrier and begin a AT 200Pro tuning cycle Memory settings will be used if available otherwise a full tuning cycle will run When the tuning cycle ends the radio will revert to its previous mode and power level Power Up Function Primary Function Manual Tune Long Auto Tune Medium Bypass Short Switch between Ant 1 and Ant 2 connectors on back panel Manually increase capacitance Manually decrease capacitance Manually increase inductance Manually decrease inductance Select Alternative Functions For Other Buttons Version Number AT 200Pro Command Reference 15 NA Mtr Scale Version Tune Mode Func Hold Key Hold on Power Up Hold on power up for All o AT 200Pro Key Reference Application Notes Mobile operation The AT 200Pro is perf
16. ectly suited to mobile operation You can install it under the dash along with your transceiver or remotely in the trunk The only requirements are that the tuner remain dry and that you provide a fused source of DC power in accordance with the specifications The AT 200Pro does not include an internal fuse you must provide one in the DC line LDG recommends a 2 Amp fast blow fuse Make sure the tuner is well grounded to the car body To install the unit under the dash you can homebrew a bracket You can also use Velcro tape although the adhesive tends to soften in hot weather In the trunk Velcro works well to secure the unit to the trunk floor Simply run coax from your transceiver to the tuner run a fused DC line to the tuner and connect your mobile antenna Simply set the tuner to Automatic mode and you re ready to go the tuner will adjust the match as needed whenever you transmit on a new band or frequency You can observe the progress of the match on your rig s SWR meter or on the power output meter not while driving keep your eyes on the road When the reading stops changing the tuner has finished tuning Most of the time this will happen very quickly as the AT 200Pro tunes from memory in less than a second When to use Auto mode Auto mode is most useful when you are often changing frequencies and bands a contest for instance With memory operation Auto mode will retune almost instantly whenever you transmit on a new
17. en press and release the C Up button You will see the highest power LED float behind the others indicating peak mode Repeat this process to toggle back to Average mode shown by the absence of the floating LED 10 20 40 60 100 150 200 250 PWR SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over Peak Mode Wattmeter Scale the LED wattmeter will indicate 25 or 250 watts maximum the default is 250 watts You will probably want to use the 12 5 watt scale when operating QRP to provide greater resolution To toggle between these two scales press and release the Func button Then press and release the L Up button The LED marked 20 or 250 will light momentarily to indicate the 25 or 250 watt scale respectively The rightmost LED blinks at 30 or 300 watt over range 10 20 40 60 100 150 200 250 10 20 40 60 100 150 200 250 PWR PWR SWR SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over 25 Watt Scale 250 Watt Scale Automatic Tuning Mode you can set your AT 200Pro to automatically begin a tuning cycle whenever the SWR exceeds a value you set or you can set it to semi automatic to tune only when you begin a tuning cycle by pressing the Tune button The default is Auto mode To toggle between Auto and Semi auto modes press and release the Func button Then press and release the C Dn button The LEDs will show the following patterns to indicate Auto and Semi mode 10 20 40 60 100150 200250 10 20 40 60 100150 2002
18. erage Your AT 200Pro provides tuning continuously over its specified range not just in the ham bands This makes it useful for MARS or CAP operation or any other legal HF operation Error indications There are four error states that are indicated on the Power LED display by all LEDs flashing twice 1 No RF is present when a tune command is executed So if you press and hold Tune for a full tuning cycle but no RF is present the LEDs will flash 2 RF removed during a tune If you stop transmitting during a tuning cycle the LEDs will flash 3 Full tune below Auto tune threshold If you start a full tuning cycle when the SWR is already below the Auto tune threshold the LEDs will flash 4 Reading over range To correct error conditions or 2 simply provide RF for the duration of the tuning cycle Error condition 3 indicates that a tune cycle is not needed Error condition 4 indicates power or SWR beyond the range of the meters 10 20 40 60 100 150 200 250 PWR SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over 18 Theory Of Operation Some basic ideas about impedance The theory underlying antennas and transmission lines is fairly complex and in fact employs a mathematical notation called complex numbers that have real and imaginary parts It is beyond the scope of this manual to present a tutorial on this subject but a little background will help you understand what your AT 200Pro is doing and how i
19. ers must operate with an SWR of 2 or less Tube exciters are somewhat more tolerant of high SWR If your 50 ohm antenna is resonant at your operating frequency it will show an SWR close to 1 However this is usually not the case operators often need to transmit at frequencies other than resonance resulting in a reactive antenna and a higher SWR 1 VR F 1 VR F SWR where F Forward power watts R Reflected power watts SWR is measured using a device called an SWR bridge inserted in the transmission line between the transmitter and antenna This circuit measures forward and reverse power from which SWR may be calculated some meters calculate SWR for you More advanced units can measure forward and reverse power simultaneously and show these values and SWR at the same time An antenna tuner is a device used to cancel out the effects of antenna reactance Tuners add capacitance to cancel out inductive reactance in the antenna and vice versa Simple tuners use variable capacitors and inductors the operator adjusts them by hand while observing reflected power on the SWR meter until a minimum SWR is reached Your LDG AT 200Pro automates this process No tuner will fix a bad antenna If your antenna is far from resonance the inefficiencies inherent in such operation are inescapable it s simple physics Much of your transmitted power may be dissipated in the tuner as heat never reaching the antenna at all A tuner simply
20. h press Func Tune to save the bypass setting erasing the memory for that frequency LDG s chief engineer a fan of Snoopy in the Peanuts comic strip calls this the Happy Dance 13 Power and SWR Indication During a tuning cycle the Power and SWR LED meter indicate forward power and the present SWR respectively If you are using a transmitter or transceiver with SWR rollback protection you will see the forward power vary up and down quite a bit during a tuning cycle During transmit both forward power and SWR are displayed if this option is selected in the startup options When no LEDs are lit on the SWR meter when RF is present it means that the SWR is less than 1 1 When the LED segment labeled 1 1 is lit it means that the SWR is between 1 1 and 1 3 The 1 3 LED indicates an SWR between 1 3 and 1 5 and so on Read each LED segment to mean equal to or greater than the marked SWR but less than the next higher marked SWR Off Mode When any tuning cycle ends the tuner automatically enters a deep sleep state in which it draws about 10 milliamps The tuner will automatically wake up the next time you start a tuning cycle when RF is present a button is pressed or when an automatic tuning cycle is required if this option is selected The tuner enters Bypass mode when you turn it off Advanced Operation Manual adjustments In rare cases it may be desirable to manually adjust the match after a tuning cycle T
21. his will happen most often with antennas that are far from resonance at the operating frequency The C Up C Dn L Up and L Dn buttons increase and decrease capacitance and inductance respectively Momentarily press any of these buttons to see the present setting the value is indicated on the display C on the upper display L on the lower left justified that is the lowest order relay is shown on the left To changes these values press repeatedly or hold any of these buttons you will see the value change Then key your transmitter to observe the achieved SWR on the SWR meter You can also manually change C and L as you transmit observing the SWR on the meter however the C and L values are not displayed in this case Frankly you won t use the manual adjustments very much your AT 200Pro is very very good at finding a match These functions are included only to provide you with the maximum utility and flexibility After manually adjusting the match you can manually store the tuning parameters for the present frequency press the Func button then the Tune button The parameters are stored for later recall replacing any previously saved parameters for that frequency Status Query You can query the status of most settings by pressing and holding the Func button while pressing the relevant setting button For example to check the power scale of the PWR meter press and hold the Func key while pressing the L Up button The PWR meter will indi
22. match With the best inductor selected the tuner then steps through the individual capacitors to find the best coarse match If no match is found the routine repeats the coarse tuning with the high low impedance relay energized The routine then fine tunes the capacitors and inductors The program checks LC combination to see if a 1 5 or lower SWR can be obtained and stops when it finds a good match The microprocessor runs a fine tune routine just after the tuner finds a match at an SWR of 1 5 or less This routine tries to get the SWR as low as possible not just 1 5 it takes about a half 21 second to run There is also a quick tune mode If the swr is below 2 0 when you press the tune button to start a tuning cycle the tuner will first try a memory tune routine to see if it can achieve a low swr without a complete re tune This also takes about a half second to run If it does not find a good match then it runs a full tuning routine A word about tuning etiquette Be sure to use a vacant frequency to tune With today s crowded ham bands this is often difficult However do your best to avoid interfering with other hams as you tune Your AT 200Pro s very short tuning cycle as little as a fraction of a second minimizes the impact of your tuning transmissions Care and Maintenance Your AT 200Pro tuner is essentially maintenance free just be sure to observe the power limits discussed in this manual The outer case may be cleaned a
23. o is rated at 250 watts maximum power input at most Many ham transmitters and transceivers and virtually all amplifiers output well over 250 watts Power levels significantly exceeding specifications will definitely damage or destroy your AT 200Pro If your tuner fails during overload it could damage your transmitter or transceiver Be sure to observe the specified power limitations IMPORTANT SAFETY WARNING Never install antennas over or near power lines You can be seriously injured or killed if any part of the antenna support or transmission line touches a power line Always follow this antenna safety rule the distance to the nearest power line should be at least twice the length of the longest antenna or support dimension Getting To Know Your AT 200Pro Your AT 200Pro is a quality precision instrument that will give you many years of outstanding service take a few minutes to get to know it e Your AT 200Pro can be used with any transceiver or transmitter with coax output operating in the HF range at no more than 250 watts output You can set the unit to tune automatically whenever the SWR exceeds a set value or you can set it to tune semi automatically when you start a tuning cycle by pressing the Tune button A T 200Pro a Ufotuner The front panel presents seven pushbutton controls and two LED meters e Power turns the AT 200Pro on and off When off the tuner is in bypass When turned on the tuner automaticall
24. s connectors Attach your antenna lead in coax to either the Ant 1 or Ant 2 jack on the back of your AT 200Pro tuner You will select the appropriate antenna from the front panel see Operating Instructions Your AT 200Pro can interface directly with many popular transceivers enabling their Tune button to start a tuning cycle and in most cases providing power to the tuner Optional cables and interface adapters are available from LDG for many Alinco Icom Kenwood and Yaesu transceivers If you are using a transceiver interface plug the adapter into the appropriate accessory jack on the radio and plug the stereo plug on the interface adapter cable into the Radio Interface jack on the back of the tuner If you are not using an interface cable to a radio capable of powering the tuner connect your AT 200Pro to a source of DC power capable of providing 11 15 volts DC at 750 mA using the provided 2 5x5 5mm coaxial cable center positive If your radio is powered by 12 VDC you can use the same power supply for the AT 200Pro providing the power supply can source the extra 750 mA required by the tuner during a tuning cycle Grounding your tuner will enhance its performance and safety LDG recommends that you connect your tuner to a suitable ground a common ground rod connected to buried radials is preferred but a single ground rod a cold water pipe or the screw that holds the cover on an AC outlet can provide a serviceable ground LD
25. s needed with a soft cloth slightly dampened in household cleaning solution As with any modern electronic device your AT 200Pro can be damaged by temperature extremes water impact or static discharge LDG strongly recommends that you use a good quality properly installed lightning arrestor in the antenna lead Technical Support We are happy to help you with your AT 200Pro Telephone technical support is available at 410 586 2177 weekdays from 9 am to 5pm Eastern Time Inquiries by Fax at 410 586 8475 are welcome and prompt e mail support is available at ldg Idgelectronics com Warranty and Service Your AT 200Pro is warranted against defects in parts or workmanship for two years from purchase The warranty does not cover damage due to abuse or exceeding specifications This warranty applies to the original purchaser only it is not transferable A copy of the receipt showing the purchaser s name and the date of purchase must accompany units returned for warranty service All returns must be shipped to us pre paid we will not accept units with postage due A return form is provided on our web site for your convenience If you need to return your AT 200Pro to us for service package it carefully keeping in mind that we will re use your packaging to return the unit to you Download the return form from our web site fill it out and return it with your tuner A self addressed return shipping label while not required will help insure speedy
26. sion Display All Reset Press and hold Func Ant Tune while powering up This will reset the unit to factory defaults and will erase all frequency memories Menu Options Your AT 200Pro offers several options to adapt the tuner to your operations Many functions are controlled using the Func button Press and release this button to place the tuner in Function mode You will see an up arrow display on the LED meters indicating Function mode Function mode will time out after a few seconds and a down arrow display will appear subsequent key presses must occur while function mode is still active You can also cancel the function mode by momentarily pressing the Func button a second time 10 20 40 60 100 150 200 250 PWR SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over Function Mode On 10 20 40 60 100 150 200 250 PWR SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over Function Mode Off The status check functions require you to press and hold the Func button The following display is shown during function hold 10 20 40 60 100150 200250 r tr r BWR Ed SWR 1 1 1 3 1 5 1 7 2 0 2 5 3 0 Over Function Hold Peak Mode On Off the LED wattmeter will read in average or peak watts Average mode is most suitable for 100 duty cycle modes like FM or RTTY Peak mode is most suitable for modes in which the amplitude varies such as SSB or AM The default is average mode To toggle between these two modes press and release the Func button Th
27. t does it In simple DC circuits the wire resists the current flow converting some of it into heat The relationship between voltage current and resistance is described by the elegant and well known Ohm s Law named for Georg Simon Ohm of Germany who first discovered it in 1826 In RF circuits an analogous but far more complicated relationship exists RF circuits also resist the flow of electricity However the presence of capacitive and inductive elements causes the voltage in the circuit to lead or lag the current respectively In RF circuits this resistance to the flow of electricity is called impedance and can include all three elements resistive capacitive and inductive vonage jiria ae x Sarrant A AN Y lt Sonage A A Paa Capacitive X TAN f A vat TAS A Inductive Reactance x wr i Reactance cvs VW c 7 7 V J 4 The output circuit of your transmitter consists of inductors and capacitors usually in a series parallel configuration called a pi network The transmission line can be thought of as a long string of capacitors and inductors in series parallel and the antenna is a kind of resonant circuit At any given RF frequency each of these can exhibit resistance and impedance in the form of capacitive or inductive reactance Transmitters transmission lines antennas and impedance The output circuit of your transmitter the transmission line and the antenna all ha
28. tive Power up your transceiver and select the desired operating frequency Begin transmitting any mode Wait for the tuning cycle to end You re now ready to operate If using SSB mode simply speak into the microphone You can tune while transmitting up to 125 watts if your transceiver has a roll back circuit to protect it from high SWR If it does not have a roll back circuit limit power when tuning to 25 watts to avoid damage to your transmitter or transceiver Specifications e 0 to 250 watts SSB and CW peak power 200 watts continuous 100 watts on 6M e Easy to read LED bargraph display for RF power SWR and status e 16 000 3 D memories for instantaneous band changing e Two position antenna switch with memories for four antennas on each position e Tuning time 0 5 to 6 seconds full tune lt 0 2 second memory tune e Built in frequency counter for memory operation e Frequency coverage 1 8 to 54 0 MHz e Tunes 6 to 1000 ohm loads 16 to 150 ohms on 6M 6 to 4000 ohms with optional 4 1 Balun LDG RBA 1 e For Dipoles Verticals Vs Beams or and Coax Fed Antenna e Optional external Balun allows tuning of random length long wire or ladder line fed antennas e Optional interfaces for Icom Alinco Kenwood and Yaesu available e Power requirements 11 to 15 volts DC at 750 mA max during tuning e Enclosure 9 x 7 x 2 inches e Weight 2 pound An important word about power levels The AT 200Pr
29. ve a characteristic impedance For reasons too complicated to go into here the standard impedance is about 50 ohms resistive with zero capacitive and inductive components When all three parts of the system have the same impedance the system is said to be matched and maximum transfer of power from the transmitter to the antenna occurs While the transmitter output circuit and transmission line are of fixed carefully designed impedance the antenna presents a 50 ohm non reactive load only at its natural resonant frequencies At other frequencies it will exhibit capacitive or inductive reactance causing it to have an impedance different from 50 ohms When the impedance of the antenna is different from that of the transmitter and transmission line a mismatch is said to exist In this case some of the RF energy from the transmitter is reflected from the antenna back down the transmission line and into the transmitter If this reflected energy is strong enough it can damage the transmitter s output circuits The ratio of transmitted to reflected energy is called the standing wave ratio or SWR An SWR of 1 sometimes written 1 1 indicates a perfect match As more energy is reflected the SWR For a very complete treatment of this subject see any edition of the ARRL Handbook for Radio Communications previously the Handbook For Radio Amateurs 19 rises to 2 3 or higher As a general rule modern solid state transmitt
30. y resets to the last tuned setting e Tune Initiates either a memory or full tuning cycle and also places the tuner in bypass mode Ant Selects one of two antennas C Up Manually increase capacitance C Dn Manually decrease capacitance L Up Manually increase inductance L Dn Manually decrease capacitance Func Selects alternate functions for the other six buttons see below PWR LED meter indicates forward power in 25 and 250 watt ranges SWR LED meter indicates SWR while tuning or transmitting After tuning it automatically enters a deep sleep state in which it draws only about 10 milliamps The tuner will automatically wake up the next time you start a tuning cycle when RF is present a button is pushed or when an automatic cycle is needed Tuning memories are stored indefinitely in EEPROM memory The AT 200Pro has a total of 16 000 3 D frequency memories There are 8 000 memories for each of the two antenna ports 2 000 tuning settings for each of four separate antennas When you transmit near a previously tuned frequency you can use Memory Tune to reset the tuner in only a fraction of a second The process of storing tuning data in memory is completely automatic your AT 200Pro learns as you use it adapting itself to all of the bands and frequencies you use On the back panel there are six connectors RF input marked Tx standard SO 239 socket Antenna connector marked Ant 1 standard SO
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