LDG AT-600ProII User manual

AT-600PROII OPERATIONS MANUAL MANUAL REV A
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LDG AT-600ProII
600W Automatic
Antenna Tuner
LDG Electronics
1445 Parran Road
St. Leonard MD 20685-2903 USA
Phone: [phone]
Fax: [phone]
[email protected]
www.ldgelectronics.com

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Table Of Contents
Introduction 2
Jumpstart, or “Real hams don’t read manuals!” 3
Specifications 4
An Important Word About Power Levels 4
Important Safety Warning 4
Getting to know your AT-600ProII 5
Front Panel 5
Back Panel 6
Installation 7
Basic Operation 10
Using the Front Panel Buttons 10
User Configuration Options 10
Transmitting and Receiving 13
Tuning 14
Basic Tuning Operation 14
Manual Memory Tune 14
Manual Full Tune 15
Bypass Mode 16
Error Indication 16
Advanced Operation 18
Manual Inductor/Capacitor Adjustments 18
High/Low Relay Adjustment 18
Manual Memory Store 18
Status Check 19
Application Notes 20
Mobile Operation 20
Internally Generated RF Noise 20
MARS/CAP Coverage 20
Operation with LDG Electronics M-600 External Meter 21
Tuning Hints 21
Theory of Operation 21
Some basic ideas about impedance 21
Transmitters, transmission lines, antennas, and impedance 22
The LDG AT-600ProII 24
A Word About Tuning Etiquette 25
Care and Maintenance 25
Quick Reference 26
Technical Support 27
Two-Year Transferrable Warranty 27
Out Of Warranty Service 27
Returning Your Product For Service 27
Product Feedback 28

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INTRODUCTION
LDG pioneered the automatic, wide-range switched-L tuner in 1995. From its laboratories in
St. Leonard, Maryland, LDG continues to define the state of the art in this field with innovative
automatic tuners and related products for every amateur need.
Congratulations on selecting the LDG Electronics AT-600ProII 600 watt automatic tuner.
The AT-600ProII provides fully- and semi-automatic antenna tuning across the entire HF
spectrum plus 6 meters, at power levels up to 600 watts (250W on 6m). It will tune dipoles,
verticals, Yagis, or virtually any coax-fed antenna. It will match an amazing range of antennas
and impedances, far greater than some tuners you may have considered, including the built-in
tuners on many transceivers.
The AT-600ProII is designed to handle 600 watts of output power, and is ideal for use with
small outboard linear amplifiers rated up to 600 watts, or even newer high power transceivers.
JUMPSTART, OR “REAL HAMS DON’T READ MANUALS!”
Ok, but at least read this one section before operating the AT-600ProII:
1. Connect a 50-ohm coax jumper cable from the antenna jack on your amplifier to the TX jack on
the back of the AT-600ProII. (This cable must be rated to 600 watts.)
2. Connect your antenna’s 50-ohm coax feedline to the ANT 1 jack on the rear of the AT-
600ProII.
3. Connect the supplied DC coax cable to the jack marked 12 VDC. Connect this cable to a DC
source between 11 and 16 volts DC, 1000 mA. The jack center tip is positive.
4. Power up the transceiver, and select the desired operating frequency and mode.
5. Bypass the amplifier.
6. Make sure Antenna 1 is selected (ANT 2 LED is off). Press ANT to toggle.
7. Begin transmitting, any mode
1
.
8. When the tuning cycle completes, activate the amplifier, and you’re ready to operate!
Note: With the amplifier active, it is suggested to place the AT-600ProII in semi-automatic
tuning mode to avoid re-tuning at high power levels.
1
In SSB mode, simply speak into the microphone while transmitting. Tuning may be performed at up to 125 watts of input power, provided that the transceiver
employs a “roll-back” circuit to protect it from high SWR. For transceivers without roll-back circuits, power should be limited to 25 watts when tuning, to avoid
damage to the transmitter or tuner.

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SPECIFICATIONS
•1 to 600 watt power range (SSB and CW), 250 watts PSK and digital modes, and 250 watts
on 6 meters.
•Silver-teflon SO-239 connectors.
•Over 4,000 memories for instantaneous band changing.
•Built-in 2-port antenna switch, with 2,000 memories each.
•Tuning time 0.2 to 15 seconds full tune, 0.2 seconds memory tune.
•1.8 to 54.0 MHz coverage. Built-in frequency sensor.
•Tunes 6 to 1,000 ohm loads (16 to 150 on 6m).
•LED bargraph displays power level, SWR, and status.
•Antenna Indicator LED shows the currently selected antenna.
•Bypass LED shows when tuner is in pass-thru.
•User-selectable operating parameters: Auto/Semi mode, 600W/60W scale, and more.
•Optional radio interface cables available. See web site for details.
•Optional large-display external analog panel meter.
•Power requirements: 11 to 16 VDC @ 1A max. 7mA when idle.
•Dimensions: 10.5”L x 8.5”W x 2.75H”; Weight 3 pounds, 6 oz.
AN IMPORTANT WORD ABOUT POWER LEVELS
The AT-600ProII is rated at 700 watts maximum power input at most. Many amplifiers
output well over 750 watts. Power levels that significantly exceed specifications will definitely
damage or destroy your AT-600ProII. If the tuner fails during overload, it could also damage
your transmitter, amplifier, or transceiver. Be sure to observe the specified power limitations.
IMPORTANT SAFETY WARNING
Never install antennas or transmission lines 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, transmission line, or support
dimension.

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GETTING TO KNOW YOUR AT-600PROII
Your AT-600ProII is a quality, precision instrument that will give you many years of
outstanding service; take a few minutes to get to know it.
Front Panel
The front panel of the AT-600ProII features eight pushbuttons, two LED bargraph scales,
and three indicator LEDs:
•Power: Turns the unit on or off. The Power LED glows when the power is on.
•Func: Activates secondary function of other buttons.
•Ant: Selects the active antenna port.
•C Up: Manually increase capacitance.
•C Dn: Manually decrease capacitance.
•L Up: Manually increase inductance.
•L Dn: Manually decrease inductance.
•Tune: Initiates memory or full tuning cycle. Momentary push places tuner in bypass.
•PWR Meter: Bargraph display indicates forward power in 0-60 and 0-600 watt ranges.
•SWR Meter: Bargraph display indicates SWR during tuning or transmission.
•Bypass LED: Indicates Bypass mode is active.
•ANT 2 LED: Lights when Antenna 2 is selected. Off when Antenna 1 is selected.
Each of the pushbuttons has the primary function listed above when pushed. Additionally,
pressing the FUNC button before pressing any other button will activate that button’s secondary
function.
The power button on the AT-600ProII actually places the tuner in bypass and enters a low-
power sleep mode, rather than turning the unit fully off. Press the Power button for 1 second to
turn off, or momentarily to turn on.