Ldg electronics AT-200PRO User Manual

AT-200Pro

Automatic Antenna Tuner

Manual Version 1.2

LDG Electronics

1445 Parran Road, PO Box 48

St. Leonard MD 20685-2903 USA

Phone: [phone]

Fax: [phone]

[e-mail]
www.ldgelectronics.com

Copyright © LDG Electronics 2006. All rights reserved.

LDG AT-200Pro

Automatic Antenna Tuner

Introduction 3
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

Application Notes 17

Mobile operation 17
When to use Auto mode 17
When to use Peak mode 18
RF Noise 18
MARS/CAP coverage 18
Error indications 18

Theory Of Operation 18

Some basic ideas about impedance 19
Transmitters, transmission lines, antennas and impedance 19

The LDG AT-200Pro 20
A word about tuning etiquette 22
Care and Maintenance 22
Technical Support 22
Warranty and Service 22
Firmware upgrades 22
Feedback 23

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, 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:

1. 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.

2. Connect your 50 Ohm antenna coax lead to the "Ant 1" jack on the back of your AT-

200Pro.

3. 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 positive).

4. Power up your transceiver and select the desired operating frequency.

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5. Begin transmitting, any mode

.

6. Wait for the tuning cycle to end.

7. You’re now ready to operate.

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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 tran sceiver.

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Specifications

pp

•

5 to 250 watts SSB and CW peak power, 200 watts continuous (100 watts on 6M)

• Easy to read LED bargraph display for RF power, SWR and status

• 16,000 "3-D" memories for instantaneous band changing

• Two position antenna switch with memories for four antennas on each position

• Tuning time: 0.5 to 6 seconds full tune, < 0.2 second memory tune

• Built in frequency counter for memory operation

• Frequency coverage: 1.8 to 54.0 MHz.

• Tunes 6 to 1000 ohm loads (16 to 150 ohms on 6M), 6 to 4000 ohms with

optional 4:1 Balun (LDG RBA-4:1)

• For Dipoles, Verticals, Vs, Beams or and Coax Fed Antenna

• Optional external Balun allows tuning of random length, long wire or ladder line

fed antennas

• Interfaces for Icom and Yaesu included

• Power requirements: 11 to 15 volts DC at 500mA (750 mA max during tuning)

• Enclosure: 9 x 7 x 2 inches

• Weight: 2 pound

An important word about power levels

The AT-200Pro 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
su

ort dimension.

4

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.

• 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.

The front panel presents seven pushbutton controls, and two LED meters:

• Power: turns the AT-200Pro on and off. When off, the tuner is in bypass. When turned on,

the tuner automatically resets to the last tuned setting

• 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 inductance

• 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 the processor turns off. 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.

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On the back panel, there are six connectors (left to right):

• Antenna connector 1 (marked "Ant 1", standard SO-239 socket)

• Ground connector (wing nut)

• Antenna connector 2 (marked "Ant 2", standard SO-239 socket)

• RF input (marked “Tx”, standard SO-239 socket)

• Stereo 1/8” jack marked "Radio" for connecting a control cable to a compatible

transceiver

• DC power in (2.5 by 5.5 mm power jack marked "Power", center positive)

6

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 “solderless”
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 some popular transceivers. For Icom radios, it will
enable their “Tune” button to start a tuning cycle and provide power to the tuner.

For Icom radios that are AH-3 or AH-4 compatible, connect the white molex connector into the
radio’s tuner port. The power and radio plugs then connect to the tuner. The tuning process can
start by either pressing the tune button on the tuner or the radio.

For Yaesu FT-897 and 857, use the Y-ACC cable and plug the red end marked “Radio” into the
radio’s ACC port. Connect the black end marked “Tuner” into the tuner’s interface jack. The radio
does not supply power to the tuner. The tune button on the tuner is used for starting the tune
process.

If you are not using an interface cable to a radio capable of powering the tuner, connect your AT­200Pro 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. LDG strongly recommends that you use a properly installed, high
quality lightning arrestor on all antenna cables.

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