LDG AT-1000Pro User guide

AT-1000 OPERATIONS MANUAL MANUAL REV C

LDG AT

-

1000 Pro

LDG Electronics

1000-Watt Automatic

Memory Antenna Tuner

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1445 Parran Road

St. Leonard MD 20685-2903 USA

Phone: [phone]

Fax: [phone]

[e-mail]

www.ldgelectronics.com

Table Of Contents

Introduction
Tuner Safety Warning

Important Antenna Safety Warning 3

Jumpstart, or “Real hams don’t read manuals!”
Specifications
Getting to know your AT-1000 Pro

Front Panel 6
Rear Panel 8

Installation
Front Panel Button Description

Power / Func Button 10
Auto / Thresh Button 10
Ant1 / Scale Button 11
C Up / Peak Button 11
C Dn Button 12
L Up 12
L Dn Button 12
Tune/Store Button 12

Operation - Basic

Tuning 13
A Word About Roll-Back Circuits 13
Fully Automatic Mode 13
Semi-Automatic Tuning: Request Memory Tune Cycle 14
Semi-Automatic Tuning: Request Full Tune Cycle 15

Operation - Fine Tuning

Manually Adjusting Tuning Parameters 16
Storing Manually Adjusted Tuning Parameters 16

Operation - LED Blink Codes
Application Hints

MARS/CAP Coverage 18
Icom Radio Interface 18
Optional Yaesu Radio Interface 18
Build-Your-Own Interface 18

Theory of Operation

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

The LDG AT-1000 Pro
A Word About Tuning Etiquette
Care and Maintenance
Technical Support
Two-Year Transferrable Warranty
Out Of Warranty Service
Returning Your Product For Service
Product Feedback 23

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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 AT-1000 Pro 1000-watt automatic tuner. The AT-1000 Pro
provides semi-automatic and fully automatic antenna tuning across the entire HF spectrum plus 6
meters, at power levels up to 1000 watts (SSB). 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, including the built-in tuners on many radios.

The AT-1000 Pro is an upgrade from LDG’s previous AT-1000 kilowatt tuner, in that it now
supports fully automatic tuning (Just talk and it tunes!) with frequency-based memories for high
power amplifier applications.

TUNER SAFETY WARNING

The AT-1000 Pro internally switches a very large amount of radio frequency energy.
Tremendous RF currents flow through the tuner, and sometimes very high RF voltages are
present during operation. The AT-1000 Pro is designed to handle this RF energy safely within its
specifications, with a reasonable margin of safety.

However, be warned that some amateur amplifiers are capable of transmitting RF energy in
excess of the AT-1000 Pro’s maximum specifications. Some are capable of levels far in excess
of these specified maximum levels.

Operation under conditions exceeding the maximum specified ratings of the AT-1000 Pro
will cause damage to or destroy the AT-1000 Pro. Operation in significant excess of the
maximum specified power levels can actually cause explosion of internal components. For this
reason, and because of the lethal RF voltages present during normal operation, never operate

the AT-1000 Pro with the cover removed.

IMPORTANT ANTENNA 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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JUMPSTART, OR “REAL HAMS DON’T READ MANUALS!”

Ok, but at least read this one section before operating the AT-1000 Pro:

SAFETY WARNING: Never operate the AT-1000 Pro with the cover removed. Lethal RF
voltages are present during operation. Also, never exceed the rated specifications.

Turn off power to your radio and amplifier.
Connect the antenna jack on your amplifier to the “Transmitter” jack on the AT-1000 Pro,

using a 50 ohm coax cable jumper. Be sure that the coax jumper can handle the RF power level
from the amplifier. Connect a 50 ohm coax antenna feedline to the “ANT1” jack on the AT-1000
Pro.

Connect the AT-1000 Pro to a source of 11 to 15 volts DC, 1A, using the supplied coaxial DC

power plug. Press the “Power” button on the front of the AT-1000 Pro to turn on the tuner. The
“Power” LED and meter backlight will come on.

Turn on power to your transceiver and amplifier and select the desired operating frequency and

mode. Place the amplifier in Standby mode so that it does not operate when transmitting.

Press the “Auto” button on the AT-1000 Pro to turn off fully-automatic mode. The Auto LED

will go off.

Transmit a carrier from the exciter of approximately 30 watts CW, FM, or AM.
While transmitting the carrier, momentarily press the “Tune” button on the AT-1000 Pro.

Continue transmitting the carrier until the tuning cycle stops.

Check the meter to see that the SWR is below 2:1 before using the amplifier.
Switch the amplifier to active mode; you are ready to transmit!

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SPECIFICATIONS

Continuous frequency coverage 1.8 to 54 MHz (Including MARS, CAP, etc).
Transmit Power Rating, 1.8 to 30 MHz:

Single Side Band: 1000 watts
CW: 750 Watts

Digital (RTTY/Packet/PSK31, etc): 500 Watts
Transmit Power Rating, 50-54 MHz: 250 watts, all modes.
Minimum power required for tuning: 5 Watts
Maximum power while tuning: 125W
Built-in relay protection will prevent relay operation when:

Greater than 200 watts input power under any load.

Greater than 150 watts input power when load is 3:1 SWR or greater.
Built-in two position antenna switch.
3” cross-needle illuminated Power/SWR meter with dual power scales, 0-100 and 0-1000

watts. Selectable Peak and Average power display.
2000 memories per antenna port for instantaneous band changing.
Microprocessor-controlled Switched L tuning network.
Fine tune controls for manually adjusting capacitance and inductance.
Time required for tuning: 200 ms for memory recall; 10 seconds average full tune; 30

seconds maximum full tune time.
Built-in frequency sensor allows instant recall of previously-tuned frequencies.
Tunes 6 to 1000 ohm loads (About 10:1 SWR), or 16 to 150 ohm loads on 6M (3:1 SWR)
For Dipoles, Verticals, Vees, Beams or any Coax Fed Antenna.
Includes 6 foot DC power cable.

Optional interface cables available.

Power Requirements: 11 to 15 VDC, 1.0A
Dimensions: 9.5”W x 13”L x 3.5”H.

Weight: 5.2 pounds

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GETTING TO KNOW YOUR AT-1000 PRO

Your AT-1000 Pro 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-1000 Pro sports eight pushbutton switches and a 3” illuminated

cross-needle meter.

The front panel pushbuttons are as follows:

Power: Turns the unit on/off. Also serves as the Function button.
ANT1: Toggle antenna selection.
Auto: Turn fully automatic tuning on/off.
C Up: Increase capacitance.
C Dn: Decrease capacitance.
L Up: Increase inductance.
L Dn: Decrease inductance.
Tune: Initiates memory or full tuning cycle. Momentary push toggles bypass.

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The Power switch on the AT-1000 Pro toggles between the “Off” and “On” modes. Note that

even in “Off” mode, the AT-1000 is not completely “off”, but rather in a very low power sleep
mode. In “Off” mode, the AT-1000 relays are completely de-energized, placing the tuner in
bypass, selecting the ANT 2 antenna, and no LEDs are illuminated. When the Power button is
pressed, to turn the AT-1000 Pro “On”, the previous relay settings are restored, including
antenna selection. The Power button must be pressed and held for 3 seconds to turn the AT-1000
Pro “off.”

Each pushbutton contains an integrated LED that indicates the status of that button’s
function. Other tuner status may also be indicated on the LEDs; see the section “Operation ­LED Blink Codes” for more detail.

Most pushbuttons on the AT-1000 Pro also have a secondary function, which is activated
when the button is pushed while in Function (FUNC) mode. The button’s secondary function is
listed under the button. Function mode is entered by pushing and holding the Power button for 1
second, until all the panel LEDs light up, and then releasing.

The illuminated cross-needle meter indicates forward and reflected power, as well as SWR,
all at once. Forward power is indicated in two ranges; 0-100W and 0-1000W. If the 1000W
range is selected, multiply the indicated power by 10 to give the actual power.

Readings are accurate to ±10% across the full scale. Forward power is indicated in “Peak
Hold” mode or average power mode. In Peak Hold mode, the peak power is indicated, then held
for a moment before dropping to a lower indicated level. Power indicated is the true peak
reading. Average power mode displays instantaneous average power.

The cross-needle meter displays SWR as the intersection of the Forward and Reflected power
indications. For example, in the photograph at the right, the indicated SWR is 2.0:1. The forward
power is 52 watts, the reflected power is 6 watts, and the two needles intersect on the red line
which indicates 2.0:1 SWR.

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