LDG AT-100Pro User manual

AT-100Pro
Automatic Antenna Tuner
Manual Version 1.1
Fa
LDG Electronics
1445 Parran Road, PO Box 48
St. Leonard MD 20685-2903 USA
Phone: [phone]
Fax: [phone]
[email protected]
www.ldgelectronics.com

LDG AT-100Pro
Automatic Antenna Tuner
Table of Contents
Introduction 2
Jumpstart, or “Real hams don’t read manuals!” 3
Specifications 4
An important word about power levels 4
Getting To Know Your AT-100Pro 5
Installation 6
Operation 8
Basic operation 8
Tuning 12
Advanced Operation 14
Application Notes 15
Mobile operation 16
When to use Auto mode 16
When to use Peak mode 17
When to turn the LEDs off 17
RF Noise 17
MARS/CAP coverage 17
Error indications 17
Theory Of Operation 17
Some basic ideas about impedance 18
Transmitters, transmission lines, antennas and impedance 18
The LDG AT-100Pro 19
A word about tuning etiquette 21
Care and Maintenance 21
Technical Support 21
Warranty and Service 21
Firmware upgrades 22
Feedback 22
2

Introduction
Congratulations on selecting the LDG AT-100Pro tuner. The AT-100Pro provides fully
automatic, any mode antenna tuning across the entire HF range plus 6 meters for less than the
cost of some manual tuners. 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-100Pro 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-100Pro
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-
100Pro.
3. Connect your AT-100Pro to a source of 11 - 16 volts DC @ 500mA 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.
5. Begin transmitting, any mode1.
6. Wait for the tuning cycle to end.
7. You’re now ready to operate.
1If 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.
3

Specifications
• 1 to 125 watt power range (SSB and CW).
• 1.8 to 54.0 MHz coverage. Built-in frequency sensor
• For Dipoles, Verticals, Vees, Beams or and Coax Fed Antenna
• Tunes 6 to 1000 ohm loads (16 to150 on 6M), 6 to 4000 ohms with optional 4:1 Balun
• Over 4,000 memories for nearly instant retuning
• Tuning time: 0.2 to 2.5 seconds full tune, 0.2 second memory recall
• Supports two antennas, with separate memories for each
• Uses latching relays, retains tuned setting indefinitely even when DC power is removed
• Enhanced tuning algorithms for fast, consistent tuning even on SSB
• Easy to read LED bargraph display for RF power, SWR and status
• Two position antenna switch. Separate memories for each antenna
• Selectable user parameters: Auto/Semi, 125/12.5 watt scale, power save and more.
• 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 16 volts DC at 500 mA Max, 7mA idle
• Size: 7.5” x 5.5” x 2.0”. Weight: 1.5 pounds
An important word about power levels
The AT-100Pro is rated at 125 watts continuous power input at most. Many ham transmitters and
transceivers, and virtually all amplifiers, output well over 125 watts. Power levels significantly
exceeding specifications will definitely damage or destroy your AT-100Pro. 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
seriousl
y
in
j
ured or killed if an
y
part of the antenna or
transmission line touches the power line. Alwa
y
s follow this
antenna safet
y
rule: the distance to the nearest power line
should be at least twice the length of the lon
g
est antenna
dimension.
4

Getting To Know Your AT-100Pro
Your AT-100Pro 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-100Pro can be used with any transceiver or transmitter with coax output operating
in the HF range at no more than 125 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:
• 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 12.5 and 125 watt ranges
• SWR: LED meter indicates SWR while tuning or transmitting
There is no “Off” button; the AT-100Pro powers up as soon as you plug in an external power
supply. After tuning, it automatically enters a “deep sleep” state in which it draws only a few
milliamps of current, effectively 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.
Your AT-100Pro employs latching relays which hold the tuned setting indefinitely, even when
DC power is completely removed by unplugging the power connector. Tuning memories are
stored indefinitely in EEPROM memory.
5

The AT-100Pro has over 2,000 memories for each of two antennas, each of which stores the
tuning settings for a specific frequency. 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-100Pro “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 1 (marked "Ant 1", standard SO-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
• Ground connector (wing nut)
6

Installation
Your AT-100Pro 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-100Pro 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; the LDG RBA4:1 or RBA-1:1 is
ideal.
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 power connector before
plugging or unplugging anything.
Connect the HF antenna jack on your transmitter or transceiver to the Tx jack on the back of your
AT-100Pro 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-100Pro tuner. You will select the appropriate antenna from the front panel (see Operating
Instructions).
Your AT-100Pro can interface directly with several 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 Icom interface for powering the tuner, connect your AT-100Pro to a source
of DC power capable of providing 11 – 16 volts DC at 500 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-100Pro, providing the power supply can source the extra 500 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.
7

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 .5 seconds), medium (.5 – 2.5
seconds) and long (more than 2.5 seconds). This sounds a lot more complicated than actually it 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 LED On/Off and Antenna selection,
which are global settings that apply to both antennas.
Startup Options
Your AT-100Pro has three startup commands, invoked by holding down one or more keys while
powering up 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 1.2 is displayed
(this is just an example; your version number may be different).
Version Display
All Reset: Press and hold Func+Ant+Tune while powering up. This will reset the unit to
factory defaults, and will erase all memories.
LEDs On/Off: Press and hold Ant while powering up. This will toggle the unit between
displaying the power and swr LED meter displays during transmit. These displays will be active
during a tuning cycle or after key presses regardless of this startup setting. You may want to
disable the LED meters when operating from battery power.
8

Menu Options
Your AT-100Pro 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.
Function Mode On
Function Mode Off
The status check functions require you to press and hold the Func button. The following display
is shown during function hold:
Function Hold
9

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. Then 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.
Peak Mode
Wattmeter Scale: the LED wattmeter will indicate 12.5 or 125 watts maximum; the default is 125
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 "10" or "100" will light momentarily to indicate
the 12.5 or 125 watt scale, respectively.
100-Watt Scale
12.5 Watt Scale
Automatic Tuning Mode: you can set your AT-100Pro 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:
Semi Mode
Auto Mode
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
10