LDG AT-200PC User Manual

AT-200PC

Automatic PC-Controlled

Antenna Tuner

Manual Version 1.0

--- Preliminary ---

LDG Electronics

1445 Parran Road, PO Box 48

St. Leonard MD 20685-2903 USA

Phone: [phone]

Fax: [phone]

[e-mail]
www.ldgelectronics.com

LDG AT-200PC

Automatic Antenna Tuner

Introduction 3
Jumpstart, or “Real hams don’t read manuals!” 3
Specifications 4
Getting To Know Your AT-200PC 5
Installation 7

Hardware Installation 7
Software Installation 9

Operation 10

Auto and Semi-Auto Modes 10
Memory Tuning 10

Operation with provided LDG software 11

Software overview and setup. 11
Software Operation 13

Operation with the N4PY Rig Control Software 16
Application Notes 18

When to use Auto mode 18
MARS/CAP coverage 18
Data Interface 18
Updating your tuner 24
Updating your tuner 24
Troubleshooting 25

Theory Of Operation 27
The LDG AT-200PC 29
About Memory Tuning 30
A word about tuning etiquette 30
Care and Maintenance 30
Technical Support 30
Warranty and Service 30
Feedback 31

2

Introduction

Congratulations on selecting the LDG AT-200PC tuner. The PC-controlled AT-200PC 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. There are no controls or indicators on the tuner itself -- all functions are
controlled by software.

The AT-200PC 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 LEDs provide simultaneous readings of power and

SWR, and readouts of internal

states and settings. LDG's design provides instant memory tuning for up to four different antennas
on each of the two antenna ports.

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-200PC
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 AT­200PC.

3. Connect your AT-200PC 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. Connect the AT-200PC to your PC via an available serial data port.

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

6. Run your PC tuner control software and select the appropriate COM port.

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7. Begin transmitting, any mode

.

8. Click the Tune button on the PC tuner control software.

9. Wait for the tuning cycle to end; stop transmitting.

10. 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 transceiver.

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Specifications

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• 5 to 250 watts SSB and CW. (100 watts on 6M)

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

• Tuning time: 0.5 to 6 seconds full tune, < 0.1 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

• Field upgradeable via software download

• Power requirements: 11 to 16 volts DC at 750 mA max during tuning

• Enclosure: 8.5 x 6.0 x 2.0 inches

• Weight: 2 pounds

Never install antennas or transmission lines over or near
power lines. You can be seriousl
of the antenna, support or transmission line touches a power
line. Alwa
the nearest power line should be at least twice the len
the longest antenna, transmission line or support dimension.

IMPORTANT SAFETY WARNING

injured or killed if any part

s follow this antenna safety rule: the distance to

th o

4

Getting To Know Your AT-200PC

Your AT-200PC 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-200PC can be used with any transceiver or transmitter with coax output operating in the
HF and six meter range at no more than 250 watts output (100 watts on six meters). You can set
the unit to tune automatically whenever the SWR exceeds a set value, or to tune semi­automatically when you start a tuning cycle by pressing the Tune button on the PC user
interface.

The front panel has no controls or readouts. All functions are controlled from a personal computer
interface. You can use any PC and operating system that supports a standard serial or USB port,
including Windows, Linux, Mac OS and others.

The AT-200PC has a total of 16,000 frequency memories. There are 8,000 memories for each of
the two antenna ports, 2,000 tuning settings for each of four separate antennas on each port.
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-200PC “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:

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)
DB-9 serial data port marked "Serial" for connecting a control cable to a PC
Ground connector (wing nut)

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Installation

Your AT-200PC 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-200PC 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.

Hardware Installation

Connect the power supply to the tuner using the provided 2.5 by 5.5 mm coaxial connector. The
power supply must supply 11 - 16 vdc at 750 ma minimum. Best practice is a regulated power
supply, but an unregulated supply can be used if it remains with the specified voltage range under
load.

Connect the HF antenna jack on your transmitter or transceiver to the Tx jack on the back of your
AT-200PC 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-200PC tuner. You will select the appropriate antenna from the PC control software (see
Operating Instructions).

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 can provide a serviceable ground. LDG strongly
recommends that you use a properly installed, high quality lightning arrestor on all antenna cables.

Your AT-200PC can interface directly with most popular PCs. Use a suitable 9-conductor serial
data cable to connect the AT-200PC to an available serial port on your PC. You can also connect
the serial cable to a USB jack on your PC by using the provided adapter. RTS and CTS lines are
required.

If you are using rig control software such as that offered by N4PY, for example, you will make
two serial connections to your PC: one for the radio and one for the tuner. Your AT-200PC is
designed to use a serial port, but in case you don't have a free port, LDG provides you with a
serial-to-USB adapter. This will allow you to connect your AT-200PC to a USB port instead of a
serial port.

In Windows 98 or XP, the USB adapter is a plug-and-play device. Place the included driver CD
in your drive, then plug the adapter into any available USB port on your PC. Follow the
instructions in the New Hardware dialog.

Select "Search for driver"; Windows will find the driver on the CD and install it automatically. If
a security panel informs you that the driver is not certified, select Continue to complete the
installation.

The USB adapter will install itself as the next available COM port. For example, if your PC is
already set for COM1 and COM2, the adapter will be installed as COM3. Thereafter, you can use
it as you would any COM port.

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To set serial port parameters for the USB adapter in Windows, select Start > Control Panel >
System, then select the Hardware tab. Select Device Manager, then click on Ports. Double
click on the USB-to-Serial Bridge, then click on the port settings tab. On that panel, you can set
port speed, number of data bits, number stop bits, parity, flow control and other serial parameters.
Set the parameters to 9600 baud, 8 data bits, no parity, 1 stop bit and no flow control. Click OK to
save your settings.

8

Software Installation

Your AT-200PC is compatible with several popular rig control programs. Simply follow the
installation instructions that come with the software.

N4PY Rig control software.

All N4PY rig control programs support the AT-200PC. N4PY publishes software for the
following rigs:

• Most Icom transceivers

• Most Kenwood transceivers

• TenTec Orion, Orion II, Pegasus, Jupiter, Argonaut V

• Elecraft K2

See the N4PY web page at www.n4py.com for more details.

LDG provided software

As a convenience, LDG provides a simple control program to get you started. Download the file
from LDG's web site (http://www.ldgelectronics.com), saving it to your desktop. Execute this
installer program and follow the installation dialog.

The Microsoft .Net Framework version 1.1 must be installed on your PC to run this software.
This is a free download from http://www.microsoft.com/downloads/

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Operation

All tuner functions are controlled through the PC interface. The details of the interface vary
among software products; see your software's documentation for details. Details of the simple
LDG-provided software are below.

Auto and Semi-Auto Modes
In Auto mode the tuner will begin a tuning cycle whenever the SWR exceeds the value you set
(see section on setting autotune threshold in the PC interface). In Semi mode a tuning cycle
begins only when you start one by pressing the Tune button on the PC interface, 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.

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-200PC 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-200PC will match up
in as little as 0.2 seconds.

Memory Tuning
Your AT-200PC has frequency memories for four antennas on each antenna port. They store the
tuning parameters for each frequency as you tune. 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 dedicated memories. When you transmit on or near a memorized frequency again,
the tuner finds the best match for that port and antenna and sets 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.

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