LDG Z-100A

LDG Z-100A Automatic Tuner

The LDG Z-100A features LDG’s famous 10:1 SWR tuning range that matches Dipoles, Verticals, End fed wires, G5RVs or even an Off center fed Windham. Easy integration means plug and play operation; installation could not be simpler. The Z-100A tuner goes anywhere with and HF radio… desktop, portable, parks, islands, or tall summits.

What makes this tuner different is that it is specifically designed for Icom line of transceivers. With ease-of-operation in mind, this tuner is powered directly by the interface on the back of the radio; no need to worry about any additional power connections. Also a single push button switch is all that’s needed to complete the tuning process!

The Z-100A also features low power consumption since it uses latching relays which require no power once it’s tuned.

Before actual use, we urge the user to read the entire manual to ensure safe operation and long life of the Z-100A. With proper care this tuner will provide many hours of enjoyable operation.

LDG Z-100A Installing and Connecting

The Z-100A tuner is designed for indoor operation only; it is not weather proof / water resistant. If you use it outdoors (Field Day, for example), ensure it is properly protected from rain, dust, etc.

The Z-100A is designed for use with coax-fed antennas. If operating with long-wire or ladder-line-fed antennas, an external balun is required. The LDG RBA-4:1 or RBA-1:1 is ideal, depending on the antenna and transmission line used.

  1.    Make sure your Icom radio is turned off.
  2.    Connect the HF/50 MHz antenna jack on the transceiver to the “TX” jack on the Z-100A, using the supplied 50Q jumper.
  3.    Connect a 50Ω coax antenna feedline to the “ANT” jack on the Z-100A.
  4.    Connect one end of the supplied radio interface cable to the tuner port on the back of your radio.
  5.    Connect the other end of the supplied radio interface cable to the “Radio” jack on the rear of the Z-100A.
  6.    Turn on the radio.
  7.    Select the desired operating frequency and mode.
  8.    Push and hold the TUNER/CALL button on the front of the radio for one second (until the Tuning LED comes on), then release. The transceiver will automatically key up with a minimal amount of power, and the Z-100A begins its’ tuning cycle.

At the end of this tuning cycle, the original mode and power level is restored.

  1.    You’re now ready to operate!

Most of the time the Z-100A’s memory tuning will allow a good match to be found quickly if transmitting on the same frequency as a previously stored match. Under certain circumstances, especially when using a different antenna, the memory tuning will recall a previous match which is acceptable, but isn’t the best match possible for this situation. In this case, forcing a full tune will cause the Z-100A to seek a better match than the match already stored in memory.

To force a full tuning cycle press and hold the Tune button on the front panel of the Z-100A until the Tuning/Status LED lights up, and continue holding until the Tuning/Status LED goes out. The Tune button can be released once the Tuning/Status LED has gone out. A full tuning cycle will begin. When tuning is complete, the transceiver will be restored to its previous operating mode and power level.

The SWR LED and Tuning LED are used to indicate both operating modes, tuning status, and error codes.

The following table lists the LED status codes and their meaning.

LED IndicationMeaning
Tuning LED on.Tuner is tuning.
Tuning LED goes out, SWR LED comes on solid.Tuner has completed a tuning cycle; a good SWR match was found.
Tuning LED goes out, SWR LED blinks 5 times.Tuning cycle is complete, tuning match is between 1.5:1 and 3.0:1 SWR.
Tuning LED goes out, no SWR LED.Tuning cycle is complete, tuning match is greater than 3.0:1 SWR.
Tuning LED blinks 4 times.Tuning cycle failed, no RF was detected.
Tuning LED blinks 5 times.Tuning cycle failed, RF was lost in the middle of the tune.

LDG Z-100A Specifications & Ratings

To ensure proper operation and to avoid equipment failure, the following specifications and ratings must be observed:

  • Frequency Range: 1.8 to 54 MHz
  • Maximum Input Power: 125W PEP (CW / SSB / AM), 30W (Digital / RTTY / FM)
  • Input Impedance: 50 Ohm.
  • Tuning Range: 10:1 SWR
  • Memories: 2000
  • Retune Time: < 1.0 s.
  • Voltage: 13.8 VDC + 15%
  • Current Draw: 500 mA tuning, 20 mA
  • idle Size: 6.3″x6.3″x1.5″ (160x160x40mm)
  • Weight: 1.5 lbs (680 g)

LDG Z-100A Compatible Transceivers

The Z-100A is designed to be used with any Icom 100-watt transceiver that supports the AH-3 or AH-4 Icom antenna tuners. Currently, this includes:

  • IC-706
  • IC-718 (select AH-4)
  • IC-746
  • IC-7000

NOTE: If using with an IC-718 select AH-4 mode. See the IC-718 owner’s manual for details.

The radio interface cable supplied is 14″ long. If the Z-100A is positioned farther from the transceiver, a custom cable can be constructed. This can be accomplished in two ways: Cut the supplied cable and solder a jumper wire between all the connections, or purchase new connectors and cable to construct a custom-length interface cable from scratch.

The 4-pin AH-4 interface connector is Molex part number 03-09-2042, available from several online component vendors, such as DigiKey1 and Mouser2. The connector also requires four pins, Molex part number 02-09-2103. The 6-pin Z-100A interface connector is Kycon Connector Part Number KMDAX-6P,

LDG Z-100A

MARS/CAP Coverage

The Z-100A provides continuous coverage over its specified range; not just in the ham bands. This makes it useful for MARS or CAP operation, or any other legal HF operation.



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. Also be aware of and follow electrical and safety codes of your municipality.

Operating your Z-100A tuner

When tuning an antenna is not required, there is no need to disconnect anything. Instead, the tuner can be placed in bypass mode by pressing the Tune button on the front of the Z-100A momentarily.

The Z-100A automatically powers up at the start of a tuning cycle, and then goes into a low-power sleep mode when tuning is complete. The latching relays hold the tuned configuration indefinitely, even when DC power is completely removed. Tuning memories are stored in FLASH memory.

The Z-100A has 2,000 frequency memories. When tuning on or near a previously tuned frequency, the Z-100A uses “Memory Tune” to recall the previous tuning parameters in a fraction of a second. If no memorized settings are available, the tuner runs a full tuning cycle, storing the parameters for memory recall on subsequent tuning cycles on that frequency. In this manner, the Z-100A “learns” as it operates, adapting to the bands and frequencies during use.

LDG Z-100A Front Panel

On the front panel there is one pushbutton and two LED indicator lights.

LDG Z-100A

Tune Button: Initiates either a memory tune or a full tune, and also toggles the tuner between “active” and “bypass” modes.

SWR LED: Lights or blinks to indicate SWR condition.

Tuning LED: Lights to give feedback on button activation; lights during tuning; provides tuning status at the end of a tuning cycle.

LDG Z-100A Rear Panel

The rear panel of the Z-100A features four connectors.

ANT connector: Connect the 50Ω coax antenna feedline to a standard SO-239 connector.

GND connector (wing nut): Connect to antenna system ground.

TX connector: Connect the 50Ω coax jumper cable from this standard SO-239 connector to the ANT jack on the rear of the transceiver.

Radio connector: This 6-pin mini-DIN connector connects to the radio interface cable (supplied), which connects to the AH-4 tuner port on the transceiver. DC power is also supplied via this cable.

Operating Hints

Transceiver Tuner Status Indication

The different models of ICOM transceivers all indicate the status of the external tuner with slight variation. Most will show a graphical or textual icon on the screen to indicate that the tuner is active and has properly tuned. For example, the IC-7000 displays a blinking icon while tuning, and a solid    icon when tuning is complete. This icon

disappears when the tuner is bypassed, and blinks if a tuning cycle failed to find a good match. Other ICOM transceivers behave similarly. Consult your transceiver operating manual’s external tuner section for more information.

Mobile Operation

The Z-100A is also perfectly suited to mobile operation. It can be installed under the dashboard along with the transceiver, or mounted remotely. The only requirement is that the tuner remain dry.

Price – $179.99 US


LDG Electronics family of amateur radio equipment! Starting in 1995 and based in St. Leonard, Maryland, LDG defines state of the art tuners and related equipment for the amateur (“ham”) radio community.

In addition to offering established equipment we’re also continuing to grow our product line. Feel free to check our web site (https://ldgelectronics.com/) often to learn about new developments! We also offer complete product support through our web site, and we’re here for you for any questions that you might haveAall of our products are supported with a two-year transferrable warranty. When you sell your LDG product provide the new owner with a copy of the original sales receipt and the two-year warranty transfers to the new owner.


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