MFJ-994B IntelliTuner Automatic Antenna Tuner
Instruction Manual
©
2004-2010 MFJ Enterprises, Inc.
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Icom Radio Interface
The MFJ-5124I radio interface allows users of AH-3 or AH-4 compatible Icom transceivers to connect to
the MFJ-994B
IntelliTuner
™ Automatic Antenna Tuner. With this interface, power and control signals
are connected between the radio and the tuner. The operator can then control the tuner with a single push
of the [TUNER] button on the front panel of the radio. Supported Icom radios are IC-706, IC-707, IC-
718, IC-728, IC-736, IC-738, IC-746, IC-756, IC-7000, and any Icom radio that supports the Icom AH-3
or AH-4 tuner.
Note: The KEY connection of the MFJ-994B RADIO INTERFACE jack is an open-collector output,
and it is safe to use with the IC-7000.
Connections
1. Insert the 3.5 mm stereo phone plug into the tuner’s RADIO INTERFACE jack.
2. Insert the 2.1 x 5.5 mm coaxial power plug into the tuner’s POWER jack.
3. Important:
Make sure the DC power to the radio has been turned off. The radio does not fuse the
DC power to the tuner, and damage to the radio can occur if the interface’s power connection
comes in contact with ground.
4. Connect the 4-pin molex connector to the mating 4-pin molex connector, marked as TUNER, on
the back of the Icom radio.
5. Push the [POWER] button on the tuner to the
in
position and then power on the radio.
6. Some Icom radios, such as the IC-706, automatically check to see if an external antenna tuner is
connected during power on. For other Icom radios, such as the IC-718, the Tuner Type menu in
the radio menu system must be enabled. Refer to your radio’s operating manual for accessing the
menu system and preparing the AH-4 antenna tuner operation. Use IC-718 as an example:
a. Push [PWR] for 1 second to turn power off.
b. While pushing and holding [SET], push [PWR] to turn power on.
c. Push [UP] or [DN] one or more times to select TUNER.
d. Rotate the Main Dial to select “4” for AH-4 antenna tuner.
e. Push [PWR] for one second to turn power off.
f. Push [PWR] to turn power on again.
Operation
The operation of the MFJ-5124I radio interface is similar to the operation of the AH-3 or AH-4 described
in the Icom radio’s operating manual.
1. Push and hold the [TUNER] button on the radio for one or two seconds to initiate automatic
tuning process. The radio will automatically switch to CW mode, transmit a 10-watt carrier, and
start the tuning process. When the tuning process is completed, the radio will stop transmitting,
return to its previous mode and power setting.
2. Push the [TUNER] button on the radio quickly to bypass the tuner or to cancel tuning in progress.
Note the [TUNE] button on the tuner will also key the Icom radio interface.
