MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners
Instruction Manual
©
2004 MFJ Enterprises, Inc.
6
Back Panel
RADIO
INTERFACE
+
POWER
12VDC
1A
REMOTE
PORT
ANTENNA
TRANSMITTER
GROUND
WIRE
MFJ ENTERPRISES, INC.
STARKVILLE, MS USA
!
Do not connect WIRE and
ANTENNA at same time!
Figure 4. Back Panel.
•
Power:
This jack accepts a standard 2.1 × 5.5 mm coaxial plug with positive center and negative
sleeve. The tuner requires 12 volts DC at up to 1 amp. The use of a regulated supply is not
mandatory but is recommended for best performance. An optional 12 volts DC 1.5 amp power
supply, the MFJ-1316, is available from MFJ Enterprises, Inc.
WARNING: Do not apply voltages greater than 18 volts to this unit, or permanent damage
to the unit may result.
Note: When the tuner power is OFF, the tuner is in bypass mode and RF from the transmitter
goes directly to the antenna with no matching.
•
Remote Port:
A female DB-9 connector for connecting to the MFJ-993RC Remote Control,
allowing remote operation of the tuner. The MFJ-993RC duplicates all the front panel buttons except
[POWER]. In addition, there are two LEDs on the remote control. The red Tuning LED lights to
indicate tuning is in progress and the green SWR LED lights when the SWR is below the target SWR.
Note: To use the remote control, the [AUTO] button on the automatic tuner must be locked in;
otherwise, Automatic mode is selected.
•
Radio Interface:
A 3.5 mm stereo phone jack for connecting to the tuner interface connector of
compatible radios. The tuner should be powered on first, and then the radio, so the radio knows a
remote tuner is present.
The Radio Interface works with radios that are compatible with the Icom AH-3, Icom AH-4 and
Alinco EDX-2 tuners. When connected to a compatible radio, it enables the Tune button on the radio.
Pressing the Tune
button on the radio causes the radio to temporarily switch to CW mode, transmit 10
watts and start the tuning process. Once the tuning process is completed, the tuner signals the radio
and the radio returns to the previous mode and power setting.
WARNING: Make sure the +13.8 volts connection on the radio’s tuner port is capable of
supplying at least 1 amp of current, since the MFJ-991/994 use up to 1 amp.
Interface cables for Alinco and Icom radios are available from MFJ Enterprises, Inc. Interface cables
for compatible Kenwood and Yaesu radios will be available in the future. The MFJ-5124A interface
Summary of Contents for IntelliTuner -991
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