MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner
Instruction Manual
©
2007-2010 MFJ Enterprises, Inc.
9
Back Panel
MFJ ENTERPRISES, INC.
STARKVILLE, MS USA
TRANSMITTER
GROUND
ANTENNA 2
AMP
ENABLE
OUT
AMP
ENABLE
IN
+
POWER
12VDC
1.4A
SERIAL
PORT
WIRE
!
Do not connect
WIRE and
ANTENNA 1
at same time!
ANTENNA 1
RADIO
INTERFACE
Figure 4. MFJ-998 Back Panel.
•
Amp Enable In:
RCA phono connector for connecting to the radio’s amplifier control output.
•
Amp Enable Out:
RCA phono connector for connecting to the amplifier’s relay control input.
•
Power:
This jack accepts a standard 2.1 × 5.5 mm coaxial plug with positive center and negative
sleeve. The tuner requires 12-15 volts DC at up to 1.4 amps. The use of a regulated supply is not
mandatory but is recommended for best performance. An optional 12 volt 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
may result.
Note: When the tuner power is OFF, the tuner is bypassed and RF from the transmitter goes
directly to ANTENNA 1 with no matching. When turned on, the tuner powers up in
bypass mode.
•
Radio Interface:
An 8-pin modular (RJ-45)
connector for connecting to the tuner interface
connector of compatible radios. While most
radios p13.8 VDC power though their
tuner interface connector, a separate power
supply is necessary to power the MFJ-998 due
to its 1.4 amp power requirement. The MFJ-
998 should be powered on first (for certain
radios,
TURN ON RADIO
will display) and
then the radio powered on so the radio knows
an external tuner is attached. The radio will
disable its internal tuner, if it has one, and use
the external tuner.
The Radio Interface works with radios that are compatible with Alinco EDX-2, Icom AH-3 and AH-
4, Kenwood AT-300, and Yaesu FC-30, FH-1 and FH-2. When connected to a compatible radio,
simply press the [TUNER] or [AT] button on the radio; for FH-1 or FH-2 compatible Yaesu, press the
[TUNE] button
on the
tuner
to start the automatic tuning process. The radio will automatically switch
+13.8 V DC input (1.4 A)
+13.8 V DC input (1.4 A)
+13.8 V DC input (1.4 A)
Ground
Ground
Key/TT/TX
TX INH
Start/TS/RX
7
8
6
5
4
3
2
1
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Rear Panel View
Figure 5. Radio Interface Connector.