MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual
© 2007-2010 MFJ Enterprises, Inc.
5
Note: During the automatic tuning process, the tuner will make some noise. These are the
relays switching at a very high rate and this is normal. Do not be alarmed.
11. You are ready to transmit with full power.
Note: When the tuner power is OFF, the tuner is bypassed and RF from the transmitter goes
directly to ANTENNA 1 with no matching. The tuner also powers up in the bypass mode.
When the tuner power is ON, pressing [C-DN] and [L-DN] simultaneously or pressing
[TUNE] quickly places the tuner in bypass mode if desired, which is indicated by one
beep.
Transceiver MFJ-998
Antenna 1
Station
Ground
+12V
Antenna 2
Amplifier
Amp Enable
Out
Amp Enable
In
Amp Enable
In
Amp Enable
Out
MFJ-5114 Radio Interface
Figure 1. Typical Installation Block Diagram.
Front Panel
AUTOMATIC ANTENNA TUNER
1500 Watts SSB / CW
MFJ IntelliTuner
TM
C-UP L-UPANT TUNE
MODE POWERC-DN L-DN
MODEL
MFJ-998
SWR
14.100MHz 1.2
FWD=1000 REF= 10
HI x10
11.2 1.52 3
SWR
0255075100
PWR
300
Figure 2. MFJ-998 Front Panel.
• SWR/Wattmeter: The cross-needle meter measures forward power, reflected power, and SWR. It
operates whenever the MFJ-998 is powered on. Full-scale readings are 300 watts forward and 60
watts reflected power. The meter can be set to a high power range of 3000 watts forward and 600
watts reflected. The SWR is measured at the point where the two needles cross. See
“SWR/Wattmeter” on page 13 for more detailed information.
• Analog Meter Zero Scale Adjustment: Two zero adjustment screws, located below the analog
meter, calibrate the zero scales of the forward and reflected needles. The small hole on the right
adjusts the forward needle and the small hole on the left adjusts the reflected needle. See “Analog
Meter Calibration” section on page 29 for the calibration procedure.
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