MFJ-993B IntelliTuner Automatic Antenna Tuner
Instruction Manual
2005-2012 MFJ Enterprises, Inc.
6
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.
•
TUNE Button:
Has three different functions based on the length of time you press and hold it before
releasing. Press [TUNE] quickly (less than 0.5 second) to bypass the tuner. RF from the transmitter
goes directly to the antenna with no matching.
Press and hold [TUNE] for 0.5-2 seconds to start the automatic tuning process. The transmitter must
be keyed first with at least two watts of power. When the SWR is already below the target SWR,
pressing [TUNE] will fine-tune the match for a lower SWR if possible.
StickyTune
TM
allows for one-handed tuning operation. Normal tuning requires keying the transmitter
with one hand and using the other hand to push the [TUNE] button to start the tuning process unless a
transceiver interface cable is installed. When
StickyTune
TM
is enabled, a bar appears on top of the
Auto/Semi indicator and the tuning process starts automatically when the transmitter is keyed with at
least two watts of power regardless of the SWR. This works in both automatic and semi-automatic
modes. To toggle the
StickyTune
TM
mode on and off, press and hold the [TUNE] button for two
seconds. The reflected power needle goes to 60-watt mark when on and to 5-watt mark when off; one
beep indicates on and two beeps indicate off. Power-On Reset (POR)
StickyTune
TM
mode is selected
via the “POR Sticky Tune” setup menu; default is ON after a power cycle.
Note:
StickyTune
TM
is disabled after tuning.
Note:
StickyTune
TM
after power cycle means that the MFJ-993B will do a full tune after a power
cycle on the first frequency you transmit on only. No other frequency or memory solutions
will be affected. So you can fully re-tune on any frequency by simply cycling power
.
Note:
If an amplifier is in-line, it should always be bypassed prior to tuning.
•
VOL Control:
A trimpot control that adjusts the volume level of the audio SWR meter. Use a small
flat blade screwdriver and turn clockwise to increase volume level.
•
POWER Button:
Used to turn the power on and off. Note that during power-on the analog meter
bounces three times (to indicate the model number, 99
3
). When the power is off, the tuner is
bypassed (straight through from TRANSMITTER to ANTENNA1 and WIRE). When turning on the
power, the tuner powers-up bypassed, but will revert to the last stored matching values or begin
tuning on application of RF power when the TUNE button is pressed – or if Automatic or Sticky-
Tune is enabled. The target SWR appears on the main screen.
WARNING:
Do not turn the power on and off rapidly, otherwise the tuning setting
memory can be corrupted and the unit will have to be reset to factory defaults.
