MFJ-993 IntelliTuner Automatic Antenna Tuner
Instruction Manual
©
2003-2004 MFJ Enterprises, Inc.
3
Fast Start
WARNING
●
Never
operate the tuner with its cover removed. Contact with the components inside the
tuner while transmitting will result in painful RF burns.
●
Locate the tuner so that the rear terminals are
not accessible
during operation. The single
wire and balanced line connection may have high voltage while transmitting.
●
Disconnect
all antennas from the tuner during lightning storms.
●
Always
tune with low power (about 10 watts). Apply maximum power only after tuning up.
●
Never
exceed tuner specifications.
●
Do
not
transmit with a high SWR for extended periods of time.
1. Connect the MFJ-993 to a 12-15 VDC voltage source capable of supplying at least 1 amp.
2. Connect your transmitter to the TRANSMITTER connector using a 50-ohm coaxial cable.
3. Connect your coax-fed antenna to the ANTENNA 1 connector using a 50-ohm coaxial cable, or
connect your random wire to the WIRE binding post, or connect your balanced line antenna to the
BALANCED LINE binding posts and connect a jumper between the other two posts as indicated.
4. Connect your ground connection to the GROUND post.
5. Press the [POWER] button to turn on the MFJ-993 tuner. Place the [ANT] button in the out position
to select antenna 1. Press the [AUTO] button in to select semi-automatic mode.
6. Key your transmitter to output a carrier of 10 watts CW, FM or AM.
7. Press and hold the [TUNE] button on the MFJ-993 for one second to start the automatic tuning
process. When completed, check to ensure an SWR of 2.0 or less before increasing RF power.
8. You are ready to transmit.
Note:
During the automatic tuning process, the tuner will make some noise. These are the relays
switching at a very fast pace and it is normal operation. Do not be alarmed.
Note:
When the tuner power is OFF, the tuner is in bypass mode and RF from the transmitter goes
directly to the antenna (ANTENNA 1) with no matching. When the tuner power is ON,
pressing [C-DN] and [L-DN] simultaneously or pressing [TUNE] quickly places the tuner in
bypass mode (zero inductance and zero capacitance) and indicates by the reflected needle
bouncing to 20 watts.
Transmitter
MFJ-993
50-ohm Coax
Antenna 1
RF Ground
12 VDC
Antenna 2
Figure 1. Installation Block Diagram.
Summary of Contents for MFJ-993
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