MFJ-939 Plug&Play IntelliTuner Automatic Antenna Tuner
Instruction Manual
2006-2015 MFJ Enterprises, Inc.
7
Installation
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. A
single wire connection may have high voltage while transmitting.
●
Disconnect
the antenna from the tuner during lightning storms.
●
Always
tune with low power (2-20 watts). Apply maximum power only after tuning
up.
●
Never
exceed tuner specifications.
1.
Place the tuner in a convenient location at the operating position. When using a random wire antenna
the feed through insulators may have high RF voltages. These voltages can cause serious RF burns if
the terminals are touched when transmitting.
Be sure to locate the tuner so these terminals cannot
accidentally be contacted during operation.
2.
Install the tuner between the transmitter and the antenna. Use a 50-ohm coaxial cable (such as RG-58)
to connect the transmitter to the connector marked TRANSMITTER on the rear of the tuner. See
Figure 1 on page 3.
3.
Connect the antenna(s) to the tuner as follows:
•
Coaxial feedlines to the SO-239 connectors labeled ANTENNA.
•
Random wire to the ANTENNA connector on the back of the unit using the enclosed adaptor.
Note:
Route all random wire antennas safely to prevent RF burn hazard.
4.
A GROUND post is provided for an RF ground connection. See “Grounding Hints” on page 25.
5.
Connect a 12 to 15 VDC power source to the input jack labeled POWER if your radio is not capable
of supplying 750mA to the tuner. See your radio operations manual.
