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MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners
Installation
● 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 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. Place the tuner in a convenient location at the operating position. With a random wire antenna the
feed through insulator can have high RF voltage. This voltage can cause serious RF burns if the
terminal is touched when transmitting. Be sure to locate the tuner so this terminal cannot
accidentally be contacted during operation.
2. Connect the tuner to the transmitter with 50-ohm coaxial cable (such as RG-8/U). See Figure 1 on
page 3.
3. Connect the antenna to the tuner as follows:
•
Coaxial feedline to the SO-239 connector labeled ANTENNA; or
•
Random wire or single wire line antennas should be connected to the WIRE binding post on the
back of the tuner. Note the back panel warning: Do not connect WIRE and ANTENNA at
same time!
Note: Route all single and 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 13.
5. Connect a 12 to 15 VDC power source to the input jack labeled POWER.
SWR/Wattmeter
Note: All meter power readings and ranges are ×2 in the model MFJ-994.
The backlit cross-needle meter measures forward power,
reflected power, and SWR, and operates whenever the tuner is
powered on. Forward power up to 300 watts is displayed on the
left-hand FORWARD meter scale. Reflected power up to 60
watts is read on the right-hand REFLECTED meter scale. For
low-power tuning, meter ranges of 30 watts forward and 6 watts
reflected are available. Divide the readings on these scales by
ten when in the low power meter range.
To toggle between the high and low meter ranges, press the
[TUNE] and [L-DN] buttons simultaneously.
8
WARNING
The forward
Instruction Manual
3.0 2.0
400-3083
Figure 7. SWR/Wattmeter.
© 2004 MFJ Enterprises, Inc.
Hi x1
Lo x.1
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