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MFJ-993 IntelliTuner Automatic Antenna Tuner
Instruction Manual
©
2003-2004 MFJ Enterprises, Inc.
8
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. 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. Place the tuner in a convenient location at the operating position. With a random wire or balanced
line, 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 (or amplifier) 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 1 and/or ANTENNA 2.
•
Random wire or single wire line antennas should be connected to the WIRE binding post on the
back of the tuner (and remove the jumper wire). Note the back panel warning:
Do not connect
WIRE and ANTENNA 1 at same time!
When a single wire antenna is connected it “becomes”
ANTENNA 1.
Note:
Route all single and random wire antennas safely to prevent RF burn hazard.
•
For a balanced feedline (open wire, twinlead, or twin-axial lines), place a jumper wire as
indicated on the back panel and connect the balanced feedline to the BALANCED LINE binding
posts. This antenna becomes ANTENNA 1. See “Antenna System Hints” on page 19.
4. A GROUND post is provided for an RF ground connection. See “Grounding Hints” on page 18.
5. Connect a 12 to 15 VDC power source to the input jack labeled POWER.
SWR/Wattmeter
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.
0
1
0
30
50
100
200 30
0
0
5
20
40
60
8
5.0
3.0 2.0
1.5 1
.2
Hi x1
Lo x.1
400-3083
1
10
Figure 6. SWR/Wattmeter.
Summary of Contents for MFJ-993
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