MFJ-989D VersaTuner V
Instruction Manual
13
Frequency
(MHz)
Transmitter
Inductor Counter
Antenna
Load (
Ω
)
14.2 9
80
0
600
18.1
7
87
8
50
18.1 10
83
0
600
21.2
8
88
8.5
50
21.2 9
85
0
600
24.9
8
89
9
50
24.9 10
86.5
4
600
28.5
8.5
90
9
50
28.5 10
88.5
5
600
Once you've reduced SWR to a minimum, go ahead and advance transmitter power to 100 Watts. The
added power should increase the
Reflected Power
meter-scale deflection enough for a touch-up of the
Antenna
and
Transmitter
controls. With the tuner properly adjusted, it is now safe to bring your
amplifier on line.
[ ] Set the meter's
Range
switch to
Hi
(3-kW)
.
[ ] Set your amplifier's
Band Switch
,
Tune
, and
Load
controls to the desired frequency.
[ ] Apply power, peaking the amplifier's
Tune
and
Load
controls for maximum output.
Follow the amplifier manufacturer's prescribed tuning procedure, paying attention to grid or screen
current. Once you've optimized tuner settings and peaked the amplifier for maximum output, don't reset
the tuner controls. If arcing or component heating occur because of an extreme load condition, reduce
transmitter power and explore taking corrective action for your antenna system.
A Word About BIG Amplifiers
Many linear amplifiers are capable of exceeding the 1500-Watt legal power limit -- some delivering
2800 Watts or more! These BIG amplifiers should always be tuned up for their maximum rated output.
However, don't tune them it through the MFJ-989D, or permanent damage to the routing switch and
other internal components may result!
If it becomes necessary use your MFJ-989D in conjunction with a BIG amplifier,
always pre-tune the
amplifier for maximum output into an external 50-Ohm dummy load that is completely isolated from the
