MFJ-962D Instruction Manual
8
Note:
The MFJ
Air Core
™ Roller Inductor is designed with an exclusive
Self-Resonance Killer
™ that
keeps potentially damaging self-resonances away from your operating frequency. This feature is
switched in and out of the circuit with a built-in switch in the roller. Therefore, as you turn the
roller up and down, you may feel a bump. This is normal and you should not be alarmed.
Increase the number the controls are set at (on a given frequency) to INCREASE the matching range.
Remember, this LOWERS the efficiency and power handling capability of the tuner.
1. Tune the exciter into a dummy load (most solid state transmitters are "pre-tuned" to 50 ohms and do
not require adjusting with the dummy load).
2. Select the desired antenna with the
ANTENNA SELECTOR
.
3. Position the
ANTENNA
and
TRANSMITTER
controls at the following settings:
160 M:
0
20 M:
4
80 M:
1
17 M:
6
75 M:
2
15 M:
7
40 M:
3
12 M:
8
30 M:
3-1/2
10 M:
8-1/2
Then place the
POWER
switch in the LO and AVG meter positions.
4. Starting from the minimum
INDUCTOR
position (highest number), turn the
INDUCTOR
control
counter-clockwise (adding more inductance) while applying a slight amount of power (less than 25
watts). Tune for the lowest reflected power and maximum forward power (lowest SWR).
5. In this order, adjust the
ANTENNA
control,
INDUCTOR
, and
TRANSMITTER
control for
lowest reflected power (and SWR). Repeat this step a few times until the reflected power is zero.
6. If the SWR did not reach 1:1 in step 5, turn the
INDUCTOR
control counter clockwise (to a lower
number) again and repeat Step 5. For maximum power handling and efficiency, always adjust the
capacitors to the lowest front panel number (highest capacitance) that allows proper antenna
matching. This insures maximum power handling and lowest power loss in the tuner.
7. Advance the power (do not exceed 100 watts) and, if necessary, touch up the
ANTENNA
and
TRANSMITTER
controls for minimum reflected power and maximum forward power (lowest
SWR). Remove the power.
8. After adjusting the tuner for minimum SWR, the amplifier may be turned on. The
METER
switch
should be placed in the HI position, and the amplifier tuned according to the manufacturer's
instruction.
9. For quick retuning of the tuner, record the
INDUCTOR
and
CAPACITOR
settings for each band.
Note:
Maximum power handling occurs when both the
TRANSMITTER
and
ANTENNA
capacitors are set at the lowest front panel numbers and the inductor is set at the highest
possible number that permit matching the antenna. Following this guideline will insure
maximum power handling capability and efficiency, and the least critical tuning
adjustments.
