MFJ-941EK Tuner Kit
Instruction Manual
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OPERATING INSTRUCTIONS
To measure forward and reflected power:
[ ] Select the desired forward power range (
300W
or
30W
) and transmit a carrier.
[ ] View the
Forward
scale to read incident power.
[ ] View the
Reflected
scale to read reverse power.
[ ] For SWR, find the red curve closest to where the two meter pointers intersect.
To obtain highly precise SWR readings, record Forward and Reflected power
levels, then plug them into the formula:
SWR =
1 + Pr
Pf
1 - Pr
Pf
Pr = Reflected Power
Pf = Forward Power
2. Using the Antenna Selector Switch:
The tuner's built-in
Antenna Selector
performs two functions:
[ ] Switches the T-network in and out of the tuner's RF path.
[ ] Selects between two coax lines, a single-wire feed*, and a dummy load.
If your transceiver has a tunable PA, you'll want to use the
Dummy Load
port in
conjunction with an external 50-Ohm load. However, for solid-state radios with
fixed 50-Ohm output, you may elect to use
Dummy Load
for a third coaxial-fed
antenna (the RF path is the same as for
Coax-1
and
Coax-2
).
To accommodate ladder line or open-wire feeders, the internal 4:1 balun can be
energized at
Balanced Line
(see balun instruction).
3. Using the T-network Tuner:
The T-network is a highly flexible tool for matching a wide range of loads into 50
Ohms. Here is a control description and the preferred method for tuning them:
[ ] The
Inductor
switch provides
maximum inductance
at setting
A
and
minimum
inductance
at
L.
Typically, you'll need more inductance at low frequencies and
