MFJ VERSA TUNER II - Using the MFJ-941 E; Tuning Procedure; Power Adjustment

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USING THE MFJ-941E
The
INDUCTOR switch on the MFJ - 941E represents minimum
inductance at position A and a maximum indu c tance at
position L. Less inductance is needed at higher frequencies
than at low frequencies for the same impedance. The
TRANSMITTER and ANTENNA controls both represent maximum
capacitance at position 10. Fo r optimum operation of the
MFJ-948, the transmitter must be tuned to a 50 ohm output
impedance at the frequency of operat ion. Set the ANTENNA
SELECTOR switch to DUMMY LOAD for tuning up the
transmitter.NOTE: Always tune the transmitter at a low
output power.
After properly tuning the transmitter, set ANTENNA SELECTOR
to the desired antenna and tune the tuner for a minimum SWR
as described below. Do NOT read just the transmitter loading
control setting after loading it to a 50 ohm load .
1. Set the TRANSMITTER and ANTENNA controls to 5. The
capacitors are h alf-opened .
2.
Rotate the INDUCfOR cont r ol until maximum noise is
obtained with your transceiver in the receiving mode.
3. While transmitting a steady state carrier (CW)
alternately adjust '' TRANSMITTER " and "ANTENNA" cont rols
for minimum SWR . Since both controls interact, the two
controls can best be adjusted by turning the TRANSMITTER
control a small increment at a time, then rotating the
ANTENNA control for minimum SWR . Repeat until minimum
SWR is obtained .
4. If a SWR of 1 :1 is not achieved, increase or decrease
the INDUCTOR control and repeat Step 3 . If arcing
should occur between capacitor plates, increase or
decrease the INDUCTOR contro l one position, then repeat
Step 3. NOTE: If you can't achieve a SWR of 1:1, repeat
Step 3 for each INDUCTOR control position .
5. After minimum SWR is achieved , transmitter power may be
increased to 300 watts. Your VERSA TUNER II will red uce
the SWR of most feed systems to 1:1. In some cases, a
1:1 SWR is not achievable. Increase or decrease the
length of your antenna to improve SWR.
6. A SWR of 1:1 may occur at more than one set of control
settings on your MFJ - 9 41 E. When an SWR of 1:1 is
obtained, check transmitter power. I nsure that
transmitter power is relatively high . If transmitter
power has decreased substantially, try anothe r INDUCTOR
control setting and repeat Step 3.
7 . When using the MFJ - 941E for receiving only, tune the MFJ -
941E
as described in S tep 1 and S tep 2 .