MFJ MFJ-945E - Operating the MFJ-945 E Tuner; Tuning Procedure; Safety and Tuning Warnings

MFJ-945E Mobile Tuner
2
MFJ-945E Front Panel
Using the MFJ-945E:
The
INDUCTOR
switch on the MFJ-945E represents maximum inductance at position
A
and a
minimum inductance 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
. For optimum operation of the MFJ-945E, the
transmitter must be tuned to a 50 Ohm output impedance at the operating frequency.
Always
tune the transmitter at a low output power!
Do
not
readjust the transmitter loading control
setting after loading it to a 50 Ohm load! After properly tuning the transmitter, tune the MFJ-945E
for a minimum SWR as described below:
NOTE
:
When using the MFJ-945E for receiving only, tune as described in Steps 1 and 2.
1.
Set the
TRANSMITTER
and
ANTENNA
controls to position
5
. The tuning capacitors are half
opened at this setting.
2.
Rotate the
INDUCTOR
control until maximum noise is obtained with your tranceiver in the
receiving mode.
WARNING:
Never transmit while changing the INDUCTOR setting!
3.
While transmitting a steady state carrier (CW), alternately adjust the
ANTENNA
and
TRANSMITTER
controls for minimum SWR. Since both of these 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 this procedure until
minimum SWR is obtained.
4.
If an SWR of
1:1
is not obtained, increase or decrease the
INDUCTOR
control and repeat
Step 3. If arcing should occur between the capacitor plates, increase or decrease the
INDUCTOR
control one position, then repeat Step 3.
NOTE:
If you can't obtain a
1:1
SWR,
repeat Step 3 for each
INDUCTOR
control position.