MFJ-986Differential-TTuner Instruction Manual
12
Meter Calibration
1. Refer
to
Figure 1
for the Test Setup and refer to the PCB layout in
Figure 2
for trim pot location.
2. Remove the top of the MFJ-986.
3. Connect the Test Setup equipment as shown in
Figure 1
. Use a 50-ohm dummy load for the
antenna. Set the Transmitter to the 14 MHz in the 20-meter band.
4. With the
3000/300 Watts
button pushed
out
for the 300 Watt scale, Transmit 100 Watts as
indicated on the reference meter. Adjust the LO FWD trim pot to set the forward power scale to
100 Watts.
5. With the
3000/300 Watts
button pushed
in
for the 3000 Watt scale, Transmit 1000 Watts as
indicated on the reference meter. Adjust the HI FWD trim pot to set the forward power scale to
1000 Watts.
6. To set the reflected power, interchange the TRANSMITTER and ANTENNA coax cables so that
the transmitter is connected to the ANTENNA connector and the dummy load is connected to the
TRANSMITTER connector.
7. With the
3000/300 Watts
button pushed
out
for the 60 Watt reflected scale, Transmit 10 Watts
as indicated on the reference meter. Adjust the LO REF trim pot to set the reflected power scale
to 10 Watts.
8. With
the
3000/300 Watts
button pushed
in
for the 600 Watt reflected scale, Transmit 100 Watts
as indicated on the reference meter. Adjust the HI REF trim pot to set the reflected power scale
to 100 Watts.
9. SWR requires no calibration.
Figure 1: Test Setup
Transmitter/
Transceiver
Standard
Reference
Wattmeter
MFJ-986
SWR/
Wattmeter
50-Ohm
Dummy Load
