Swr Meter Calibration; Meter Calibration - MFJ VersaTuner III -962D Instruction Manual

SWR Meter Calibration

The MFJ-962D has been calibrated at the factory. If it should ever need to be recalibrated, then follow
this procedure:
Equipment Needed
1. Transmitter capable of supplying enough power to obtain ½ to full-scale reading at 14 or 21
MHz.
2. 50-ohm dummy load that is capable of handling full transmitter output power and has better than
a 1.15:1 SWR.
3. Power meter of know accuracy. The calibration will only be as good as the standard reference
meter.
4. 50-ohm cables capable of handling the power. RG-58/u is recommended. DO NOT USE RG-59
or RG-11.

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-962D.
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.
Transmitter/
Transceiver
Standard
Reference
Wattmeter
Figure 1: Test Setup
MFJ-962D Instruction Manual
MFJ-962D
SWR/
Wattmeter
50-Ohm
Dummy Load
12