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MFJ-1278B MULTI-MODE APPENDIX B MODEM CALIBRATION
MODEM CALIBRATION
The MFJ-1278B Modem is factory calibrated to operate all the operational modes it is
capable of. If it becomes necessary to re-calibrate the MFJ-1278B modem, please follow the
following procedure:
MODULATOR/DEMODULATOR FREQUENCY CALIBRATION
Here we present you with two (2) Modulator and Demodulator Calibration. Calibration
Method I requires test equipment as noted, and is the most accurate. Calibration Method II
does not require test equipment, and is meant for those who do not have test equipment.
Calibration Method I
Calibration Method I below, as mentioned previously is the most accurate method. In order
to do the best job possible. please follow the procedure as closely as possible. Following the
procedure closely will ensure that you will calibrate the MFJ-1278B accurately. If any step is
missed or not performed properly, then the performance of the MFJ-1278B becomes
questionable.
Test equipment needed:
a. Calibrated Frequency Counter with 10:1 probe
b. Computer with terminal software or terminal
c. RS-232 Serial Cable
d. MFJ-1315 Power Supply/ or 12 VDC supply
Calibration Proedure:
1. Install jumpers on JMP4 and JMP7.
2. Place frequency counter at Pin 1 of JMP 9. Pin 1 is the top pin of JMP 9.
3. In the following procedure all frequencies must be calibrated to within +/- 2 Hz.
4. Type: TUNEPROC <CR>
The MFJ-1278B will respond with:
Calibration
Install loopback for TX alignment
R139 For 700Hz..
Adjust
R139
for
700Hz
+/
-
2Hz
. Press the
S
PACE BAR
on the computer keyboard.