User Manual

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16. Depress and release the front panel EXECUTE pushbutton switch. The SRPT-40A is now in the Forward Power
Calibration mode.
17. On the FRONT PANEL CONTROL & METER board, adjust S1 dip-switches with switch 1, 2, and 4 “OFF” and
switch 3 “ON”.
18. Set the front panel FREQUENCY SELECT pushwheel switches as follows:
DECIMAL 7 (far left digit) = “1”
DECIMAL 6 = “any number”
DECIMAL 5 = “any number”
DECIMAL 4 = “any number”
DECIMAL 3 = “any number”
DECIMAL 2 = “any number”
DECIMAL 1 (far right digit) = “any number”
19. Depress and release the front panel EXECUTE pushbutton switch. This command will set the internal power control
pot to maximum and the position of the POWER ADJUST pot is ignored.
20. Put the TRANSMIT/STANDBY switch in the “TRANSMIT” position. The output power (as indicated by the
WATT METER) should be close to 0 Watts.
NOTE
THE HIGH VSWR LED MAY BLINK FROM TIME TO TIME, BUT SIMPLY IGNORE IT DURING
THIS CALIBRATION PROCEDURE.
21. The front panel TRANSMIT LED should be off. On the SYNTHESIZER, tweak the MAX PWR pot (R74)
clockwise until the TRANSMIT LED just comes on. The output power should increase as indicated by the WATT
METER.
22. Referring to Table (2) - Forward and Reverse Power Calibration, find the row that lists your model. Follow this
row to the first number listed under the FWD PWR LEVELS (W) column (@ Decimal 5 = 0). This number is the
maximum calibrated power.
23. On the TWO-STAGE POWER AMFLIFIER board, tweak the FP CAL pot (R20) counter-clockwise (slowly) until
the output power (as indicated by the WATT METER) reaches this maximum calibrated power.
WARNING
THE FP CAL POT (R20) IS NOW CALIBRATED.
DO NOT ADJUST IT ANYMORE!
STEPS 24 THROUGH 29 ARE REQUIRED FOR RE-PROGRAMMING THE INTERNAL FORWARD
POWER CALIBRATION TABLE. THIS WILL YIELD THE MOST ACCURATE CALIBRATION.
HOWEVER, IN MOST CASES THESE STEPS CAN BE SKIPPED WHILE STILL MAINTAINING A VERY
ACCURATE CALIBRATION. IF DECIDE TO SKIP, PLEASE CONTINUE AT STEP 30.
24. Set the front panel FREQUENCY SELECT pushwheel switches as follows:
DECIMAL 7 (far left digit) = “2”
DECIMAL 6 = “any number”
DECIMAL 5 = “0”
DECIMAL 4 = “any number”
DECIMAL 3 = “any number”
DECIMAL 2 = “any number”
DECIMAL 1 (far right digit) = “any number”
25. Depress and release the front panel EXECUTE pushbutton switch. This command will store the raw power into the
internal calibration table.