Table of Contents
Advertisement
Reverse Power Calibration - SRPT-40A Only
Note: The SRPT-30 Reverse Power Calibration can only be performed at the factory.
THIS ADJUSTMENT HAS BEEN SET AT THE FACTORY AND SHOULD NOT REQUIRE ANY
TO MAINTAIN CALIBRATION, NEVER ADJUST THE RP CAL (R17) POT ON THE TWO-STAGE RF
PA BOARD, OTHERWISE THE REVERSE POWER MUST BE RECALIBRATED.
IF IT BECOMES NECESSARY TO RECALIBRATE, READ AND STUDY THIS SECTION
1.
Power down the SRPT-40A (i.e., turn off AC LINE switch or turn off external supply).
2.
Make sure that the WATT METER is connected to the ANTENNA connector.
IT IS PRESUMED THAT A BIRD WATT METER OR EQUIVALENT IS USED.
3.
Disconnect the 50-Ohm load from the Bird WATT METER.
4.
Rotate the element in the Bird Watt Meter 180 degrees counter-clockwise for measuring reverse power.
5.
Remove cover from SYNTHESIZER.
6.
On the SYNTHESIZER place jumper on P2 in the RP position.
7.
On the TWO-STAGE POWER AMPLIFIER board, tweak the RP CAL pot (R17) fully clockwise (approximately
20 turns).
8.
On the SYNTHESIZER, tweak the MAX PWR pot (R74) fully counter-clockwise (approximately 20 turns).
9.
Power up SRPT-40A, but leave front panel TRANSMIT/STANDBY switch in the "STANDBY" position. Wait for
SRPT-40A to become locked on frequency.
10. Referring to Table (2) – Forward and Reverse Power Calibration, find the row that lists your model. Follow this
row to the CAL FREQUENCY column. This number represents the frequency your model is to be calibrated at.
Change the SRPT-40A to this calibrated frequency.
11. Measure the B+ voltage. Adjust the B+ if necessary by referring to Switching Power Supply Adjustment or B+
Adjustment When Using 15-30VDC External Supply. If using a 12-15 volt external supply, adjust its voltage to
12 to 15 volts. It is recommended that the VOLT METER is monitoring B+ throughout this procedure.
12. On the FRONT PANEL CONTROL & METER board, adjust S1 dip-switches with switch 1, 3, and 4 "OFF" and
switch 2 "ON".
13. Set the front panel FREQUENCY SELECT pushwheel switches as follows:
DECIMAL 7 (far left digit) = "1"
DECIMAL 6 = "4"
DECIMAL 5 = "0"
DECIMAL 4 = "0"
DECIMAL 3 = "0"
DECIMAL 2 = "0"
DECIMAL 1 (far right digit) = "0"
CAUTION
FURTHER ADJUSTMENTS.
WARNING
CAREFULLY BEFORE PROCEEDING.
NOTE
8/7/2003
46
Hide quick links:
Advertisement
Table of Contents
