RA6790/GM
Alignment
ALIGNMENT FOR THE RA6790/GM RECEIVER
A4 ALIGNMENT
- Pre-Settings
- R-39 MID-RANGE
- R-47 CCW
- R-105 CW
- R-119 MID-RANGE
- INJECT A FREQUENCY OF 455 KHz CW AT A LEVEL OF -68dBm INTO A4J1 AND SELECT AGC SHORT & BANDWIDTH 4 (6.8 KHz FILTER) ON THE RECEIVER.
- ADJUST R-39 FOR -10dBm ON THE SPECTRUM ANALYZER (IF OUTPUT 50 OHMS AT REAR OF THE RECEIVER).
- CHANGE INPUT LEVEL TO -35dBm AND BANDWIDTH 3 (3.2 KHz FILTER) ON THE RECEIVER.
- CONNECT A DMM TO TP9 AND ADJUST R-47 FOR 8.5VDC ON THE DMM.
- SELECT MAN AGC ON THE RECEIVER AND ADJUST IF GAIN POT FOR 8.5VDC ON THE DMM.
- CONNECT A RF VOLTMETER WITH A HIGH-Z PROBE TO TP7.
- ADJUST R-105 UNTIL LEVEL STARTS TO CHANGE ON RF VOLTMETER.
- SELECT AGC SHORT ON THE RECEIVER AND REMOVE THE INPUT SIGNAL TO A4J1. THE DMM IS STILL CONNECTED TO TP9.
- ADJUST R-119 FO 10.0VDC ON THE DMM.
A7 ALIGNMENT
• TUNE THE RECEIVER TO 29.999999 MHz. • CONNECT THE POSITIVE LEAD TO DMM TO TP12 AND THE NEGATIVE LEAD TO GROUND. • ADJUST L5 FOR READING OF 13.5VDC ON THE DMM. • TUNE THE RECEIVER TO 00.500000 MHz. • VOLTAGE ON DMM SHOULD BE GREATER THAN 3.00VDC. • CONNECT THE POSITIVE LEAD TO DMM TO TP5 AND THE NEGATIVE LEAD TO GROUND. • ADJUST R-16 FOR READING OF 5.2VDC ON THE DMM.
A8 ALIGNMENT
• CONNECT A SIGNAL GENERATOR TO THE RECEIVER AND SET ITS OUTPUT AS FOLLOWS. • FREQUENCY OF 29.999999 MHz & MODE CW. • SET THE RECEIVER TO 29.999999 MHz, CW, BFO+1KHz AND SHORT AGC. • CONNECT A FREQUENCY COUNTER TO THE AUDIO OUTPUT. • ADJUST TCXO Y1 TO 1.000 KHz ON THE FREQUENCY COUNTER. • CONNECT THE POSITIVE LEAD OF THE DMM TO TP8 AND THE NEGATIVE LEAD TO GROUND. • RESET BFO ON THE RECEIVER TO 0.00 KHz OR BFO CENTER. • ADJUST L4 FOR A READING OF 5.00VDC (+/-0.2VDC) ON THE DMM.
GARY E. WINGERD
9107 JORDAN RD.
FAIRPLAY, MD. 21733
301-582-2424
gewingerd@netzero.com