TB 9-6625-2059-24
(6) Adjust VAR control until measuring receiver indicates 20 kHz.
Adjust
A1A13R79 (fig. 5) until DEVIATION (kHz) meter indicates 20 kHz.
16. Spectrum Analyzer Signal Strength
a. Performance Check
(1) Set GEN-RCVR switch to RCVR and adjust ANALY DISPR control cw just
out of detent. If bottom of trace on oscilloscope is not between -108 and -110 dBm, perform
b (1) through (3) below.
CAUTION
Do not exceed signal strength greater than -30 dBm.
(2) Connect signal generator to ANTENNA INPUT.
(3) Adjust signal generator frequency for 125.500 MHz and amplitude for -50 dBm
indication on TI display. If signal generator does not indicate between -45 and -55 dBm,
perform b (1) through (17) below.
(4) Adjust signal generator amplitude in 10 dB steps from -30 to -100 dBm. If
signal strength as displayed on TI does not indicate respective signal generator amplitude
outputs 4 dBm relative to reference set in a (3) above, perform b (1) through (17) below.
b. Adjustments
NOTE
See NOTE in figure 2 for access to adjustments.
(1) Connect multimeter to +11V TP (fig. 1) and chassis ground.
(2) Adjust +11 VOLT ADJ A4A2R43 (fig. 6) for an 11 V indication on multimeter.
(3) Adjust VERT CTR A4A2R30 (fig. 6) until bottom of trace indicates -109 dBm.
(4) Connect oscilloscope to INPUT TEST POINT (fig. 6).
(5) Adjust signal generator amplitude for -30 dBm.
(6) Adjust IF GAIN A4A2R4 (fig. 6) for 0.4 V p-p spike on oscilloscope.
(7) Adjust VERT GAIN A4A2R29 (fig. 6) for 30 dBm indication on TI.
(8) If bottom of trace does not indicate -109 dBm, repeat b (3) above.
(9) Adjust signal generator amplitude to -40 dBm.
(10) Adjust LOG LIN A4A2R5 (fig. 6) for a -40 dBm indication on TI. If a -40 dBm
indication cannot be obtained go on to next step.
(11) Adjust signal generator to -30 dBm and repeat b (7) through (10) above until no
further adjustments are required.
(12) Adjust signal generator amplitude for -60 dBm.
(13) Adjust AMP 1 GAIN A4A2R13 (fig. 6) for a -60-dBm indication on TI.