17.
Loop Phase Lock Adjustments
42.
43.
44.
45.
On the second spectrum analyzer, press
(
CENTER FREQUENCY
)
140
MHz MARKER
(
PEAK SEARCH
]
to position a marker on the peak of
the displayed 140 MHz signal, and verify that the output power
level of the
IF is at least -14
If it is
not,
slightly readjust
165 MHz NULL to increase
the amplitude of the 140 MHz signal displayed on the second
spectrum analyzer to -14
Refer to Figure 3-78 for the
location of
165 MHz NULL adjustment.
Key in MARKER
SEARCH
],
REF
on the second
spectrum analyzer to position the peak of the 140 MHz signal at
the top graticule line. Press MARKER la] on the second spectrum
analyzer.
On
the
synthesized sweeper, key in
FREQ
)
320.3 MHz
326.3 MHz
100
320.3 MHz.
Press
[
CENTER FREQUENCY
)
163 MHz TRACE A
on the
second spectrum analyzer. Allow the synthesized sweeper to tune
slowly from 320.3 MHz to 326.3 MHz, noting the corresponding
160 MHz to 166 MHz signal on the display of the second spectrum
analyzer.
The corresponding 160 MHz to 166 MHz signal might be below the
displayed noise level on the second spectrum analyzer.
46. On the second spectrum analyzer, press MARKER
[
PEAK SEARCH
)
to position the second marker on
the
peak response between 160
MHz and 166 MHz. This level should be at least 60
down from
the level of the 140 MHz signal in step 42.
47. Set the RF Section LINE switch to STANDBY. Disconnect the
second spectrum analyzer from
OUT
IF, and
disconnect the synthesized sweeper from the cable 4 (yellow).
48. Reinstall
IF Assembly in the RF Section. Reconnect
the cable 6 (blue) to
OUT 160-166 MHz, the cable 4
(yellow) to
OUT 200-300 MHz, and the cable 3 (orange)
to
OUT
IF.
3-152 Adjustments
