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19. Second Converter Adjustments
9. Readjust
A23A3
2ND
MIXER
A23A3Z4
for maximum power
indication.
10. Disconnect the amplifier’s input from A23A3J3 and connect to
A23A3J4.
11. Adjust
A23A3
PILOT
2ND
MIXER
A23A3Z8
for maximum power
meter indication. See Figure 3-73 for location of adjustment.
12. Disconnect power meter and connect frequency counter to
amplifier’s output.
13. Key in [SHIFT)
@)
u
to shift Second LO up and
ISHIFT)
a
T
to shift
Second LO down.
14. Continue to shift Second LO up and down while adjusting
A23A3
2ND
LO SHIFT
A23A3ZlO
for a frequency difference of 5.0
MHz fO.l MHz. Ignore the absolute value of either frequency.
Clockwise rotation of
A23A3ZlO
decreases the frequency
difference.
15. Key in (SHIFT)
a
T
(Second LO shifted down).
16. Adjust
A23A3
2ND
LO FREQ
A23A3Z9
for frequency counter
indication of 1748.6 MHz fO.l MHz.
17. Repeat steps 13 through 16 until specifications of steps 14 and 16
are achieved.
18. Disconnect frequency counter and connect power meter to the
amplifier’s output.
19. Shift Second LO up and down, using
m
m
u and (SHIFT)
a
T
while adjusting
A23A3
PILOT
2ND
MIXER
A23A3Z8
for equal
power out in both states of Second LO.
20. Power difference between Second LO shifted up and shifted down
should be less than 0.5
dB.
21. Disconnect amplifier’s input from A23A3J4 and connect to
A23A3J3.
22. Shift Second LO up and down, using
(SHIFTY
a
u
and
ISHIFT)
@)
T
while adjusting
A23A3
2ND
MIXER
A23A3Z4
for equal power out
in both states of the Second LO.
23. Power differences between Second LO shifted up and shifted
down should be less than 0.5
dB.
24. Disconnect power meter and connect frequency counter to
amplifier’s output.
25. Key in
[SHIFT)
a
T.
Note frequency counter indication. If
necessary, readjust
A23A3
2ND
LO FREQ
A23A3Z9
for frequency
counter indication of 1748.6 fO.l MHz.
26. Shift Second LO up and down, using
ISHIFT)
@)
’
and
ISHIFT)
a
T
and note frequency difference between low and high state
of Second LO. If necessary, readjust
A23A3
2ND
LO SHIFT
A23A3ZlO
for a frequency difference of 5.0 MHz fO.l. Repeat
steps 27 and 28 until specifications contained in each step are
achieved.
Adjustments 3-125