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CDR-3250/80 TECHNICAL MANUAL
Issue 2.2
5-3
5-4.3.1
Receiver Check.
1. Ensure receiver and local frequency standard
(if used) have warmed up for at least 10
minutes.
2. Connect known accurate frequency standard
to ANTENNA jack J5.
3. Using 1 Hz frequency resolution, tune receiver
to the same frequency as the frequency
standard.
4. Set receiver to AM, 100 Hz BW, with AGC on.
5. Select METERS display on the front panel
display.
6. Observe FRQ meter for 000 Hz ± 1 Hz.
7. If the frequency is not 000 ± 1 Hz, remove the
top cover and adjust the INT REF ADJ
potentiometer until correct reading is
obtained. (See figure FO-5A (CDR-3250) or
FO-5B (CDR-3280).)
8. Replace top cover if removed.
9. Return receiver to normal configuration.
5-4.3.2
TCXO Check.
1. Ensure receiver and local frequency standard
(if used) have warmed up for at least 10
minutes
2. Connect the REF OUT J3 to the frequency
counter.
3. If the frequency is not 10,000,000 ±1 Hz,
remove the top cover and adjust the INT REF
ADJ potentiometer until correct reading is
obtained. (See figure FO-5A (CDR-3250) or
FO-5B (CDR-3280).)
4. For better accuracy, connect J3 REF OUT to
channel 1 of the oscilloscope and the local
10MHz frequency standard to channel 2.
5. Set the oscilloscope timebase to “X-Y” and
observe the Lissajous pattern. Adjust the INT
REF ADJ potentiometer until the pattern
stops.
Courtesy of http://BlackRadios.terryo.org