Radio Alignment Procedures: Transmitter Alignments 6-5
6.5 Transmitter Alignments
6.5.1 Reference Oscillator Alignment
Adjustment of the reference oscillator is critical for proper radio operation. Improper adjustment will
result not only in poor operation, but also in a misaligned radio that will interfere with other users
operating on adjacent channels. For this reason, the reference oscillator should be checked every
time the radio is serviced, or once a year, whichever comes first. The frequency counter used for this
procedure must have a stability of 0.1 ppm (or better).
NOTE: Reference oscillator alignment is required after replacing (or servicing) the transceiver board.
This test can be done with either the R-2670 Communication Analyzer or the 8901_ Modulation
Analyzer.
• Initial setup using the R-2670 Communication Analyzer:
- RF Control: Monitor
- B/W: WB
- Freq: CPS frequency under test
- Attenuation: 20dB
- Mon RF in: RF I/O
- Meter: RF Display
- Mode: STD
- Input Level: uV or W
- Display: Bar Graphs
- Squelch: Mid-range or adjust as necessary
• Initial setup using the 8901_ Series Modulation Analyzer:
- Press the green Automatic Operation button on the analyzer.
- Press the FREQ key.
- Type 7.1 followed by SPCL button to set the 8901B_ modulation analyzer for maximum
accuracy.
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