Radio Information; Reference Oscillator Alignment; Figure 6-5. Radio Information Screen - Motorola Astro XTS 4000 Service Manual

6-4
Adjusting the softpot value sends information to the radio to increase (or decrease) the voltage in the
corresponding circuit. For example, left-clicking the UP spin button in the New Softpot Value scroll
box on the Reference Oscillator screen instructs the radio's microcomputer to increase the voltage
across a varactor in the reference oscillator, which increases the frequency.
In ALL cases, the softpot value is just a relative number corresponding to a digital-to-analog (D/A)
generated voltage in the radio.
Perform the following procedures in the sequence indicated.
NOTE: Some of the following screens may vary depending upon the radio under test and the version
of tuner software you are using. Refer to the software's online help.
6.4

Radio Information

Figure 6–5 shows a typical Radio Information screen. This screen is informational only and cannot
be directly changed.
6.5

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 mainboard.
This test can be done with either the R-2670 Communication Analyzer or the 8901_ Modulation
Analyzer.
When keying the radio during a test, always transmit into a
dummy load.
Figure 6–5. Radio Information Screen
Radio Alignment Procedures: Radio Information