Motorola Commercial Series, Basic Service Manual

Page: 44 / 100

December, 2009 68009328001-A
5-8 Radio Alignment Procedures: Transmitter Alignment Options
8. Exit the Transmit Low Power function.
5.4.4 VCO Attenuation
Note: Modulation Balance Tuning must be done first. The Transmit Deviation Limit softpot
sets the maximum deviation of the carrier. Tuning is performed for all (12.5 kHz, 20
kHz and 25 kHz) channel bandwidths. Tuning for 25 kHz channels must be done first
for all frequency points. Tuning for 12.5 and 20 kHz channels determines only the
offset to the previously tuned deviation for 25 kHz tuning channel spacing. For 12.5,
and 20kHz channels, only the last non-0 transmit frequency point (normally F7) is
used for tuning. The 30 kHz channel bandwidths that use 5.0 kHz maximum system
deviation are covered by the 25 kHz tuning.
When using test box RLN4460:
• Set the METER OUT toggle switch to the “MIC PORT” position
• Set the METER OUT selector switch to "MIC”.
• Inject a 1 kHz tone with the levels given below for each radio model to AUDIO IN.
• Measure the level at the radio input at the AC/DC meter.
Figure 5-6. VCO Attenuation Window (12.5 kHz)