User's Manual

Tuning Procedure
Board-Level Tuning Procedure
1. Place the VRS in the test mode:
a. Turn off the mobile radio control head.
b. Place the VRS into Test Mode by setting dipswitch S1 pins 1, 2, 3, and 4 to OFF.
c. Turn on the mobile control head and re-enable the VRS.
d. While in Test Mode, the VRS will not have portable priority interrupt and will not
transmit PL with VRS-to-portable transmissions.
f. Figure 15 illustrates the relative placement of the tuning potentiometers.
Figure 15 Tuning Potentiometers
2. Adjust the VRS Deviation Level:
a. Set the Mobile Communications Analyzer RF output to -50 dBm, with a standard
test modulation (1 kHz tone, 3 kHz deviation).
b. Set the Mobile Communications Analyzer frequency to the current mobile mode.
c. Switch on the Mobile Communications Analyzer RF.
d. Adjust R150 on the VRS board until 3.0 kHz deviation is obtained on the VRS
Communications Analyzer.
e. Switch off the Mobile Communications Analyzer RF.
3. Adjust the Mobile Microphone Deviation Level:
o This adjustment requires specialized equipment. If a problem is found with the
audio transmitted to the portable while using the mobile microphone, Motorola
engineering should be contacted.
4. Adjust the Mobile Deviation Level:
NOTE: Set the VRS Communications Analyzer RF output to -50 dBm with a
standard test modulation (1 kHz tone, 3 kHz deviation) and any receive PL for which the
VRS is programmed (750 Hz deviation). If the receive PL for "select mode" is not used,
the Mobile Communications Analyzer frequency may need to be adjusted.
a. Set the Mobile Communications Analyzer frequency to the current mobile mode.
b. Switch on the VRS Communications Analyzer RF.
c. Adjust R146 on the VRS board until 3.00 kHz deviation is obtained on the Mobile
Communications Analyzer.
d. Switch off the VRS Communications Analyzer RF.
5. Check the VRS RF Sensitivity:
a. Set the VRS Communications Analyzer RF output to -115 dBm with a standard
test modulation (1 kHz tone, 3 kHz deviation) and any receive PL for which the VRS is
programmed (750 Hz deviation).
NOTE: If the receive PL for "select mode" is not used, the Mobile
Communications Analyzer frequency may need to be adjusted.
b. Switch on the VRS Communications Analyzer RF. The unit should not retransmit
this signal to the Mobile Communications Analyzer.
c. Slowly increase the input signal. The unit should begin repeating to the Mobile
Communications Analyzer at no more than -104 dBm.
d. Switch off the VRS Communications Analyzer RF.
6. Take the VRS out of test mode:
a. Turn off mobile control head and set the dipswitch S1 pins 1, 2, 3, and 4 to ON.