Motorola ASTRO XTS 5000 I - Miscellaneous Hardware; Disassembly and Reassembly; Vacuum Test; Conducting the Test

Radio Alignment Procedures
30
Front End Filter
Alignment
Definition This alignment procedure adjusts the front end receiver bandpass filters for
best receiver sensitivity and selectivity. It should be performed for all test
frequencies to allow for proper software interpolation for frequencies in
between the test frequencies in the band (see Figure 12).
NOTE: Rx Front End Filter Alignment is required after
replacing (or servicing) the transceiver board.
Procedure for 700 MHz
Frequencies
1. Left-click the desired frequency field.
2. Apply an RF signal with no modulation at -90 dBm on the current
operating frequency.
3. Start with a softpot value (approximately 10 or 20), increase
softpot in ascending order, and note the RSSI values. The RSSI will
reach a peak value and remain stable and then decrease. Allow the
limits of the peak range to be defined as RSSI PEAK - 3. Choose
the middle of the peak range and program the corresponding
softpot value as the tuned softpot value.
4. Repeat the above process for all 700MHz frequencies.
5. Click on the “Program All” button to save the tuned values in the
radio.
Procedure for 800 MHz
Frequencies
1. Left-click the desired frequency field.
2. Apply an RF signal with no modulation at -90 dBm on the current
operating frequency.
3. Start with a softpot value of 50, increase softpot in ascending
order, and note the RSSI values. The RSSI will reach a peak value
and remain stable and then decrease. Allow the limits of the peak
range to be defined as RSSI PEAK - 3. Note the upper end of the
peak range and program the corresponding softpot value as the
tuned softpot value.
4. Repeat the above process for all 800MHz frequencies.
5. Click on the “Program All” button to save the tuned values in the
radio.
Procedure for UHF/VHF 1. Left-click the desired frequency field.
2. Apply an RF signal with no modulation at -90 dBm on the current
operating frequency.
3. Adjust the softpot value until the maximum RSSI value is found.
4. Repeat the above process for all frequencies.
5. Click on the “Program All” button to save the tuned values in the
radio.
This procedure should only be attempted by qualified service
personnel.
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C a u t i o n