Front End Filter Alignment; Definition; Procedure For 700 Mhz Frequencies; Procedure For 800 Mhz Frequencies - Motorola XTS 2500 Basic Service Manual

Radio Alignment Procedures
Front End Filter
Alignment

Definition

Procedure for 700
MHz Frequencies
Procedure for 800
MHz Frequencies
Procedure for UHF/
VHF
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8. Left-click the Close button on the screen to return to the Transmitter Alignments
menu.
!
Refer to your Radio Service Manual for alignment procedure details.
This procedure should only be attempted by qualified service personnel.
C a u t i o n
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.
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.
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.
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.