Motorola APX 4000 Basic Service Manual

Radio Alignment Procedures: Front End Filter Alignment 6-17
6.6 Front End Filter Alignment
The alignment procedure adjusts the front end receiver bandpass filters for the best receiver
sensitivity and selectivity. This procedure should be performed for all test frequencies to allow for
proper software interpolation of frequencies between the test frequencies in the band
(see Figure 6-21 and Figure 6-22).
NOTE: Rx Front End Filter Alignment is required after replacing (or servicing) the transceiver board.
6.6.1 Procedure for UHF1/ UHF2 (Auto Tune)
Tuning of the radio is done through Rx Front End Filter tuning screen
1. Select the Rx Front End Filter alignment screen. See Figure 6-21 and Figure 6-22.
2. Click on the slider or the "New Softpot Value" text box to select which frequency to tune.
3. Apply RF test signal input with no modulation at -90 dBm on the Test Signal Frequency
displayed at the top of the screen.
4. Left-click the Autotune button.
5. Repeat the steps 2–4 for all frequencies.
6. Left-click the Program All button on the screen to save the tuned values in the radio.
Figure 6-21. Front End Filter Alignment Screen (UHF1)
This procedure should only be attempted by qualified service
technicians.
!
Caution

Motorola APX 4000 Specifications

General

IP Rating	IP67
Operating Temperature	-30°C to +60°C
GPS	Optional
Frequency Range	VHF: 136-174 MHz, UHF: 380-470 MHz, 450-520 MHz
Power Output	VHF: 1-5W; UHF: 1-4W
Digital Protocol	APCO P25
Dimensions	5.2 x 2.4 x 1.5 inches (without battery)