Tuning Procedure; Reference Oscillator Alignment; Squelch - Motorola GTX 2000 Service Manual

Radio Tuning Procedure

Tuning Procedure

keyboard UP/DOWN arrow keys respectively. A
graphical scale is displayed indicating the minimum,
maximum, and proposed value of the softpot, as
shown in Figure 3.
Tuning Procedure
NOTE
Perform the following procedures in the
sequence indicated.

Reference Oscillator Alignment

Adjustment of the reference oscillator is critical for
proper radio operation. Improper adjustment will not
only result in poor operation, but also a misaligned
radio that will interfere with other users operating on
adjacent channels. For this reason, the reference
oscillator should be checked every time the radio is
serviced. The frequency counter used for this
procedure must have a stability of 0.1 ppm (or better).
1. From the SERVICE menu, press F2 to select
ALIGNMENT: TRANSMITTER & RECEIVER.
F3 TX Deviation Adjustment
F5 Reference Oscillator Warp
F7 Transmitter Power
F8 Squelch Adjustment
7-2
F2
Alignment
Menu
Figure 7-2. Service Menu Structure
0
Min.
Value
Figure 7-3.
68P02945C75-A
GTX/GTX LTR/LTS 2000 Portable Radios Service Manual
2. Press F5 to select the REFERENCE OSCILLA-
TOR softpot.
3. Press F6 to key the radio. The screen will indi-
cate that the radio is transmitting.
4. Measure the transmit frequency on your fre-
quency counter.
5. Use the UP/DOWN arrow keys to adjust the
reference oscillator.
6. Press F6 again to dekey the radio and then
press F8 to program the softpot value.
7. Press F10, F10 to return to SERVICE menu.

Squelch

The squelch softpots set the signal to noise ratio at
which the squelch opens.
1. From the SERVICE menu, press F2 to select
ALIGNMENT: TRANSMITTER & RECEIVER.
2. Press F8 to select SQUELCH Adjustment.
Service
Menu
Board
Replacement
F2 Logic or RF Board Replacement
F3 Tx Power
F4 Warp Reference Frequency
F5 Tx Power Calibration
F6 Tx Deviation Calibration
F9 Squelch Adjustment
15
Max.
Value
MAEPF-22858-O
Softpot Concept
F6
Menu
June 1999