7-2
6880905Z99-O
June, 2000
Radio Tuning Procedure
GTX LTR/Privacy Plus 800 MHz Mobile Service Manual
Tuning Procedure
Each SERVICE screen provides the capability to
increase or decrease the ‘softpot’ value with the key-
board UP/DOWN arrow keys respectively. A graphi-
cal scale is displayed indicating the minimum,
maximum, and proposed value of the softpot, as
shown in Figure 7-3.
Tuning Procedure
Starting the Tuning Procedure
1.
From the SERVICE menu, press F6 to select
BOARD REPLACEMENT.
2.
Press
F2
for LOGIC OR RF BOARD replace-
ment.
NOTE
Perform the following procedures in the
sequence indicated.
Alignment Default Data
1.
Press
F2
to select ALIGNMENT DEFAULT
DATA.
2.
Press
F8
for PROGRAM VALUE.
Tx Power
1.
Press
F3
to select Tx POWER.
2.
Press
F6
to key the radio. The screen will indi-
cate that the radio is transmitting.
3.
Adjust the transmit power value with the UP/
DOWN arrow keys.
4.
Press
F6
again to dekey the radio, and then
press
F8
to program the softpot value.
Reference Oscillator Alignment
NOTE
The frequency of the transmitter must be
checked on installation and at least annu-
ally.
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 oscilla-
tor 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.
Press
F4
to select the REFERENCE OSCILLA-
TOR softpot.
2.
Press
F6
to key the radio. The screen will indi-
cate that the radio is transmitting.
3.
Measure the transmit frequency that appears
on the screen of your frequency counter.
4.
Use the UP/DOWN arrow keys to adjust the
reference oscillator.
5.
Press
F6
again to dekey the radio and then
press
F8
to program the softpot value.
F6
F2
Alignment
Menu
Board
Replacement
Menu
Service
Menu
F2 Logic or RF Board Replacement
F3 Tx Power
F4 Warp Reference Frequency
F5 Tx Power Calibration
F6 Tx Deviation Calibration
F3 Deviation Adjustment
F5 Reference Oscillator Warp
F7 Transmitter Power
F8 Squelch Adjustment
F9 Squelch Adjustment
Figure 7-2.
Service Menu Structure
MAEPF-22858-O
Min.
Value
Max.
Value
0
15
Figure 7-3.
Softpot Concept