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Figure 59: Preselector Tuning — VHF
Procedure:
1
Turn the base radio power supply
ON
(to provide a 50 Ohm termination).
2
Adjust the signal generator to the frequency calculated in
Frequency For a Single Receive Frequency on page 160
Frequency for Multiple Receive Frequencies on page 161
. Set the level to +5 dBm.
3
Insert tuning probe into cavity H1 and adjust tuning screw 1 for a
PEAK
.
4
Leave tuning probe in cavity H1 and adjust tuning screw 2 for a
DIP
.
5
Insert tuning probe into cavity H2 and adjust tuning screw 3 for a
DIP
.
6
Insert tuning probe into cavity H3 and adjust tuning screw 4 for a
DIP
.
7
Insert tuning probe into cavity H4. Decrease output from the signal generator to –5 dBm.
8
Adjust tuning screw 5 for a
DIP
. Then turn tuning screw 5 an additional 1/4 turn
counterclockwise. (
DIP
is not as sharp for screw 5 as it was for screws 2 through 4.)
5.9.2
UHF Tuning Procedures
UHF tuning procedures include the following:
•
Calculating Proper UHF Alignment Frequency on page 163
•
Preparing the Equipment for UHF Alignment on page 164
•
Tuning The UHF Preselector on page 164
MN003286A01-E
Chapter 5: GTR 8000 Base Radio Optimization
162