Uhf Tuning Procedure; Calculating Proper Alignment Frequency; Figure 13 Location Of Tuning Screws And Cavity Probe Holes - Motorola PDR 3500 Basic Service Manual

UHF Tuning Procedure

Calculating Proper
Alignment Frequency
68P81093C75-O
Step 3. Insert the tuning probe into the cavity "H1" and adjust
tuning screw 1 for a PEAK.
Step 4. Leave the tuning probe in cavity "H1" and adjust
tuning screw 2 for a DIP.
Step 5. Insert the tuning probe into cavity "H2" and adjust
tuning screw 3 for a DIP.
Step 6. Insert the tuning probe into cavity "H3" and adjust
tuning screw 4 for a DIP.
Step 7. Insert the tuning probe into cavity "H4" and decrease
the output from the signal generator to -5 dBm.
Step 8. Adjust tuning screw 5 for a DIP. Then turn tuning
screw 5 one-quarter turn counterclockwise.
NOTE: The DIP will not be as sharp for screw 5 as it was for
screws 2 through 4.
TUNING SCREW 1
TUNING SCREW 2
TUNING SCREW 3
TUNING SCREW 4
TUNING SCREW 5

Figure 13 Location of Tuning Screws and Cavity Probe Holes

Use one of the following two methods to calculate the alignment
frequency to be generated by the signal generator.
For stations with a single receive frequency, calculate the frequency
of the alignment signal as follows:
Step 1. From the site documentation, or the RSS, determine
the station receive frequency. Add 200 kHz.
Step 2. If the Receiver Module is Range 1, determine the
alignment frequency as follows:
September 27, 2000
Preselector
Assembly
H1
To
H2
Receiver
Board
H3
H4
H5
To
Station Receive
Antenna Port
MAEPF-27039-O
9-39