User's Manual

9-40 68P81093C75-A
VHF Tuning Procedure Step 1. Provide power to the PDR 3500 through either DC or
AC (to provide the active 50 Ω termination).
Step 2. Adjust the signal generator to the frequency calculated
on page 9-38. Set the level to +5 dBm.
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.
Figure 13. Test Equipment Setup for Preselector Field Tuning
Tension Nut
Tuning Screw
To Dip/Peak
Monitor
(RF Millivoltmeter
or Power Meter)
From
Signal
Generator
Tuning
Probe
To
Receiver
Board
To RX
Connector
on Top Panel
Preselector
Assembly
RX
TX
MAEPF-27038-O