User's Manual

68P81093C75-A 9-39
Step 2. Calculate a midpoint frequency as follows:
F
mid
= (F
highest
+ F
lowest
) ÷ 2
Step 3. Using F
mid
in place of the station receive frequency,
perform Step 2 through Step 4 above.
Preparing Equipment Step 1. Make sure the Receiver Module (with the Preselector
Assembly) is installed in a functional PDR 3500.
Step 2. Remove the chassis from its case by removing the
eight Phillips screws from the edges of the station’s
top panel.
Step 3. Remove the two Torx screws from the Receiver
Module front panel and remove the four Phillips
screws. Remove the panel.
Step 4. De-tune the preselector as follows:
If the alignment frequency (calculated in the previous
section) is greater than 148 MHz (Range 1), or
greater than 156 MHz (Range 2), turn the five tuning
screws in (clockwise) until 1/8" protrudes past each of
the tension nuts.
If the alignment frequency is less than, or equal to
148 MHz (Range 1), or 156 MHz (Range 2), back out
(counterclockwise) the five tuning screws until 3/4"
protrudes past each of the tension nuts.
Step 5. Using the torque driver and deep-well socket, tighten
the five tension nuts on the adjustment screws to
6 in. – lb.
Step 6. Connect the test equipment as shown in Figure 13.