User's Manual

68P81093C75-A 9-37
After Installing the New
Backplane
Perform the following alignment procedures as described in the
Setup and Connections section of this manual:
• Power Output
Using the RSS, run a complete battery of diagnostics to exercise all
boards and modules.
Preselector Field
Tuning Procedure
The VHF and UHF Receiver Modules comprise a circuit board and
a preselector assembly. Both are secured in a slide-in module
housing.
The preselector assembly is a 3-pole (UHF) or a 5-pole (VHF)
bandpass filter, equipped with tuning slugs to adjust the passband
corresponding to the operating frequencies of the station. The
preselector assembly must be field-tuned if replaced in the field, or
if the station operating frequency (or frequencies) is (are) modified.
The tuning procedure follows.
IMPOR
TANT! Tuning for best SINAD response DOES NOT result in optimum
tuning of the preselector assembly. You must use this field-
tuning procedure to obtain optimum preselector performance.
Required Test
Equipment
The following test equipment is required to properly tune the
preselector assembly:
• RF Signal Generator: Motorola R2600 Communications
Analyzer, R2001 Communications Analyzer (see note), or
HP8656A signal generator (or equivalent)
• Dip/Peak Monitor: HP435B Power Meter (or equivalent) with
HP8484A sensitive power head, Boonton Model 92E with BNC
input, or R2001/R2600, using the spectrum analyzer function.
• Torque Driver, capable of delivering 12 in. – lb. of torque, and 10
mm deep well socket.
• Tuning probe: Motorola Part number 0180763D22, part of
TRN7799A tuning kit.
• Flat-blade screwdriver
NOTE: The R2600 Communications Analyzer can both
generate and measure simultaneously. The R2001
may be used for either the generator or monitor
function, but not both simultaneously. When using
the R2001 as a signal generator, RF signal must be
taken from the antenna port.