User's Manual

68P81093C75-A 9-21
• Power Supply Module
• 2.1 MHz Reference Oscillator Circuitry
• Receiver-related circuitry in the Station Control Module (SCM)
The transmitter circuitry is exercised by injecting and measuring
signals using a Motorola R2670 Communications Analyzer (or
equivalent), and analyzing the Bit Error Rate using the RSS.
Measured values outside the acceptable range indicate a faulty
module; values within range verify proper operation of the above
modules and circuitry.
Required Test Equipment The following test equipment is required to perform the procedure:
• Motorola R2670 Communications Analyzer with ASTRO CAI
Option (or equivalent)
• PC running Radio Service Software (RSS) program
• Female N-type to Female N-type coaxial cable
• Dummy Load (50Ω, station wattage or higher). Required for
repeater stations only.
IMPOR
TANT! If the station operates as a repeater, the transmit output from
the station must be connected to a dummy load to prevent over-
the-air broadcast during receiver testing.
Step 1. Proceed to ASTRO Bit Error Rate Report (located in
Chapter 4 of the RSS User’s Guide, part number
68P81085E35). Follow the instructions for setting up
the test equipment and initiating a BER report using
the RSS.
Step 2. If the BER reading is above 5%, suspect the
following:
• Faulty Station Control Module (2.1 MHz
reference)
• Faulty Receiver Module
• Faulty top panel-to-preselector RF cable
• Faulty R2670-to-station RF cable
Step 3. If you are injecting RF directly into the top panel
receiver port, change the R2670 injection signal level
to:
• VHF: 0.25 µV (-119 dBm)