Tx Wireline Alignment; Rx Wireline Alignment; Transmitter Testing; Tuning A Preselector - Motorola ASTRO 25 GTR 8000 Manual

When measuring SINAD, the pre-emphasis and high pass filters are set as they would be for analog
voice operation. Because the channel characteristics are different, this procedure allows for CSQ
Alignment and is done for both 12.5 kHz and 25 kHz channel bandwidth. If the station is configured for
only one channel bandwidth, there is no need to perform a CSQ Alignment for the other bandwidth.
See "Base Radio Service Help → Service Screens → Alignment Screens" in the CSS Online Help
for the alignment procedures.
5.6

Tx Wireline Alignment

Tx Wireline Alignment is used to set the levels to result in 60% system deviation for both Wireline Level
Line 1(WL1) and Wireline Level Line 3 (WL3) and for setting the Wireline Squelch levels.
See "Base Radio Service Help → Service Screens → Alignment Screens" in the CSS Online Help
for the alignment procedures.
5.7

Rx Wireline Alignment

Rx Wireline Alignment is used only for a base radio that processes analog receive audio and is
connected with a 2- or 4-wire link to a console or a comparator in an analog only topology or an
®
ASTRO 25 Analog/Mixed mode topology.
See "Base Radio Service Help → Service Screens → Alignment Screens" in the CSS Online Help
for the alignment procedures.
5.8

Transmitter Testing

The Metering Screen displays current values for power supply and transmitter metering points on multi-
site base radios, site repeater base radios, HPD base radios, and digital conventional base radios.
See "Base Radio Service Help → Service Screens → Metering Screen" in the CSS Online Help for
the procedures for testing the transmitter.
5.9

Tuning a Preselector

The optional VHF or UHF preselector assembly is mounted on the back of a base radio. 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 base radio. If the preselector
assembly is replaced in the field, or if the base radio operating frequencies are modified, the
preselector must be field tuned.
IMPORTANT: Tuning for best SINAD or Bit Error Rate (BER) response DOES NOT result in
optimum tuning of the preselector assembly. Use this field tuning procedure to obtain optimum
preselector performance.
The following test equipment is required to properly tune the preselector assembly:
• RF Signal Generator - Aeroflex 3900 Series Service Monitor (or equivalent)
• Dip/peak Monitor - HP435B Powermeter (or equivalent) with an HP8484A sensitive power head,
Boonton Model 92E with BNC input, or Aeroflex 3900 Series Service Monitor using the spectrum
analyzer function
Chapter 5: GTR 8000 Base Radio Optimization
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