Instruction Manual

Table Of Contents
Port /
Type
Device it connects to:
Port /
Type
Description
EXT
FREQ
REF*
TRAK (Simulcast Site
Reference)
BNC
1 In an Analog or ASTRO
®
25 simulcast
configuration, this input is connected to
an external reference signal source
(TRAK 9100) to drive an internal oscilla-
tor for precise frequency stability. The
source can be 5 or 10 MHz.
2 In an ASTRO
®
25 simulcast (TRAK
9100) or ASTRO
®
25 site repeater
(TRAK 9100 or TRAK 8835) configura-
tion, it is used as an input connected to
an external reference, which provides a
composite 5 MHz + 1 PPS signal
source to drive an internal oscillator for
precise frequency stability and provides
a time reference for precisely launching
ASTRO
®
25 signals over the air.
1 PPS* TRAK 9100 (Simulcast
Site Reference)
BNC This input is used when a composite 5
MHz + 1PPS signal source is not used. It is
connected to an external 1 PPS time refer-
ence source to provide an accurate time
source used for precisely launching AS-
TRO
®
25 signals over the air. This input is
used in conjunction with EXT FREQ REF
option 1.
* See GTR 8000 Base Radio Time and Frequency Inputs
on page 158.
NOTICE: The EXT FREQ REF input on the rear of the device is high impedance. Use an
external termination to properly terminate the cable connected to the input. It is recommended
that a BNC "T" and a 50 Ohm BNC termination is connected to the input to terminate the cable.
If the cable is daisy chained (multiple base radios connected together and driven by one
TRAK/PSC output), only the last base radio in the chain has the termination.
3.4.7
GTR 8000 Base Radio Rear Connections (HPD)
The base radio connects with each of the site controllers and to the transmit and receive paths.
MN003286A01-H
Chapter
3: GTR 8000 Base Radio Installation
109