ANTENNA
INPUT
CD CHANGER
INPUT
RADIOS
SYSTEM
BUS
CAR AM/FM
AMPLIFIER
975A
Model 975A AM/FM Distribution Amplifier
Installation Instructions
The Model 975 is a 12-volt powered AM/FM antenna amplifier designed to drive car radio antenna distribu-
tion systems. It also accepts the RF output of one or more CD changers. Your Car RF system can be expanded
to serve up to 32 radios using Audio Authority
®
KIT17s. Each KIT17 contains a 4-way tap and Motorola
cables for 4 radios. If you need to distribute RF to more than 32 radios, call Audio Authority at 800-322-8346
or 859-233-4599.
Installation
Mount the Model 975A close to the radios and switching system and connect as shown in Figure 1. Place each
4-way tap within 2 to 3 feet of the radios it serves. Connect the distribution system as shown in Figure 2,
tightening all F-connectors securely. Be sure to add the termination plug to the last tap in the system as
shown.
Caution
: Prevent unused Motorola cables from contacting live conductors inside the display.
In Access
™
switching systems, power the Model 975A from the Access
™
System Bus like any other Access EZ
™
module.
In non-Access
™
System applications, plug a length of Access
™
System Bus
cable into the System Bus port. Connect the red wire to a source of 12V (+)
DC and cut off the other three wires (ground is supplied through radios).
An indoor antenna will suffice for
input to the Model 975A in most cases.
Use either the included wire antenna
or a car antenna. Plug the antenna
directly into the antenna jack of the
Model 975A as shown in Figure 1. If
an indoor antenna produces too little
FM signal or too much multipath
distortion, an outdoor antenna may be
desired. Use an omnidirectional FM
antenna if the only problem is a weak
FM signal, or use a directional FM or
VHF TV antenna to improve
multipath problems. Bring the 75-ohm
downlead from the outdoor antenna
into the building via a well-grounded
lightning arrestor as shown in Figure
2. Install a Motorola plug on the cable
going to the Model 975A’s antenna
jack or use an F-to-Motorola adapter.
NOTE: Outdoor antennas will reduce
AM performance.
From CD Changers
Car Antenna
To Radios
System Bus from any Access
™
Module
Figure 1. Model 975A Hookup
Details. Use one of these
indoor antenna options, or an
outdoor antenna, as shown in
Figure 2.
Yellow wire on
this side
Included Wire
Antenna
