Installation Advisory - Firecom 3000C Installation & Operation Manual

DON'T
DO
IMPORTANT
4.
I N S T A L L A T I O N A D V I S O R Y
Firecom Apparatus Intercom Systems have been successfully installed in various fire
apparatus for several years. During the last year, we have experienced increasing cases of
alternator noise making its way into these systems. Because of the high load demands in
some apparatus, alternators have to work harder, and in some cases, can be undersized for
the growing load. When this occurs, the alternator injects noise on the DC power lines. The
combination of an over-loaded alternator, radio equipment interfaced to an intercom
system, and RF emissions can enhance noise that is already present but not normally heard.
In some cases the alternator may need to be replaced.
Careful attention should be paid to microphone ground references, wire splices, and wires
that run near other high emission equipment, such as radios, antennas, antenna coax, strobes
and computer cables. Contact your local Firecom Dealer if you have any questions
regarding installations and wire connections.
Here are a few tips that could help in subduing alternator whine problems:
DON'T
• Bundle up headset wire runs (CA Cables).
• Run headset wires near antennas, antenna coax or near other equipment and their
cables.
• Leave splices exposed.
• Connect mic low from radios to chassis ground.
DO
• Use crimped connectors for any wire splices.
• Run headset wires (CA Cables) against the chassis when possible.
• Connect intercom power to the same connection points as the radio equipment.
• Monitor the power connections at the intercom with an AC Voltmeter for less
than a 300 mV AC signal. Check this signal with the engine running at idle, and
with the engine fully under load.
• Check for a bad diode in the alternator.
The sections in this manual on System Orientation (page 1), Pre-Installation
(page 5) & Installation (page 10) should be read and understood BEFORE
proceeding with the installation!!!!!