2.3.3.2
Communication Links
Transmission line between the transmitter/receiver and the antenna shall be
50-ohm impedance rated for the transmitter output power. As a minimum,
cable shall exhibit an attenuation not exceeding 1.1 dB per 30.5 m 100 feet
at 200 mHz.
2.4
FIRE ALARM SYSTEM PERIPHERAL EQUIPMENT
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NOTE: Check the terrain and distances to determine
if a repeater will be needed to transmit a signal
from a remote location to the main control console.
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2.4.1
Repeaters shall be provided where indicated or required to meet system
requirements. The repeater shall receive on [_____] MHz and transmit on
[_____] mHz. The receiver and transmitter sections shall conform to the
requirements specified for transceivers. Two-way data transmission shall
be relayed between the base station and remote stations. Repeater shall
utilize a bandpass-type duplexer and one antenna, or multiple-bandpass
cavity filters and multiple antennas. The duplexer or filter cavities
shall isolate the receiver from transmitter spurious noise and prevent
receiver desensitization. The duplexer or filter cavities shall be rated
to handle the output power of the transmitter. Repeater shall be keyed
with tone-encoded control circuit. A transmitter time-out circuit shall be
provided to prevent system lockup.
2.4.2
Radio Fire Alarm Transmitter Box Location Light
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NOTE: Use with fire alarm boxes only. Delete
paragraph where a light is not required. Do not use
for radio fire alarm transmitters that operate on
batteries only.
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Each indicated transmitter providing publicly accessible actuating
functions shall be provided with a vapor-tight, incandescent type light
fixture constructed of a flame retardant, nonplastic, polycarbonate
material with a threaded ruby globe. The light shall be supported with 15
mm 1/2 inch galvanized steel conduit and located approximately 300 mm 1 foot
above the box. The light shall be provided with an incandescent, 50-watt,
120-volt extended service lamp. Transmitters which are powered by battery
only shall not be equipped with location lights.
2.4.3
Conduit
Conduit and fittings shall comply with UL 6, UL 1242, and UL 797.
2.4.4
Ground Rods
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NOTE: Designer will determine the size, type, and
number of ground rods to be used based on local
conditions, earth resistivity data, and on the size
and type of the electrical installation.
SECTION 13852A
Page 17
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