reserved for DOD use. Frequencies in the 162 to 174
MHz and 450 to 470 MHz bands are shared with other
users on a first-come, first-served basis. In order
to avoid potential contract delays, the frequency
assignment should be included in the specification
when possible. For additional information, contact
the base radio officer or the Naval Electromagnetic
Spectrum Center at (202) 433-0689, OPNAVINST
2400.20E issued by OPNAV Code N60 (previously Code
OP941), telephone (703) 695-7284.
**************************************************************************
System shall be a full duplex supervised RF polling specifically designed
for alarm data communications with components manufactured by one
manufacturer. System shall operate in the VHF, 134 to 154 MHz band. System
shall interface directly with IDS hardwire data link from control unit to
central alarm reporting and display location and shall translate (reduce)
the data rate for RF transmission, modulate and demodulate the data signal,
and transmit and receive IDS data. Provide a factory-tested complete RF
link which both automatically and upon operator command transmits a signal
with a unique identification from the central alarm monitoring location to
the control unit locations. Message receipt at control unit location shall
be ignored by all units except the addressee. Unit with the correct address
shall decode the interrogation signal and respond to the interrogation with
the status of the reporting sensors. When the addressee fails to respond,
reinterrogate. Failure to respond a second time shall cause a line
supervision alarm. Remote units in the RF system shall be individually
polled in turn. Polling response time and transmission data rate, data
error rate, and equipment reliability shall ensure that overall IDS alarm
annunciation time reliability and Ps is not degraded. Provide RF
transmitters, receivers, or transceivers in sufficient quantities to meet
specified requirements. RF link transmissions shall be on one or more of
the frequencies within the specified band as required to meet specified
requirements and shall neither interfere with other IDS components nor any
facility electronic components. Provide transmitters which are in
accordance with applicable requirements of 47 CFR 15. Message types and
content shall be identical to those transmitted by other portions of the
IDS data communications subsystem. IDS alarms sent by RF link shall not
fail to be transmitted by the RF link due to event occurrence during "off
air" periods. RF link shall provide message transmission priority in the
following order:
a.
Intrusion alarms
b.
Tamper alarms
c.
Access denial alarms
d.
Other alarms on a first-in, first-out basis including loss of
communication signal, fail-safe, low battery, and power loss.
Provide [omnidirectional, coaxial, half-wave dipole] [_____] antennas for
alarm transmitters and transceivers with a driving point impedance to match
transmission output. Antennas and antenna mounts shall be corrosion
resistant and designed to withstand wind velocities of [160] [_____] km/h
[100] [_____] mph and physical damage caused by vandalism.
Antennas
shall not be mounted to any portion of the facility fence or roofing
system. Antennas shall be furnished by the same manufacturer as the rest
of the RF link. Provide coaxial cable in lengths as required. Cable shall
SECTION 13703N
Page 45
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