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2.0
EQUIPMENT OVERVIEW / DESCRIPTION
MBTA System Wide Radio Tunnel Antenna Distribution System provides extended radio
coverage within MBTA rail transit tunnels. The new tunnel antenna system is a two-way
communication system consisting of 400 MHz base transceiver stations, 800 MHz base
transceiver stations, antennas, radiating cable, fiber optic cable and BDAs. Both the 400
MHz and 800 MHz systems operate independently. The 400 MHz system operate as a
conventional analog voice communication system and the 800 MHz system operate as a
digital trunked radio system for voice and data communications. Radio signals routed
from the base transceiver stations to the BDAs are performed via fiber optic cable. Once
the optical signal is received by the BDA, it is converted back into an electrical (RF)
signal, amplified and transmitted throughout the tunnel antenna distribution system. For
RF signals transmitted within the tunnel, they are received by the BDA, amplified,
converted into a optical signal and sent via fiber cable to the base transceiver stations.
Each BDA is designed for a 19" rack mount cabinet and is equipped with interchangeable
modules. These modules are field replaceable by removing them from the front chassis
of the BDA. The modules consist of a downlink amplifier, uplink amplifier, high
isolation duplexer, low isolation duplexer (400 MHz RF fed BDA only), fiber optic
transceiver (fiber fed BDA only) and a AC to DC power supply. and alarm module
(Optional Equipment). All BDA controls are performed via a RS232 connector located
on the front panel of each amplifier module.
Each BDA has 30 dB of gain adjustment for both the uplink and downlink RF path. This
adjustment is varied electronically thru the amplifier modules' front panel RS232
connector. Additionally, each of the amplifier modules are equipped with an Automatic
Level Control (ALC) circuit which can limit the maximum power level produced by the
BDA.
OPTIONAL EQUIPMENT
An alarm module is available as an option to serve as a central communication agent to
monitor the status of each module and send a summary alarm to remote locations via the
fiber optic transceiver module.
3.0
SPECIFICATION
DWG NO:
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(Not Used By MBTA)
400/800 MHz Fiber Optic & RF Fed Bi-Directional
Wireless Innovations Group
2601 Telecom Parkway
Richardson, Texas 75082
Rev:
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link.
Amplifier Operations / Maintenance Manual
Date:06/16/2004
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