User's Manual

Bronx Justice Centre Radio Repeaters
Handbook Number: 80-283501HBKM Page: 8 of 86
3. EQUIPMENT OVERVIEW
3.1 System Description
The New York Justice Centre needs three different frequency bands of radio coverage within its
designated areas, each having specific channel allocations, some of which are simplex type, i.e. Tx &
RX on a single frequency, and some duplex where the Tx & Rx are on two different frequencies so
that both parties may transmit (or receive) simultaneously.
The AFL equipment supplied for this task is in several different parts:
VHF Channel selective Cell Enhancer 150MHz band, 5 channels (50-146501)
UHF Channel Selective Cell Enhancer 400MHz band, 6 channels (50-146601)
800MHz Channel Selective Cell Enhancer 800MHz band, 2 channels (50-146701)
Multi-Band Combiner All three frequency bands (80-146705)
All the cell enhancers have two switched attenuators in each path, a 0-30dB device to adjust the
signal level entering the channel selective module, and a 0-15dB unit which varies the output power
(after the channel module) that drives the leaky feeder antennas. In this way the system may be finely
tuned to both receive and transmit at the correct levels.
Each cell enhancer will be described separately in this document but where enhancers have common
modules, these will be detailed only once.
An alarm system is fitted that monitors all active devices and is easily integrated into any series ‘loop’
type system (where any break will trigger an alarm and show a local fault LED in the area where the
fault originated).