User's Manual

Tetrapol Band Selective Repeater
User Handbook
Handbook Nō.-55-124801HBKM Issue No:-1
Date:-22/01/2004
Page:-
10 of 32
2. OVERVIEW/SYSTEM DESCRIPTION
The AFL Band Selective Cell Enhancer is a 2-way on-band repeater. Various models are
available to cover frequency bands from 50MHz to 3000MHz with power levels up to
100Watts. Its main sphere of applications is in urban areas where the topology is such that
shadows occur in the propagation pattern (for example within large buildings, conference
centres and tunnels, etc.)
The Band Selective Cell Enhancer is a 2-port device for direct connection to two antennas,
usually a highly directional Yagi or similar aligned towards the base (donor) site and an
omni-directional or leaky feeder antenna to cover the mobiles. The frequency bands that
are passed by the Cell Enhancer are set as per the specific customer requirements.
AFL manufacture a wide range of Cell Enhancers, configured for each customer's specific
requirements. Two basic physical variants are available, a rack mounted version to fit in a
standard 19" rack and an environmentally sealed wall mounted version which requires no
further enclosure.
This system consists of a bi-directional band selective, cell enhancer operating in the
390MHz band. It is housed in a wall-mounted environmentally protected (IP65) case
powered from an externally supplied 24Volt DC source. Alarms are provided for each
amplifier as a summary, volt-free relay contact pair for easy integration into an existing
alarm system. A supply isolator switch is fitted inside the unit and there are D.C. and
Alarm on indicators on the outside of the door.
An automatic gain control system is employed in the uplink path in an attempt to negate
the overloading effect from mobiles operated close the antenna.