User's Guide

Maintenance Handbook (1)
Baltimore Radio Repeater System
Handbook No. 60-166101HBKM Page 8 of 33
3.1 Master Site Equipment
3.1.P Master Site Photographs
3.2 PRESTON (60-166301) & OCC (60-166401) Master Sites Description
The equipment is divided into functional parts;
The Master Site equipment is supplied in two, 43U standard size (19”) rack cabinets with eight
shelves containing all the electronics to fulfil the required coverage. There is an off-air channelised
amplifier which feeds seven fibre transmitters for remote RF distribution with a complementary uplink
path from the remote sites being received in the same shelf by seven FO receiver/modems. The
master site also has the ability to vary the RF attenuation to each path remotely, via a binary
switching arrangement with the actuating wiring being available on a ‘krone-block’ connector mounted
in the lower rack space.
The two master sites are very similar and so only the PRESTON site will be specified – the two parts
lists are identical.
Alarms are provided for all the active modules, individually and in summary form as volt-free normally-
closed relay contacts.
3.3 Master Site Technical Specifications
PARAMETER SPECIFICATION
494.3-495.3MHz (Downlink)
Frequency range:
497.3-498.3MHz (Uplink)
Bandwidth: 1.0MHz
Number of FO RX outputs 7
Number of FO RX inputs 7
Number of RF channels: 15
Downlink air interface gain: 55dB
Uplink air interface gain: 75dB
Manual Gain Adjustment: 0-15dB (in 1dB steps)
Remote gain adjustment: 0-15dB (in 1dB steps)
Rejection at opposing band: > 60dB
Downlink1dB Compression Point: > +42.5dBm
Downlink 3
rd
Order Intercept Point: > +56dBm
Uplink 1dB Compression Point: > +30.5dBm
Uplink 3
rd
Order Intercept Point: > +43dBm
Noise Figure: <6.0dB at any gain setting
Impedance: 50 ohms
RF Connectors: N type, female
Power Supply: 110V AC (nominal)
Power consumption: <8A ( @ 12V)
operational:
-10qC to +60qC
Temperature range:
storage:
-40qC to +70qC