User's Manual

Weehawken Tunnel VHF Repeater System
User/Maintenance Handbook
Handbook N.-Weehawken_VHF Issue No:-A Date:-05/08/05
Page:-
24 of 75
4.2 VHF Duplex BDA (55-154801)
4.2.1 VHF Duplex BDA Description
The duplex shelves are part of the VHF amplification and like the simplex shelves, have
crystal filters instead of bandpass filters to set bandwidths. There are two downlink bands
and three uplink bands, the downlink paths having isolators fitted to each of the 5Watt
output stages to prevent reflections from interfering with the other channel.
The uplink channel module has a dedicated noise muting circuit fitted externally to the
channel module which operates when the downlink path is active.
All amplifiers have built-in alarms which are configured as a summary, volt-free relay
contact pair terminating at pins 1 & 2 on the ‘D’ type alarm connector.
4.2.2 VHF Duplex BDA Electrical Specification
PARAMETER SPECIFICATION
153.75-155.3MHz (Downlink1)
159.0-161.0MHz (Downlink2)
153.75-155.3MHz (Uplink1)
158.85-159.3MHz (Uplink2)
Frequency range:
161.5-162.0MHz (Uplink)
Gain: >90dB
Gain Adjustment: 0 – 15dB (in 1dB step)
Uplink Power: >5.0Watts
Downlink Power: >5.0Watts
Uplink +48dBm
IP3:
Downlink +48dBm
Noise Figure: <6dB
AGC level: -2dBm (uplink & downlink)
23dB (downlink)
Channel module gain:
24dB (uplink)
VSWR: better than 1.5:1
RF Connectors: N type, female
operational:
-10°C to +55°C
Temperature range:
storage:
-40°C to +70°C
1 U/L amplifiers
2 D/L amplifiers
Alarms Fitted:
(volt-free contacts/TTL)
3 Channel modules