User's Manual

Weehawken Tunnel Remote Repeater
User/Maintenance Handbook
Handbook Nō.-Weehawken_River_P Issue No:-A
Date:-05/08/05
Page:-
22 of 36
5.3 Crossband Coupler (07-005705)
5.3.1 Description
The purpose of a crossband coupler is to either combine/split transmission signals from
different parts of the frequency spectrum.
It basically comprises of a 3 port device, two filters, one a low pass, the other a high pass
feeding a common output. In this case, a VHF spectrum signal source is to be combined with a
band 2 FM source, (many other combinations are also possible). The couplers are built into a
machined aluminium casing having a centre screening wall between the filter sections and lid
secured by screws at frequent intervals over its perimeter to obtain a tight seal and to ensure
linearity and stability of response.
5.3.2 Technical Specification
PARAMETER
SPECIFICATION
250 MHz:
Passband
380 MHz:
70-250MHz
380-960 MHz
Power Rating: 50 Watts (CW)
Number of Input ports: 2
Number of Output ports: 1
Insertion loss: 0.5 dB
Isolation:
> 50 dB 70-250MHz
> 50 dB 380-960MHz
(15 dB typical Return loss 500-960)
Impedance: 50 ohm
Connectors: SMA- female
5.4 ¼Watt 0- -30 & 0-15dB Switched Attenuator (10-000701 & 10-000901)
5.4.1 General Application
In many practical applications for Cell Enhancers etc., the gain in each path is found to be
excessive. Therefore, provision is made within the unit for the setting of attenuation in each
path, to reduce the gain.
5.4.2 Switched Attenuators
The AFL switched attenuators are available in two different types; 0 – 30dB in 2 dB steps, or 0
– 15dB in 1 dB steps. The attenuation is simply set using the four miniature toggle switches on
the top of each unit. Each switch is clearly marked with the attenuation it provides, and the total
attenuation in line is the sum of the values switched in. They are designed to maintain an
accurate 50Ω impedance over their operating frequency at both input and output.