Handbook
Axell Wireless Limited
Technical Literature
WMATA CRCS Redundant Antenna System
General Overview
Document Number 60-228701HBK Issue No. 3 Date 28/05/2010 Page 45 of 114
4.7. Splitter/Combiner Unit 60-228702
Splitter/Combiner Unit 60-228702 is built into a 2U, 19” rack-mount case.
Band 1 Downlink RF from 8 Ch. Squelch Gated BDA 60-228704 enters the Splitter/Combiner Unit via the N
type port labeled “A” (annotated “A” in section 4.7.4.) and passes into the Downlink 3dB Splitter/Combiner
05-002603.
Band 2 Downlink RF from 8 Ch. Squelch Gated BDA 60-228705 enters the Splitter/Combiner Unit via the N
type port labeled “B” (annotated “B” in section 4.7.4.) and also passes into the Downlink 3dB
Splitter/Combiner 05-002603 which combines the two Downlink paths and the combined path then passes
through the Downlink Variable Switched Attenuator 10-000901 (annotated “A” in section 4.7.5.) which can
provide up to 15dB of signal gain (in 1dB steps) if required; the attenuation value is controlled by the four
toggle switches on the attenuator body; each switch is clearly marked with the attenuation it provides, and
the total attenuation in-line is the sum of the values switched in.
After passing through the Downlink attenuator the Downlink signal exits the Splitter/Combiner for Dual Fiber
Optic Unit 60-228703 via the N type port labeled “TX” (annotated “C” in section 4.7.4.).
Uplink RF from Dual Fiber Optic Unit 60-228703 enters the Splitter/Combiner via the N type port labeled
“RX” (annotated “D” in section 4.7.4.) and the Uplink signal passes through the Uplink Variable Switched
Attenuator 10-000701 (annotated “B” in section 4.7.5.) which can provide up to 30dB of signal gain (in 2dB
steps) if required; the attenuation value is controlled by the four toggle switches on the attenuator body;
each switch is clearly marked with the attenuation it provides, and the total attenuation in-line is the sum of
the values switched in.
After passing through the Uplink attenuator the signal path passes into the Uplink 3dB Splitter/Combiner 05-
002603 which splits the signal into two equal paths, One path (Band 1) exits Splitter/Combiner Unit 60-
228702 for 8 Ch. Squelch Gated BDA 60-228704 via the N type port labeled “C” (annotated “E” in section
4.7.4.) and the second path (Band 2) exits Splitter/Combiner Unit 60-228702 for 8 Ch. Squelch Gated BDA
60-228705 via the N type port labeled “D” (annotated “F” in section 4.7.4.).
4.7.1. Splitter/Combiner Unit 60-228702 List of Major Sub-Components
Component
Part
Part Description Qty Per
Assembly
05-002603 3dB Splitter/Combiner 2
10-000701 Variable Switched Attenuator 0-30dB 1
10-000901 Variable Switched Attenuator 0-15dB 1
4.7.2. Splitter/Combiner Unit 60-228702 Specification
PARAMETER SPECIFICATION
Downlink
Frequency range
Band 1, 489.5MHz to 491.0MHz
Band 2, 496.3MHz to 496.7MHz
Switched attenuator
0dB to 15 dB in 1dB steps
Uplink
Frequency range
Band 1, 492.5MHz to 494.0MHz
Band 2, 499.3MHz to 499.7MHz
Switched attenuator
0dB to 30 dB in 2 dB steps