User Manual
Table Of Contents
- AMENDMENT LIST RECORD SHEET
- INTRODUCTION
- 1.SAFETY CONSIDERATIONS
- 2.OVERVIEW/SYSTEM DESCRIPTION
- 3.SPECIFICATION
- 4.SYSTEM DRAWINGS
- 5.SUB-UNIT MODULES
- 5.1VTA Downlink Duplexer Shelf 60-025302 (4U chassis)
- 5.2VTA Downlink Amplifier Shelf (50-025303, 8U Chassis)
- 5.2.1UHF 3dB Splitter (05-002603)
- 5.2.2¼Watt 0- -30dB Switched Attenuator \(10-00
- 5.2.3Low Noise Amplifier (11-006102)
- 5.2.4Low Noise Amplifiers (11-007302 & 11-007402)
- 5.2.4.1Description
- 5.2.4.2Technical Specification, (11-007302)
- 5.2.4.3Technical Specification (11-007402)
- 5.2.4.4Drg. No. 11-007302, LNA Assembly With Alarm Relay
- 5.2.4.5Drg. No. 11-007370, LNA RF Circuit Diagram
- 5.2.4.6Drg. No. 11-007371, LNA DC Wiring Diagram
- 5.2.5.7Drg. No. 11-003971, LNA DC Circuit Diagram
- 5.2.63 Stage Amplifier Alarm Boards (12-002201)
- 5.2.7450MHz 20W Power Amplifier (12-004201)
- 5.2.8Single DC/DC Converter (13-001702)
- 5.2.924V Single Relay Board (80-008902)
- 5.2.1024V 410W Power Supply (96-300054)
- 5.3VTA Downlink Channel Shelf (50-025304)
- 5.4VTA Uplink Duplexer Shelf (50-025305, 4U Chassis)
- 5.5VTA Uplink Amplifier Shelf (50-025306, 8U Chassis)
- 5.5.120Watt Class A Power Amplifier (12-016301)
- 5.5.2Automatic Gain Control (17-001101, Det. & 17-001201, Atten.)
- 5.5.2.1Description
- 5.5.2.2Technical Specification
- 5.5.2.3Drg. No. 17-001101, ACG Detector Assembly
- 5.5.2.4Drg. No. 17-001171, AGC Detector Circuit Diagram
- 5.5.2.5Drg. No. 17-001171C, AGC Detector Parts List
- 5.5.2.6Drg. No. 17-001201, AGC Attenuator Assembly Drawing
- 5.5.2.7Drg. No. 17-001270, AGC Attenuator Circuit Diagram
- 5.5.2.8Drg. No. 17-001270C, AGC Attenuator Parts List
- 6.INSTALLATION
- 7.MAINTENANCE
- APPENDIX AINITIAL EQUIPMENT SET-UP CALCULATIONS
9 Way Channelised UHF Cell Enhancer
Maintenance Handbook
H/book Number:-50-025301HBKM
Issue No:-
1
Date:-04/07/2003
Page:-
19 of 69
5. SUB-UNIT MODULES
5.1 VTA Downlink Duplexer Shelf 60-025302 (4U chassis)
5.1.1 Bandpass Filters (02-011204 & 02-013401)
5.1.1.1 Description
The bandpass filters are multi-section designs with a bandwidth dependent upon the
passband frequencies, (both tuned to customer requirements). The response shape is
basically Chebyshev with a passband design ripple of 0.1dB. The filters are of combline
design, and are carefully aligned during manufacture in order to optimise the insertion loss,
VSWR and intermodulation characteristics of the unit. The tuned elements are silver-plated
to reduce surface ohmic losses and maintain a good VSWR figure and 50 load at the input
and output ports.
Being passive devices, the bandpass filters should have an extremely long operational life
and require no maintenance. Should a filter be suspect, it is usually most time efficient to
replace the module rather than attempt repair or re-tuning.
No adjustments should be attempted without full network sweep analysis facilities to
monitor both insertion loss and VSWR simultaneously.
5.1.1.2 Technical Specification (02-011204)
PARAMETER SPECIFICATION
Passband 491.4-492.2 MHz
Insertion Loss 1.9 dB typical
> 485 MHz > 55 dB
Rejection
> 458-459 MHz > 60 dB
Power Rating 50 Watt
Impedance 50 ohm
VSWR Better than 1.2:1
5.1.1.3 Technical Specification (02-013401)
Passband 485.5875MHz
Insertion Loss 1.9 dB typical
> 492 MHz > 60 dB
Rejection
> 488-489 MHz > 55 dB
Power Rating 50 Watt
Impedance 50 ohm
VSWR Better than 1.2:1