Antenna Systems

10.2.1 Standards, Specifications and Drawings

type

Document Title Document

Number

Specification Tunnels Engineering Standard ESC 340 Standard Telecommunications Earthing and Surge

Protection Standard

ESM 109

Standard Insulation Coordination AS 1824.1 – 1995

10.2.2 Requirements

Wireless systems design shall include antenna systems to provide adequate coverage within tunnels, cuttings and the above ground rail corridor.

10.2.2.2 Mounting structure

Antenna systems above ground along rail corridor shall include foundation, building, antenna and mounting structure at each site as required. Design and components used for above ground infrastructure shall be compatible and common with existing designs.

10.2.2.3 Earthing

Earthing of base station huts and masts including antenna systems shall be in accordance with RailCorp specifications.

10.2.2.4 Radiating coaxial cable Earthing

Radiating coaxial cable shall float free of earth at all times. Devices such as earthing switches shall not be provided.

10.2.2.5 Tunnel Coverage

Wireless infrastructure coverage in tunnels shall be provided by radiating coaxial cable (leaky cables).

10.2.2.6 Radiating coaxial cable frequency compatibility

The leaky cable systems in the tunnel shall optimise performance at specific Ultra High Frequency (UHF) bands. 400 - 470 MHz for UHF radios, 1.8 GHz for DTRS and up to 2.1GHz for mobile phones.

10.2.2.7 Radiating coaxial cable loss

Radiating coaxial cables (leaky cables) shall be the constant system loss type, where signal strength output at one end is identical to signal strength output at the other end.

a) Radiating coaxial cables

b) Two separate Radiating coaxial cables (leaky cables) shall be installed at suitable locations within the tunnels and station areas where applicable.

c) Where technically feasible, the two leaky coaxial cables should be the same type of cable capable of handling between 400 MHz to 2.1GHz.

d) One of the two leaky coaxial cables is to be dedicated to RailCorp Radio systems.

10.2.2.8 Segments in Tunnels

Leaky coaxial cables in the tunnel shall be divided into segments in the up and down directions from respective station.

10.2.2.9 Compliance with fire regulations

The leaky coaxial cable and mounting hardware shall be of low smoke, fire retardant and zero halogen type.

10.2.2.10 Safe locations and installation

a) The antenna systems installed shall be operationally safe. Electromagnetic emission from the antenna system shall comply with relevant ARPANSA frequency exposure standards.

b) No part of the radiating system shall be located directly underneath live parts of the overhead system or where there is a reasonable probability that parts of the overhead system might fall on it as a result of failure or damage.

c) All electrical parts forming the radiating system shall be physically located out of normal reach of rail staff and passengers, and suitably protected in areas where mechanical damage might occur (for example due to ladders being carried or rested against a wall).

d) Antenna systems (excluding leaky coaxial), mast, or poles shall be designed to maintain a clearance of at least 3m from the nearest rail or traction power structure or overhead wire at all times including while conducting service activities.

10.2.2.11 Radiating coaxial cable safe locations and installation

a) Radiating coaxial cable (leaky cable) shall be located at safe locations with adequate separations between the cables, out of reach by the public and a minimum clearance of 300mm from the overhead 1500Vdc power lines.

b) Radiating coaxial cable (leaky cable) shall be supported in accordance with the manufacturer's recommendations.

c) Spacing of cable supports shall be sufficiently close that sag does not exceed 100 mm

d) Radiating coaxial cable (leaky cable) shall be retained using non-flammable materials (e.g. stainless steel cable tie) at pre-determined intervals to prevent the cable from falling down in the event of a fire in that section of the tunnel.

10.2.2.12 Aesthetics

Antennas in public area shall be aesthetically compatible with its surrounding building structure and design.

10.2.2.13 Sub systems

The antenna systems shall include multicoupling subsystems for transmitters and receivers to include combiners, splitters, filters, diplexer, isolators, amplifiers and associated components to combine different frequencies into antennas and radiating coaxial cable (leaky cable).

10.2.2.14 Splitters

Where splitting of the signal is required to connect more than one radiating cable to the base station, or one or more radiating cables and an antenna, the isolating device(s) and the splitter shall be installed together in a sealed non-conductive housing.

10.2.2.15 Interference

There shall b e no interference between all radio, wireless, and mobile phone services.

10.2.2.16 Lightning protection

Above ground antenna system shall include lightning protection.

10.2.2.17 Installation procedure

Installation procedure for the radiating antenna cable used in the tunnel shall be as used for the RailCorp City underground network.

10.2.2.18 Isolation

• An isolating device shall be provided to separate the radiating system from the base station equipment.

• Electrical isolation shall be provided by an isolating device (capacitive or transformer) installed between the radiating system and the base station.

10.2.2.19 Radiating coaxial cable Isolation

Radiating cables shall not be brought into equipment rooms.

10.2.2.20 Isolation specification

• Isolating device shall be rated to withstand 2kV continuously and 5kV for a period of 1 min.

• The isolation level shall be in accordance with IEC 820.3 Protection Level Class 3

10.2.2.21 Insulation

Insulation performance of the radiating system shall be tested after installation in accordance with relevant clauses of AS 1824.1 Insulation Co-ordination