Sydney Harbour Tunnel's AM/FM rebroadcast upgrade

Trantek MST chose RFI to supply a rebroadcast system for the Sydney Harbour Tunnel intelligent transport system upgrade project.

Sydney-based company Trantek MST was given the task of designing and installing an upgrade to the intelligent transport system (ITS) of one of Sydney's busiest transport routes, the Sydney Harbour Tunnel. The project involved upgrading the AM/FM radio rebroadcast system, providing audio break-in capabilities, ensuring compatibility for a future DAB+ digital radio upgrade and implementing a performance monitoring capability.

The AM/FM radio rebroadcast system is a relatively minor, but vital, component of the ITS — not only to maintain the rebroadcast of AM and FM radio stations within the tunnel, but also to ensure that vital incident management capabilities can be maintained in the event off a subsystem failure.

An audio break-in capability enables prerecorded or live audio announcements to be inserted into the AM and FM rebroadcasts to notify drivers of incident information via their car radios.

Trantek MST sought a partner that could design, install and commission the rebroadcast system upgrade as a turnkey subcontractor and meet stringent operational requirements.

Trantek MST selected RFI to provide the rebroadcast system due to the latter's experience and expertise with this technology. RFI delivered a flexible and feature-rich system utilising a comprehensive suite of its products and services, including RF surveys, system design, equipment manufacture, integration, factory acceptance testing, installation, commissioning, site acceptance testing and coverage testing.

“We chose RFI because of their proven technical, manufacturing, installation and integration capabilities," said Trantek MST Managing Director Lionel Ascone.

“They have provided the Sydney Harbour Tunnel with an upgraded rebroadcast system that has met the customer's operational requirements, whilst also providing a feature-rich capability that allowed us to incorporate it into our fault-resilient intelligent transport control system."

The key components of the upgrade were:

• rebroadcast AM and RM repeaters;
• broadband multicarrier power amplifiers;
• AM/FM crossband couplers;
• a custom-manufactured RF changeover unit enabling switching between the redundant subsystems, either manually or automatically by Trantek MST's fault-resilient ITS system;
• performance monitoring of the radiating cables at both ends of both tunnels, implemented to continuously monitor the performance of the system and contribute to the switching control of the system redundancy in the event of a fault condition; and
• fibre-optic cable to link equipment in the various installation locations.

RFI's project manager actively liaised with Trantek MST and Sydney Harbour Tunnel personnel during the project. Working closely with Trantek MST and its customer enabled several unexpected issues that arose to be addressed and resolved with minimal impact to the customer's operations and tunnel motorists.

“RFI performed well within the often challenging multidisciplined environment that exists in a major project and has delivered their system to the project on budget, assisting Trantek MST to deliver another successful project to its customers," said Ascone