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KOALATYAUSTRALIA

AM/FM rebroadcast with audio break-in

Broadcast radio carried through the bore so drivers keep the station they entered on, and an override that interrupts every carried service with a live announcement from the tunnel control room.

RFI's rebroadcast range covers road and rail tunnels, mines, underground car parks and any structure where broadcast coverage is lost. Audio break-in places live or pre-recorded announcements onto the rebroadcast RF output for incident control and public safety. Koalaty Australia supplies the range across Asia and EMEA.

SERVICES CARRIED
AM, FM, DAB+
FM HEADEND
87.5 – 108 MHz
DAB HEADEND
174 – 230 MHz
DISTRIBUTION
Radiating cable
BREAK-IN
Live or pre-recorded

PRINCIPAL PARTS

System schematic

LONGITUDINAL SECTION — NOT TO SCALE

Select a numbered callout to see the equipment at that position and its published specification. Keyboard: tab to a callout, press Enter.

Road tunnel AM/FM rebroadcast systemLongitudinal schematic showing an off-air receive antenna and headend building at the portal, feeding a radiating cable that runs the length of the tunnel bore with in-line amplifiers and a cross-passage antenna.GROUND LEVELCARRIAGEWAY — BORE LENGTH 2 140 mEQUIPMENT ROOMRADIATING CABLE 1-1/4"TO TUNNEL CONTROL ROOMCallout 1 — Off-air receive antennaSide-mounted dipole on a mast at the portal, receiving broadcast services for re-radiation.1Callout 2 — FM rebroadcast headendRack mounted DSP-based FM rebroadcast headend in the portal equipment room.2Callout 3 — AM headend and audio break-inAM rebroadcast headend with the override that interrupts all carried services.3Callout 4 — Cross-band couplerCoupler combining AM/FM and VHF/UHF onto the single radiating cable run.4Callout 5 — Radiating cableLeaky feeder run at crown height along the full bore, the primary distribution element.5Callout 6 — In-line amplifier stationBi-directional amplifier in a bore-mounted enclosure, spaced to hold the design signal level.6Callout 7 — Cross-passage antennaLow-PIM dipole covering cross passages and egress routes off the main bore.7Callout 8 — Monitoring and alarmsLevel and fault monitoring reported to the tunnel control room over the operator network.8
CALLOUT 01ANT-01

Off-air receive antenna

Side-mounted dipole on the portal mast, custom tuned across band II to receive the broadcast services nominated for re-radiation.

SUPPLIED PRODUCT
SMD1-99
VHF Side Mounted Dipole, 66–108 MHz
FREQUENCY
66 – 108 MHz
POWER
300 W
TERMINATION
N female, RG213 tail
TUNED BANDWIDTH
10 %
SYSTEM
Road tunnel
VIEW
LONGITUDINAL SECTION
CALLOUTS
8 positions
PARTS CITED
8 of 8

Where this applies

  • 01Road tunnels long enough that broadcast reception is lost and an emergency announcement path is required.
  • 02Cut-and-cover underpasses and covered motorway sections where an existing service drops out mid-run.
  • 03Retrofit into an operating tunnel, staged in night possessions alongside an existing emergency services system.
  • 04Shared radiating cable infrastructure carrying broadcast, emergency services and operator radio on one run.

Equipment in this system

Every numbered callout on the schematic names a real RFI part. Select a callout to open its published specification, or browse the full range in the catalogue.

Browse the product catalogue

Request a quote

Send the part numbers and quantities you need. If you are working from a specification or a bill of materials, attach it in your reply to our acknowledgement and we will price it as listed.

TERRITORY
Asia and EMEA
BRANDS
RFI · ANDREW · RFS

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