airports
This car is driven by the team leader of the traffic department, airport operations, who is responsible for controlling traffic on the tarmac throughout the airport and for attending to any emergency. On the dashboard is an array of communications and GPS equipment. The task includes ensuring that the runway is safe and clear of debris. A friction tester carried by the car is used to determine whether the runway has become slippery
a central Dimetra IP switch cover the whole airfield, right out to the perimeter fence and to some distance beyond. Overlapping coverage between the base stations helps to ensure that communication will be maintained even if one of them fails; users’ radios will simply roam to another station.
Each base station transmits five TETRA radio carriers, four for voice and one for data only. Tese provide 15 channels for voice traffic at each site. Michael Zaddach comments that this large capacity might seem somewhat luxurious in times of normal operation, but it becomes very important when the airport is under stress – for example, in adverse weather, when flights are delayed, or when there is an alarm condition. Within the airport buildings, a comprehensive indoor distribution system incorporating radiating cables (‘leaky feeders’) ensures excellent radio coverage even on the underground levels of the terminals. In addition, the TETRA network is interconnected with the telephone system and with control centre applications for the airport’s security and fire service. It also includes some dispatcher workstations – including two PC stations for dispatching the passenger shuttle buses – and interfaces for voice recording. Plans exist to enlarge the system with a further TETRA base station to the north if the third runway is built. With the IP-based Dimetra system, installing it is likely to be a fairly simple task.
Service structures Users across the airport campus buy their radio service on a subscription plan with three levels of service – economy, business and premium. Tey are offered a choice of Motorola TETRA terminals – a handportable and a vehicle-mounted radio, with or without GPS. On top of this, users can choose their grade of network access: basic radio communications only, radio plus internal telephone interconnect, external telephone calls, data services. Prices on this menu begin at €52 per month for a basic
‘economy’ radio service – a rate which, as Michael Zaddach freely acknowledges, is noticeably more than an ordinary
Issue 1 November 2010 - February 2011 TE TRA TODAY
mobile phone would cost. “Many people ask us, ‘Why is it so expensive?’”, he says. “And that’s a big problem for us, especially for users that need no very high availability and reliability and so on. But we have set up an airport usage policy – and we have set up a clause in this policy that everyone who is on the apron needs a TETRA device, especially for emergency situations.” In such an emergency, he says, a user carrying only a mobile phone might be out of contact, which could be dangerous.
Also for safety reasons, he continues, the department does not normally allow user bodies to bring private radio systems to the airport, but insists that they use the TETRA network instead. “If the customer wants to introduce his own radio system, he has to get an admission from the airport and of course we have control of all the frequencies
In a ramp marshal’s car, the radio’s colour display provides ready identification of talk groups and callers. Beneath is a separate transceiver used for primary alarm communications on the airfield in the event of emergency. “It’s a conventional
analogue system”, explains ramp supervisor Peter Waltner. “In the case of alarm, all relevant people – fire department, security, traffic department – all use this”
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