In car radio

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Effective communication is important in any modern working environment. But when that environment moves at 300km/h (185mph), between buildings and trees, accompanied by the deafening scream of a racing V8, the need for messages to be received clearly becomes all the more critical.

That's why Team McLaren Mercedes' CBX780 car-to-pit radio has been developed by the best brains in the business. The unit is designed in Japan by Official Supplier Kenwood, a world leader in communications and audio equipment. It is assembled at the

McLaren Technology Centre by McLaren Electronics, which designed a lightweight enclosure machined from magnesium alloy.

The radio runs off the car's power system and is positioned under the knees of the driver, who pushes a button on the steering wheel when he wants to transmit. The signal is transmitted via the antenna on the car's nose to a mast mounted either at the back of the pit facility or on one of the team's race transporters. The car sends a VHF FM signal,

but a repeater system – effectively another transmitter attached to the pit receiver – converts it to a UHF FM signal.

The latter is better suited for passing through the pit walls into the engineers' headsets. Car-to-pit radios were first used in 1984, but were initially dogged by interference and cross-talk. At one British Grand Prix, for example, Ayrton Senna was mystified by strange messages in his earpiece. They were eventually traced to a catering firm working on the infield. Early transmission blackspots have now been overcome by advances in technology, particularly in the field of antennae, and the compact nature of modern circuits. Yet radio design continues to evolve. “Whenever you make an advance,

you want to push the limits even further,” says Phill Asbury, Head of Systems Engineering. “Weight is vital. You are continually pushing to optimise the packaging, but never compromising the performance requirements of the system.”

Team McLaren Mercedes is one of only two teams to have switched from analogue to a digital system. Although the digital revolution has already swept through high streets, the narrow bandwidths within which Formula 1 teams have to operate have hampered its widespread introduction in the sport. Team McLaren Mercedes applies in advance for 24 independent channels for every race – enough for everything from car-to-pit radios, to a weather radar system and channels for the marketing and catering teams. The airwaves must be shared by the other teams, as well as local businesses, so only narrow bandwidths are allocated.

This technical obstacle was overcome by redesigning what is essentially commercially available equipment. However, a further layer of encryption is added to ensure complete trackside security. “Total safety from eavesdropping is the biggest advantage of the fully

digital system,” says Kenwood's Makoto Oikawa, who is seconded to Team McLaren Mercedes and attends every race. “Continuously improving sound quality is another benefit we are always working on.”

To eliminate confusion, a standard terminology is used in all radio conversations, and information is always channelled to the drivers through a single source: Steve Hallam for Kimi and Dave Redding for Pedro. “That rapport is absolutely crucial because there is no margin for error,” notes Asbury. “When a car pits, there is frequently only half a kilo of fuel left in the tank. For a driver to miss a call to come in would be disastrous.”

Driver preference dictates when messages are delivered. Some like to talk when the car is on the straight, others in the slower corners when engine noise is lower. Drivers such as Juan Pablo and David Coulthard request plenty of information during a grand prix. Kimi, on the other hand, prefers the quieter approach adopted by the likes of Alain Prost and fellow Finn Mika Häkkinen.

Technical Specifications

Size: 140 x 115 x 35mm
Weight: 400g
Material: Machined magnesium alloy

Special thanks to McLaren