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Fed up with hearing your neighbour’s CDs on your radio headphones? German
audio company Vivanco has developed a headphone system that automatically tunes
itself for best reception. A small transmitter plugs into a hi-fi system and
radiates stereo sound at 863 megahertz. Battery-powered headphones pick up the
signal anywhere within 100 metres. But if two neighbours are using similar
devices, they can interfere with each other’s reception, so Vivanco’s
transmitter searches three frequencies within the band and automatically
switches to the one with the least interference.