Situated on the summit of North Hessary Tor in Devon, England is an FM radio and television transmitter which uses as aerial a 196 metres (643 ft) high guyed mast. It was built by the BBC in 1955 when a transmitter was needed to introduce 405 line television into Devon. It now carries a small UHF TV transmitter which serves Princetown and Dartmoor. FM radio transmissions began in 1956 and cover most of Devon and eastern parts of Cornwall. It is owned and operated by Arqiva.