North Hessary Tor is a 517 metres hill just above Dartmoor Prison, in Princetown within Dartmoor Forest civil parish, which is in the borough of West Devon, Devon, England ( grid reference SX578742). The tor is one of the boundary points mentioned in the perambulations of the Forest of Dartmoor. [1]
Standing on the summit is the North Hessary Tor transmitting station, an FM radio and television transmitter which uses 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.