The North Hessary Tor is a hill 517 metres high just above Dartmoor Prison

Dartmoor (HM Prison)

HM Prison Dartmoor is a Category C men's prison, located in Princetown, high on Dartmoor in the English county of Devon. Its high granite walls dominate this area of the moor...

, in Princetown

Princetown

Princetown is a town situated on Dartmoor in the English county of Devon.In 1785, Sir Thomas Tyrwhitt, Secretary to the Prince of Wales, leased a large area of moorland from the Duchy of Cornwall estate, hoping to convert it into good farmland. He encouraged people to live in the area and suggested...

 within Dartmoor Forest

Dartmoor Forest

Dartmoor Forest is a civil parish in Devon, England. It was formed in 1987 by the splitting of the former parish of Lydford. It covers about entirely within Dartmoor National Park, and is the largest parish in Devon. Despite its size its population in 2001 was only 1,619....

 civil parish

Civil parish

In England, a civil parish is a territorial designation and, where they are found, the lowest tier of local government below districts and counties...

, which is located in the borough of West Devon

West Devon

West Devon is a local government district and borough in Devon, England. Towns in the district include Chagford, Okehampton, Princetown, and Tavistock, where the council is based....

, Devon

Devon

Devon is a large county in southwestern England. The county is sometimes referred to as Devonshire, although the term is rarely used inside the county itself as the county has never been officially "shired", it often indicates a traditional or historical context.The county shares borders with...

, England . The tor is one of the boundary points mentioned in the perambulations of the Forest of Dartmoor

Forest of Dartmoor

The Forest of Dartmoor is an ancient royal forest covering part of Dartmoor, Devon, England.A royal forest was an area reserved by the king for hunting, and William the Conqueror introduced the concept of forest law in England in the 11th century...

.

Situated on the summit is an FM

Frequency modulation

In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...

 radio and television

Television

Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...

 transmitter which uses as aerial a 196.0 metre (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

Cornwall

Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...

. It is owned and operated by Arqiva

Arqiva

Arqiva is a telecommunications company which provides infrastructure and broadcast transmission facilities in the United Kingdom and Republic of Ireland. The present company, with headquarters located at Crawley Court in the village of Crawley, Hampshire, was formed by National Grid Wireless...

.

Analogue radio (FM

Frequency modulation

In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...

 VHF)

Frequency	kW	Service
88.1 MHz	160	BBC Radio 2 BBC Radio 2 BBC Radio 2 is one of the BBC's national radio stations and the most popular station in the United Kingdom. Much of its daytime playlist-based programming is best described as Adult Contemporary or AOR, although the station is also noted for its specialist broadcasting of other musical genres...
90.3 MHz	160	BBC Radio 3 BBC Radio 3 BBC Radio 3 is a national radio station operated by the BBC within the United Kingdom. Its output centres on classical music and opera, but jazz, world music, drama, culture and the arts also feature. The station is the world’s most significant commissioner of new music, and its New Generation...
92.5 MHz	160	BBC Radio 4 BBC Radio 4 BBC Radio 4 is a British domestic radio station, operated and owned by the BBC, that broadcasts a wide variety of spoken-word programmes, including news, drama, comedy, science and history. It replaced the BBC Home Service in 1967. The station controller is currently Gwyneth Williams, and the...
97.7 MHz	160	BBC Radio 1 BBC Radio 1 BBC Radio 1 is a British national radio station operated by the British Broadcasting Corporation which also broadcasts internationally, specialising in current popular music and chart hits throughout the day. Radio 1 provides alternative genres after 7:00pm including electronic dance, hip hop, rock...
100.0 MHz	160	Classic FM Classic FM (UK) Classic FM, one of the United Kingdom's three Independent National Radio stations, broadcasts classical music in a popular and accessible style.-Overview:...
103.4 MHz	15	BBC Radio Devon BBC Radio Devon BBC Radio Devon is the BBC Local Radio service for the English county of Devon. It began transmissions on 17 January 1983, replacing a previous breakfast show for Devon and Cornwall broadcast on the local frequencies of Radio 4....

NB In all BBC publications the National FM erp for North Hessary Tor are listed as 160 kW (Mixed Polarisation)
Classic FM list their erp as 80 kW (Horizonal) and 80 kW (Vertical) for North Hessary Tor which is the same as the BBC eg 160 kW (Mixed Polarisation) erp.

Digital Radio:
12B
BBC National Multiplex (3.2kW erp)

Analogue television

Analogue television was switched off at this mast between 12 August 2009, when BBC Two was switched off, and 9 September 2009 when the remaining three were switched off. They were replaced by three digital public service multiplexes.

Frequency	UHF	kW	Service
743.25 MHz	55	0.012	BBC One BBC One BBC One is the flagship television channel of the British Broadcasting Corporation in the United Kingdom. It was launched on 2 November 1936 as the BBC Television Service, and was the world's first regular television service with a high level of image resolution...
775.25 MHz	59	0.012	ITV1 ITV1 ITV1 is a generic brand that is used by twelve franchises of the British ITV Network in the English regions, Wales, southern Scotland , the Isle of Man and the Bailiwicks of Jersey and Guernsey. The ITV1 brand was introduced by Carlton and Granada in 2001, alongside the regional identities of their...
799.25 MHz	62	0.012	BBC Two BBC Two BBC Two is the second television channel operated by the British Broadcasting Corporation in the United Kingdom. It covers a wide range of subject matter, but tending towards more 'highbrow' programmes than the more mainstream and popular BBC One. Like the BBC's other domestic TV and radio...
823.25 MHz	65	0.012	Channel 4 Channel 4 Channel 4 is a British public-service television broadcaster which began working on 2 November 1982. Although largely commercially self-funded, it is ultimately publicly owned; originally a subsidiary of the Independent Broadcasting Authority , the station is now owned and operated by the Channel...

Digital television

Frequency	UHF	kW	Operator
746.0 MHz	55	0.0025	BBC BBC The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...  B
778.0 MHz	59	0.0025	Digital 3&4 Digital 3&4 Digital 3&4 is a consortium consisting of regional Channel 3 companies and Channel 4 Television Corporation, which operates a multiplex broadcasting from a number of transmitter sites in the UK, carrying television and radio channels from both ITV and Channel 4; however three per-cent of the...
801.8 MHz	62-	0.0025	BBC A

External links

• The Transmission Gallery: North Hessary Tor Transmitting Station photographs, coverage maps and information
• North Hessary Tor Transmitter at thebigtower.com