thebigtower


north hessary tor

 


THE NORTH HESSARY TOR STATION provides the main transmission for BBC National/Local FM Radio and Classic FM across Devon and East Cornwall.

Sited centrally within the Dartmoor National Park, the station overlooks Princetown which is the primary recipient of coverage from the Caradon Hill-dependent UHF relay that is also located here.

With a ground height of 510 metres (1673ft) above sea level, the station is the second-highest main broadcast transmitter facility in the United Kingdom, exceeded only by Holme Moss at 524m (1719ft).    

TRANSMISSION STRUCTURE

North Hessary Tor transmits from a four-sided lattice stayed-mast, which currently stands at 196.7m (646-ft) and is secured in place by twenty stay lines which descend from five attachment points on the structure to a total of twelve ground anchor blocks.


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UPDATED JANUARY 1014

 

UPDATED JANUARY 1014

 

UPDATED JANUARY 1014

 


STATION HISTORY

EARLY VHF TELEVISION

North Hessary Tor was built principally as a medium-power transmitter for the BBC 405-line VHF Band I television network for the purpose of expanding coverage across the south-west of England.

The BBC had provided a service across North and East Devon since Wenvoe, the last of their four provincially-sited high-power television transmitters, commenced full power operation on 20 December 1952.  The North Hessary Tor station, whilst providing duplicated coverage across parts of the same area, would extend the service to the remainder of Devon and most of Cornwall.

The Dartmoor Hills provided an ideal siting for the new transmitter, placing it centrally within the intended service area and also on the region's highest ground.  From this base point, the robust Band I signals could with relative ease traverse the peaks and troughs of Dartmoor and Bodmin as well as the region's lower lying towns and cities.  In this respect and others subsequent, the station emulated the BBC Holme Moss transmitter in the Pennines.  

Since their first medium-power transmitter at Pontop Pike the BBC had begun implementing new stations with provisional facilities in order to get them on-line as soon as possible.  The North Hessary Tor station was no exception to this, utilising a temporary mast and improvised transmitters housed in BBC Outside Broadcast vans.  From these facilities, the station came into regular operation (at reduced power) on 17 December 1954, broadcasting on VHF Channel 2.

Development of the permanent station proceeded over the following eighteen months, with the construction of a 228 metre (750-ft) stayed mast and station building.  The latter utilised local stone in its construction, another characteristic the station would share with Holme Moss.  The completed permanent mast and station came into operation on 7 August 1956, with 405-line transmissions increased to a maximum output of 15kW (vision) e.r.p. 


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**(NEW ADDITION - JANUARY 2014)**

 

 

 


EXTENDING WESTWARDS

Whilst the opening of the permanent station dramatically increased the transmission range, reception across the far west of Cornwall and The Scilly Isles remained poor.  This issue was resolved from 1 February 1962 with the opening of the Redruth station which, for the purpose of 405-line transmission, operated as a relay of North Hessary Tor but would in due course become the main UHF transmitter for its respective area.

RIVAL TRANSMITTERS

The start of Independent Television (ITV) in the south-west on 29 April 1961 brought further television transmitters to the region.

Typically, the Independent Television Authority (ITA) had wherever possible built their VHF Band III transmitters close to existing BBC Band I stations.  However, the ITA faced the same problem here as they had in Northern England, due to the almost identical topography, in that VHF Band III could not serve as effectively as VHF Band I an area of such diverse terrain from a single centrally-placed transmitter.

Consequently, in the same way separate ITA transmitters (Winter Hill) and Emley Moor) were sited on either side of the Pennines to cover the same area as Holme Moss, the ITA built separate stations to the west and east of Dartmoor, respectively sited at Caradon Hill (serving Cornwall and West Devon) and Stockland Hill (serving East Devon).

This left North Hessary Tor in the same unfavourable position as Holme Moss with regards to selecting sites for UHF transmission.

UHF AND THE END OF 405

The start of UHF in the south-west came in 1969 and with transmissions in Band IV even less able than Band III to negotiate hilly terrain, responsibility inevitably fell (as it did in Northern England) to the two ITA transmitters to provide the UHF-Colour service, with Caradon Hill carrying the first regular transmissions (BBC2) from 5 July that year.

North Hessary Tor continued with BBC1 transmission on VHF Band I only until the end of the 405-line service in January 1985. The Band I aerial system was in due course removed from the top of the mast and the structure cut down to its current height of 196.7 metres (646-ft).

FM RADIO

In common with all the other main BBC Band I Television sites, the secondary function of North Hessary Tor was to carry the BBC National FM Radio services.  Incorporated into the construction of the permanent mast and station facility, the FM service commenced in 1956.  Rather like the VHF Band I Television service however, transmissions covered only eastern parts of Cornwall satisfactorily, again requiring the Redruth transmitter to eventually fill the void across West Cornwall and The Scilly Isles.

In 1988, as part of a network upgrade, the North Hessary Tor mast was re-fitted with the current Band II aerial system to support mixed-polarised transmission for portable and in-car radio reception.


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  STATION INFORMATION


Location:

North Hessary Tor, Princetown, Dartmoor, PL20 6SS

Grid Reference:

SX578742

Landlord:

Arqiva (Legacy: BBC/Crown Castle/NGW)

Ground Height:

510.5m

BBC Region:

South-West

Mast Height:

196.7m

ITV Region:

West

Aerial Height: (*)

570m

 

UHF Tx Number:

13143

(*) UHF aerial height above sea level (a.o.d)

 

 


  CURRENT TRANSMISSIONS

Digital Television

 

 

Analogue Radio (FM)

 

 

 

 

 

 

 

 

 

Service

: Ch/Polarisation/e.r.p

 

 

 Service:

(MHz)

(e.r.p)

PSB1

: 62 / V / 2.5W 

 

 

BBC Radio 1:

97.7

160kW

PSB2

: 59 / V / 2.5W 

 

 

BBC Radio 2:

88.1

160kW

PSB3

: 55 / V / 2.5W

 

 

BBC Radio 3:

90.3

160kW

COM4

: No service

 

 

BBC Radio 4:

92.5

160kW

COM5

: No service  

 

 

BBC Radio Devon:

103.4

15kW

COM6

: No service

 

 

Classic FM:

100.0

160kW

 

 

 

 

 

 

 

 

 

Digital Radio

 

 

 

 

 

 

 

 

 

No service

 

 

 

 

 

 

 

 

PRE-DIGITAL SWITCHOVER UHF TRANSMISSIONS

(Shutdown 9 September 2009)

Analogue Television 

 

 

 

Digital Television

 

 

 

 

 

 

 

 

 

Service

  Ch/Polar/e.r.p

 

 

 

 

Service

 Ch/Polar/e.r.p

BBC1

: 55 / V / 12.5W

 

 

 

 

 

 

BBC2

: 62 / V / 12.5W  

 

 

 

 

No pre-DSO service

ITV1

: 59 / V / 12.5W 

 

 

 

 

 

 

Ch4

: 65 / V / 12.5W

 

 

 

 

 

 

Five

: No Service

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Beacon Hill  Caradon Hill  Huntshaw Cross  Redruth  Stockland Hill

 

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