Winter Hill transmitting station
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The Winter Hill transmitting station is a broadcasting and telecommunications site situated on Winter Hill between Chorley and Bolton, in Lancashire, England.
The mast is 296 m (987 ft) high and is owned and maintained by Arqiva. It is one of the tallest masts in the country, the tower at Belmont is taller at 385 m (1283 ft). The addition of a DTT digital antenna to the top of the mast extended its height to ~312 m (~1040 ft).
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[edit] Construction
Unlike most masts, which are of a lattice design, Winter Hill mast is of a tubular construction. 5 other masts in England share this design (Belmont, Bilsdale, Mendip, Waltham and the original ill-fated structure at Emley Moor). Support wires, to hold the mast vertical, are pitched at 120° when viewed from above. These are connected at 5 heights, giving 15 supports in total. These wires have recently been strengthened (and dampened) by arqiva, presumably to prevent the mast collapsing in the manner of Emley Moor's original structure.
[edit] Maintenance
An advantage of the tubular design is that engineers can ascend the inside of the mast and not be subject to adverse weather, which is a problem on frame structures. Maintaining the outside of the mast is typically performed using a bosun's chair.
The mast has always had a series of red aircraft warning lights but in October 2006 these lights were substantially brightened making the mast far more visible to passing aircraft. These lights can be maintained from the inside, as the bulbs swing inwards for maintenance.
Eight external platforms encircle the mast along its height, these can be accessed from the inside of the mast, and are used to maintain the supporting wires, and the ILR antennas.
[edit] Coverage
The mast has an average coverage of 50 miles circumference, although this is a theoretical figure, it all depends on having a "line of sight" reception path to the transmitter. It is relatively common to find locations only a few miles away (say behind a hill or large building) who will receive a very poor signal and under these circumstances alternative transmitter(s) would be utilised, see external links. Although not the correct television region, it is the preferred region for many in North Wales, mainly due to the fact of the carriage of Channel 4 (as apposed to S4C), Five and its much more powerful digital terrestrial output compared to the Welsh transmitters. The region's ITV franchisee, Granada Television (which launched in 1956), was also on air much earlier than North Wales' franchisee, WWN (Teledu Cymru) (which launched 1962), giving viewers more choice than they would with the Welsh transmissions. After Digital Switch Over, the Welsh transmitters will be broadcasting DTT at a much higher power than present, of which Channel 4 and Five are included in the line-up. However, because of terrain and rough landscapes of North Wales, many will find it easier to stay with Winter Hill (as small local relays will only broadcast half the digital channels as Winter Hill will and does).
[edit] Output
[edit] Television
Overall, the Winter Hill Transmitting Station broadcasts television signals on a total of 14 UHF frequencies using horizontal polarisation. As with UK standards, the analogue television is output 625 line PAL, with NICAM stereo sound. Analogue channels 1-4 broadcast at 500 kW ERP. Five broadcasts at 12.5 kW ERP.
DTT transmissions are also carried from the site, and have been since 1998. Multiplexes 1, 2, B, C and D broadcast at 10 kW, while multiplex A (SDN / Five) broadcasts at 5 kW. As of 2006, a test transmission of a new multiplex (rumoured to accommodate a trial of BBC HD, however still unconfirmed) fluctuates broadcasting on UHF 50 at a lower power. [1] The provider name carried on multiplex itself reads "NGW", National Grid Wireless.
- UHF 56: Multiplex 1 (BBC)
- UHF 66: Multiplex 2 (Digital 3&4 Limited)
- UHF 68: Multiplex A (SDN Ltd / Five)
- UHF 67: Multiplex B (BBC)
- UHF 60: Multiplex C (National Grid Wireless)
- UHF 63: Multiplex D (National Grid Wireless)
also
- UHF 43: Multiplex C (National Grid Wireless) - to accommodate reception blindspots in the East
- UHF 40: Multiplex D (National Grid Wireless) - to accommodate reception blindspots in the East
- UHF 50: Trial Multiplex (National Grid Wireless, BBC)
Frequency planning for DTT from Winter Hill proved difficult and it was not possible for two of the 6 main channels to cover enough of the target area (mainly the East of the region). Multiplexes C & D are therefore broadcast on two pairs of channels from 2 sets of more directional aerials, known as Winter Hill B. The duplicated copy (at UHF 43 and 40 respectively) acts as a filler for the area which the first pair could not cover. The network label carried on the HD Trial Multiplex also reads "Winter Hill B".
This temporary complication will come to an end with Digital Switchover, where more suitable frequencies can be used to accommodate both multiplexes to the entire region, plus the overall power of digital transmissions will be increased greatly.
[edit] Radio
[edit] FM
- BBC Radio 1: 98.2 MHz†
- BBC Radio 2: 88.6 MHz†
- BBC Radio 3: 90.8 MHz†
- BBC Radio 4: 93.0 MHz†
- BBC Radio Lancashire: 103.9 MHz
- Rock FM: 97.4 MHz
- Smooth FM: 100.4 MHz
- Century 105: 105.4 MHz
† Relays the signal from Holme Moss to cover South and Central Lancashire
[edit] DAB
- CE Manchester: 11C [1]
- Digital One Network: 11D
- EMAP Central Lancashire: 12A [2]
- BBC National DAB: 12B
- MXR North West: 12C
- ^ CE Manchester broadcasts from a directional aerial to cover Greater Manchester
- ^ EMAP Central Lancashire broadcasts from a directional aerial to cover Central Lancashire (Wigan, Preston, Southport, Blackpool and surrounding areas)
[edit] Plane crash
On February 27, 1958, a Silver City Bristol 170 Freighter (G-AICS) travelling from the Isle Of Man to Manchester crashed into Winter Hill (also known as Rivington Moor) several hundred yards away from the mast. 35 people died and 7 were injured. The weather that night was so severe that none of the engineers working in the transmission centre were aware of the crash. Several feet of snow hampered rescue efforts, and a snow cat vehicle had to be diverted from the A6 to cut a path for emergency vehicles.
[edit] Timeline
- 1956: Granada Television commences black and white television broadcasting prior to main mast construction.
- 1958: Fatal plane crash kills 35 people, 7 survive.
- 1962: BBC commence broadcasting.
- 1965: Main mast is completed, replacing the old 450' construction, which is removed.
- 1966: VHF transmissions start.
- 1968: ITV build the single storey engineering building.
- 1969: ITV and BBC transmit in UHF.
- 1970: Relaying service set up with Emley Moor mast.
- 1974: Local radio stations set up wire frame ILR transmitters on the hill.
- 1981: Channel 4 create additional engineering building.
- 1982: Additional ILR transmitter put into operation for further local radio. Channel 4 commences transmission.
- 1983: Channel 4 set up relay service.
- 1997: Channel 5 commences transmission
- 1998: Century FM radio start broadcasting from the main mast.
[edit] See also
[edit] Further reading
- The Devil Casts His Net, Steve Morrin, ISBN 0-9534503-1-7, The Winter Hill Air Disaster.
