Winter Hill transmitting station

Infobox UK Transmitter
name = Winter Hill


Click to view the hi-res version and see the supporting cables
height = convert|315.4|m|ft
gridref=SD660145
built =
demolished =
collapsed =
relay =
BBC = BBC North West
ITV = ITV GranadaThe Winter Hill transmitting station is a broadcasting and telecommunications site situated on Winter Hill, at the southern boundary of the Borough of Chorley, in Lancashire, England. It is owned and operated by Arqiva.

Height

The main mast structure is convert|309.48|m|ft|0|lk=on tall and has a diameter of convert|2.75|m|ft. The DTT antenna attached to the top of the mast brings the overall height to convert|315.4|m|ft [http://planning.chorley.gov.uk/PublicAccess/tdc/DcApplication/application_detailview.aspx?caseno=JCBKD6ETO3000 Chorley Council - Planning Applications - Ref: 07/00056/FUL] ] . It is one of the tallest structures in the United Kingdom, the tallest being the mast at Belmont with a height of convert|387.75|m|ft. At convert|778.1|m|ft above sea level, Winter Hill has the highest television transmitting antenna in the UK. After digital switchover, the DTT antenna on top of the mast will be removed, reducing its overall height to convert|309.48|m|ft.

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. In recent years, these wires have been strengthened, and 150 tons of dampening chains have been fitted by Arqiva to reduce the oscillations caused by high winds that were a factor in the collapse of Emley Moor's original structure in 1969 [ [http://tx.mb21.co.uk/gallery/winterhill/index.php The Transmission Gallery - Winter Hill] ] .

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.

Coverage

The station's coverage includes approximately 6.3 million people. Although not the ‘correct’ television region, it is the preferred region for some in North Wales, mainly because it carries Channel 4 (as opposed to S4C), Five and a much more powerful digital terrestrial output than 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).In July 2007 it was confirmed by Ofcom that Winter Hill would be remaining a C/D group transmitter after DSO (Digital Switchover).

Output

Television

Analogue television

Overall, the Winter Hill Transmitting Station broadcasts television signals on a total of 14 UHF frequencies using horizontal (H) polarisation. Aerial Group C/D. 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.

* UHF 55 - BBC One North West
* UHF 62 - BBC Two
* UHF 59 - ITV1 Granada
* UHF 65 - Channel 4
* UHF 48 - Five

Digital television

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. [http://forum.digitalspy.co.uk/board/showthread.php?t=439151] The provider name carried on multiplex itself reads "NGW", National Grid Wireless.

* UHF 56 - Multiplex 1 - BBC
* UHF 66 - Multiplex 2 - Digital 3&4
* UHF 68 - Multiplex A - S4C Digital Networks
* 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 wasnot possible for two of the 6 main channels to cover enough of thetarget area. Two of Winter Hills MUXES (on CH60 and 63) are co-channel with Llanddona in North Wales [http://www.aerialsandtv.com/winterhilltx.html#WinterHillsChannels see frequency table] . As a consequence these two frequencies are not transmitted towards the West/South West and Ll Multiplexes C & D are therefore broadcast on two two different frequencies 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".Although CH40 and 43 are not technically within Winter Hill's original C/D group they should still be picked up on a C/D aerial [http://www.aerialsandtv.com/aerials.html#AerialGainCurves see graph] .

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.

Radio

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

DAB

* CE Manchester: 11C (CE Manchester broadcasts from a directional aerial to cover Greater Manchester)
* Digital One Network: 11D
* EMAP Central Lancashire: 12A (EMAP Central Lancashire broadcasts from a directional aerial to cover Central Lancashire (Wigan, Preston, Southport, Blackpool and surrounding areas))
* BBC National DAB: 12B
* MXR North West: 12C

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.

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: UHF 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.

References

ee also

* List of masts
* List of tallest structures in the United Kingdom
* List of radio stations in the United Kingdom

Further reading

* "The Devil Casts His Net", Steve Morrin, ISBN 0-9534503-1-7, The Winter Hill Air Disaster.

External links

* [http://tx.mb21.co.uk/gallery/winterhill/index.php MB21 Winter Hill index.]
* [http://www.aerialsandtv.com/winterhilltx.html Info and pictures of Winter Hill including co-receivable transmitters, see Coverage section above.]
* [http://www.the-moores.co.uk/MediaGallery/Default.aspx?directory=87 Winter Hill photo gallery at www.the-moores.co.uk]
* http://www.skyscraperpage.com/diagrams/?b2455
* [http://www.d.lane.btinternet.co.uk/winterhillthebook.htm Winter Hill scrapbook] Section on the stay blocks for the mast