thebigtower


mendip

 

1024x768 version (106kB)


THE MENDIP TRANSMITTER is the UHF main station that serves the West of England region, sited near the Cathedral City of Wells and principally serving the counties of Avon, Somerset, South Gloucestershire, West Wiltshire and North Dorset.

Central to the service area are the cities of Bristol, Bath and Wells, whilst on the outer fringes the station serves Taunton, Bridgewater, Yeovil, Cirencester and Swindon.  

 

UHF OVERLAP COVERAGE

Signals from this transmitter also cross the Bristol Channel into parts of South Wales, overlapping with coverage from the Wenvoe transmitter.  Conversely some lower-lying areas close to Mendip, where the signals effectively 'pass-over', receive better reception from Wenvoe.

 

BBC NATIONAL RADIO (FM)

There is no BBC National FM service from Mendip as the West of England is served principally by transmissions from Wenvoe.


 Aerials Index>  Transmission Site>  Supersize Images>  UHF Coverage Map


 

 

 

Station Plate (2002)

 

 

 

 


TRANSMISSION STRUCTURE

The Mendip station is the site of the third BBC-built cylindrical 'steel-tube' mast.  At a basic height of 281 metres (920-ft), it is the shortest of the five UK-based cylindrical masts still in existence.  It is however only marginally shorter than the two other BBC-built masts at Bilsdale and Waltham, which both stand at a basic height of 290 metres (950-ft) before the addition of their respective surmounting main UHF antennas.  The current main UHF antenna at the top of the Mendip mast (installed in March 2009 as part of the re-engineering for Digital Switchover) extends the overall height of the structure to 293 metres.

 

Unlike the Bilsdale and Waltham masts which have always had a charcoal-grey appearance, the Mendip mast was originally painted white.  However, this became prone to rapid deterioration and when a full repaint commenced in September 2005 (by which time the last coating of white paint was seriously dilapidated) the mast was painted to match the charcoal-grey colour of the Bilsdale and Waltham masts.

 

The Mendip mast has the same stay-line configuration as Bilsdale and Waltham, comprising twelve lines which attach to the structure at layer platform levels 2, 4, 6 and 8, and descend in three directions in sets of four to six ground anchor blocks.

Mendip, Bilsdale and Waltham were the tallest structures owned by the BBC and, under privatisation, Crown Castle UK and National Grid Wireless.  

The other two remaining cylindrical masts are located at Belmont and Winter Hill and, along with Emley Moor, were the tallest built by the Independent Television Authority (ITA).


 

 

 

 

 

 

 

 

 

Compare Aerial Sections of Crown Castle & NTL Cylindrical Masts

 

800x600        1024x768

 

800x600        1024x768

 

800x600      1024x768

 

800x600      1024x768

 

 

 

 

 

 

 


DIGITAL SWITCHOVER

In preparation for Digital Switchover, re-engineering at Mendip commenced in 2008, the visual changes culminating in April 2009 with the removal and replacement of the main UHF aerial at the top of the structure.  See Aerials Index for image

The switchover process as usual took place in two stages.  The principal changes were as follows -

Stage 1 (DSO1) - 24 March 2010

  • DTT Multiplex 1 on Channel 59 ceased transmission permanantly
  • BBC2 Analogue on Channel 64 ceased transmission permanently
  • ITV1 Analogue moved from Channel 61 to Channel 64 pending DSO2 to enable release of Channel 61 to new DSO PSB1
  • New DSO Multiplex PSB1 (BBC A) commenced transmission on Channel 61

Stage 2 (DSO2) - 7 April 2010

 

  • All remaining analogue and low power DTT services ceased transmission permananently
  • Remaining Public Service Broadcast (PSB) Multiplexes PSB2 (D3&4) and PSB3 (BBC B) commenced transmission
  • COM multiplexes commenced operation at provisionally reduced power until 2012

 

 

 

 

 

 

 

 

 

 

800x600      1024x768

 

800x600      1024x768

 

800x600      1024x768

 

800x600      1024x768

 

 

 

 

 


 Aerials Index>  Transmission Site>  Supersize Images>  UHF Coverage Map


 

 

 

 

 

 

 

 

 

 

 

 

Transmission Site

 

Aerials Index

 

UHF Coverage Map

 

 

 

 

 (Including DSO work)

 

 

 



Mendip Transmitter - Brief History

The purpose of the Mendip transmitter was to bring UHF coverage to the West of England region, where coverage on the original 405-line system was provided principally by transmissions from the Wenvoe (BBC) and St Hilary (ITV) stations near Cardiff.

The BBC were responsible for the construction of Mendip and aimed to bring the new station into service, initially as a BBC2 transmitter, during 1967.  However the proposed site in the Mendip Forest failed to gain local authority approval on amenity grounds.  The BBC then found a new location outside the forest on Penn Hill, two miles north of Wells.  Although this site was eventually secured, it was only after lengthy negotiations with the land owner which added to mounting delays.

Penn Hill offered an above-sea-level ground height of 1000ft (305m).  A mast of similar height was required in order to elevate the UHF transmission aerials to around 2000ft.  The BBC therefore selected for the site a 920ft (281m) mast of cylindrical-design, construction of which commenced in the autumn of 1967.

At this time, the BBC were completing the rebuild of the 950ft (290m) cylindrical mast at Waltham (the original collapsed near completion in November 1966), whilst embarking on the construction of a further 950ft mast at the new Bilsdale site in North Yorkshire.  Mendip was to be the third and last BBC cylindrical mast installation and unlike it's predecessors it was to be painted white in order to meet the asthetic requirements of the local authority.      

Construction of the Mendip mast took two years to complete having been plagued by the usual variety of unforeseen delays, in particular problems with installing the engineers lift.  The collapse of the Emley Moor mast in March 1969 did little to improve sentiment.  However, by late October 1969, the Mendip mast was finally complete and broadcasting trade test transmissions.  

On 1 December 1969, some two years later than scheduled, the Mendip transmitter entered programme service, transmitting BBC2 on Channel 64.  UHF-colour transmitters for BBC1 (Channel 58) and ITV (Channel 61) followed on 11 May 1970 and 30 May 1970 respectively.


 

 

 

 

 

 

 

 

 

 

 

 

 

800x600  1024x768

 

800x600  1024x768

 

800x600  1024x768

 

800x600  1024x768

 

800x600  1024x768

 

 

 

 

 

 

 

 

 


STATION INFORMATION


Location:

Penn Hill, Wells, Somerset, BA5 8TX

Grid Reference:

ST563488

Landlord:

Arqiva (Legacy: BBC/Crown Castle/NGW)

Ground Height:

302.3m

ITV Region:

West

Mast Height:

293m

BBC Region:

West

Aerial Height: (*)

589m

 

UHF Tx Number:

11000

(*) 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

: 49 / H / 100kW 

 

 BBC Radio Bristol & Somerset:

95.5

9kW

PSB2

: 54 / H / 100kW 

 

 

Kiss FM:

101.0

40kW

PSB3

: 58 / H / 100kW 

 

 

 Heart FM:

102.6

4kW

COM4

: 48 / H / 100kW

 

 

 

 

 

COM5

: 56 / H / 100kW

Digital Radio (DAB)

COM6

: 52 / H  /100kW

 

 

 

 

 

 

 

 

 

BBC National (Block 12B)

 

Digital One (Block 11D)

     

  MXR Severn Estuary (Block 12C)

 

 

PRE-DIGITAL SWITCHOVER UHF TRANSMISSIONS

(Shutdown completed 7 April 2010)

Analogue Television 

 

 

 

Digital Television

 

 

 

 

 

 

 

 

 

Service

  Ch/Polar/e.r.p

 

 

 

 

Service

 Ch/Polar/e.r.p

BBC1

: 58 / H / 500kW

 

 

 

 

Mux1

: 59 / H / 10kW

BBC2

: 64 / H / 500kW  

 

 

 

 

Mux2

: 55 / H / 10kW

ITV1

: 61 / H / 500kW 

 

 

 

 

MuxA

: 62 / H / 10kW

Ch4

: 54 / H / 500kW

 

 

 

 

MuxB

: 65 / H / 10kW

Ch5

: 37 / H / 126kW

 

 

 

 

MuxC

: 56 / H / 10kW

 

 

 

 

 

 

 

MuxD

: 67 / H / 10kW

 

 

 

 

 

 

 

 

 


 

Other Cylindrical Masts

 

 

 

 

 

Bilsdale 

Waltham

Belmont

Winter Hill

(North Yorkshire)

(Leicestershire)

(Lincolnshire)

(Lancashire)


Mendip Transmitter @ A.T.V (Aerials and Television)

 

Site Home