The Oxford transmitting station (sometimes known as the Beckley transmitter) is a broadcasting and telecommunications facility, situated on land 129.5 metres (425 ft) above Ordnance Datum (mean sea level) to the north east of the city of Oxford, in Oxfordshire, England (grid referenceSP567105). It has a guyed steel lattice mast which is 154.4 metres (507 ft) in height to the top of the main steel structure. The UHF television antenna, which consist of a vertical array of transmitting panels, is mounted above the steel structure. The total height of the mast to the top of this UHF antenna is 165.7 metres (544 ft). It is owned and operated by Arqiva.
The station was originally constructed by the BBC during the early 1960s to provide the BBC's VHF/FM national and regional radio networks and the BBC-TV service on 405-line VHF to the city of Oxford and the surrounding area. The mast carried a two-tier Band I array above a six-tier slot array for Band II FM. A smaller 150-foot tower in the western corner of the site carried receiving aerials.
The station was extended in 1968, having been chosen as a suitable site for high power colour UHF transmissions, which entered service on 17 February 1968 carrying BBC Two. BBC One followed in May 1970 and ITV (ATV/Central) in June of the same year. Channel 4 was carried from launch day in November 1982. The effective radiated power (ERP) of these four analogue TV transmissions was 500 kW
In 1997, the station began analogue transmissions of Channel 5 at an ERP of only 40 kW. The lower power was necessary to avoid co-channel interference with other transmitters sharing this frequency in the surrounding areas.
The Oxford transmitter was included in the first 81 transmitters to carry the UK digital terrestrial television service when it was launched in the UK on 15 November 1998. Six digital multiplex signals were transmitted at low power from the station in addition to the five existing analogue television services.
In 1999, the station began analogue transmissions of Oxford's RSL local channel, Six TV on low-power. At this time the Oxford transmitting site carried a total 12 television transmissions, six analogue services, and six digital multiplexes.
On 28 September 2011 all the analogue television services at Oxford transmitter were switched off as part of the UK Digital Switch Over project. Three of the frequencies (uhf channels 53, 57 and 60) that had been used for the analogue service were transferred to the digital television service at high power (100 kW). The remaining three multiplex signals continued to be operated at lower power until the completion of switchover on 18 April 2012 when their power was increased to 50 kW. At the same time the highest frequency multiplex, on uhf channel 62, was moved to channel 50 as part of the UK scheme to clear the 800 MHz frequency band for use by mobile 4G services.
In December 2014 a low power local television multiplex was added to the site. In November 2015 the service had a soft launch as That's Oxfordshire with studios based in Abingdon
During 2015 two additional television multiplexes (known as Com7 and Com8) were broadcast from the Oxford site both using the DVB-T2 transmission system. This allowed a range of new channels to be broadcast to the Oxford area including the high definition versions of some of the channels only available at standard definition on the main Freeview service.
In 2014 the UK telecommunications regulatory Ofcom decided that the 700 MHz band should be cleared of digital television to be used for mobile broadband services by the summer of 2020. As a result the frequencies of the six main Freeview digital television transmissions were moved to lower frequencies during 2018 with the task being completed on 23 May 2018. The two additional services of Com7 and Com8 were moved temporarily into the 700 MHz band pending a resolution on their future location in the UK's digital television spectrum.
The coverage area provided by the digital television service is roughly the same as that provided by the analogue service. The transmitting station covers Oxfordshire, western Buckinghamshire, small parts of eastern Gloucestershire and northern parts of Berkshire and Wiltshire. It is sometimes called the Beckley mast, a reference to an adjacent village, or the Ot Moor mast, this referring to the area on which it is located.
In early 1970 the BBC Home Service South & West region transmission on 95.85 MHz was closed down in prior to the introduction of BBC Radio Oxford which launched on 29 October 1970 on 95.0 MHz. The frequency was changed to 95.2 MHz on 26 June 1973 as part of a reorganisation of local radio frequencies in and around the London area.
In the late 1980s the BBC Radio 1 service was added to site to be followed by Classic FM in the mid 1990s. During the same period the FM transmitting antennas were replaced by a mixed polarised antenna better suited to providing a service to portable and car aerials. To maintain the coverage of the horizontally polarised signal the transmitter power was roughly doubled to give an ERP of 46 kW.
On 15 September 1989 the independent local radio station Fox FM was launched on 102.6 MHz at a ERP of 9 kW. In 2005 the station became a part of GCap Media and in March 2009 the station was rebranded to Heart Oxfordshire.
The Oxford site transmitted the AM service of Virgin Radio from its launch on 30 April 1993 on a frequency of 1197 kHz. The service is radiated from a vertical antenna which is supported by a slopping wire from the Oxford mast.
When the BBC launched its Digital Radio national service on 27 December 1997 the Oxford transmitter was included in the network to provide coverage to Oxfordshire and to boost the coverage to surrounding areas. The first national commercial network, Digital One, was added to the transmitter on 23 September 1999 and a second national commercial network, Sound Digital on 29 February 2016.
On 21 December 2012 Now Digital, a local digital radio multiplex owned and operated by Arqiva, started transmission from the Oxford site. It provides a mix of local and national radio stations to a population of some 610,000 in the city of Oxford and surrounding area.
On 13 May 2010 the digital and analogue television transmitters (except Channel 5) went off the air at about 13:20 UTC following an incident when smoke was seen drifting from the top of the mast. The fire service reported that there had been an intense fire and that the cause was unknown. Engineering work to reinstate service began once fire crews left and the mast was made safe. Transmissions were restored via the reserve transmitter at reduced power by 20:30 UTC.
The incident occurred during testing of a new main antenna which had been installed during the previous few months in readiness for the proposed digital switchover. Investigation into the cause of the fire established that it was damaged beyond repair and a replacement was installed by the end of September 2010.
Services transmitted from the Oxford site as of June 2018 – listed by frequency
Arqiva A & B and SDN increased to 50 kW on 18 April 2012, after completion of the digital switchover at Crystal Palace transmitting station.
SDN was moved to UHF 50 from UHF 62 due to the clearance of the 800 MHz Band.