Saffron Green transmitting station was a facility for

medium wave Medium wave (MW) is a part of the medium frequency (MF) radio band used mainly for AM radio broadcasting. The spectrum provides about 120 channels with more limited sound quality than FM stations on the FM broadcast band. During the daytim ...

broadcasting near Saffron Green Meadows in Hertfordshire, 19km north-west of

London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...

. It was built by the

Independent Broadcasting Authority The Independent Broadcasting Authority (IBA) was the regulatory body in the United Kingdom for commercial television ( ITV and Channel 4 and limited satellite television regulation – cable television was the responsibility of the Cable Author ...

in March 1975 to transmit two

Independent Local Radio Independent Local Radio is the collective name given to commercial radio stations in the United Kingdom. As a result of the buyouts and mergers permitted by the Broadcasting Act 1990, and deregulation resulting from the Communications Act 2 ...

stations -

Capital Radio Capital London is an Independent Local Radio station owned and operated by Global Media & Entertainment as part of its national Capital (radio network), Capital Network. As Capital Radio it was launched in the London area in 1973 as one of Bri ...

and

LBC LBC (originally the London Broadcasting Company) is a British phone-in and talk radio station owned and operated by Global and based in its headquarters in London. It was the UK's first licensed commercial radio station, and began to broadc ...

. An earlier medium wave transmitting station is

Brookmans Park Brookmans Park is a village in Hertfordshire, southeast England, known for its Brookmans Park transmitting station, BBC transmitter station. Brookmans Park railway station, on the East Coast Main Line, is operated by Thameslink and Great North ...

, also in Hertfordshire and built by the BBC in the 1920s. The last station broadcasting from this site stopped in October 2024 and the future of the site is unknown. Until the 1970s the BBC had a monopoly on radio broadcasting in the UK, with the exception of pirate stations and

Radio Luxembourg Radio Luxembourg was a multilingual commercial broadcaster in Luxembourg. It is known in most non-English languages as RTL (for Radio Television Luxembourg). The English-language service of Radio Luxembourg began in 1933 as one of the earlies ...

. This changed in 1972 with the Sound Broadcasting Act BFI researchers' guide - legislation
Retrieved 4 January 2006 and the IBA let two contracts for commercial radio in London, one for "news and information" and one for "general and entertainment".Croston, Eric (Ed.) ''Television and Radio 1985 - Guide to Independent Broadcasting'' Independent Broadcasting Authority, London 1984. The news and information contract went to London Broadcasting Company (LBC) which started broadcasting on 8 October 1973; the general and entertainment contract was won by Capital Radio which started broadcasting on 16 October 1973.

Engineering

All ILR stations were allocated an FM frequency and a MW frequency which had to broadcast the same material. Both stations launched using temporary MW transmitters and a

T-antenna A ‘T’-antenna, ‘T’-aerial, or flat-top antenna is a monopole antenna, monopole antenna (radio), radio antenna consisting of one or more horizontal wires suspended between two supporting radio masts and towers, radio masts or buildings and ...

strung between the chimneys at Lots Road, a power station in Chelsea used by London Underground. The IBA struggled to get planning permission for the permanent station but after appealing, planning permission was granted in 1972, allowing the station to open in 1975. The station was designed to operate without staffing and monitoring of the output was done by the radio station, error codes were transmitted on a 4.7 kHz subcarrier which were picked up by remote monitoring but were too quiet to be audible. There were two input feeds - one was a single ''Tariff M'' music circuit from the studio, and provided by the

Post Office A post office is a public facility and a retailer that provides mail services, such as accepting letter (message), letters and parcel (package), parcels, providing post office boxes, and selling postage stamps, packaging, and stationery. Post o ...

. The back up was the feed from the FM transmitter. The MW frequencies allocated to the two stations were 1546 kHz and 1151 kHz, shared with other stations in the UK. In order to avoid interference the new station needed to use a

tower array A tower array is an arrangement of multiple radio towers which are mast radiators in a phased array. They were originally developed as ground-based tracking radars. Tower arrays can consist of free-standing or guyed towers or a mix of them. Tower ...

directional antenna A directional antenna or beam antenna is an antenna that radiates or receives greater radio wave power in specific directions. Directional antennas can radiate radio waves in beams, when greater concentration of radiation in a certain directio ...

so that the broadcasts were focused on London rather than interfering with other transmissions such as 1546 kHz in Bristol and 1151 kHz in Birmingham. Saffron Green has a line of four mast radiators 71 m tall and 61 m apart at an angle of 161° ETN . Buried 30–45 cm underneath each mast there is an earth mat of copper wire. The site had seven

Marconi Guglielmo Giovanni Maria Marconi, 1st Marquess of Marconi ( ; ; 25 April 1874 – 20 July 1937) was an Italian electrical engineer, inventor, and politician known for his creation of a practical radio wave-based wireless telegraph system. This ...

B6029 transmitters running at a power of 10 kW, 5 main and 2 standby. On 1 July 1985 there was a fire in the LBC reserve transmitter which took out both services over night. Services were restored next day, although the reserve transmitter needed to be replaced. In September 2020 one of the masts in the array was struck by lightning which damaged the

antenna tuning unit An antenna tuner, a matchbox, transmatch, antenna tuning unit (ATU), antenna coupler, or feedline coupler is a device connected between a radio transmitter or receiver and its radio antenna, antenna to improve power transfer between them by Impeda ...

. Since then the reserve antenna, a wire from one of the masts, has been in use instead.

Transmissions

In 1987 the IBA required stations to stop

simulcasting Simulcast (a portmanteau of "simultaneous broadcast") is the broadcasting of programs or events across more than one resolution, bitrate or medium, or more than one service on the same medium, at exactly the same time (that is, simultaneously) ...

on AM and FM and to provide different services. Capital radio split into Capital FM and Capital Gold, an oldies station. In 2007 Capital Gold was merged with

Classic Gold Classic Gold was a network of three "Gold" music formatted stations which broadcast on AM in Bradford, Hull and Sheffield. They were the sister stations of Pennine Radio, Viking Radio and Radio Hallam respectively and they were part of the ...

to produce Gold, a similar oldies station. Gold stopped broadcasting on MW in London on 29 September 2023, as part of a move by owners

Global Global may refer to: General *Globe, a spherical model of celestial bodies *Earth, the third planet from the Sun Entertainment * ''Global'' (Paul van Dyk album), 2003 * ''Global'' (Bunji Garlin album), 2007 * ''Global'' (Humanoid album), 198 ...

to stop using medium wave. It remains on DAB. LBC has a complicated history of takeovers and renames. It remained broadcasting on medium wave until 30 October 2024. It remains on DAB and in London on FM 97.3.

References

External links

* coverage by ''

Engineering Announcements ''Engineering Announcements for the Radio and Television Trade'', sometimes abbreviated to ''Engineering Announcements'', was a weekly television program of news and information intended for technicians and salespeople in the United Kingdom, pro ...

'' following the fire in 1985 * {{YouTube, C3eN6Jr6UH8, Fire At The 121,000 Watt Transmitter - Saffron Green includes drone footage of the site in 2024 Transmitter sites in England Infrastructure in London Mass media in Hertfordshire LBC Capital (radio network)