The Cairn Hill transmission site is located on a 277 metre hill ( Carn Clonhugh) at Dernacross in County Longford that lies 10 km north east of

Longford town Longford () is the county town of County Longford in Ireland. It has a population of 10,008 according to the 2016 census. It is the biggest town in the county and about one third of the county's population lives there. Longford lies at the meet ...

. Cairn Hill was the first of two new UHF television transmission sites to be opened in

Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

by RTÉ in 1978, the other being

Three Rock Three Rock Mountain (; archaic: ''Sliabh Ruadh'') is a mountain in Co Dublin, Ireland. It is high and forms part of the group of hills in the Dublin Mountains which comprises Two Rock, Three Rock, Kilmashogue and Tibradden Mountains. The mo ...

in County Dublin. This was to facilitate the introduction of the second television channel

RTÉ 2 (RTÉ) (; Irish for "Radio & Television of Ireland") is the national broadcaster of Ireland headquartered in Dublin. It both produces and broadcasts programmes on television, radio and online. The radio service began on 1 January 1926, whil ...

on UHF, as all the available VHF frequencies were in use by existing transmitters in Ireland. The site was located to cover an area of poor reception in the

Irish midlands The Midland Region (coded IE063) is a NUTS Level III statistical region of Ireland. It consists of the territory of the counties of Laois, Offaly, Westmeath and Longford. The Midland Region spans 6,524 km2, 9.5% of the total area of the st ...

, and when it opened it was the most powerful television transmitter in all of Ireland, with an

Effective Radiated Power Effective radiated power (ERP), synonymous with equivalent radiated power, is an IEEE standardized definition of directional radio frequency (RF) power, such as that emitted by a radio transmitter. It is the total power in watts that would h ...

(ERP) of 800 kW. In later years another two television channels were added, TG4 and TV3.

Digital terrestrial television Digital terrestrial television (DTTV or DTT, or DTTB with "broadcasting") is a technology for terrestrial television in which land-based (terrestrial) television stations broadcast television content by radio waves to televisions in consumers' ...

(DTT) broadcasts began from Cairn Hill in February 2009, with analogue television services subsequently ending nationally on 24 October 2012. Today the transmission site, owned and operated by 2RN (a subsidiary of RTÉ), provides the Irish national DTT service

Saorview Saorview ( ) is the national digital terrestrial television (DTT) service in Ireland. It is owned by RTÉ and operated by 2RN. The service began operation on 29 October 2010 on a trial basis with a full launch on 26 May 2011. By legislation i ...

to an extensive area in central Ireland and also into Northern Ireland. FM radio transmissions from the site began in 2005 but to date (2022) only

RTÉ Radio 1 RTÉ Radio 1 ( ga, RTÉ Raidió 1) is an Irish national radio station owned and operated by RTÉ and is the direct descendant of Dublin radio station 2RN, which began broadcasting on a regular basis on 1 January 1926. The total budget for th ...

and local station

iRadio iRadio is a music-driven youth radio station broadcast in the Border, West, Mid-East and Midland regions of Ireland. The station is one of four music-driven youth stations that were licensed by the Broadcasting Authority of Ireland to challe ...

are broadcast from the site.

Current transmissions

Digital television

FM radio

Cairn Hill relay transmitters

Gallery

Image:Cairn Hill.JPG Image:Cairn Hill2.JPG Image:Cairn Hill3.JPG Image:Cairn Hill4.JPG Image:Cairn Hill top of mast.jpg Image:Cairn Hill Tx.jpg

References

{{Main broadcast transmitters in Ireland, state=collapsed Transmitter sites in Ireland 1978 establishments in Ireland Buildings and structures in County Longford