The Cairn Hill transmission site is located on a 278-metre hill (Carn Clonhugh) in County Longford that lies 10 km north east of Longford town. This was the first UHF television transmitter to be opened in the Republic of Ireland by RTÉ to facilitate the introduction of their second television channel (RTÉ 2) in 1978, two new channels TV3 and TG4 were also added later. The transmitter was designed to cover an area of poor reception in central Ireland, and when it opened in 1978 it was the most powerful television transmitter in all of Ireland, with an effective radiated power of 800 kW. FM radio transmissions started in 2005 but to date (2016) only RTÉ Radio 1 and local station iRadio are broadcast from here. Digital terrestrial television (DTT) broadcasts began from Cairn Hill in February