The Clarkstown radio transmitter was a longwave radio transmitter in County Meath, Ireland. The mast was located approximately east of the village of Summerhill, in a field south of the R156 regional road at Clarkstown. At 248 metres high, it was more than double the height of the Spire in Dublin.
Constructed in 1988 for the transmission of Atlantic 252 on 252 kHz, it used one high guyed steel framework mast with triangular cross section, insulated from ground. The original transmitters were two 300 kilowatt Continental transmitters built by Varian Associates of Dallas. These were replaced in 2007 by a single 300 kilowatt Transradio TRAM 300L transmitter. The ground around the mast and the entire transmission site bed are lined with copper for conductivity. The site has an ITU-cleared transmission power of 500 kW by day and 100 kW at night but was later only capable of operating at 300 kW by day and 100 kW at night.
Atlantic 252 ceased operations on 2 January 2002 and sports radio station TEAMtalk 252 briefly took over the frequency for a few months in 2002. The transmitter was later taken over by RTÃÂ Networks Limited (now 2RN). It was used for the AM version of RTÃÂ Radio 1 on 252 kHz from 2004 to 2023, and was the sole source of RTÃÂ Radio 1 on AM from 24 March 2008, when the medium wave Tullamore transmitter on 567 kHz was taken off air, to 2023.
In 2007, the transmitter carried a Digital Radio Mondiale multiplex overnight, featuring Radio 1, RTÃÂ Digital Radio Sport, RTÃÂ Digital Radio News and the World Radio Network, before reverting to AM transmission for the daytime. DRM tests since ceased, with AM transmissions operating full-time once again until closedown in 2023.
On 24 September 2014, RTÃÂ announced that broadcasting of RTÃÂ Radio 1 on 252 kHz would cease on 27 October 2014, however following representations from Irish listeners in the UK and others, that date was postponed. On 31 March 2023, RTÃÂ announced that the longwave service would be discontinued on 14 April of that year., and this happened as planned.
The mast was felled on Thursday 27 July 2023.