I found a very interesting (to keberoxu and me at least) page on Radio Teilifis Eireann archives but got a failure message when I tried to play sound http://www.rte.ie/archives/2013/0213/367559-unesco-world-radio-day/

"To mark UNESCO World Radio Day, RTÉ Archives takes a look back to the first day of radio broadcasting in Ireland with the opening of 2RN on the 1st January 1926.

On 1 Jan 1926 at 7.45 2RN, the first Irish radio station, went on the air from a studio on Little Denmark Street, Dublin. Dr. Douglas Hyde was there to officially open the radio station. At the opening night, the army number one band played a selection of music arranged by Colonel Fritz Brase. It contains a recording of the first Director of Broadcasting, Séamus Clandillon, singing 'Cnocáinín Aerach Chill Mhuire'.

This report is taken from a programme '50 Years of Irish Radio', from 1975, on the opening of 2RN on the 1st January 1926.

The accompanying image shows the 2RN Control Room in 1926.

Jimmy Mahon is pictured at the control desk in the control room of 2RN in Little Denmark Street, Dublin. He is using Marconi battery operated equipment with A+ B amplifiers. Jimmy Mahon is presenter Pat Kenny's uncle."