Sir, - Your articles on the North Strand Bombing (The Irish Times, December 23rd) based on Micheal Holmes' interview with the German pilot "Heinrich", raise the old allegation of beambending by perfidious Albion. The idea of bending beams is misleading.
The three transmitters of the German navigational system, X Verfahrung, laid down a field or pattern which pilots could interpret in order to establish their co-ordinates. It was easily accessible and, in fact, the RAF availed of it during the war. In order to confuse the German code-breakers, they invented the name CONSOL, the letters of which stood for nothing. In the interview, "Heinrich" claimed that the Allies sabotaged the system by contaminating the pattern with other signals. That makes more technical sense than beam-bending.
A transmitter was subsequently taken from Stavanger and installed in Bushmills, Co Antrim where it was certainly functioning in 1955 when I read a paper on CONSOL to fellow engineering students in Belfast. Anyone who tuned through the long-wave band in those days will recall the slightly muffled throb of the transmissions. An improved system with five transmitters, Bushmills, Quimper and three in Norway, was used up to the late 1970s. I understand that Bushmills and Stavanger are still functional but that the others operate simply as beacons. - Yours, etc. Aodh O Canainn,
Carraig an tSionnaigh, Baile Atha Cliath 18.