RTE Radio One - 729 khz from Cork, Ireland
of RTE transmitter in Mahon, South East of Cork City
photo showing inner harbour and Lough Mahon to the East
view showing Blackrock (top half) and Mahon (bottom half). You can make
out where the South link road
passes the RTE site. To the South of the mast is the Douglas Estuary
which no doubt helps to improve the radiated signal.
this close up, you are looking down on top of the 120 metre high mast.
You can see it's shadow going towards the top of the picture and
crossing the road. Also shown is the small dam which fills at every
high tide and ensures that there is always water close to the base of
the mast. This dam is now part of an amenity walkway which passes the
this mast was first erected, it was in a very quiet area surrounded by
fields. Today, the City of Cork has expanded and now the mast is now
alongside the major housing development of Jacob's Island and the Mahon
Point shopping centre.
Photo shows the rush hour traffic on the South link road driving past the mast and heading for the Lee tunnel.
photo shows the pond at the base of the mast.
view from the dam which keeps the water at a high level in the pond.
2007 - View from the adjacent walkway showing some development work
Height : 120 metres, Power Output : 10 kilowatts, Frequency : 729 khz
At 729 khz, the wavelenght is appox 412 metres. With a 120 metre mast, this would make it approx 0.29 wavelenghts long and it would behave as a slightly long quarter wave ground plane.
From 1979 to 2004, RTE used to transmit their 2FM music channel here as well on 1278 khz. At that wavelenght (235 m), the mast was 0.51 wavelenghts long and would have acted as an end fed half wave vertical.
Note also that there are 3 sets of guide wires. Along each set on the photo above, you can see 'black' objects. These are insulators which split the steel cable up into smaller lenghts. These lenghts are so small, i.e. percentage of a wavelenght, that they have no effect on the transmitted signal. If they were not used, the guide wires would become part of the antenna system and would interfere with the radiated signal.
John Desmond 2007. Last
Updated May 2007