Navaid beacon?

[B314]

Back in the 1970’s during a visit to my native Valentia Island in Kerry I opted to climb Geokaun Mt (elevation 261 meters, oxygen not required...). The result was a very rewarding view of all points, in a rare spell of sunshine. I noticed there was a short radio mast at the summit, possibly 3 meters high topped with what seemed like a brass ball. I assumed it was some sort of navigation aid to aircraft however I’ve often wondered exactly what it was. Whilst I’m 80% certain it is related to aviation would anybody be able to confirm this and would it appear as a waypoint or a beacon on aviation charts?

[HEATHROW DIRECTOR]

If it was an aeronautical navaid it would appear on charts and be listed in the AIP, together with co-ordinates, frequency,etc. I am not familiar with any navaid which has the sort of aerial you describe. However, there is a possibility. NDBs operate on low frequencies so they require very long aerials. For navaid purposes it is desirable to have the aerial in the vertical dimension to provide omnidirectional coverage (NDB= Non Directional Beacon). To reduce the aerial to a manageable size it can be "loaded" so that although it is short, the transmitter sees it as the correct match. Loading can be achieved by attaching wires to the top of the mast but this could, possibly, be done by some sort of metal sphere.

Alternatively, it may have nothing to do with aviation; perhaps some sort of meteorological instrument?

Perhaps someone with more knowledge will respond...

[Bushfiva]

Irish Coast Guard MF receive mast? Currently a unipole, replacing a previous structure in 2004.

[B314]

Thanks Heathrow Director, it is possible it could be a meteorologically related as the Valentia Meteorological Observatory (based ironically on the mainland!) exists there.
Bushfiva an equally possible scenario. I'll contact both and perhaps also Valentia Radio a Maritime service who may just know what the "stick on the hill" might be about!

[HEATHROW DIRECTOR]

Interesting about the Met presence. Did you get a really good look at the "thing", or was it from some distance? I'm wondering if it might be a sunshine recorder - a glass ball which focuses the sun to burn a line on a strip of paper which is marked with time segments?

[B314]

I was standing a few feet away from it and no it wasn't a sunshine recorder, but from memory a three sided mast, no guy wires and the brass ball on top. I don't recollect any power cabinet nearby or power cables routing into the ground which begs the question if it were some form of TX where would the power come from? I'm strectching my memory now but I can't recall an antenna feed inside the mast as such, but it was back in the early 70's!

I've emailed Met Eirann, and the the Valentia contact address for the Irish Coastguard, who are responsible for Valentia Radio, so hopefully I'll get a reply in the next few days, which I'll happily publish on here.

[HEATHROW DIRECTOR]

Hmmm.. I wonder if it's some form of lightning conductor? There are devices for plotting lightning strikes but I don't know how the information is derived.
Keep us posted; I'm mega-curious now!

[holyflyer]

I wonder if this is it :
http://www.transport.ie/upload/general/8559-0.pdf
See page 5 couple of references.
Looks like it was replaced in 2004.

[B314]

It must be as there was only the one mast there (also a Unipole) and not a collection of them. Ironically Bushfiva did suggest this above.

I also had confirmation from Met Eirann it was not one of thier instruments, further indication that it must be related to the Coast Guard. The report in question also originates from them so I'm happy to say "Case closed"!

Thanks all for your help!
B314