What was this building used for? - Searchlights??

[ww2ni]

I photographed the building shown here today.
It is on the Lough Neagh shoreline beside Langford Lodge and is marked on the NIEA Website as being a "Searchlight Battery"

I am not sure what it is but I dont think it had anything to do with searchlights. - I was even on the roof!

Please look at the attached.

It does not look WW2 vintage to me so perhaps it was Cold War???

[PETERTHEEATER]

There was an Air to Ground and a couple of PB Ranges here. If that is the building that I have marked as a Quadrant Shelter No4 then I may be wrong.

PNK will answer this I think.

[PNK]

Interesting. It was an old searchlight shelter and is marked as such on the 1949 plans of Lough Neagh ranges. It is also labelled as No.1 Dive Screen shelter for the RP Range. Quadrant No.4 would have been a less than a hundred yards further north along with the direction arrow. QS 4 serverd No.2 practice bombing, the HLB and Live bombing target and the RP range.
For info a dive screen was a piece of perspex mrked out with various angle so that the angle of dive of attacking aircraft could be measured. This was for RP and dive bombing practice.
At present I can't quite figure out how the dive screen was setup as it would have needed a clear view of the approaches. Exising structure were often used or adapted for range use.

[PETERTHEEATER]

Then I was close in assuming that the remains visible in satellite views are QS4. Will now correct my record.

In this case, 'Searchlight' almost certainly refers to a coastal unit used to sweep the area to detect and illuminate marine vessels. The remains of the mounting are visible on the roof. These were referred to as D.E.L.s (Defence Electric Lights) and some were remotely controlled. I opine that this unit may have been bombing range requirement.

This is an 18 inch diameter Halls Light used as a DEL and tripod mounted:

[ww2ni]

Thanks very much for the information guys!