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The AN/FLR-9 'Type' Array








Sources and Recommended additional reading by Dr Bob Clarke

"The Illustrated Guide To Armageddon ISBN 978-14456-0915-7"

“Four Minute Warning, Britain's Cold War ISBN 0-7524-3394-6”

"AN/FLR-9" via Wikki and Internet sources

With kind thanks to Chris Morshead, and Dr David Abrutat, Departmental Historian, of GCHQ,

The famous wooden chain home mast formed part of another antenna set similar to an AN/FLR-9 array,

Firstly, the AN/FLR-9 was a type of very large circular "Wullenweberantenna array, built at eight locations during the cold war for HF/DF direction finding of high priority targets. The worldwide network, known collectively as "Iron Horse", could locate HF communications almost anywhere on the planet. Because of the exceptionally large size of its outer reflecting screen (1056 vertical steel wires supported by 96 120-foot towers), the FLR-9 was commonly referred to by the nickname "Elephant Cage." Constructed in the early to mid 1960s, in May 2016 the last operational FLR-9 at Elmendorf-Richardson in Alaska was decommissioned. It can be confused with the US Navy's AN/FRD-10, which also used a Wullenweber antenna.


Blakehill's central aerial array was similar to this, but not understood to be identical. 

FLR-9s were constructed at the following places:

The similarities to these sites and Blakehill?


Just look at an aerial view of the FLR-9 array in Karamursel in Turkey, compared to a Google Earth image of the former RAF Blakehill (black lines marking the conduit scars added for clarity)


The results are rather striking;


Former AN/FLR-9 array in Karamursel, Turkey 

2018 result from Google Earth of Blakehill

September 2021 - new photos released - © CROWN COPYRIGHT GCHQ


Thanks to the assistance of project contributor, Chris Morshead, permission was given to us via Dr David Abrutat, Departmental Historian, of GCHQ, to release these official declassified photos of the mast and array area.

Aerial view of Blakehill 4 April 1967.jpg

In this aerial photo of 4th April 1967, the flower like pattern of the array can be clearly. seen - compare this to the Karamursel array in Turkey - the similarity is striking.




The perimeter of the aerial array - unknown date




Blakehill Aerial field .jpg
B & W photo of Tower, Blakehill.jpg

The famous wooden chain home mast -  unknown date - possibly 1970's/1980's




To the north west of the array site (PRIVATE LAND) are the remains of electrical and cable boxes - it has been discussed but never proven that the receiving equipment at Blakehill picked up the first distress transmission from the Falkland Islands following the Argentine invasion in 1982 - the first time the UK had been alerted - it may well have been through this very conduit below that this transmission traveled,  going on to alert Margaret Thatchers cabinet and the launch of the UK task force.

A second ring of aerials was located in the 'Glider Field' which is a field behind the Foresters Pub where Horsa Gliders were parked during the airfield's wartime operation (eye witness source Mr Tony Harris, Churchview Nursing Home)  

Nothing remains in the field today.     It is not yet known what this array was for.   The Ordinance Survey Pathfinder Map 1981 shows these masts, along with other mast locations (not considered accurate due to the secretive nature of the operations).

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