The remoteness of this 12 mile long shingle spit made it suitable for experimenting with aerial machine guns, bombs, navigation, photography and parachutes, which continued in the interwar period.
Radar's early development
The Orfordness Beacon (set up in 1929) was one of the earliest experiments in long range radio navigation, then in the mid 1930s work started on a new defence system that became known as radar.
Led by Sir Robert Watson-Watt, early work took place in the old WW1 huts before moving further down the coast to Bawdsey Manor. Their work brought about the Chain Home network, instrumental in overcoming the German threat from the air.
Second World War
Though the airfield was not used, the Aeronautical Armament Experimental Establishment was based here. Activities included "assessment of the vulnerability of aircraft to hostile fire" (English Heritage).
More buildings went up on 'The Street' and batteries were built to counter VI Flying Bomb guided missiles.
Atomic Weapons Research Establishment and 'controlled ruination'
Ballistics observation tower
According to English Heritage's detailed report, in 1960 the Establishment stated "there will be no tests involving the release of radioactive matter".
However, it describes how one former employee said tests were done with "either high explosives or their fissile/fusion components, but never both together", and "remembered being present during an overnight test on a system with components made of plutonium".
Laboratory 1
Laboratory 3
Laboratory 2
The structures were designed to contain any accident, like the Vibration Test Buildings or pagodas, whose roofs would collapse
Since 1993 this part of the peninsula has been owned by the National Trust whose policy is to allow the site to decay while minimising human interference.
Survivors of high pressure, shock, extreme temperatures and high vibrations, the buildings' main threat is the encroaching sea, constantly eroding and reshaping this fragile environment.
Cobra Mist, a $1 billion folly
Further north, construction began in 1967 on a new Anglo-American project codenamed Cobra Mist.
AN/FPS-95 441a was an over-the-horizon (OTH) radar system pointed at Moscow, designed to monitor soviet activity.
Testing began in 1971 but in 1972 problems emerged with noise interference affecting reception for which no explanation was found. Spyflight suggests the Russians could have been to blame, its signals jammed by agents in a trawler in the North Sea.
The USAF gave up and left in June 1973. Costing around $1 billion in today's money, it was the largest, most powerful and sophisticated OTH radar at the time with a broadcast signal of 10MW.
Globalsecurity.org gives an impression of what the array might have looked like before removal in the mid 1970s.
"...a huge fan-shaped array of aerials supported on masts from 42 feet to 195 feet high. The antenna consisted of 18 log-periodic antenna strings, which radiated like spokes in a wheel from a central "hub." Each string was 2,200 ft in length and carried both horizontal and vertical radiating dipoles. The strings were separated by 7 deg in angle, and they thus occupied a 119-deg sector of a circle. The complete antenna was located over a wire-mesh ground screen, which extended beyond the strings in the propagation direction."
Spyflight says
"The radar was controlled from a large steel blockhouse which stood on short legs behind the array and was connected to the array by cables running to an underground chamber, lined with copper, in front of the array."
The above photo is at the 'hub' of the fan, but no underground chamber was found. Taught lines of wire remain on parts of the ground, remnants of the wire mesh screen.
The 80 acre expanse is a now a haven for wildlife, from rare insects, plants and fungi to grey canine-like animals that when startled bolt toward the main building.
Orfordness Transmitting Station - the BBC looks east
In the late 1970s the Cobra Mist site came under control of the Foreign Office as Orfordness Transmitting Station, and from 1982 to 2011 was owned by the BBC, broadcasting the World Service to continental Europe.
Wikipedia describes the three types of aerial:
"The directional aerial for 648 kHz (erected in 1981-82) consisted of a row of five 106.7 metre (350 ft) freestanding steel lattice towers of triangular cross section."
"The directional aerial for 1296 kHz (erected in 1978) consisted of six freestanding steel lattice towers. Unlike the directional aerial for 648 kHz, they were arranged in two parallel rows with three towers in each."
"There was also a back-up omni-directional mast radiator for 648 kHz (erected in 1983), which could only handle transmitter powers of up to 250 kW and was only used when maintenance work was being carried out on the directional antenna"
Future plans
The site closed then transferred to private ownership in 2015. Martin Fletcher visited last year for the Economist's 1843 Magazine and described the Cobra Mist building:
"Empty halls except for one that was filled with huge grey transmitters [...] an old glass-fronted control centre, rooms within rooms to thwart electronic eavesdropping, inner sanctums with beryllium-coated steel doors and handles on the inside only. Labyrinthine passages to offices with fading maps of Europe on the walls, tool shops, a canteen, a recreation room, a sick bay, old filing cabinets and packing cases stuffed with who knows what. Internal staircases descending into the murky flood waters below."
Interviewed, the new owner said he bought it as "it's a folly of grandiose proportions" and hopes to create local employment. Broadband, communications, a data centre and a solar farm are mooted as potential new uses for the site.
