John
This makes for interesting reading:
http://www.cufon.org/cufon/cobramst.htmOTH = Over The Horizon
NB: I am not a radar technician and know nothing about radars so what follows has been taken from the document displayed by following the link shown above and the sources shown below.
Cobra Mist was suddenly terminated in June 1973 due to various technical problems, primarily noise - the source of which was never established but Electronic Counter Measures (ECM) were not ruled out. This suggests the Soviets were jamming the emissions. However, whilst it was up and running, its designed max power was 10MW but it only achieved (apparently) a max output of 3.5MW There was a phenomenon known as 'aerial arcing' at high power outputs. Also, the 81st TFW must have had some involvement with the project as references to it appear in the history of the 81st TFW (apparently).
...However "antenna arcing" and "corona" are mentioned. Both of these are electrical effects which occur at high power levels and reveal the strength of the electrical fields surrounding the radar antenna which itself was physically massive. As a speculation, we suppose it is remotely possible that SOME sightings or other effects MIGHT be attributed to the intense radio frequency electrical field present when the radar was being operated at high power levels. Note that, according to the documents, the design power level of the radar was never realized.
The sudden termination of the programme is attributed to the technical problems and in particular the noise issue. However, the US had pumped something like US$150m into the programme, so to close it suddenly was surprising. The closure was so swift that staff were only given a matter of a few hours notice and were so incensed that some of them staged a protest lock in. However, approx 40 technicians were subsequently employed at Bentwaters. This tends to suggest that work on OTH radars continued, or why would the US retain the technicians? Something was going on on the 'ness after June 73, e.g. RAF lorries were often going onto the 'ness, ostensibly as part of an ordnance disposal programme.
Sources:
(1) 40 Years of Marconi Radar from 1946 - 1986; GEC Review, Vol 13, No 3 (1991) Pages 172 - 189.
(2) Orfordness: Secret Site. Kinsey, G; Lavenham Press (1981)Keeping with Obs Chevaline theory, there is a very tenuous link between UK OTH radar technicians being employed at Bentwaters post June '73, on-going work on the 'ness involving the RAF, the 81st TFW and Orfordness, Chevaline stress testing on the 'ness circa '79 and the possibility of 'odd lights' being generated by high power radar emissions causing arcing and coronas....and if such strange lights occured, they would be on a bearing of 110 from Woodbridge, almost the same bearing as the lighthouse....
Projects can be closed for a variety of reasons but to close a project as abruptly as they did with Cobra Mist suggests a couple of things (a) it was compromised (b) the concept had been proved (c) a major breakthrough had been achieved and given the concept had been proved but compromise was suspected, then it was essential to move the project core team to a much less visible and highly secure area.... Nacking great aerials on the coast, with technicians drinking in the local pubs and going to and fro on a daily basis is hardly conducive to secrecy. I'll bet there must have been a fleet of AIG's off the coast, outnumbering the local fishing boats by two to one and more 'tourists' visiting Orford than you could shake a stick at. So I'd reckon, given the US regarding the UK's ability to keep a secret (e.g. Philby, Burgess, Maclean, Blunt etc etc) as non existent, they couldn't wait to get the scientists behind the wire and out of the way of prying eyes and pricked up ears.
Therefore, although there is no hard evidence, I suspect that the activity on the 'ness regarding Chevaline, the work involving the OTH radar techicians working at Bentwaters, the 81st TFW, odd lights produced by high power radar and the RFI are somehow linked. No idea how...just a gut feeling.
You can fool all of the people some of the time and some of the people all of the time but you cannot fool all of the people all of the time (Winston Churchill)...causa latet, vis est notissima