On Aug 12, 2014, at 11:38 AM, David Shaw <dj.shaw@btconnect.com> wrote:

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> On 12/08/14 17:28, shadow@shadowgard.com wrote:
>> The US invented the magnetron tbe (you've got one in your microwave).
>>
>> The Brits couldn't manage to make a working unit from the info the
>> Yanks sent over. The Yanks sent over working tubes. They worked. Then
>> the Brits disassembled them (they were bolted together) to make sure
>> that parts matched. They did. But upon reassembly they didn't work.
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> An apocryphal tale, unfortunately.  The world's first working cavity magnetron was constructed by Sir John Randall and Harry Boot at Birmingham University in the UK as part of project to produce centrimetric gunlaying radar for the Royal Navy.  It was first switched on on 21st February, 1940 and was sealed, not by bolting two halves together, but by two British halfpennies held in place with sealing wax.  Later, improved versions were sealed using a gold fusion technique and were water cooled while the later NT98 design was air cooled, first operated on 29th June 1940 and giving a pulse output of 10kW at 10cm. GEC made several copies of this - reputedly using the chamber from a Colt revolver as a drilling jig - and it was number 12 of this version that was taken to the USA in August 1940 with the Tizard mission.  It was later described by the Americans as 'the most valuable cargo ever to reach these shores.'
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> And before anyone wonders at my knowledge in a field so widely at variance with my training - I just happened to be reading all about it last night :-)

Care to share the book/article title? Sounds interesting!

--
Bruce Johnson
University of Arizona
College of Pharmacy
Information Technology Group

Institutions do not have opinions, merely customs