[ARC5] Magnetron/Klystron 1936-40

[J. Forster]

There were crystal detectors and bolometers in labs. The Rad Lab or
Harvard's RRL built a 26odd GHz RADAR  but it was no good because of H2O
absorbtion. I think Ed Purcell was involved.

-John

=================



>   G'day list.
>   This is interesting.  I remember a cover picture on the front page of
>   Electronics Australia when I was in high school.
>   (That was 457 BC, not BC-457)
>   An article in the magazine featured the Varian brothers, and stated
>   they developed the Klystron on a budget of $100, but this is an
>   approximation.
>   They were given a room to work in and a budget for materials of $100
>   in exchange for 1/2 the royalties on the Klystron.
>   They did this work between '36 and 39.
>
>   In contrast, the magnetron was developed in Manchester (or Birmingham)
>   I forget which in 1940.  The Brits got more power from their unit, and
>   their work assisted the US RADAR development a good deal.
>  Cleeton got his PhD in the mid-30s, and he worked at about 1cm so ...
>  this must be around 30GHz.  I'd take 24GHz as "close".
>  Whatever he used - it swept the GHz region where ammonium absorbed.
>  God only knows how they measured what they were doing at that
>  frequency, back then.  Amazing!
>  Anyway, Cleeton/Williams must have had more than an acorn 955 in their
>  pocket.
>
>   What do other list readers know?
>   This is interesting.
>
>   73 de Les Smith
>   vk2bcu at operamail.com
>
>
>
>
> On Sat, Nov 16, 2013, at 12:49, Geoff wrote:
>> I thought the Brits and MIT Rad Lab developed the magnetron during WW2.
>>
>> Carl
>>
>>
>> ----- Original Message -----
>> From: "Tom Dawson" <wb3akd at earthlink.net>
>> To: "David Stinson" <arc5 at ix.netcom.com>; "ARC-5 List"
>> <arc5 at mailman.qth.net>
>> Sent: Friday, November 15, 2013 2:50 PM
>> Subject: Re: [ARC5] 77 GHZ
>>
>>
>> >I think the prize goes to Cleeton and Williams at U Mich in the early
>> '30's
>> >for discovering the absorption spectra of Ammonia at 24 (I think)  GHz.
>> >
>> > Used Western Electric Magnetrons as models and scaled them down in
>> size to
>> > the desired frequency to generate the RF.
>> >
>> > Polished brass parabolic mirrors on transmit and receive, selenium rod
>> as
>> > a detector.
>> >
>> > Wavelength measured with metal diffration gratings.
>> >
>> > Ammonia at 1 ATM in a rubberized canvas bag, they observed absorption
>> of
>> > the microwave energy.
>> >
>> > The idea came from their consideration that if quantumtheory was true,
>> > then there ought to be an absorption line at 24 GHz or so, and they
>> found
>> > it. Opened up the field of microwave spectroscopy, as far as I know.
>> >
>> > Pretty durn neat for the time.
>> >
>> > 73
>> >
>> > Tom
>> > ----- Original Message -----
>> > From: "David Stinson" <arc5 at ix.netcom.com>
>> > To: "ARC-5 List" <arc5 at mailman.qth.net>
>> > Sent: Friday, November 15, 2013 1:40 PM
>> > Subject: Re: [ARC5] 77 GHZ
>> >
>> >
>> >> Similar surprise:
>> >> I have an Aircraft Radio Corporation 1945 catalog, flogging their
>> surplus
>> >> parts from cancelled contracts at the end of WWII.
>> >> All kinds of Command Set parts being offered.
>> >>
>> >> But they were also offering feedlines, cavities
>> >> and other "plumbing" for 21 GHZ.
>> >> Who knew anyone was "plumbing" 21 GHZ in 1945?
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