[ARC5] 77 GHZ

[J. Forster]

The cavity magnetron came over on the Tizzard Mission. The practical
fabrication technique (furnace brazed stack od thin plates) was developed
by Percy Spencer at Raytheon in Waltham, MA.

The Rad Lab was certainly involved in the development.

-John

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


> 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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