[ARC5] 77 GHZ

[Tom Dawson]

Brits applied the maggie to pulse radar, for sure,  I think once the 
klystron became common for Local Oscillators, CW Magnetrons were less 
common, maybe until Microwave ovens.   Cleeton and Williams definitely 
discuss scaling down a Magnetron and assembling under a microscope.

regards,

Tom
----- Original Message ----- 
From: "Geoff" <geoffrey at jeremy.mv.com>
To: "Tom Dawson" <wb3akd at earthlink.net>; "David Stinson" 
<arc5 at ix.netcom.com>; "ARC-5 List" <arc5 at mailman.qth.net>
Sent: Friday, November 15, 2013 8:49 PM
Subject: Re: [ARC5] 77 GHZ


>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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>