[ARC5] 77 GHZ

[Tom Dawson]

Here's the reference
Phys. Rev. 45, 234-237 (1934) 

I've not seen anything available for free download, I printed out a microfilm copy in about '81 from a university library, but couldn't put my hands on the paper unless I was looking for something else.  

Certainly an outstanding effort on the part of the authors.  


regards, 

Tom



----- Original Message ----- 
From: "Leslie Smith" <vk2bcu at operamail.com>
To: "ARC-5 List" <arc5 at mailman.qth.net>
Sent: Friday, November 15, 2013 5:03 PM
Subject: Re: [ARC5] 77 GHZ


>  Hello Tom,
>  This is pretty interesting, I'd like to know more.
>  Where can I read about this?
> 
>  Recently I've been repairing older Varian NRM spectrometers, and the
>  precision of the signals (wrt frequency) is astonishing.
>  Flipping a proton (in a molecule) results in a frequency shift of
>  several Hz - measured at 90.000 MHz.
>  Fascinating - and this is measured using 1970's technology.  No uP,
>  nothing digital, even the chart-recorder used the older motor and
>  error pot to position the pen.
>  All that - and it still works nicely.
> 
>  73 de Les Smith
>  vk2bcu at operamail.com
> 
> 
> On Sat, Nov 16, 2013, at 6:50, Tom Dawson wrote:
>> 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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