[ARC5] 77 GHZ

[Tom Dawson]

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?
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html