[time-nuts] Nifty old GR OCXO?

[Dave Brown]

Since the topic has been raised- herewith a few pix of an equally old 
(well, nearly!) OCXO using mercury-in-glass high and low set point 
thermometers for temperature control.
http://homepages.ihug.co.nz/~tractorb/oven/
This came out of an early openwire carrier system-of UK 
origin-probably immediately post WW2 manufacture. One of the original 
glass xtals has been replaced with a much less interesting style 
holder.

DaveB, NZ

----- Original Message ----- 
From: "Tom Van Baak (mobile)" <tvb at LeapSecond.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Thursday, January 25, 2007 7:31 PM
Subject: Re: [time-nuts] Nifty old GR OCXO?


>> eBay item 150082419799 (Genrad 475-C)--is this some kind of OCXO 
>> frequency
>> reference?  From the description, it sounds like it might be used 
>> to
>> monitor a broadcast transmitter frequency.  Be sure and scroll down 
>> and
>> check out the wood and foam oven box and the "quartz plate" 
>> resonator.
>>
>> The '56 GR catalog at the bama site doesn't show a 475-C, but 
>> that's not
>> surprising as the 475-C looks quite a bit older.
>
> Yes, that's a nice example of a mercury thermometer
> regulated, ovenized quartz plate oscillator, complete
> with balsa wood case and lots of asbestos (not foam)
> insulation. I have a couple of these ovens -- though
> with 100 kc xtals, not the special broadcast freq.
> spkr_volume -- please send me email, OK?
>
> For other old GR oscillator stuff see:
> http://www.leapsecond.com/museum/gr1103a/
> http://www.leapsecond.com/museum/gr1190a/
> http://www.leapsecond.com/museum/gr676b-50kc/
> http://www.leapsecond.com/pages/old-genrad/
>
> Of special note, see the 4 patents I have there
> on the web page, like this one:
> http://www.leapsecond.com/museum/gr676b-50kc/US1967185.pdf
>
> Would you believe that GR had double ovens all
> figured out back in 1931? HP wasn't the first...
>
> /tvb
>
>
>
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