[time-nuts] Nifty old GR OCXO?

[Tom Van Baak (mobile)]

> 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