[time-nuts] Mystery hp Ovens For Sale

Mike Cook michael.cook at sfr.fr
Sat Jun 4 03:45:38 EDT 2016

> Le 4 juin 2016 à 06:59, Ian Stirling <is at opus131.com> a écrit :
>  It looks like the quartz is in the sealed glass "valve", or "tube".
>  I have removed a similar glass vacuum enclosed 100 kHz frequency
> marker generator from my Eddystone EA12 receiver that I bought from
> Tom Roberts, G3YTO (SK 1985), in September 1978. I don't use the EA12
> any more and I wonder what kind of timing device I can make from this
> beautiful slab of quartz, approximately 28 x 5 x 2 mm. I don't have a
> data sheet for it, but I can see which pins are connected to the quartz.
> In the receiver, it has a spring stabilized black metal cover that mates
> to the socket. I suspect that is so that the thirteen valves and their
> heaters create a thermal equilibrium and the black shroud lets the
> crystal bathe in it. I ran the EA12 24/7 from then until I bought and
> used an IC-735 in January 1987.

If you haven’t yet thrown out the EA12 you could try to trace the oscillator circuit into which it was plugged, recover the socket and duplicate the circuit with modern components. Once working you could add a divider circuit and include it in a led clock.  

I have been trying to get some old crystals  singing again using a Pierce circuit. Results are not brilliant. 
I could start some of the later 1-5MHz range , but had no luck with low frequency. I cannot get really clean output from even those that start so I am missing something. Some of the slabs are giants ( one marked 1292Hz +/- 10^-5) and I would love to get them started. Some of them are real works of art as well. 

I’ll post to a new thread with a req. for ideas.

> It is a GEC Crystal Unit, 100 kHz, serial number 82690 and type JCF/193,
> "Made in England", and it looks like it means business.
> Ian, G4ICV, AB2GR
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"The power of accurate observation is commonly called cynicism by those who have not got it. »
George Bernard Shaw

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