[time-nuts] Double ovened 10811-60158 on ebay

Bruce Griffiths bruce.griffiths at xtra.co.nz
Sat Jul 12 05:16:41 EDT 2008

Magnus Danielson wrote:
> I keep wondering if not a passive oven (metal box, insulation, metal box)
> would be sufficient. Worst case temperature change rates would be significantly
> reduced such that the oven loop can track it better. The remaining temperature
> shift will be less. Basically acts like a lowpass filter.
> What strikes me is the lack of isolation between the oven shells. Oh yes, they
> have tried to bring the heating around the outer shell, but never the less.
> Cheers,
> Magnus

A box with multilayer walls: insulator/metal/insulator/ metal etc does a 
much better job of attenuating thermal fluctuations.
The insulator layer only need be significantly poorer at conducting heat 
than the metal layer.
Tufnol sheets are OK for the insulator layers, they bond well to 
aluminium sheets with epoxy.
You just need to remove the few watts of heat from the OCXO without too 
large an internal temperature rise.


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