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

[Magnus Danielson]

From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
Subject: Re: [time-nuts] Double ovened 10811-60158 on ebay
Date: Sat, 12 Jul 2008 21:16:41 +1200
Message-ID: <48787679.80108 at xtra.co.nz>

Hej Bruce,

> 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.

Well, it was not about doing the perfect box in any sense, but just "casing"
an OCXO within a box can have rather noticeable effects on the OCXOs ability
to handle temperature changes. The degree of the filter can then be varied at
need.

> You just need to remove the few watts of heat from the OCXO without too 
> large an internal temperature rise.

Indeed, but the over will not burn as much as it's immediate surrounding is
hotter than if it was sitting there alone in the box.

Providing a too good insulation is certainly a concern. The trick is really
to make the insulation-heatmass-insulation-heatmass stages. Just adding one
such stage can be sufficient.

Cheers,
Magnus