[time-nuts] Thunderbolt stability and ambient temperature
Tom Van Baak
tvb at LeapSecond.com
Tue Jun 9 22:43:38 UTC 2009
> Adding mass increases the thermal capacitance adding insulation
> increases the thermal resistance.
> It is possible to construct an enclosure with a long thermal time
> constant together with relatively low thermal resistance so that the
> temperature of a GPSDO or similar device within the enclosure only
> increases by a relatively small amount.
>
> Multiple alternating layers of thermal conductor and thermal insulator
> reduce thermal gradients as well as temperature fluctuations.
>
> Having an outer conductive layer reduces the temperature gradients over
> the insulator surface.
>
> Readily available inexpensive aluminium foil is a cheaper alternative to
> expensive noble metal foils.
>
> Silica aerogel is one of the most effective insulators.
>
> Balsa wood has been used as the insulator in portable temperature
> controlled ensclosures for standard cells.
>
> Bruce
And the amazing thing is that this temperature control double
oven technology for oscillators was well advanced in 1931. See:
http://www.leapsecond.com/museum/gr676b-50kc/
and especially the "temperature control apparatus" patent:
http://www.leapsecond.com/museum/gr676b-50kc/US1967185.pdf
/tvb
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