[time-nuts] Thunderbolt performance vs temperature sensor

Steve Rooke sar10538 at gmail.com
Sun Mar 8 19:57:35 EDT 2009


2009/3/9 Magnus Danielson <magnus at rubidium.dyndns.org>:

> So, you can expect that the metal can of the OCXO reacts fairly quickly
> and the temperature sensor is a thad slow. This also matches exercises
> we have done by using a fan to do forced air convection tests on OCXO
> and tempsensor. Putting a *plastic* hood over it significantly lowered
> the risetime and the consequence is that the lower risetime allowed the
> tempsensor inside the OCXO to sense the change and react to it. This
> introduces a third time constant, the time-constant of the OCXO control.
> The effect of using a hood or not was significant. The change of
> frequency shape was distinct and for the measurement interval we looked
> at the phase drift was about 1/3 for this simple addition.

So would boxing in an ocxo with something like polystyrene foam
improve the tc of the unit? Thinking about this it is a stage towards
having a double oven.

73, Steve
-- 
Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW
Omnium finis imminet




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