Hi Consider that a lot of the heat flow is through the glass wall of the vacuum gizmo. You want to tie your heater(s) to it in order to create an iso-thermal “wall”. Often this is done by gluing the whole assembly together.
In addition, you probably also want a foam plug in the end of the beast to keep from creating an even more non-uniform (= very directional) heat flow. Yes, the directivity issue is inherent in the design approach. It’s not clear that you want to exaggerate it …. Bob > On Jun 7, 2017, at 6:03 PM, Attila Kinali <att...@kinali.ch> wrote: > > On Wed, 7 Jun 2017 22:20:50 +0100 > Peter Vince <petervince1...@gmail.com> wrote: > >>> Additionally: if I would set out to build my own OCXO today, I would >>> go and buy one of those lunch thermos flasks to house everything. Their >>> isolation is higher than anything you can easily build yourself, >>> especially at that size. I would place the (inner) oven at the bottom, >>> probably using a puck design similar to the E1938, place the electronics >>> on top of it and close the lid using an aluminium plate which forms >>> the outer oven. >> >> Might there be a problem that a thermos flask is TOO well insulated, and >> even the minimal heat generated in the electronics would be more than could >> escape through the vacuum, and so the unit would cook? > > That's why the top of the flask is closed with an aluminium plate. > Assuming the plate on the top is around 5x5cm, that should give a > thermal resistance in the order of 20-40°C/W. That's not low, but > should be enough to support 100-400mW of heat generated inside > with a moderate temperature differential. If it turns out not to > be enough, making the plate bigger and attaching a few fins, or > having a small fan blowing lightly on it should solve the problem. > > > Attila Kinali > > -- > You know, the very powerful and the very stupid have one thing in common. > They don't alters their views to fit the facts, they alter the facts to > fit the views, which can be uncomfortable if you happen to be one of the > facts that needs altering. -- The Doctor > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.