Hi There are a lot of dewar / vacuum flasks on eBay in a wide variety of shapes and sizes. Some get into the proper combination of affordability, size and shape. There does not appear to be a constant supply of any one version so it is very much shop and see.
Dewar based OCXO’s go way back ( in this case that’s into the 1950’s :) ). They are still made today in very limited quantities. Heat flow is highly asymmetric so it is a somewhat different design approach than a “normal” oven. Heating a TCXO is generally a bad idea. You get the low circuit Q / poor ADEV of the TCXO and the warmup time and complexity of an OCXO. Yes, there are some fairly unusual TCXO’s that do pretty well on ADEV. They aren’t what you are going to buy at DIgikey. Bob > On Aug 2, 2019, at 4:18 AM, Bill Slade <[email protected]> wrote: > > Hello! > I have done this and can attest that it works well. I did not use a TCXO, > though. I used a 48 MHz, third-overtone AT-cut crystal in a Colpitts > oscillator configuration. The vacuum flask was ovenized to maintain > temperature near the stationary point of the temp characteristic (near 50 deg > C). The oscillator could be phase locked to an external atomic reference > (in our case, a rubidium) or 10 MHz from a GPS receiver. > > The inspiration was a couple of excellent NASA reports from some years ago, > which I have attached (as links because files are large) for convenience. > Cheers, > Bill > Nasa Precision Quartz > 1<https://onedrive.live.com/embed?cid=3CBCA1CF8AB21FE1&resid=3CBCA1CF8AB21FE1%213504&authkey=AA4EqyT05-Iz2nU&em=2> > Nasa Precision Quartz > 2<https://onedrive.live.com/embed?cid=3CBCA1CF8AB21FE1&resid=3CBCA1CF8AB21FE1%213505&authkey=AEG_NqxtMFVIE_o&em=2> > > On 02/08/19 01:35, Perry Sandeen via time-nuts wrote: > > Yo Bubba Dudes!, > If one has the space, a simple cure might be to get one of the wide mouth > thermos containers that they sell in large variety stores such as Wal-Mart > for being able to eat something like stew or some semi-solid hot food out of > the container itself. > Regards, > Perrier > _______________________________________________ > time-nuts mailing list -- > [email protected]<mailto:[email protected]> > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
