[time-nuts] poor-man's oven

[jimlux]

I recall some years ago folks were talking about putting a PTC 
thermistor on the TCXO of a FlexRadio SDR1000 to stabilize the frequency 
as a sort of poor-man's OCXO.
It's also referenced at
http://www.setileague.org/askdr/xtaloven.htm
where he says "order of magnitude improvement" with no numbers (from 1% 
to 0.1% or from 1 ppb to 0.1 ppb?)

I wonder how well that actually works.

Say you bought an inexpensive (perhaps non TC) XO and an equally 
inexpensive thermistor, glued on on the other, hooked em both up to 3.3 
or 5V.

Yeah, there's issues with room air blowing on it, and tolerances in both 
the XO and thermistor, so your absolute frequency accuracy may not be so 
hot. But what sort of medium to long term performance can one expect.

I did some searches, because I'm sure we've discussed this before, but I 
couldn't find it.  There was some stuff from Oct 2007, but that was in 
the context of a more complex circuit, and the thermistor was the 
sensor. (discussions of TE devices too)