[time-nuts] Linear voltage regulator hints...
not.again at btinternet.com
Sat Dec 13 16:48:48 EST 2014
Have you varied the of the GPSDO board itself, say by covering it,
shining a lamp on it, blowing a fan on it, or something?
(It would be even better if you could vary the temperature of parts of
If you're seeing supply voltage variations, you could then just vary
the supply and see what happens.
You may have done this already, but I just didn't see it mentioned.
On Thu, 11 Dec 2014 07:13:14 -0500, you wrote:
> Yeah, I suffer from time-nuts digest lag, family lag, day job lag,
>among other things. So please excuse delayed responses...
> The oscillator has proven to be relatively immune to 'reasonable'
>changes in voltage, as would be expected. About the range of Numbers
>Bob Camp has suggested, or maybe even better. The EFC voltage is not an
>issue at this point. It was previously, and the solution to that was a
>low drift 'roll your own' design.
> It would be nice to replace it with a COTS part, but it looks like
>there aren't any available. Thus the reason for pinging the list.
>Sometimes you all pull things out of thin air... ;) That said, the
>LT3081 looks interesting. At the very least it's easily controllable
>from an external source. I've got a few on order, and if it pans out
>I'll report back here.
> What I'm after right now is in reality small. Temp cycles are
>somewhat apparent from looking at what the EFC voltage is doing locked
>with the GPSDO. It's on the order 10^-12 range, if I did my math right.
>It is visible, so it may be worth trying to fix. Of course, now that
>Bob has his new CS to play with anything I do is judged by a completely
>different standard! ;)
> Again, thanks for the responses!
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