[time-nuts] TCXO improvement

[Mark Goldberg]

I am purchasing TCXOs from a reputable supplier and building boards to
install in Ham radios. Every one is indeed different. They also exhibit
hysteresis, sometimes very strong, more than the variation with
temperature. They test in one direction and meet the .25 ppm variation spec
over temp, but if you change the temp in the other direction, it may be .50
ppm offset from what was measured in the other direction. They also drift
with time, several ppm over a year. I also see frequency jumps, likely due
to whatever digital process is used inside the TCXO.

Mark


On Thu, Aug 1, 2019 at 6:04 AM Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
> If you look at any sort of “TimeNut” sort of level of detail, every unit
> in the batch will be different.
>
> Bob
>
> > On Aug 1, 2019, at 3:05 AM, Clint Jay <cjaysharp at gmail.com> wrote:
> >
> > I'd imagine the effort required to characterise a TCXO to that level and
> > add the monitoring hardware/software would put the cost in the region of
> an
> > OCXO but it's an interesting idea, I wonder what the variance across a
> > batch would be
> >
> > On Thu, 1 Aug 2019, 08:01 Tom Van Baak, <tvb at leapsecond.com> wrote:
> >
> >> An email came in asking if it was possible to improve the performance of
> >> a TCXO if one monitors the temperature of the PCB or enclosure and then
> >> applies timekeeping corrections in s/w based on that data. I don't have
> >> specific P/N or other details so treat this as a generic question. Has
> >> anyone tried this?
> >>
> >> /tvb
> >>
> >>
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