[time-nuts] Brand new OCXO/TCXO reccomenations

[Forrest Christian (List Account)]

Some of these sites already have a internet-connected temperature sensor on
a PCB inside a unvented plastic (electronics) enclosure inside the outdoor
weatherpoof metal enclosure.  With just a quick look, I found one which
slewed from 21C to 65C over 2 hours within the last couple weeks.   I don't
have enough data from that day to tell how much of that 44C was during a
short period - I only have the two samples 2 hours apart.

It's amazing how quickly though a bit of sun on a grey metal box will heat
the box insides up.  Cooling is a lot slower though.

I will say though that the idea of adding some thermal mass/insulation
around the oscillator to reduce the temperature change during holdover is
something I'm going to investigate.

On Fri, Sep 25, 2020 at 3:50 AM Hal Murray <hmurray at megapathdsl.net> wrote:

>
> > 1) In an unconditioned/semi-conditioned space.   The ambient temperature
> can
> > slew 20*C easily over the holdover period.   (Think sun hitting an
> outdoor
> > enclosure first thing in the morning - the ambient temperature tends to
> rise
> > quickly).
>
> It would be interesting to get some data on that.  Clouds blocking the sun
> or
> holes in the cloud cover would be a variation.
>
> If the sun hits the enclosure, how long does it take the air inside to
> heat up
> and then how long does it take the gear inside to warm up?
>
> One of the classic tools for problems like this is to attach a big blob of
> stuff to the crystal to dampen thermal changes.  When you design your test
> setup, can you leave room for a brick and collect data with and without
> when
> you toss it into the freezer?
>
> --
> These are my opinions.  I hate spam.
>
>
>
>
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-- 
- Forrest