[time-nuts] Re: UCCM OCXO Temperature

[Bob Camp]

Hi

Any time you measure a surface temperature, the “rest of the environment” 
matters quite a bit. Check it in a room at 30 C you get a different answer than
25C. Have a very modest amount of air flow ( = you can barely feel it) and 
you get yet a different answer. 

The OCXO is likely rated to 70 or 85 C (who knows which one. Having an internal 
temperature 20 to 30C above that would not be out of the question. 

You have *maybe* 4 mm of insulation between the oven and the case. That’s not
a lot ……

Bob

> On Jun 23, 2023, at 3:09 PM, Askild via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Hi Keelan,
> 
> It's not unusual for OCXO's too have an internal temperature of 80ºC, and
> even higher.  So the amount of insulation affects the external temperature
> of the OCXO.
> So 50ºC should be perfectly fine.
> 
> Regards,
> Askild
> 
> 
> On Fri, 23 Jun 2023, 19:40 Keelan Lightfoot via time-nuts, <
> time-nuts at lists.febo.com> wrote:
> 
>> I just received a Trimble UCCM module, and the OCXO gets quite hot, 50ºC or
>> so. It holds at 50°, so it doesn't appear to be in any kind of runaway
>> condition, and the UCCM works fine and achieves full lock. But is this
>> temperature normal?
>> 
>> I only own two other things with OCXOs in them, and they barely get warm to
>> the touch, but they're larger units and decades older than the UCCM, so my
>> sample size for what a modern-ish compact OCXO should feel like is quite
>> limited.
>> 
>> - Keelan
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