[time-nuts] Re: Is SC the most stable cut for lowest phase noise?

[Magnus Danielson]

Hi,

It is in this context one should look at the CSAC, as the low power 
consumption can enable it to be powered on much earlier. It's not that 
it's performance is stellar, but when you consider power consumption and 
what that can enable, it becomes impressive and another approach to 
solve things.

Cheers,
Magnus

On 2022-06-11 00:00, Bob kb8tq via time-nuts wrote:
> Hi
>
> Well …. folks have made AT based OCXO’s that heat up in “seconds” ( as in under
> a minute ). Back in the 1980’s they stabilized to < 1x10^-7 at least as fast as the
> then typical SC based OCXO’s did ….  ( < 6 minutes ). Collins bought quite a few of
> them over the years.
>
> Bob
>
>> On Jun 10, 2022, at 1:25 PM, Dr. David Kirkby via time-nuts <time-nuts at lists.febo.com> wrote:
>>
>> On Fri, 10 Jun 2022 at 17:39, Lux, Jim via time-nuts <
>> time-nuts at lists.febo.com> wrote:
>>
>>> On the subject of rapid warm up. I suppose if you had a need, one could
>>> dump as much power as you need into the heater. Turn on oscillator,
>>> lights in room dim for a few moments.
>>>
>> Is that not likely to damage a crystal? Different parts of the crystal and
>> likely to be at significantly different temperatures at the same time,
>> putting a lot of stress on the crystal due to a thermal gradient. It's
>> probably a bit academic, as nobody is going to make an oven that heats up
>> in fractions of a second, but if one did, I suspect it might not do the
>> crystal a lot of good. This is only an educated guess - I don't have
>> anything to back it up.
>>
>> At the other extreme,  would there be any advantage in actually heating the
>> crystal very slowly, over the course of an hour/day/week, so the
>> temperature gradient across the crystal is very small? Of course, if an
>> oven took ages to reach the correct temperature, it would be inconvenient
>> for most applications, but for some applications, the advantages might
>> outweigh the disadvantages. Of course, if one does this, I suspect one
>> would have to cool the crystal slowly too to prevent a significant thermal
>> gradient across the crystal.
>>
>> I know it's a bit different, but I have a 600 mm f4 Nikon camera lens. I
>> was told that Nikon cools the front element over a period of 6 months to
>> reduce stresses in the glass.
>>
>> Dave
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