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

[Richard (Rick) Karlquist]

I think there is a severe misunderstanding of this issue.
First of all, "rapid warmup" is a red herring.  The real
issue is "rapid frequency stabilization".

The time it takes for the oven to cut back (typically only
a minute or two) is a very minor part of the time budget
to get to frequency stabilization.  You could have an AT
cut oscillator that reached "oven warmup" in 1 second, but
then you would have something like a 1 hour wait to get
frequency stability, due to the thermal stresses.

Part of the reason for the misunderstanding is that the
problem I have described is basically orthogonal to the
proverbial time nut with his master OCXO in an underground
bunker running on an uninterruptible power supply, that has been
powered up continuously for umpteen years.


Rick N6RK

On 6/10/2022 6:47 AM, Lux, Jim via time-nuts wrote:
> On 6/9/22 8:53 PM, Bob kb8tq via time-nuts wrote:
>> Hi
>>
>> There happen to be *some* AT cut based OCXO’s that beat the typical
>> SC cut on warmup … just saying …. :)
>>
>> Bob
>>
> 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.
> 
> But everything is a tradeoff, and I suspect that over time "standard 
> designs" sort of migrate to particular ratios of things like peak vs 
> average heater current, etc.  Especially in applications driven by 
> design rules for things like "maximum current per connector pin" or 
> "component derating" - I suspect that drives things more than the 
> fundamental physics, in most cases.  Why are diodes rated at 1 or 3 
> Amps?  And not 2?
> 
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