[time-nuts] What’s the BEST crystal?

[jimlux]

On 2/29/20 2:47 PM, Attila Kinali wrote:
> On Sat, 29 Feb 2020 17:01:27 -0500
> Bob kb8tq <kb8tq at n1k.org> wrote:
> 
>>> Isn't that where "whispering gallery" modes come into the picture ?
>>
>> …… and done with sapphire.
>>
>> This is the real answer to “why is nobody going to do this?”. You already
>> have something ( the sapphire resonators ) that does better than
>> anything you could reasonably expect.
> 
> It's the other way round. Yes, we have *a* solution for better phase noise
> and stability, but not *the* solution. A CSO is a full size 19" rack
> filled with equipment that needs constant maintenance. Nothing you can
> put on a satellite, much less carry around. People wouldn't even put it
> in cellphone base station, although they would love to have the additional
> frequency stability and phase noise performance to squeeze in some
> more customers into the limited frequency space.


How does a CSO compare with a Mercury Ion clock - the latter does fit in 
a satellite and is intended to replace the USO kind of function.

> 
> It is actually very hard to beat crystal oscillators and vapor cell
> frequency standards in the stability/phase noise/size/power consumption/cost
> trade-off. And until recently, quartz oscillators and vapor phase
> standards occupied seperate areas in this trade-off space. Until the
> CSAC came around and connected them.
> 
> 
> 			Attila Kinali
>