[time-nuts] Rb standard questions

[Bob Camp]

Hi

On Jul 29, 2013, at 1:13 PM, Robert Roehrig <k9eui at yahoo.com> wrote:

> Recently acquired a LPRO-101 and have a few questions:
> 
> 1) Does an Rb standard "deteriorate" with age alone or only with power applied?


There is nothing specific to an Rb that causes it to wear out sitting around. It does have all the normal electronics sort of issues, so yes they do break from things like blown electrolytic caps. Humidity will cause more "aging" when the power is off than when it's on, so aging rate is a toss up.


> 2) From a cold start, how long does it normally take for the unit to stabilize to its
>     final accuracy?

What's your definition of final accuracy?

Should be within 1x10^-9 in 10's of minutes
Should be within 1x10^-10 within an hour
Should be within 1x10^-11 within a day

Keep in mind that the aging rate will drop off for a couple of months after it's turned on and that the ADEV at < 3 seconds is likely worse than 1x10^-11. That makes the "final" in the numbers above a bit vague. Best reference would be the average frequency at 48 hours. 

Temperature stability may be as loose as several parts in 10^10. If your device warms up as it turns on (small heatsink) you'll have to add that into the stability above. 

> 3) what is the typical life of such a unit?

If it's run without a heat sink, about two years.

If it's power off on the shelf,  many decades.

Run well cooled, > 10 years for 90% of the units

Bob

> TIA
> Bob, K9EUI
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