[time-nuts] Frequency comparison

[Joop]

>It is best to leave your stable quartz and Rubidium oscillators 
>running continuously, preferably on a UPS in case of power failure, 
>for best results.
>
>Best regards,
>
>Charles
>

I can understand. But I will not need that high accuracy very often. 
So I just wanted to examine what can be expected after power-on. Just
saving a bit of environment where possible.

>From a Datum LPRO specifications document I read:

Warm-up: (at -20°C) (at 25°C)
Time to Lock: < 8.7 min < 5.4 min
Time to <1E-9: <10.2 min <7.3 min
Time to <4E-10: <12.7 min <10.6 min

Frequency Retrace: <±2.5E-11
(after 24 hrs power on @ 25°C & up to 48 hrs power off)

I guess my readings are all within the above specs. The retrace value is
probably the limiting factor. 2.5E-11 translates in my setup to 90ns/hour.
Which looks being reached already in about 2 hours after power-on. So if
the Efratom is essentially the same as the Datum, then all looks fine.

Joop