[ntp:questions] ntpdate refusing ntp.nmi.nl

David Woolley david at ex.djwhome.demon.co.uk.invalid
Sat Jan 10 09:57:24 UTC 2009


Terje Mathisen wrote:

> 
> Assuming the clock itself is OK, then I believe the problem might be 
> with their dispersion calculation, i.e. the dispersion value will be 
> assumed to increase linearly from the time of the last sync to a better 
> (lower stratum) reference clock.

Root dispersion calculations don't extend back into the reference clock.
> 
> For a standards lab Cs clock, that dispersion value should be in the low 
> ns range even after multiple days, and never get up to a single us, afaik.

That would imply they are using very special hardware, with the PC 
software clock motherboard crystal directly phase locked to the atomic 
clock.

Assuming more conventional hardware, either they are not locked to PPS, 
or ntpd is ignoring the PPS signal in determining the reference time.




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