[ntp:questions] Stratum goes back to 16 all the time

Timo Felbinger Timo.Felbinger at physik.uni-potsdam.de
Tue Jan 16 08:54:29 UTC 2007

On Sun, 14 Jan 2007, David Woolley wrote:

> In article <Pine.LNX.4.58.0701141646090.16319 at uranos.quantum.physik.uni-potsdam.de>,
> Timo Felbinger <Timo.Felbinger at physik.uni-potsdam.de> wrote:
> > Or just use tickadj, which can adjust the frequency in steps of 100ppm
> > and thus can bring your clock into +/-50ppm of the correct frequency;
> > ntpd is then well able to cope with the remaining error.
> The reason I didn't suggest this is that I don't believe that there isn't
> any reasonable way in which a working crystal oscillator could be out
> by 500ppm, which implies that either the oscillator isn't being
> disciplined by the crystal, or that something else is causing the
> frequency to be misinterpreted.

It seems that such lousy crystals do exist: I have several (on various
types of PC mainboards) which need ticks from 9992 to 10003. Without
tickadj, ntpd will have a very hard time to stabilize or will not
converge at all.
After setting the optimal "tick", there are no more problems.
The oscillator frequency seems to be pretty stable over time, just
different from what it is supposed to be (in particular, I never
had to change an "optimal" tick value once I had determined it).


More information about the questions mailing list