[ntp:questions] Re: Compensating DCF77 radio signal propagation delay

Ulrich Windl Ulrich.Windl at RZ.Uni-Regensburg.DE
Tue Nov 25 09:40:05 UTC 2003


Xisco Lladó <timekeeper at bitic.net> writes:

[...]
> I supose it is, in part, due to propagation delay of the radio signal
> from transmiter (Germany) to Mallorca (Balearic Islands - Spain) where
> I am situated. (about 1265km).
> 
> This propagation delay varies during day and seasons but I think it
> could be compensated with a mean value of it.
> 
> Do you know any method to calculate it? I would like to fix it with
> fudge parameter.

I'd suggest to enable peerstats for a week or so. Then average the
offset for every peer to get a set of values: offset_peer_1,
offset_peer_2, ..., offset_DCF77. Then combine all your non-DCF77
offsets to one value. Then avarage that value and the DCF77 offset.
This is not correct, especially if some of your peers are
systematically wrong, but it would be a good starting point.

Or maybe arrange a friend visiting you with a PC and a GPS clock to
calibrate your offset... ;-)

Regards,
Ulrich



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