[ntp:questions] NTP absolute accuracy?

David Malone dwmalone at maths.tcd.ie
Mon Nov 2 11:34:05 UTC 2009

"David J Taylor" <david-taylor at blueyonder.not-this-bit.nor-this.co.uk.invalid> writes:

>Thanks, David, David and Jan.  A few milliseconds is what I had expected, 
>so if you are on a consumer line, what implications does that have for 
>unruh's comment?

I've been plotting the offset reported by "ntpq -p" for my Rugby
receiver and a GPS-based server over DSL at:


(Appologies if you're using IPv6, the link to the machine is a bit
wonkey right now.) I take a sample every 64s from the Rugby peer,
and "lanczos" is the other peer uses ntp's standard polling.

The Rugby unit was built by Ian Dowse, and is described here:


It was calibrated to be within about 1ms of the GPS unit when they
were connected to machines on the same LAN.


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