[ntp:questions] Slow convergence of NTP with GPS/PPS

Richard B. Gilbert rgilbert88 at comcast.net
Fri Oct 24 13:00:09 UTC 2008

Nicola Berndt wrote:
> Unruh schrieb:
>> "Richard B. Gilbert" <rgilbert88 at comcast.net> writes:
>>> David Woolley wrote:
>>>> Richard B. Gilbert wrote:
>>>>> To turn your equipment on after months of downtime and expect it to 
>>>>> lock on to the correct time with millisecond accuracy within seconds 
>>>>> is asking for a hell of a lot.
>>>> Not really.  He's starting a GPS receiver at the same time and that has 
> Btw, I have minpoll 4 maxpoll 4 in my ntp.conf and ntpq -p says: "poll 
> 16". Is it the poll of ntpq -p or of ntpd?

It's the poll interval of ntpd.  Ntpq does not poll!  The poll interval 
varies between 2^MINPOLL and 2^MAXPOLL.  You have set MINPOLL=MAXPOLL=4 
giving a poll interval of 2^4 or 16 seconds.  This is usually the 
correct choice for a GPS receiver.  For getting time over the internet 
it would, under most circumstances, be a horrible choice!

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