[ntp:questions] ntpd: time reset problem

David Lord snews at lordynet.org
Wed Sep 16 22:47:31 UTC 2009


David Lord wrote:
> Steve Kostecke wrote:
>> On 2009-09-15, David Lord <snews at lordynet.org> wrote:
>>
>>> Meanwhile I'll see if ntpd will step from refclock source as
>>
>> It will.
> 
> It does, sort of :-(
> 
> On NetBSD-5.0.1 with radioclkd2 + shm and Conrad module tuned
> to MSF connected via serial-usb converter, from four attempts
> I've twice hit ctrl+c after about 20 minutes, another attempt
> completed after 18 minutes with time reset -17.345sec, and
> last try completed after 7 minutes with time slewed 0.008s.
> 
> If the 7 minutes was typical, I'd go with that method
> but waiting 20 minutes or more is just too long.
> 
> That's most I can do today and I'll try similar with
> chrony either tomorrow or Friday before trying again
> with ntpd.
> 

Must have been some sort of interference this morning, but
led on module had been pulsing at 1s each time I looked.
Radioclkd2 -v -d had shown it was seeing MSF (rather than
WWVB or DCF) but I hadn't left that running long enough to
see it had actually worked out correct time.

Tonight I gave it another couple or tries with "ntpd -q"

reset +0.150s within 300s
then used date to give a bigger initial offset
reset +66.9s within 330s
then started ntpd and was in sync within 260s

That's good enough for me. The usb connection rules out
PPS mode and seems to limit to +/-10ms.


cheers

David




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