[ntp:questions] Fwd: Re: NetBSD GPS/PPS using 4.2.6p3

David Lord snews at lordynet.org
Tue Aug 23 15:29:55 UTC 2011


David Lord wrote:
> A C wrote:
>> On 8/20/2011 17:41, David Lord wrote:
>>
>>> My config for NetBSD-5.1 on i386:
>>>
>>> # GPS Sure serial tty00 /dev/gps2
>>> server 127.127.20.2 mode 18 prefer
>>> fudge 127.127.20.2 time2 0.350 refid GPSb
>>>
>>> server 127.127.22.2
>>> fudge 127.127.22.2 flag2 0 flag3 1 refid PPSb
>>>
>>> The Sure output is at a higher baud rate than default hence the
>>> use of 'mode 18'.
>>> offset
>>> *GPS_NMEA(2) GPSb 0 377 -80.444 6.309
>>> oPPS(2) PPSb 0 377 -0.013 0.004
>>>
>>>
>>> Offset is normally lower than above but peaks at 25-30us when
>>> system is under heavy load.
>>
>>
>> I've reconfigured like yours and tried it, too (with the addition of a
>> minpoll to speed up the GPS):
>>
>> server          127.127.20.1  minpoll 4 mode 1 prefer
>> fudge           127.127.20.1  time2 0.245 refid GPS
>>
>> server          127.127.22.1
>> fudge           127.127.22.1  flag2 0 flag3 1 refid PPS

I went back through ntp.conf files from 2009 to date and see
that I used "fudge 127.127.22.1 flag3 1" for just under half
of them. I can't remember there being any advantage in using
either setting.

David




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