[ntp:questions] Thunderbolt at NTP ref clock.

DaveB spam.goes at nowhere.com
Wed Jul 31 19:17:52 UTC 2013


In article <dajlca-267.ln1 at ns2.lordynet.org.uk>, snews at lordynet.org 
says...
> 
> unruh wrote:
> > On 2013-07-30, David Lord <snews at lordynet.org> wrote:
> >> Dave Baxter wrote:
> >>> Hi again.
> >>>
> >>> In reference to my other thread.
> >>> "THunderbolt monitor/control on Win7 ?"
> >>>
> >>> Well, as that device seems happy in it's potential new home.
> >>>
> >>> I've been poking about the interweb looking for info as to getting the 
> >>> TB used as a reference clock for NTP.
> >>>
> >>> I found this page:-
> >>> http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver29.html
> >>>
> >>> That on the face of it, seems to tell me what I need.
> >>>
> >>> So, poking arround (no changes yet) my ntp.conf file, I "think" I need 
> >>> this:-
> >>>
> >>> # Trimble Thunderbolt on /dev/gps1 (first serial port)
> >>> server 127.127.29.1    mode 2  minpoll 4 maxpoll 4   prefer
> >>> fudge  127.127.29.1    time1 0.020
> >>> fudge  127.127.29.1    flag2 1  refid GPS
> >>> server 0.uk.pool.ntp.org iburst minpoll 5 maxpoll 12
> >>> server 1.uk.pool.ntp.org iburst minpoll 5 maxpoll 12
> >>> server 2.uk.pool.ntp.org iburst minpoll 5 maxpoll 12
> >>>
> >>> Would this be suitable for general purpose local time sourcing?  With 
> >>> fallback to the pool if the TB burps, dies or is otherwise compromised.
> >> I'd add a few more public servers, I've been using five.
> > 
> > Why not 47?
> > His are backups. 3 is fine. 
> 
> Mine are backups for my gps/pps but sometimes here the internet
> might not be as reliable as at your location and I've known two
> or three of my backups go unreachable. My gps also has bad days
> in certain weather conditions.
> 
> >>> Could all the fudge factors go on one line?
> >> Shouldn't be a problem.
> >>
> >> fudge  127.127.29.1    time1 0.020  flag2 1  refid GPS
> > 
> > That looks like a huge time1 fudge. Are you sure that the pool servers
> > do not actually give better time than does the Trimble? 
> 

Hi.

Thanks for the info.  Yes, those fudge figures are from the doc's on the 
website.  I suspect it's related to the use of the serial data stream, 
as I don't recall mention of teh PPS signal.

More on that later...

Yes, I'm running "older" than optimum(?) versions, but it's stable at 
present, and that's my priority.  I do plan on building another system 
to replace it with, but that's on the back burner at present.  However, 
when it happens, it'll use whatever is stable and current at that time.

Cheers.

Dave B.



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