David, I would like to add that, from my own experiences, the GPS has to be configured to output $GPRMC sentences only. Otherwise the PPS part of NTP doesn't work.
I have a related question: given that my system clock is synced to an external GPS within ms, how do I read time that gives me the same accuracy? When I tried to read time at 60Hz, I found that the times returned are not periodic, sometimes even the same. Jack On Dec 1, 9:28 am, "David J Taylor" <david-tay...@blueyonder.not-this- bit.nor-this-part.co.uk.invalid> wrote: > "Dave Baxter" <g8...@nospam.uko2.co.uk> wrote in message > > news:mpg.257f2d55775bad5a989...@news.demon.co.uk... > [] > > > Hi David... > > > I'll put the BSOD details in another post, beneath David Harts post, to > > keep the tree branches sane... > > > You did help me out a while back, by pointing me at the exact same > > distribution of F'BSD as you used, I managed (at the third attempt) to > > get it to install on a suiable PC (P3/766MHz, 512M Ram) and it in it's > > original guise seemed happy. At least, all the things I tried sort of > > worked as documented. > > Ah, I remember now.... > > > It took me two more attempts to get the kernel recompiled with PPS > > support enabled (needing another full re-install in the process, though > > I now know where the "backup" kernel file is if I do that again!) > > I was luckier. > > > My single biggest problem, and no disrespect to you or anyone else here, > > is that (and I've done exactly the same with stuff I work with for other > > lesser people) is one is "too close" to it all in many ways to get a > > truly idiot proof (for that's what us newbies need :) ) install working > > safely. (If at all in some instances!) > > I agree, and that's why I have a user-group for my own software and > encourage people to try beta versions. Having different people explain > things in different ways can often be helpful when you have a mental block > about something. I've tried to simplify things at the top of my Web page: > > http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html > > by adding a "for the impatient" paragraph - i.e. for those who don't or > can't RTFM! I'd welcome any input to try and improve that page for > "novices". > > > I think I now know what I did wrong with the serialpps.sys in Windows, > > you'll probably laugh when you read it in my reply to the other Dave > > (maybe we should all use the name Bruce instead?) > > You can save playing with that for another day, though, > > > The version on the Meinberg windows port of NTPD I've used so far is:- > > ntpd 4.2...@copenhagen-o May 22 2009 If that helps (as shown in the > > NTP monitor program) > > > I realy would preffer a stable version, rather than any bleading edge > > versions, as the rest of the system can be left to it's own devices for > > weeks if needed with no issues. > > I agree, but the "stable" branch doesn't yet include the PPS support, so > we're stuck with the "development" branch. Quite honestly, I would treat > most of the development branch as being of "production" quality. I had > one problem when it wouldn't work with Windows 2000 (now resolved, I > think, I'm using ntpd 4.2.5p231 on PC Bacchus), and one more subtle > problem where something didn't work as well after a reboot of a Windows-7 > system. That's also now resolved. > > > > > > > I think I need at least single figure mS stability and resolution, not > > absolute uS accuracy, but better is sort of better I guess, I'll bow to > > superior knowledge on that though. > > > There are at least two other Faros users (just thought of someone else) > > so that's 4 that I know of, who would also like a fully self contained > > system for this purpose (Faros) as they are not well connected to the > > 'net, with resulting NTP issues as a reuslt. > > > Have to say, my main problem with this, is that there are so many > > versions of this and that, plus knowledge I'm still learning is needed > > to make it fly. > > > Best Regards. Now to answer Dave Harts post. > > > Dave Baxter. > > Keep asking the questions, even if they seem elementary - and I will try > to both provide answers and record them on my Web site for others. One > issue which you haven't addressed (as far as I know) is how the Faros > program uses an accurate time. I take it that the author of the program > gets the time from Windows - he does know that time is typically only > updated once every ten milliseconds, I guess? NTP doesn't have an API > which can tell you the time more accurately than that, which is a pity > because that would be very handy.... > > 73, > David _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions