Is there a way you can force your currently disciplined oscillator to free-run, and log the phase difference between oscillator and GPS over a couple of days?
Tim N3QE On Tue, Oct 3, 2017 at 2:15 PM, Skip Withrow <skip.with...@gmail.com> wrote: > Hello Time-Nuts, > > Well, I think I know a little more about my GPSDO problem, but > probably have more questions now than before. Thanks for all the > replies to the first post with thoughts and suggestions. > > I first tried restarting Lady Heather and doing a cold boot on the > NTGS50AA (then entering the same disciplining values). Same behavior. > > I let it run over the weekend and the same behavior happened on > Saturday and Sunday morning. > > So, yesterday (Monday morning) I changed the gain to the gain of the > oscillator (.0072Hz/V), damping to 1.2, and time constant to 900s. On > the attached PRS10-2 plot you can see that it quickly settled. This > morning, it looks like all is well from the plot (about an hour before > the furnace kicks in at the right of the plot). HOWEVER, when the > plot is expanded there is still funny business going on with the DAC > control voltage at the same time of day. I just think the changed > parameters limit the disturbance. The expanded plot is the attached > PRS10-1. > > At this point I'm beginning to think that the NTGS50AA is the issue, > but there are lots of questions left. > > 1. There are various version of the NTBW50AA/NTGS50AA GPS/operating > firmware. Mine is 10.3 and I notice that it has the LH 'ro' > designation (as does the 10.4 version). The 10.5 version does not > give the LH ro notice. Maybe it behaves better with the disciplining? > I will have to give a 10.5 a try. > > 2. Why does the glitch occur at 8am in the morning? Will have to try > powering the NTGS50AA up at different times and see it the glitch > moves around. > > 3. Which disciplining parameters are affected by this glitch and which are > not? > > 4. Have other people seen this same behavior? Does it happen on > Thunderbolts too? > > I'll update again when I have more data. > > Regards, > Skip Withrow > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.