Hi The other gotcha is that (as noted in other posts) the signal is not particularly clean noise wise. Given the low cost of a GPSDO these days, going that way is not a really big deal investment wise. Even the low end units will give you a *much* better 10 MHz to drive an instrument than the raw output from a GPS module.
Bob > On Jun 20, 2019, at 7:20 AM, David Slipper <[email protected]> wrote: > > That is probably good enough for my needs and certainly better than the cheap > XOs in the instruments. > > BTW I just came across a document "GPS-based Timing Considerations with > u-blox 6 GPS receivers - Application Note" that makes interesting reading. > > Many thanks > Dave > > > On 20/06/2019 00:19, Bob kb8tq wrote: > > Hi > > On a second to second basis, the 10 MHz will be off by < +/- 0.02 ppm. > Averaged over 24 hours ( = your frequency counter is set to a > 80,0000 second > gate time) you will be much closer. +/- 0.0000001 ppm is a good guess. > > The important point is that the first number is more often the one you bump > into. > The second one only “counts” if you have some sort of flywheel that does the > > > 80,000 second averaging for you. > > > > Bob > > > > On Jun 19, 2019, at 4:31 PM, David Slipper > <[email protected]><mailto:[email protected]> wrote: > > > Hi, I am running a UBlox Neo-6M and have configured it with LadyHeather > to produce a 10MHz output for use as a better reference for a couple of > instruments. > > Is there any way with LH to determine the accuracy of the 10MHz output > in ppm?? > > I am aware that the 10MHz output is jittery on my scope (is that phase > noise??) due to the fact that the internal clock is divided by a > non-integral value to reach 10 (I believe the internal oscillator is > 16MHz). If I set it to produce 8MHz it is rock solid. > > I am really interested in the long term accuracy of the 10MHz signal - > say over 24 hours. > > I'm a bit of a newbie at this so any clarification would be welcome. > > TIA Dave > > > _______________________________________________ > time-nuts mailing list -- > [email protected]<mailto:[email protected]> > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > > > > _______________________________________________ > time-nuts mailing list -- > [email protected]<mailto:[email protected]> > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
