[time-nuts] Segal law: freq difference for GPSDO

Henry Hallam henry at pericynthion.org
Wed Mar 30 02:24:57 EDT 2016


On Tue, Mar 29, 2016 at 5:48 PM, Vlad <time at patoka.org> wrote:
>
> I tried to see the 1PPS on my oscilloscope. Here is the series of
> screenshots from that experiment:
>
> https://www.patoka.ca/OCXO/TBvsSL/

>From those scope shots it looks like one or both of the GPSDOs does
not have any kind of lock to GPS time.  The PPS leading edges from the
two receivers should be aligned to within a few tens to hundreds of
nanoseconds, but yours are hundreds of milliseconds apart.

The screenshot you have at
https://www.patoka.ca/OCXO/TBvsSL/StarLocIImonitor.png shows a
receiver only tracking one satellite, which is not sufficient.  Maybe
the antenna signal connection to that unit is poor or maybe it's
defective. The filename says StarLoc but the window title says
Thunderbolt, which is it?

Good luck,
Henry


More information about the time-nuts mailing list