Hi Getting into the ~2 ns region is not as hard as it once was. The real gotcha is needing a L1/L2 receiver to do it *consistently*. If you just have L1, then you can easily get more than a couple of ns over a day due to various atmospheric effects.
It’s not at all clear what sort of GPS they have in these boxes. (at least not with a quick Google check). If it’s an L1 / L2 device they could probably hit 2 ns on a consistent basis. If it’s L1 only it would depend a lot on conditions . Simply put - I’d look closely at the data sheet to see just what is in the box. I’d ask a few questions about the conditions the testing was done under. Bob > On Aug 16, 2018, at 2:40 PM, Ralph Devoe <rgde...@gmail.com> wrote: > > I've seen several spec sheets on high end GPSDO's that seem to have > performance approaching a low-noise cesium standard, but only cost $3-6$K > new. One is the SRS FS740 which appears to combine a GPSDO with the > interpolator of the SR620 counter. This gets down below 10(-13) in one day > and drops below 10(-14) for longer times. The other is the EndRun > Technology Meridian II, which has been tested at NIST, as shown in > https://www.endruntechnologies.com/pdf/NISTReport-EndRun-MeridianII-US-Rb.pdf > . This shows a TDEV <2 ns (according to NIST) and and ADEV that gets into > the 10(-15)'s for times longer than 1 day. > Has anyone had any experience with these? > > Ralph DeVoe > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.