Re: [time-nuts] ZED F9T first look
Hi Not to surprisingly: the same set of tests on the F9P give pretty much identical results. He ran a bunch of navigation tests. Not at all surprising. It wouldbe nice if *somebody* could get that board and compare it to a Cs …. maybe also check it out against a popular piece of software as well ….hmmm…. Things may be moving along ( = getting better) as far as sawtooth correction of the F9P PPS output. If something becomes available to look at there should be a pretty good way to check it out. Another firmware update for the F9P came out in the last week or two. No big or really useful improvements. It does appear that the use of the EXT-INT pin as a “measure a pps” (to within 8 ns ….yuck …) has vanished. Not clear at all if that change is temporary or permanent. The Digikey C099-F9P kit from uBlox does seem to do all it is supposed to. The puck antenna that comes with it is nothing fancy, but it does work. The $80 eBay antennas do a better job. It the kits ever come back into stock, they are a better deal than the Sparkfun boards. Bob > On Mar 3, 2019, at 6:55 PM, Chris Burford wrote: > > For those that are interested in the soon to be released ZED-F9T receiver > here is a quick write up on the RTLExplorer blog: > > https://rtklibexplorer.wordpress.com/ > > ___ > 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.
Re: [time-nuts] ZED F9T first look
Fwiw, I have been evaluating the F9P for post-processed time transfer (code-based) and it's looking significantly better than the NEOM8T. Tdev is about 3 times better, mainly due to a reduction in the tdev of the sawtooth-corrected pps. Zero baseline performance is getting close to that of a top of the line time-transfer receiver for code-based transfer. Cheers Michael On Mon, 4 Mar 2019 at 1:30 pm, Chris Burford wrote: > For those that are interested in the soon to be released ZED-F9T receiver > here is a quick write up on the RTLExplorer blog: > > https://rtklibexplorer.wordpress.com/ > > ___ > 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.
[time-nuts] ZED F9T first look
For those that are interested in the soon to be released ZED-F9T receiver here is a quick write up on the RTLExplorer blog: https://rtklibexplorer.wordpress.com/ ___ 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] GPSDO Educational Tool
I was doing a set of measurements and realized I'd come up with everything you need to understand about GPSDO in one ADEV plot. :-) I thought I'd pass it along. This shows a sawtooth-corrected GPS PPS and two GPSDOs -- one quite good (Z3805), and the other quite awful (u-Blox M8F VCTCXO). You can see that the quality of the crystal oscillator determines what the control loop time constant should be -- the better the oscillator, the longer the time constant. As different as their performance is, both these units have their constants pretty well chosen. John ___ 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.
