Hi The variable frequency output on the uBlox (and other) GPS receivers has come up many times in the past. If you dig into the archives you can find quite a bit of data on the (lack of) performance of the high(er) frequency outputs from the various GPS modules. They all depend on cycle add / drop at the frequency of their free running TCXO. Regardless of the output frequency, that will put a *lot* of jitter into the output.
Bob > On Apr 4, 2016, at 4:15 PM, Dimitri.p <[email protected]> wrote: > > Regarding "as good a place to start as any", ublox receivers will do 10KHz > all day long. > I didn't realize ublox receivers have dual output until after I built a > couple of other GPSDOs, (well, maybe four) > > As for a good OCXO: other than the Morion MV89a, ($20-$50) for anything > else, figure about one or two hundred bucks depending on new vs used and > "luck". > > But as it's been said before it all depends on if you are building "to use" > or "to play/learn/experiment/get your hands dirty" > > Building does not save money or time and buying doen't give you an excuse to > fire up the soldering iron. > Decisions...decisions... > > > Dimitri.p > > > At 12:00 PM 4/4/2016, Chris Caudle wrote: >> On Mon, April 4, 2016 11:18 am, Tom Holmes wrote: >> > The preceding questions always come up when a newbie >> > comes up on the list wanting to build their own GPSDO. >> >> It is good to make sure the person actually wants to build a GPSDO. >> A few years back I was in a similar position, and my answer was I actually >> needed a high accuracy reference to check frequency accuracy of some >> clocks, and the recommendation was just get a Thunderbolt. I didn't know >> about surplus GPSDO's available so that was good advice for me, I didn't >> actually >want< to build a GPSDO myself. It would have been fun, but the >> end goal was more important to me. >> >> So I think really the first question should be do you want to build a >> GPSDO, or do you want a high accuracy time and frequency source for its >> own use? Because if you want to own a GPSDO to use, building one yourself >> is probably not the way to go. Get a surplus unit, or save up a little >> more and get a new Jackson Labs. >> If you just like to build stuff and a GPSDO is the particular stuff you >> want to build next, then go ahead and have fun. Chris Albertson's arduino >> based design is probably as good a place to start as any, it should be >> cheap and I think the pieces are easier to find than that CPLD based >> design that relies on having a GPS that can output 10kHz instead of just >> PPS. >> >> -- >> Chris Caudle >> >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
