Hi Ok, so Bob took a little literary license to make a point :)
_________________ If you spread out past just MV 89’s you can indeed span a range from about 4x10^-13 out to 2 or 3x10^-11 for various parts you see for sale on the auction sites. Yes you will buy a *lot* of OCXO’s and sort through them before you find the one that is at the low end of that range. Even if you stick with one model, some of them seem to have a pretty wide spread …. Bob > On Oct 20, 2014, at 7:01 PM, Bert Kehren via time-nuts <[email protected]> > wrote: > > Allow me to clarify. > I started out with 7 MV 89 one of it a total loss. The remaining 6 after 3 > month + burn in show better than 1 E-11 aging per day, 2 closer to 5 E-12. > Only two have been tested for ADEV and are close to 1 E-12, 2X not 10 X. > Bert Kehren > > > In a message dated 10/20/2014 5:58:37 P.M. Eastern Daylight Time, > [email protected] writes: > > Hi > > The problem is that there are no “magic coefficients”. What you run > depends very much on the exact OCXO you have, the environment you run it in, > and > the result you are after. > > For instance, Bert is after frequency stability. Tom is after the right > time. Each of them will have very different coefficients for the same > oscillator. > > My Morion OCXO has a floor of 2x10^-12, Bert has some that are 10X better > than that (maybe). His coefficients and mine will be very different. > > I had an antenna outdoors. It got many sat’s all the time. Now I have one > indoors. It’s not getting lots of sats all the time. My old coefficients > are not going to be my new coefficients. > > No magic bullet, you have to do the work. > > Bob > >> On Oct 20, 2014, at 1:20 PM, Brian Lloyd <[email protected]> wrote: >> >> On Mon, Oct 20, 2014 at 6:48 AM, Bob Camp <[email protected]> wrote: >> >>> Hi >>> >>> We tend to focus on this or that enhanced feature in a piece of code. It > ’s >>> fun to talk about. That’s not what keeps most designs from doing what > they >>> should. By focusing on this rather than the testing required, we set > people >>> up to fail. If you start off the project believing you mostly need > fancy >>> code when you mostly need long term testing instead, you hit a wall > pretty >>> fast. Setting up for one is not at all the same as setting up for the > other. >>> >> >> Sounds to me like the hardware and code are pretty straight-forward. The >> difference comes from the terms and coefficients in the PLL loop filter > and >> those need to be optimized for each OCXO. There appear to be here a > handful >> of people who have a pretty good idea of what those coefficients should > be >> for various well-known OCXOs out there. >> >> So why not do the GPSD hardware, software, and then provide the >> coefficients that will get a handful of the more popular OCXOs available >> out there to within a decade of optimum, certainly closer than what one >> would be talking about by just bolting x-random OCXO onto an LTE-lite? I >> suspect there would be a market in the time-nut world for such a > critter. >> >> -- >> Brian Lloyd >> Lloyd Aviation >> 706 Flightline Drive >> Spring Branch, TX 78070 >> [email protected] >> +1.210.802-8FLY (1.210.802-8359) >> _______________________________________________ >> 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. _______________________________________________ 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.
