Hi One thing to keep in mind:
If you are looking at stuff like sawtooth on most (but not all) GPS modules, the counter you use to take the data does not have to be some sort of monster machine. An old 5334 or 5335 will let you see the basic structure. If you spend time shopping, neither one is terribly expensive. If you need one “right now” you will pay a lot for the availability (like > 3X the price). There are also things like the PicTIc that have way more resolution than you would need. They are not in the same league as a 53132 either. They will give you quite a bit more resolution than the 5334. Lots of choices, no big need to spend a boatload of money. Bob > On Apr 6, 2016, at 3:00 AM, Hal Murray <[email protected]> wrote: > > > [email protected] said: >> I may never get around tooth's as the Rb is very good all by itself to the >> limit of my ability to measure it. > > Wait longer. :) > > If your Rb doesn't have a PPS, make one. One of tvb's divider chips is > probably the simplest approach. You can probably do it with an Arduino if > you have one handy and like writing that sort of code. > > Compare the PPS from the Rb with the one from your GPS. It's probably > simplest if your Rb PPS is offset a bit from the GPS PPS. The idea is to > make the difference always have the same sign. > > Feed both PPS pulses to some equipment that can measure the time difference. > Collect data. > > If you have a typical low cost (non GPSDO) GPS device, you should be able to > make graphs like the ones that show a hanging bridge. Look at a sawtooth > region, not a bridge. Pick the top or the bottom or the middle or whatever > you can remember. Call that the offset. Wait an hour collect more data. > Has your offset shifted? If not wait longer... > > You are measuring the average frequency of the Rb. It might be temperature > sensitive. Can you see the offset change over a day? (That assumes you turn > the heat down at night...) Or maybe you are seeing the GPS night/day shift. > > > -- > These are my opinions. I hate spam. > > > > _______________________________________________ > 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.
