Hi The only Rb’s I know of that go out to the 24 to 72 hour tau’s are full blown GPSDO Rb’s.
Bob On Aug 25, 2014, at 1:53 PM, Dave M <[email protected]> wrote: > I found the parameters for the X72's 1PPS input. The range of Tau is 5 - > 10,000 seconds, or about 2 hrs, 45 min. at the longest setting. It defaults > to 400 seconds. However, mine doesn't have the firmware to enable the 1PPS > input, so it really doesn't matter. > Out of curiosity, does anyone know of any Rb units that can be programmed to > a 24 hr (or longer) Tau, either by EFC or 1PPS input? > > Dave M > > > Bob Camp wrote: >> Hi >> >> It is not what is done in the Efratom Rb’s. Their pps input is set up >> to get things on frequency / on time quickly. The assumption is that >> you plug it into a pps to get it “right” and then take off on your >> mission. That takes them into the short (for a Rb) time constant >> region. >> >> Bob >> >> On Aug 24, 2014, at 5:56 PM, Brooke Clarke <[email protected]> wrote: >> >>> Hi Bob: >>> >>> I think that's what's done in the SRS PRS10 >>> http://www.prc68.com/I/PRS10.shtml >>> >>> Have Fun, >>> >>> Brooke Clarke >>> http://www.PRC68.com >>> http://www.end2partygovernment.com/2012Issues.html >>> http://www.prc68.com/I/DietNutrition.html >>> >>> Bob Camp wrote: >>>> Hi >>>> >>>> If you lock an Rb to GPS, you need / want / should do it with a >>>> *very* long time constant. Numbers in the one day to several days >>>> range are commonly seen. If you lock it up with a tighter (shorter >>>> time constant) loop, it will just wander around as it follows the >>>> GPS input. That’s what would happen if you hook your Rb to your >>>> Trimble and turn on the disciplining on the Rb. It will >>>> significantly degrade the stability of the Rb. >>>> >>>> If you have a temperature stable environment (or create one) you >>>> can get some very good results with an (good) Rb locked to a (good) >>>> GPS via a proper long time constant setup. It’s not easy, but it >>>> can be done. >>>> >>>> Bob > > > _______________________________________________ > 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.
