Hi The Rb's have a couple of issues:
1) Its been years since they were set on frequency and they do have a yearly drift rate 2) They have a temperature coefficient of drift that may be fairly large (0.1 ppb over -30 to +70) 3) They self heat quite a bit, so they do move temperature / need a heatsink The solution to the temperature issue is a servo controlled fan. The solution to the first drift / accuracy issue is to calibrate them against something else. Bob On Sep 18, 2013, at 7:13 PM, "John C. Westmoreland, P.E." <[email protected]> wrote: > Azelio and Fellow Time Nuts, > > Isn't the GPS 1PPS signal supposed to be 'precise' to within what error? I > imagine this is in the specs of the specific receiver - > but I was wondering if some of you have actually measured what that is - > and could report the numbers that you have found. > > Thanks! > John Westmoreland > > > > On Wed, Sep 18, 2013 at 3:07 PM, Azelio Boriani > <[email protected]>wrote: > >> Instead of using the Rb's PPS, use the GPS receiver's PPS. Maybe you >> will find out that the Rb is slow... you can also check the Rb's PPS >> against the GPS's PPS. >> >> On Wed, Sep 18, 2013 at 11:47 PM, Bob Stewart <[email protected]> wrote: >>> I hooked the Rb's 1PPS to the trigger input on my old Tek 455, 10MHz >>> GPSDO to Channel A, .05us trace, and turned the lights out so I could >>> see it. The 10MHz is marching right to left about 1 cycle every 20 >>> seconds. So, can I say that the Rb considers my GPSDO to be too fast by >> about 5ppb? >>> >>> >>> 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. >> > _______________________________________________ > 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.
