Bob, I've been mulling over the question of a case, and I was thinking of getting a 2M brick amp and putting it inside, bolted upside down to the heat sink. Good idea? Anybody got a busted one?
Bob >________________________________ > From: Bob Camp <[email protected]> >To: Discussion of precise time and frequency measurement <[email protected]> >Sent: Wednesday, September 18, 2013 7:22 PM >Subject: Re: [time-nuts] GPSDO vs Rb standard > > >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. > > > _______________________________________________ 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.
