OK seems no matter what I do compared to the Tbolt and Z3801the 5061/5060 still drifts right on the scope. Granted a big shift in the cfield seems to get the unit to advance, but then after some hours it returns back to the same slow rate. But I did learn about the magical A1 synthesizer and built an excel calculator to see what the jumper settings do. If anyone wants it I will forward it. Putting the A! synth on the bench and feeding a 5 Mhz source in I could see how it behaved. It tends to run a little high in frequency. I mean fractions of a hertz. As far as the jumpers go one change really does move the synth quite a ways from the atomic frequency. So what I learned is that changing the jumpers really would make a heck of a jump either fast or slow, not some fine grain shift. Regards Paul WB8TSL
On Fri, Jan 3, 2014 at 9:04 PM, paul swed <[email protected]> wrote: > Tom and Corby > Thanks for the help. I suspect that the 5060/5061 is perhaps as good as it > can get. > My other references such as the 3801 and Tbolt have it down now in the > 1X10-11 region. Close to 1 but goes above and below. I did find the magical > cfield R to be 70 ohms and will have to calculate the current. > When I do measurements for 10 ns displacement it takes some 13-18 minutes. > I also use a 5370b counter much easier to measure the ns drift than the > scope. > Regards > Paul > WB8TSL > > > > On Fri, Jan 3, 2014 at 1:13 PM, Tom Van Baak (lab) <[email protected]>wrote: > >> Hi Paul, >> >> About cesium clocks: hp 5060A and early versions of the hp 5061A needed >> to be able to keep *either* atomic time (true, accurate, stable, SI >> seconds) or astronomical time (inaccurate, unstable, slow, and gradually >> slowing, earth rotation time). >> >> The larger C-field range allowed this user choice of time-scales. I have >> many examples of both clocks here. >> >> It appears most time & frequency labs converted to "atomic time" in the >> late 60's and 70's which is why all later 5061A, all 5061B, every 5071A, >> and all modern atomic/ion/optical clocks tick "atomic" seconds instead of >> the slightly larger and monthly / seasonally / climatically / geologically >> / gravitationally variable "earth" seconds. And why we have leap seconds. >> >> In the past 50 years even die-hard astronomers have thrown in the towel >> and conceded that atomic time is a more stable time reference than earth >> rotation rate. In order to point modern, super-accurate telescopes they use >> a high-precision (sub-millisecond!) "DUT1" correction to convert >> physics-stable atomic time into engineering-accurate astronomical time; >> "close enough for government pointing work" as they say. >> >> Now that we're well into the post-astronomical time age, the narrow >> C-field range is adequate. If you have a 5060 or older 5061 there is no >> harm in using resistors to restrict the C-field range. >> >> /tvb (i5s) >> >> > On Jan 3, 2014, at 7:51 AM, paul swed <[email protected]> wrote: >> > >> > Corby >> > Having a good time tinkering with the 5061. Did change the resistors for >> > the cfield regulator so that its much close to the schematic and am >> > experimenting with that. >> > The system does seems to be able to be tuned through a stable position >> that >> > reduces the drift to 2 min/10ns drift and the CS is slow compared to the >> > 5065 RB set to loran C when its on the air. >> > I do have a older synth div board. No thumbwheel switches. It appears >> to me >> > to be jumpered at 8634. I think that may be wrong. The book says 2095 >> for >> > atomic time. >> > Appreciate your thoughts. >> > Regards >> > Paul >> > >> > >> >> On Thu, Jan 2, 2014 at 4:52 PM, paul swed <[email protected]> wrote: >> >> >> >> Corby >> >> I pulled the a15 board and there are no resistors, just a short across >> >> what would have been r19 and 21. So I suspect that there is to much >> current >> >> actually. Further speculation is that when the pot is toward ground >> more >> >> current flows from what I see in the schematic. >> >> I may guess that more current equals lower frequency? >> >> Regards >> >> Paul. >> >> >> >> >> >>> On Thu, Jan 2, 2014 at 4:22 PM, <[email protected]> wrote: >> >>> >> >>> Paul the C-field current is the same for the 5061A and 5060A. >> >>> >> >>> The 5060A C-field pot has LOTS more range than the later 5061A where >> they >> >>> installed resistors on each side of the pot to reduce the range. >> >>> >> >>> Corby >> >>> >> >>> _______________________________________________ >> >>> 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.
