Hi The 5 Hz (or whatever) switching and the hump definitely both originate in the same “feature” of the design. Does disabling the switching nuke the hump? If one has a PRS-10 I’d say it’s well worth trying.
The “filter” in the PRS-10 is not really set up for a GPS sort of signal. It’s designed to handle a nice clean lab generated 1 pps. It’s there to lock the device up as part of a calibration routine. The 1 pps sync setups on other Rb’s are designed with the same target in mind. Bob > On Nov 18, 2021, at 7:50 AM, Dana Whitlow <k8yumdoo...@gmail.com> wrote: > > Poul, > > You did not really answer the basic question: "Does the 2.5 Hz > (or 5 Hz if applicable) C-field reversal cause the 2-sec bump in > the ADEV plot for the PRS-10?". > > BTW, some radio hams are involved with microwave and even > MMW communications between mobile stations, and I'd bet they > benefit quite a bit from any scheme that reduces magnetic field > sensitivity of their frequency references. Therefore, the C-field > reversal thing cannot be *all* bad. > > Dana K8YUM > > > Dana > > > On Thu, Nov 18, 2021 at 2:41 AM Poul-Henning Kamp <p...@phk.freebsd.dk> > wrote: > >> -------- >> Matt Huszagh writes: >>> "Poul-Henning Kamp" <p...@phk.freebsd.dk> writes: >>> >>>> The PRS-10 switches the polarity of the C-field solenoid at 5Hz to >>>> cancel out varying external magnetic fields. >>>> >>>> If that is not a concern for you, for instance because you use it >>>> in a stationary application, it can be disabled with the "MS0" command. >>>> >>>> It's all in the manual. >>> >>> How does the 5Hz switching relate to the 2s hump in the ADEV plot? >> >> The manual says: >> >> "[...]the current in the coil is switched at a 5 Hz rate." >> >> You can either read that as: >> >> "There are five positive and five negative periods every second" >> >> or >> "The sign changes five times per second" >> >> It is not entirely obvious which reading is the correct one. >> >> When I experimented with it ages ago, I concluded the latter fit >> my data best, but that was a pretty early firmware version, with >> quite a number of variances from the manual. >> >> If your ambient magnetic field is stable, and it should be for >> time-nuts purposes, modulating the hyperfine transition is a bad >> idea, no matter the frequency. >> >> -- >> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 >> p...@freebsd.org | TCP/IP since RFC 956 >> FreeBSD committer | BSD since 4.3-tahoe >> Never attribute to malice what can adequately be explained by incompetence. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.