Hi It depends a *lot* on just where you are and how the “gird” is managed. Many years ago, we figured out that the local power company corrected things between 4 and 5 PM. It became a habit to fire up WWV and watch them slip seconds one way or the other. A ten second delta was not at all unusual. ( as in 10 seconds over the hour …). Our guess (later confirmed) was that they ran local generation part of the day (independent of the grid) and then went over to interconnect.
Bob > On Dec 15, 2017, at 12:14 PM, Jeremy Nichols <jn6...@gmail.com> wrote: > > I'm surprised Vlad is seeing as much as six seconds differential but maybe > I don't understand the experiment. I've done measurements of the line > frequency here in California and never seen much variation. > > Jeremy > > > On Fri, Dec 15, 2017 at 9:02 AM Vlad <t...@patoka.org> wrote: > >> >> >> I have one of my project boxes, which monitor the main freq. Here is >> graph which reflect the time difference between of RTC (based on number >> of pulses from OCXO) and the "MAIN TIME" which is based on number of >> zero-cross events. >> The observation period is 486 hours. >> >> >> >> >> On 2017-12-14 23:13, Jim Harman wrote: >>> On Thu, Dec 14, 2017 at 10:53 PM, Bob kb8tq <kb...@n1k.org> wrote: >>> >>>> >>>> >>>> Of course this *assumes* an electronic approach. Given that it’s >>>> moving >>>> pretty slow and you >>>> only are looking at fractions of a millisecond, one *could* do an >>>> electro >>>> mechanical design …... >>>> >>>> Bob >>>> >>>> There is interesting background on power grid frequency/time >>>> adjustment >>> procedures here >>> >> https://en.wikipedia.org/wiki/Utility_frequency#Time_error_correction_(TEC) >>> >>> and here >>> https://en.wikipedia.org/wiki/Electric_clock#Accuracy >> >> -- >> WBW, >> >> V.P._______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > -- > Sent from my iPad 4. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.