The station at Santa Rosa, California (#853 in the Western Interconnection) is mine. Have had their receiver for several years. Only downside is that i can't record the data directly from the supplied receiver.
Jeremy On Wed, Jul 3, 2019 at 12:01 PM Paul Theodoropoulos via time-nuts < time-nuts@lists.febo.com> wrote: > This stuff is fascinating to a time-nut-level:Novice such as myself. > While falling down the rabbit-hole searching on all the various bits of > the info below, I ran across this - not sure if you're aware of it, or > if it's old news, but it seems at least peripherally interesting: > > http://fnetpublic.utk.edu > > > On 7/3/19 08:56, Tom Van Baak wrote: > > Bob, > > > > Several of us do long-term measurement of mains frequency. We tend to > > time-stamp cycles and then compute period or frequency, rather than > > measuring frequency or period directly. Traditional counters in gated > > frequency or time interval mode have dead time and this will skew > > results. > > > > In my case I just run a 5 VAC wall-wart through a 10k resistor > > directly to the input pin of a PIC. No scaling, no filtering, no opto, > > no ZCD, no nothing. If I measure every cycle I get 155 million samples > > per month. If I extract one cycle each second (decimate by 60) it's > > only 2.5 million samples a month. Many months there is not a single > > glitch in the data in spite of all the FUD about power line noise. > > Once in a while a month contains an extra or missing sample but the > > beauty of timestamp data is that this can be detected and repaired as > > part of data processing with no loss of phase. > > > > Here's a page where Kevin (in New Mexico) and I (in Seattle) both used > > picPET's to measure mains for a few days and then we compared the > > results. Although thousands of miles apart, we're both on the same > > grid so the agreement was astonishing. It was milliseconds in time and > > ADEV down to e-8 over a day: > > > > http://leapsecond.com/pages/mains-cv/ > > > > See also: http://leapsecond.com/pic/mains-adev-mdev-gnuplot-g4.png > > > > /tvb > > > > > > On 7/2/2019 10:09 PM, Bob Albert via time-nuts wrote: > >> I have tried to measure the power line frequency with spotty > >> success. My best results came from a period measurement, as many > >> periods as the counter can accumulate. Due to noise, one is never > >> sure at quite what point the source is measured. Perhaps a brick > >> wall filter would clean it up for a more reliable measurement. > >> Of course, at 60 Hz the period is 16-2/3 milliseconds. So the > >> counter should properly show a 1 followed by a row of 6s, with the > >> last digit bouncing between 6 and 7 most of the time. > >> If there is a filter used, it will not only remove noise but also > >> short term variations. But generatlly speaking you don't want to > >> measure those, unless you are trying to evaluate a rotary generator. > >> Getting this reading can be a challenge. > >> On Tuesday, July 2, 2019, 10:01:03 PM PDT, jimlux > >> <jim...@earthlink.net> wrote: > >> On 7/2/19 4:09 PM, Dana Whitlow wrote: > >>> I've always noted that casual attempts to pick up 60 Hz with small > >>> antennas > >>> etc see more harmonics and other trash than actual line frequency. > >>> But if > >>> you're in an office environment, why not plug something in? It's > >>> quite easy > >>> to build a simple passive diode clipper/filter that will plug into a > >>> wall > >>> outlet and > >>> which will provide a sort of soft (but clean) squarewave at a > >>> voltage level > >>> convenient for lab instruments and with good protection against big > >>> spikes > >>> and > >>> other trash riding on the line. > >> > >> Safety approvals are one obstacle (of course one could use a AC wall > >> wart). > >> > >> Actually, it's because someone asked me about a science experiment where > >> you'd place them in a neighborhood outdoors. > >> > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > -- > Paul Theodoropoulos > www.anastrophe.com > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.