Re: [time-nuts] 60 Hz frequency and phase measurement
Interesting. Thanks. I plotted your data next to mine. http://users.megapathdsl.net/~hmurray/time-nuts/60Hz/60Hz-2019-June.png There are actually 2 lines there. At this scale, they are on top of eachother. My samples are roughly every 10 seconds. So there should be a 6 to 1 ratio. If you zoom in, you can see some quirks. This is June 10th. http://users.megapathdsl.net/~hmurray/time-nuts/60Hz/60Hz-2019-June-10.png This is zoomed in enough so that you can see the offset which is arbitary. Zooming in farther. http://users.megapathdsl.net/~hmurray/time-nuts/60Hz/60Hz-2019-June-10a.png Looks like I picked up at extra cycle. I see that occasionally - ballpark of once a day. This is June 25th. http://users.megapathdsl.net/~hmurray/time-nuts/60Hz/60Hz-2019-June-25.png Here is one area that caught my attention. http://users.megapathdsl.net/~hmurray/time-nuts/60Hz/60Hz-2019-June-25a.png It looks like the cycle count on one sample is off by one. I see that occasionally. I assume it's a missing lock in the Linux PPS kernel API that I'm using to read the data. I get pairs of time-stamp and count. A pulse comes through between when it has grabbed the time stamp and when it grabbed the count. The following sample looks good so it's not a extra or missing cycle. -- These are my opinions. I hate spam. ___ 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
We have used line frequency counting for time keeping in the past it works very well in the USA - EXCEPT in locations with lots of dimmers - theaters in particular chop the AC waveform creating lots of noise and can make the internal timer run fast. I think at one location we had 5 volts of noise on the mains. TXO chips just always work - so we use them now, or GPS. I had a recent tour of a power station - the operators had no idea the output was synchronized to a time standard - they just synchronize with the local grid. For a history of line frequency time keeping, Wikipedia has a good entry. https://en.wikipedia.org/wiki/Telechron Though Tesla I believe demonstrated this at the Chicago World's fair. I have a master in my small museum. https://electricclock.omeka.net/items/show/12 Thomas D. Erb p:508-359-4396 f:508-359-4482 a:97 West Street, Medfield, MA 02052 USA e: t...@electrictime.com w:www.electrictime.com Tower & Street Clocks Since 1928 ___ 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
It gets time from GPS and frequency from the power line at my house. I suspect a certain amount of frequency wobble due to inductive loads somewhere upstream of my home. On Wed, Jul 3, 2019 at 8:01 PM jimlux wrote: > On 7/3/19 3:20 PM, Jeremy Nichols wrote: > > 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 > > > > > > but what can you tell us about the receiver - I assume it's line > connected. How does it get time hacks? GPS? Maybe it takes a feed from > the de-rigueur Hydrogen maser, Cs fountain, or cryogenic sapphire > oscillator that time-nuts just happen to have around? > > > -- Jeremy Nichols Sent from my iPad 6. ___ 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
On 7/3/19 3:20 PM, Jeremy Nichols wrote: 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 but what can you tell us about the receiver - I assume it's line connected. How does it get time hacks? GPS? Maybe it takes a feed from the de-rigueur Hydrogen maser, Cs fountain, or cryogenic sapphire oscillator that time-nuts just happen to have around? ___ 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
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 > >> 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-nut
Re: [time-nuts] 60 Hz frequency and phase measurement
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 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
Wow Tom that is great work! I won't pretend to understand what you did and how you did it or, even, what the various graphs represent. But one thing I get out of it is the amazing correlation of measurements made across such a distance. And the equally amazing accuracy, stability, and precision of the mains frequency. It inspires me to push aside my current project and see how consistent my own results can be. I would revert to my original method of period measurement, perhaps modified by the addition of a simple filter. Now that my counter is solidly on the money due to the rubidium oscillator, I can trust the readings for as many digits as I can count. My little motor driven electric clock has never needed resetting other than the switch to and from daylight time. But of course that's a rather gross measurement. I wonder what method the power companies use to control frequency and who decides what is the correct signal. Presumably there is an ivory tower somewhere with a cloistered team of bearded scientists who hold magnifying glasses to oscilloscope screens to decide when to throw another lump of coal into the furnace. Bob On Wednesday, July 3, 2019, 09:01:16 AM PDT, 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 >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. ___ time-nuts mail
Re: [time-nuts] 60 Hz frequency and phase measurement
On 7/3/19 8:56 AM, 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 yes indeed http://fnetpublic.utk.edu/anglecontour.html shows a pretty constant phase shift of tens of degrees. (except Texas, because, after all, they're Texas) ___ 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
On 7/2/19 11:47 PM, Hal Murray wrote: jim...@earthlink.net said: Actually, it's because someone asked me about a science experiment where you'd place them in a neighborhood outdoors. Sounds like another science experiment: build an antenna to pick up 60 Hz. You could start with the typical ferrite, coil, and cap. Just adjust the cap to your new target frequency. Simple to try. I ran through some quick calculations on that - unlike for AM band, you need a fairly good sized capacitor. I think it's doable. A typical loopstick for AM is around 0.5 to 1 mH, so you'd need about 7000 microfarads to resonate it at 60Hz. So, a LOT more turns on that inductor. And then you have to start worrying about phase shift - it's going to be a fairly high Q resonant circuit, with the phase varying most rapidly around resonance. So a resonant antenna probably isn't the way to go.. The whole goal is to look for phase shifts after all. That's why I was thinking about magnetic field sensors.. The little electronic compass sensors sample at 100-300 Hz and have sensitivities comparable to the Earth's field (i.e. something like 2 Gauss, 200 microTesla, full scale). I don't know that they're sensitive enough - I recall that typical line frequency fields are in the "single digit milliGauss" range. If I convert that the E field, I get "single digit Volts/meter" - which is consistent with my tens of mV holding the scope probe in my hand. Well... since it's a holiday weekend, it's time to break out the Beagles and Teensys and do some experiments. It's just that I don't like E field sensors (if for no other reason than High Z amplifiers get destroyed by ESD).. ___ 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
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 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
Jim, almost any mains powered lighting has a substantial 120Hz component in light intensity. It's quite reasonable to trigger off this at nighttime if the light is on and only that single light is in field of view of a phototransistor (no car headlights allowed to come into view!) It's still far far easier to plug in an AC wall wart. Tim N3QE On Wed, Jul 3, 2019 at 1:01 AM jimlux 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
On 7/2/19 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. The idea would be to look at the phase variations over time across a neighborhood and see if you can see effects from people turning on and off loads (air conditioners and sags causing light flicker brought up the discussion). It's a whole lot easier for someone to ask "can I put this little recording box here" than "can I plug something into your wall socket" The idea is that you get cheap GPS receivers as the time hack and record *something* at a suitable rate after some low pass filtering, and then post process. 1kHz sample rate for a day is 86 Megasamples, so it's not an enormous dataset that needs to be recorded. Maybe it's just time [sic] for an experiment - stick a wire on an ADC on a Beagle or Arduino and make some recordings. On Tuesday, July 2, 2019, 10:01:03 PM PDT, jimlux 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
jim...@earthlink.net said: > Actually, it's because someone asked me about a science experiment where > you'd place them in a neighborhood outdoors. Sounds like another science experiment: build an antenna to pick up 60 Hz. You could start with the typical ferrite, coil, and cap. Just adjust the cap to your new target frequency. Simple to try. -- These are my opinions. I hate spam. ___ 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
I'd normally use an optocoupler. But it doesn't need to be an 8-pin dip with the mains and low-voltage pins 0.3" apart - it can be a neon lamp and a photodiode, or a photodiode near a mains-fed lamp. Even an incandescent has a very strong modulation of the light. You just need to avoid leds that have smoothed DC, and flourescents with HF ballasts. On Wed, Jul 3, 2019 at 7:00 AM Bob Albert via time-nuts < time-nuts@lists.febo.com> 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
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 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
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.
Re: [time-nuts] 60 Hz frequency and phase measurement
I built a 6 Volt filament transformer into a small metal box and connected the secondary to a couple of 5-way banana jacks. In addition to the 6 Volt output, I put a 100KΩ pot across the terminals with the wiper connected to a third jack. That way, I can have any voltage from 0 to 6 VAC, avoiding possible damage to sensitive front ends. Jeremy On Tue, Jul 2, 2019 at 8:00 PM Gerhard Hoffmann wrote: > > Am 03.07.19 um 01:25 schrieb Tim Shoppa: > > Jim, most of us are satisfied to use a 6.3VAC filament transformer to > step down from 120VAC and isolate from the power line. > > Exactly. I used an old 6 or 9V AC wall wart and a resistive 1:3 divider > last year when the European grid frequency was low because of some > trouble in the distant south-east. That gave a really stable reading. > > < > > https://www.flickr.com/photos/137684711@N07/38870750440/in/dateposted-public/ >> > > > regards, Gerhard > > > > > > ___ > 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. > -- Jeremy Nichols Sent from my iPad 6. ___ 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
Am 03.07.19 um 01:25 schrieb Tim Shoppa: Jim, most of us are satisfied to use a 6.3VAC filament transformer to step down from 120VAC and isolate from the power line. Exactly. I used an old 6 or 9V AC wall wart and a resistive 1:3 divider last year when the European grid frequency was low because of some trouble in the distant south-east. That gave a really stable reading. < https://www.flickr.com/photos/137684711@N07/38870750440/in/dateposted-public/ > regards, Gerhard ___ 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
Jim, most of us are satisfied to use a 6.3VAC filament transformer to step down from 120VAC and isolate from the power line. Tim N3QE > On Jul 2, 2019, at 5:56 PM, jimlux wrote: > > There's some designs on the list (using a PICPET, for instance) to measure > the local line frequency and phase.. > > but the schemes we've discussed require connecting to the power line in some > way. > > What about a non-contact sensing approach? Something you could put in a box > and it would pick up the electric or magnetic field as the input? > > Just how strong is the field anyway? I've always been trying to cancel or > shield it or reduce it in some way, so I've never actually measured it in a > calibrated way. A 10cm antenna on a 1Meg scope probe looks like about 40 mV > peak to peak (for the 60 Hz component) along with lots of other high > frequency stuff (40 kHz and a few hundred kHz in my office) from switching > power supplies. > > I realize that in a office/industrial area you'll probably pick up all three > phases in some way. > > What about using a small loop? or a magnetoresistive sensor (like the > compasses in phones)? > > Has anyone tried any of these? > > > > ___ > 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.
Re: [time-nuts] 60 Hz frequency and phase measurement
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. If you're willing to do this and need help with a design, contact me off-list at k8yumdoo...@gmail.com. Dana On Tue, Jul 2, 2019 at 6:00 PM jimlux wrote: > There's some designs on the list (using a PICPET, for instance) to > measure the local line frequency and phase.. > > but the schemes we've discussed require connecting to the power line in > some way. > > What about a non-contact sensing approach? Something you could put in a > box and it would pick up the electric or magnetic field as the input? > > Just how strong is the field anyway? I've always been trying to cancel > or shield it or reduce it in some way, so I've never actually measured > it in a calibrated way. A 10cm antenna on a 1Meg scope probe looks like > about 40 mV peak to peak (for the 60 Hz component) along with lots of > other high frequency stuff (40 kHz and a few hundred kHz in my office) > from switching power supplies. > > I realize that in a office/industrial area you'll probably pick up all > three phases in some way. > > What about using a small loop? or a magnetoresistive sensor (like the > compasses in phones)? > > Has anyone tried any of these? > > > > ___ > 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.
