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I am the dot just below the Canadian border in WA State. Dave > -----Original Message----- > From: time-nuts [mailto:[email protected]] On Behalf > Of Philip Gladstone > Sent: Friday, February 27, 2015 07:47 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Recording mains frequency/phase > [WAS: No GPSsatellites] > > On 2/26/15 20:39, Charles Steinmetz wrote: > > ben wrote: > > > >> I'm going to have to build one of these. Assume you have > some sort of > >> circuit that converts low-voltage AC from a transformer > secondary to > >> a pulse train, start a timer, and count x amount of pulses? > > > > Here is a zero-cross detector designed for this purpose: > > > > > <http://www.ko4bb.com/manuals/download.php?file=02_GPS_Timing/ > Simple_AC_Mains_Zero_Crossing_Detector.pdf> > > > > > > Most mains-nuts feed the ZCD pulse to the DCD line of a PC's RS232 > > port and use the computer to time-stamp the crossings and > append them > > to a file of such time stamps. > If we all did this, then I realize that we could identify the > different > power grids. However, I wonder if there is any interesting variation > *within* a grid. As the electricity flows vary throughout the day, it > seems possible that the phase difference between two people > on the same > grid would actually change (a bit). > > Has anybody done this experiment? > > Philip > _______________________________________________ > 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.
