[time-nuts] Recording mains frequency/phase [WAS: No GPSsatellites]

[DaveH]

Like this?

http://fnetpublic.utk.edu/gradientmap.html

I am the dot just below the Canadian border in WA State.

Dave 

> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] 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
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