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

[Tom Van Baak]

> 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

Yes, it's really quite interesting and very easy to do. Check the time nuts archives -- over the years there are by now hundreds of postings about measuring mains phase and frequency. See also:

http://leapsecond.com/pages/mains/
http://leapsecond.com/pages/mains/mains-picpet-23.gif
http://leapsecond.com/pages/ac-detect/

There are many wonderful web sites that deal with power line frequency; some with live plots. Just google for words like: mains frequency detect accuracy stability measurement

Also, make sure to read the growing literature about ENF:
http://en.wikipedia.org/wiki/Electrical_network_frequency_analysis

/tvb