Dave,
That's cool. I am the dot just above the US / Canada border and just
below the Ontario/Quebec border in Eastern Ontario.
There are many (many) documents that can found using Google on the
subject of power grids and frequency and monitoring. I have only been
able to read through only a small handful. An interesting application of
time and frequency measurement.
cheers, Graham ve3gtc
On 2015-02-28 19:50, DaveH wrote:
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:[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
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