[time-nuts] Mains frequency

Bill Hawkins bill at iaxs.net
Sun Nov 17 12:46:43 EST 2013


You can get some idea of industrial productivity if you can estimate
and remove non-industrial loads, perhaps by comparing weekends to
work weeks.  The dip during working hours and the rise at 4-5 AM are
proportional to the total power used, for the same generating
capacity.

The business of making up lost cycles on a daily business is not
easy for utilities. A year or two ago they proposed to let the 
system float in order to eliminate failures caused by catching up.
Fortunately for timenuts, the proposal did not become practice.

Bill Hawkins 

St. Paul: Money is the root of all evil.
Ben Franklin: Time is money.
Ergo - Time is the root of all evil.


-----Original Message-----
From: Tom Van Baak
Sent: Saturday, November 16, 2013 9:17 PM

---%<---

We measure mains because we can.

We also measure it because millions of wall-clocks are based on mains
frequency; it was the original "GPSDO".

We measure it because its phase plot, frequency histogram, and ADEV plot
are really quite interesting.

We measure it because Seattle, WA (tvb) and New Mexico (Kevin) are both
on the same grid and mutually agree to 10 microseconds (!) over an hour
even though they can both wander by many seconds relative to UTC. It's a
textbook example of common view time transfer. See also:
http://leapsecond.com/pages/mains/
http://leapsecond.com/pages/ac-detect/

You too can join the mains party. Measure it with your own method, or a
fancy TrueTime time/frequency deviation meter (TFDM) or use something
simple like a picPET (http://www.leapsecond.com/pic/picpet.htm) or
Arduino or even a NTP/Linux/serial DCD pin hack.

/tvb




More information about the time-nuts mailing list