Does an ac transformer hurt me? I was looking for that dang megohm page when I started this. Couldn't find it so I used a transformer.
Doc Sent from my iPad On Nov 16, 2013, at 9:17 PM, "Tom Van Baak" <t...@leapsecond.com> wrote: >> Again, why are you measuring the AC line? I'd think maybe to measure the >> noise that is on it. The fundamental freq. changes second by second. >> It's not a clean 60Hz my any means. The rate of frequency change is one >> thing you'd like to measure >> >> I was just watching a minute ago and can see a 0.01Hz/second drift. It is >> likely MUCH worse as what I was watching is filtered over second > > Chris, > > No, forget the noise (it's actually quite clean: look at it sometime). > > 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 > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
