--- Tom Van Baak <[EMAIL PROTECTED]> wrote: > > Your report, though, inspires me to look into more > reliable and precise > ways > > to measure the frequency of one's local grid. I > had not actually > considered > > monitoring electric fields "off the air" before, > but it seems like this > > might be fairly practical. > > One very simple method that I have used is plug in a > AC wall wart transformer with the 6 VAC secondary > going directly into a HP53131A frequency counter. > The serial data you get then looks like this: > > 53747.845696 59.996,154,495,1 Hz > 53747.846854 59.999,588,387,2 Hz > 53747.848012 60.001,434,856,1 Hz > 53747.849172 60.001,288,258,8 Hz > 53747.850330 60.002,697,145,5 Hz > 53747.850330 N : 36 > 53747.850330 STD DEV: 0.004,660,852,51 Hz > 53747.850330 MEAN : 60.004,606,291,05 Hz > 53747.850330 MAX : 60.020,723,348,6 Hz > 53747.850330 MIN : 59.996,154,495,1 Hz > 53747.851489 60.006,143,055,9 Hz > 53747.852646 60.001,106,173,4 Hz > 53747.853805 60.003,317,733,6 Hz > 53747.854963 60.000,519,248,1 Hz > 53747.856122 59.997,117,006,6 Hz > > which you can run as long as you like and process > the data as you see fit. In this particular example > the > gate time was 100 s and so the statistics were > hourly. > > Another way is to use a surplus TrueTime TFDM: > http://www.leapsecond.com/pages/mains/ > > /tvb > > > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >
I've always been interested in the AC mains frequency precison... I've even imagined a mechanical phase accumulator, but never made it... However, my interested was in the actual AC mains PHASE instead of frequency, since electrical clock lead/lag is more dependant of the actual phase (compared to a 60 Hz Cs/Rb/GPS standard) of the hydro line (a lead/lag of 21600 degrees would correspond to a one second L/L) than the actual frequency. Also because phase is the integral of frequency, it is far easier to monitor errors in phase rather than in frequency on a long term basis. Have a good day! Normand Martel VE2UM Montreal, Qc. Canada ____________________________________________________________________________________ Want to start your own business? Learn how on Yahoo! Small Business. http://smallbusiness.yahoo.com/r-index _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
