We have used line frequency counting for time keeping in the past it works very well in the USA - EXCEPT in locations with lots of dimmers - theaters in particular chop the AC waveform creating lots of noise and can make the internal timer run fast. I think at one location we had 5 volts of noise on the mains. TXO chips just always work - so we use them now, or GPS.
I had a recent tour of a power station - the operators had no idea the output was synchronized to a time standard - they just synchronize with the local grid. For a history of line frequency time keeping, Wikipedia has a good entry. https://en.wikipedia.org/wiki/Telechron Though Tesla I believe demonstrated this at the Chicago World's fair. I have a master in my small museum. https://electricclock.omeka.net/items/show/12 Thomas D. Erb p: 508-359-4396 f: 508-359-4482 a: 97 West Street, Medfield, MA 02052 USA e: t...@electrictime.com w: www.electrictime.com Tower & Street Clocks Since 1928 _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
