bill.iaxs@pobox.com said: > Different regions can have different phase behavior. I have only seen West > Coast plots on this list. When I did some work with this in Minnesota in the > eighties, the phase variation was only about 6 seconds during a day and zero > from day to day. On the west coast, the "zero from day to day" part is optimistic. I agree that they generally do a good job, but there are times when they shift by more than 1 second per day, averaged over a month. Here is an example: http://users.megapathdsl.net/~hmurray/time-nuts/line/Calif-60Hz-2015-May.png Zooming out: http://users.megapathdsl.net/~hmurray/time-nuts/line/Calif-60Hz-2014-2015.pn g ------ There is an interesting question. If you keep time by counting cycles, how do you get started? I assume there is an official cycle counting clock deep in a control center. Is there a backup? What do they do when the control center loses power? ... -- These are my opinions. I hate spam.

I have a couple of Nixie clock kits I got from pvelectronics.co.uk. They have a plug in GPS module. No doubt it does not meet time-nuts standards but to my eye and ear, the tick is spot-on with WWV, which makes it suitable for setting my watch and knowing when to walk the dogs. With the Pound Sterling doing so poorly against the dollar, these actually seem like a pretty reasonable deal. http://pvelectronics.co.uk Besides, Nixies are cool. -- Brian Lloyd 706 Flightline Spring Branch, TX 78070 brian@lloyd.aero +1.210.802-8FLY (1.210.802-8359)