HI Most WWVB clocks are unable to pick up a signal continuously. The signal to noise simply isn’t good enough 24 hours a day. Because of this (and power considerations) they do a check or three in the middle of the night and go back to sleep. If they sync up, fine. If they don’t, try again tomorrow. That approach works fine most of the time. When it gets close to a time shift, you notice the process a lot more. My wife’s watch is not as good picking up WWVB as the rest of the stuff here. I can pretty reliably predict that I will hear about that twice a year ….oddly enough, I can also predict the dates when I will hear about it ;)
Bob > On Mar 14, 2016, at 12:38 AM, Tom Van Baak <t...@leapsecond.com> wrote: > > Hi Andy, > > No, there's nothing about 0200Z. Correct, WWVB doesn't know your local zone. > > WWVB itself doesn't "switch" to/from DST. It always only transmits UTC. It is > up to your receiver-clock to translate UTC to local time for the user > display. This is why most of WWVB radio controlled clocks have a little PMCE > (Pacific / Mountain / Central / Eastern) switch. > > The WWVB data format also includes bits which announce if DST change will > occur. It is up to the receiver-clock to decode these bits and make the 1 > hour adjustment at the appropriate time (usually 2 am local time). > > See also: > https://en.wikipedia.org/wiki/WWVB > http://tf.nist.gov/general/pdf/2422.pdf > http://www.nist.gov/pml/div688/grp40/radioclocks.cfm > > /tvb > > ----- Original Message ----- > From: "Andy" <ai.egrps...@gmail.com> > To: "Discussion of precise time and frequency measurement" > <time-nuts@febo.com> > Sent: Sunday, March 13, 2016 7:21 PM > Subject: Re: [time-nuts] When does NIST change to DST? > > >> I wonder if WWVB switches to DST around 0200Z, maybe? Since it can't >> tell where your local zone is. >> >> Andy >> _______________________________________________ >> 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. _______________________________________________ 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.
