An NIST Mistake on "Atomic Clock"
 

Hello, Everyone:

I bought an "atomic clock" in February, 2005, and it has since been
working fine. I live on the eastern coast and now use EDT.

But then at about 2:00 PM, July 20, 2005, I noticed the clock display
"SAT" while it was actually "WED". The Month, Date, Hour, Minute, and
Second were all correct, though. Also, the logo of a radio wave tower
was on, meaning the clock had received the NIST signal for the day.
When I got home after midnight (It was now July 21), the clock
displayed "THU" correctly.

Could it have been that NIST sent a wrong signal for the weekday on
July 20, 2005?

--Roland

"qquito" wrote in message
oups.com...
Hello, Everyone:

I bought an "atomic clock" in February, 2005, and it has since been
working fine. I live on the eastern coast and now use EDT.

But then at about 2:00 PM, July 20, 2005, I noticed the clock display
"SAT" while it was actually "WED". The Month, Date, Hour, Minute, and
Second were all correct, though. Also, the logo of a radio wave tower
was on, meaning the clock had received the NIST signal for the day.
When I got home after midnight (It was now July 21), the clock
displayed "THU" correctly.

Could it have been that NIST sent a wrong signal for the weekday on
July 20, 2005?


I don't think the WWVB signal has that much information on it. I think only
the minutes and seconds information, because of the different time zones.

Long as my clocks are within about five minutes of the time frame,I
couldn't care less.I am looking at my old antique Ansonia clock tick
tockin on the wall right now and it is about five minutes slow.It has a
right to be slow,that old 120 year old clock has a wobbled out worn out
gear bearing hole on the back of the works.I wouldn't take anything in
the World (UP You!,ebay!,Sideways!) for that big old wooden case
clock.Besides,it lullabys me to sleep.
cuhulin

I have an "Atomic"
cuhulin

"Brenda Ann" ) writes:
"qquito" wrote in message
oups.com...
Hello, Everyone:

I bought an "atomic clock" in February, 2005, and it has since been
working fine. I live on the eastern coast and now use EDT.

But then at about 2:00 PM, July 20, 2005, I noticed the clock display
"SAT" while it was actually "WED". The Month, Date, Hour, Minute, and
Second were all correct, though. Also, the logo of a radio wave tower
was on, meaning the clock had received the NIST signal for the day.
When I got home after midnight (It was now July 21), the clock
displayed "THU" correctly.

Could it have been that NIST sent a wrong signal for the weekday on
July 20, 2005?


I don't think the WWVB signal has that much information on it. I think only
the minutes and seconds information, because of the different time zones.




No, they can be set right just by getting sync'd up.

The time zone is merely an offset from UTC, which is what WWVB sends out.
You tell the clock what time zone you are in, and it adds the needed
offset to the data recovered from WWVB.

Michael

That apparently is not the case. When I first put the battery in the
clock after I bought it in February, all it displayed---Month, Date,
Day, Hour, Minute, etc.---were wrong. I did not adjust anything and
just left it that way. I wanted to see if everything would be signaled
by the WWVB. Yes, it was what happened: EVERYTHING got correct
automatically!

Brenda Ann wrote:

...... I think only the minutes and seconds information, because of the
different time zones.

Check this link:
http://tf.nist.gov/stations/wwvbtimecode.htm
The chart shows the timecode includes:
S, M, D, Y, UT correction, and, LY data.
The logic in the device must reduce the raw data to
month, day etc.

I once wrote a computer program to do this.
For me it was a "non trivial task", but I am not
much of a programer.

Terry

In article ,
Brenda Ann wrote:

I don't think the WWVB signal has that much information on it. I think only
the minutes and seconds information, because of the different time zones.

The data format is available in their time standards doc, NIST Special
Publication 432. It's at their web site, somewhere in ?.nist.gov.
About a 3 megabyte .pdf, 80 pages. (Hey, I never looked at the WWVB
section before. Cool pictures of the antennas and transmitter).

There's 60 bits with minute, hour, day of year, two decimal digits of
year, and bits for leap year and daylight savings time and other stuff.
There's no seconds information, as it's sent at 1 baud and it takes
a minute to send the packet.

Mark Zenier Washington State resident

Then, on SAT, July 23, 2005, my clock displayed "TUE, January 4"
(January 4 in 2005 is indeed Tuesday). On Sunday, starting my midnight,
it displayed "WED, January 5". But, after 2:00 PM on Sunday, the hour
when the NIST signal is supposed to be transmitted, my clock was
displaying the right information again.

--Roland

"qquito" ) writes:
Then, on SAT, July 23, 2005, my clock displayed "TUE, January 4"
(January 4 in 2005 is indeed Tuesday). On Sunday, starting my midnight,
it displayed "WED, January 5". But, after 2:00 PM on Sunday, the hour
when the NIST signal is supposed to be transmitted, my clock was
displaying the right information again.

--Roland

Have you changed the battery? I can see the clock acting up because
the battery is low, and then not getting proper reception to resync properly.

You do realize that they are not continuously receiving the WWVB signal.
To save power, and because the internal crystal oscillator is good enough
for a day or so without an update from the time station, they only gather
the information once a day, usually in the very early hours of the day when
propagation may be best, and when man made interference (like all those
light dimmers and tv sets) will be at a minimum.

Since the times you note aren't in the early hours of the morning,
even if WWVB was sending out the wrong signal at odd times, the
clocks would not notice unless the problem is there when they are
scheduled to sync up.

Also keep in mind that if WWVB was really sending out the wrong information,
it would be noticed by others, and that's not happening.

So change your batteries, and then get back to us.

Michael