Happy Leap Hour Day !
Have a happy Leap Hour day !
Today is happy :-)
Tomorrow will not :-(
Didier KO4BB
Brian Kirby wrote:
Have a happy Leap Hour day !
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I have two Chinese-made "atomic clocks" that did not adjust to the new time.
My Casio "atomic watch" did adjust correctly.
----- Original Message -----
From: "Brian Kirby" kirbybq@bellsouth.net
To: "Time Nuts" time-nuts@febo.com
Sent: Sunday, March 11, 2007 6:32 AM
Subject: [time-nuts] Happy Leap Hour Day !
Have a happy Leap Hour day !
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I have several of those that did not adjust either. I simply changed the
time zone and I will have to think about changing back in 3 weeks.
I suppose the time signal includes DST info and these clocks do not use
it, while the Casio does? Or is the Casio a new model that may have the
right DST programming?
Didier KO4BB
Joseph Gray wrote:
I have two Chinese-made "atomic clocks" that did not adjust to the new time.
My Casio "atomic watch" did adjust correctly.
----- Original Message -----
From: "Brian Kirby" kirbybq@bellsouth.net
To: "Time Nuts" time-nuts@febo.com
Sent: Sunday, March 11, 2007 6:32 AM
Subject: [time-nuts] Happy Leap Hour Day !
Have a happy Leap Hour day !
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I suppose the time signal includes DST info and these clocks do not use
it, while the Casio does? Or is the Casio a new model that may have the
right DST programming?
Didier KO4BB
The clocks and the watch were all purchased within the last four months. Of
course, I don't know how long they have been sitting in the store. It is
annoying to have clocks that are supposed to be synced to WWVB and still
have to set them.
I have had mine for a while and all I could say is, it was nice while it
lasted :-)
Well, on the positive side, you may be off by an hour, but the seconds
will be right :-)
I plan to take tomorrow off anyhow, that will give me another day to
adjust my own body clock (with is not disciplined to anything...)
Didier KO4BB
Joseph Gray wrote:
I suppose the time signal includes DST info and these clocks do not use
it, while the Casio does? Or is the Casio a new model that may have the
right DST programming?
Didier KO4BB
The clocks and the watch were all purchased within the last four months. Of
course, I don't know how long they have been sitting in the store. It is
annoying to have clocks that are supposed to be synced to WWVB and still
have to set them.
One of the most important pieces of equipment I own is working ok without a
DST update - my TiVo :-) DirecTV left a phone message just yesterday (very
short notice) to tell me that my TiVo needed a software update, so I should
plug it into the phone line. I can just imagine thousands of people trying
to get that update all day yesterday.
Actually, the TiVo uses UTC for automatic recordings, so unless I manually
schedule a recording, I don't need the update. The time display is off by
one hour. I may just set the time zone East, as you mentioned about clocks.
That solution was recommended on the TiVo forums.
If you're wondering why I didn't get the software update, let's just say
that my unit has been customized and I don't want to mess things up. Since
the TiVo runs Linux, I may just find the updated timezone files and manually
fix things.
----- Original Message -----
From: "Didier Juges" didier@cox.net
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Sunday, March 11, 2007 12:39 PM
Subject: Re: [time-nuts] Happy Leap Hour Day !
I have had mine for a while and all I could say is, it was nice while it
lasted :-)
Well, on the positive side, you may be off by an hour, but the seconds
will be right :-)
I plan to take tomorrow off anyhow, that will give me another day to
adjust my own body clock (with is not disciplined to anything...)
Didier KO4BB
Joseph Gray wrote:
I suppose the time signal includes DST info and these clocks do not use
it, while the Casio does? Or is the Casio a new model that may have the
right DST programming?
Didier KO4BB
The clocks and the watch were all purchased within the last four months.
Of
course, I don't know how long they have been sitting in the store. It is
annoying to have clocks that are supposed to be synced to WWVB and still
have to set them.
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
To address some of the recent DST postings...
Clocks with hard-coded USA DST rules will be off by an
hour for the three weeks from 11-Mar to 1-Apr-2007.
Given how long it's been since the DST rules changed you
can see why someone in a cheap or weak moment would
design a clock with hardcoded rules. Still, a bad design.
WWVB radio-controlled "atomic clocks", on the other hand,
do not have hardcoded rules; instead they switch to DST
based on command from Boulder. This is why many of us
saw our RC clocks/watches do the right thing this morning.
This is a good design.
But a big problem remains. The WWVB subcode has only
the ability to give 1 UTC day of advanced warning of a DST
change. So if your clock happened to have poor reception
yesterday it still doesn't know of the DST change and will
remain in error by an hour until it ever gets good reception,
which could be day(s) later.
The problem is compounded by the fact that most RC clocks
only enable reception late in the evening (e.g., starting at
11 PM), that the DST switch occurs at 2 AM local time, and
that most of the USA is 5 to 8 hours left of Greenwich.
These three factors make the window for DST notification
much smaller than one day. And the result is that every time
a DST change occurs there are tens of thousands of RC
clocks that get it wrong (by not getting it at all). It's all a little
embarrassing since these clocks are often advertised to be
accurate to a millionth of a second, etc.
Further embarrassing is that NTP, the great internet clock is
so academically pure, and that GPS, the great clock in the
sky, is so globally available, that neither dare taint themselves
with the geographical and political mess of timezones or DST.
A solution would be to carve out a few more DST bits in the
WWVB subcode. So instead of giving a few hours of notice
an RC clock would see, for example, a 7- or 15-day binary
countdown to the DST event. That way, poor reception the
night before DST, or even a couple of nights before, would
not make the clocks fail at 2 AM Sunday.
Don't hold your breath waiting for a fix; but at least you better
understand the problem now. Actually, the solution may be
that more and more people are using cell phones instead of
clocks/watches/computers to get accurate local time...
/tvb
http://www.LeapSecond.com
Links:
NIST Radio Station WWVB
http://tf.nist.gov/stations/wwvb.htm
WWVB Time Code Format
http://tf.nist.gov/stations/wwvbtimecode.htm
WWVB Radio Controlled Clocks
http://tf.nist.gov/stations/radioclocks.htm
http://tf.nist.gov/general/pdf/1976.pdf
http://tf.nist.gov/general/pdf/1383.pdf
Decoding WWVB from a Sony atomic...
http://www.leapsecond.com/pages/sony-wwvb/
WWVB Subcode Test Generator - wwvb2
http://www.leapsecond.com/notes/wwvb2.htm
Tom, I was under the same impression as you, regarding RC clocks. However, I
just pulled/replace the battery on one of mine and then forced an update. It
still is an hour off. Am I missing something, or is the clock?
----- Original Message -----
From: "Tom Van Baak" tvb@LeapSecond.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Sunday, March 11, 2007 2:34 PM
Subject: Re: [time-nuts] Happy Leap Hour Day !
To address some of the recent DST postings...
Clocks with hard-coded USA DST rules will be off by an
hour for the three weeks from 11-Mar to 1-Apr-2007.
Given how long it's been since the DST rules changed you
can see why someone in a cheap or weak moment would
design a clock with hardcoded rules. Still, a bad design.
WWVB radio-controlled "atomic clocks", on the other hand,
do not have hardcoded rules; instead they switch to DST
based on command from Boulder. This is why many of us
saw our RC clocks/watches do the right thing this morning.
This is a good design.
But a big problem remains. The WWVB subcode has only
the ability to give 1 UTC day of advanced warning of a DST
change. So if your clock happened to have poor reception
yesterday it still doesn't know of the DST change and will
remain in error by an hour until it ever gets good reception,
which could be day(s) later.
The problem is compounded by the fact that most RC clocks
only enable reception late in the evening (e.g., starting at
11 PM), that the DST switch occurs at 2 AM local time, and
that most of the USA is 5 to 8 hours left of Greenwich.
These three factors make the window for DST notification
much smaller than one day. And the result is that every time
a DST change occurs there are tens of thousands of RC
clocks that get it wrong (by not getting it at all). It's all a little
embarrassing since these clocks are often advertised to be
accurate to a millionth of a second, etc.
Further embarrassing is that NTP, the great internet clock is
so academically pure, and that GPS, the great clock in the
sky, is so globally available, that neither dare taint themselves
with the geographical and political mess of timezones or DST.
A solution would be to carve out a few more DST bits in the
WWVB subcode. So instead of giving a few hours of notice
an RC clock would see, for example, a 7- or 15-day binary
countdown to the DST event. That way, poor reception the
night before DST, or even a couple of nights before, would
not make the clocks fail at 2 AM Sunday.
Don't hold your breath waiting for a fix; but at least you better
understand the problem now. Actually, the solution may be
that more and more people are using cell phones instead of
clocks/watches/computers to get accurate local time...
/tvb
http://www.LeapSecond.com
Links:
NIST Radio Station WWVB
http://tf.nist.gov/stations/wwvb.htm
WWVB Time Code Format
http://tf.nist.gov/stations/wwvbtimecode.htm
WWVB Radio Controlled Clocks
http://tf.nist.gov/stations/radioclocks.htm
http://tf.nist.gov/general/pdf/1976.pdf
http://tf.nist.gov/general/pdf/1383.pdf
Decoding WWVB from a Sony atomic...
http://www.leapsecond.com/pages/sony-wwvb/
WWVB Subcode Test Generator - wwvb2
http://www.leapsecond.com/notes/wwvb2.htm
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Hi Tom:
So, what's it take to make a Cell Phone Disciplined Oscillator?
I've seen some timing products based on CDMA cell systems, but haven't
seen any that use an actual cell phone.
Have Fun,
Brooke Clarke
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com
Tom Van Baak wrote:
To address some of the recent DST postings........ Actually, the solution may be
that more and more people are using cell phones instead of
clocks/watches/computers to get accurate local time...
I do not know if my clocks (WWVB controlled types) are one of these hard
coded one, or a smart one, but I will say the one feature that made me
choose it over others was the low price (for a WWVB controlled model).
Let's be honest, it was cheap. However, if it happens to have simply
missed yesterday's transmission, I can see that my "solution" of
changing time zone may come back and bite me when I go to bed one day
and the clock decides to update itself at midnight and I get up one full
hour earlier... It's bad enough to have to get up on time, it's against
my religion to get up early.
Maybe I should reset it by hand...
Thanks Tom, you quite possibly saved me an hour of sleep...
Didier
PS: for the record, I have 4 clocks of the same type (nightstand size)
and another wall mounted, and it seems all missed the update. Maybe
60kHz propagation was just very bad last night?
Tom Van Baak wrote:
To address some of the recent DST postings...
Clocks with hard-coded USA DST rules will be off by an
hour for the three weeks from 11-Mar to 1-Apr-2007.
Given how long it's been since the DST rules changed you
can see why someone in a cheap or weak moment would
design a clock with hardcoded rules. Still, a bad design.
WWVB radio-controlled "atomic clocks", on the other hand,
do not have hardcoded rules; instead they switch to DST
based on command from Boulder. This is why many of us
saw our RC clocks/watches do the right thing this morning.
This is a good design.
.....
/tvb
So, what's it take to make a Cell Phone Disciplined Oscillator?
I've seen some timing products based on CDMA cell systems, but haven't
seen any that use an actual cell phone.
Is it too late to ask Apple for an iPhone 1PPS?
/tvb
Tom, I was under the same impression as you, regarding RC clocks. However, I
just pulled/replace the battery on one of mine and then forced an update. It
still is an hour off. Am I missing something, or is the clock?
What make/model? This is interesting. I have seen
something like this before. It might work tomorrow. It
might take one 2 AM transition. Or it might work in
another hour when 11-Mar-2007 UTC is over. Can
you try it again a few times and tell me when it first
comes up with the correct time?
If so, it's another untested bug in RC clock firmware.
Read the WWVB docs and note the two DST bits (57
and 58) are quite tricky on the day of the switchover,
especially considering the difference between the UTC
day and the local day, when the reception is made vs.
when the clock needs to (or needed to) be advanced.
See also:
WWVB Radio Controlled Clocks: Recommended
Practices for Manufacturers and Consumers
http://tf.nist.gov/general/pdf/1976.pdf
NIST Special Publication 432
http://tf.nist.gov/general/pdf/1383.pdf
/tvb
Hi Tom:
It's interesting that NIST has specified the dates for DST- ST changes
in 1976.pdf.
So that document is now wrong.
Have Fun,
Brooke Clarke
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com
Tom Van Baak wrote:
Tom, I was under the same impression as you, regarding RC clocks. However, I
just pulled/replace the battery on one of mine and then forced an update. It
still is an hour off. Am I missing something, or is the clock?
What make/model? This is interesting. I have seen
something like this before. It might work tomorrow. It
might take one 2 AM transition. Or it might work in
another hour when 11-Mar-2007 UTC is over. Can
you try it again a few times and tell me when it first
comes up with the correct time?
If so, it's another untested bug in RC clock firmware.
Read the WWVB docs and note the two DST bits (57
and 58) are quite tricky on the day of the switchover,
especially considering the difference between the UTC
day and the local day, when the reception is made vs.
when the clock needs to (or needed to) be advanced.
See also:
WWVB Radio Controlled Clocks: Recommended
Practices for Manufacturers and Consumers
http://tf.nist.gov/general/pdf/1976.pdf
NIST Special Publication 432
http://tf.nist.gov/general/pdf/1383.pdf
/tvb
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
What make/model? This is interesting. I have seen
something like this before. It might work tomorrow. It
might take one 2 AM transition. Or it might work in
another hour when 11-Mar-2007 UTC is over. Can
you try it again a few times and tell me when it first
comes up with the correct time?
I have two of them. They are little travel alarms I bought for $10 each at
Walgreens. The brand is "Living Solutions". The model is "C17D3403". I will
make sure they are oriented properly and see if they are synced by tomorrow.
Actually, I bought two of these in the hope that one will die, so I can
remove the radio module and play with it :-)
WWVB Radio Controlled Clocks: Recommended
Practices for Manufacturers and Consumers
http://tf.nist.gov/general/pdf/1976.pdf
NIST Special Publication 432
http://tf.nist.gov/general/pdf/1383.pdf
I read these a while back. Very informative.
might take one 2 AM transition. Or it might work in
another hour when 11-Mar-2007 UTC is over. Can
you try it again a few times and tell me when it first
comes up with the correct time?
Tom, I did another forced sync and now it has the correct time.
might take one 2 AM transition. Or it might work in
another hour when 11-Mar-2007 UTC is over. Can
you try it again a few times and tell me when it first
comes up with the correct time?
Tom, I did another forced sync and now it has the correct time.
Cool. Yeah, it sounds like it has the bug. I predict that if
this receiver does not get a signal the night before, or is
reset on the transition Sunday between 2 AM local time
and 24h UTC (early evening, local time) it will be off by an
hour.
I suspect the person/company who wrote the firmware for
the RC clock didn't think about this case, or didn't test for
it, or didn't code general enough so that this case wasn't
special in the first place.
If you or anyone on the list wants a challenge, try reading
the spec yourself and pseudo code an algorithm that will
correctly convert WWVB subcode to local date & time,
accounting for USA timezones and DST. It's much harder
to get right than you might think. Extra credit: see if it's
simple enough to run on a 32 kHz 4-bit CPU...
/tvb