Slightly OT: Atomic Clocks

WWVB broadcasts a daylight bit starting at 00:00 UTC for
that day. The clock has to receive it, and then remember it
without acting on it for some number of hours until 2 in the
morning local time; then set itself forward; and then manage
to avoid stumbling over the logic to achieve this for the
rest of the day.

La Crosse atomic wall clocks all set themselves back to
standard time in the spring as soon as it's the next UTC
day, in a fairly spectacular chip design bug. It's correct
again the following local day.

In particular though, the clock itself doesn't know about
the calendar but just follows the daylight bit as broadcast,
and a little local processing that may be wrong.
--
Ron Hardin [email hidden]

On the internet, nobody knows you're a jerk.

Quoted post said:

Originally posted by Onefred
Hey,

I know this is a tad OT, but I also know that you are the
type that take notice of these things and probably already
have done a little research into the matter.

Last weekend, there was a TMBRA series mtn bike race about
two hours northwest of Dallas in St. Jo, TX. It was a
relaxing 7 hour drive of mostly flower covered highways. It
was just what the doctored ordered! Anyway, I brought my
atomic alarm clock and, before going to sleep, set it
forward one hour just incase there was no reception in my
hotel room. To cut to the chase, one hour before the race I
telephoned my wife to see how everyone was doing. I was on
the road in route to the race and the first thing that comes
out of her mouth is "What are you doing?" "I'm going to the
competition to warm-up and get ready.What else would I be
doing?", I replied. "I don't know what time it is there, but
here it's 8:30", she explained. "Are you sure?" "Yes, the
television station shows 8:30!" Suddenly, I had a terrible
case of tunnel vision and was in disbelief of the
circumstances... "Holy fauking shee-ite!", I thought. It
wasn't one hour before the race -- it was the start-time of
the race! My gauddamn clock set itself back!!! Well,
needless to say, I rushed as fast as I could and got to the
starting line an incredibly spirit-dampening 17 minutes
after my group had left. I started w/ the last men's group
which was better than having to start w/the ladies who were
all lined up after us waiting for their start! I was really
excited when I finally reached the last rider in my group,
but he was riding at what seemed like -5 MPH. He may as well
have been going in reverse!! Something was obviously wrong,
so I asked him how he was feeling. "Not great. I have leg
cramps.", he said. I quickly lost my grin when I realized he
probably wouldn't even finish... I managed to pass a few
more in my group and was happy not to finish last.

Sigh. Well, the course was super fast. It was the first dry
one of this race season and the weather was nice. So I still
had a blast, and that's a good thing.

But back to the atomic clock problem. Mine didn't change to
the correct hour until Monday morning!!! What is the point
of having an atomic alarm clock if it does not change the
hour automatically when daylight savings comes and goes???
So that I wake up at exactly the same second every
morning??? Now, that's laughable!

The amazing thing to learn from this experience was that
NASA engineers don't need to get to work on time until a few
days after we non-NASA folk do! I guess their communications
satellites don't need to know the correct time until Monday,
too. I thought it was Federal law that required us to
observe daylight savings, so why wouldn't the government
have it right? Maybe the government employee who is
responsible for setting their official clock was late
getting to work to set it forward one hour. Now wouldn't
that be appropriate!!

I am harboring really nasty feelings towards my alarm clock
and half of me wants to throw it into a brick wall, or run
over it w/ my car, but my other half knows that this would
be unreasonable.

Dave

Dear Dave,

This sounds like another reason to prefer
solar over nuclear.

Carl Fogel

onefred said:

But back to the atomic clock problem. Mine didn't change
to the correct hour until Monday morning!!! What is the
point of having an atomic alarm clock if it does not
change the hour automatically when daylight savings comes
and goes??? So that I wake up at exactly the same second
every morning??? Now, that's laughable!

The amazing thing to learn from this experience was that
NASA engineers don't need to get to work on time until a
few days after we non-NASA folk do! I guess their
communications satellites don't need to know the

correct

Quoted message said:

time until Monday, too. I thought it was Federal law that
required us to observe daylight savings, so why wouldn't
the government have it right? Maybe the government
employee who is responsible for setting their

official

Quoted message said:

clock was late getting to work to set it forward one hour.
Now wouldn't that be appropriate!!

Two comments:

1) Complex systems fail in complex ways.

2) Daylight savings time is a bogus idea. Take no notice of
it. It's for idiots!

Back to the atomic clock. The clock gets a signal from
station WWVB in Fort Collins, CO. WWVB operates on the
ungodly frequency of 60 kHz. Since the "D" layer of the
ionosphere absorbs low frequency RF during daylight hours,
the clock will only get the WWVB signal at night (if you're
lucky, and depending where you live.) This is probably not
the best clock to use if you have an important event that
you don't want to miss. Atomic clocks work best when you set
them up in a fixed location, and then don't mess with them.

Here's a picture of the WWVB transmitting site:

boulder.nist.govwwvb.htmOpen ↗

Art Harris N2AH

onefred said:

The amazing thing to learn from this experience was that
NASA engineers don't need to get to work on time until a
few days after we non-NASA folk do! I guess their
communications satellites don't need to know the correct
time until Monday, too. I thought it was Federal law that
required us to observe daylight savings, so why wouldn't
the government have it right? Maybe the government
employee who is responsible for setting their official
clock was late getting to work to set it forward one hour.
Now wouldn't that be appropriate!!

WTF are you talking about. "Federal law"? There are two
and a half states that don't use any Daylight Savings
Time at all.

I had never heard of "atomic alarm clocks" until now, and a
little Google research. Of course, they are not "atomic
clocks" in any meaningful sense. They're radio-controlled
clocks tuned to a time standard. If the maker of your clock
can't manage to make it update to WWV properly, don't blame
the government. What do you do if you're in a place that
gets bad reception on the time of the DST switch - like a
building with aluminum siding?

I don't know what NASA engineers prefer (NASA has nothing to
do with NIST or WWV, of course), but anyone who really needs
to know what time it is for serious purposes, especially space-
based, is using UTC anyway.

Quoted message said:

I am harboring really nasty feelings towards my alarm
clock and half of me wants to throw it into a brick wall,
or run over it w/ my car, but my other half knows that
this would be unreasonable.

It sounds perfectly reasonable to me. Get a clock that
operates in a known fashion and remember to set the time
your own self.

"Arthur Harris" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

onefred said:

But back to the atomic clock problem. Mine didn't change
to the correct hour until Monday morning!!! What is the
point of having an atomic

alarm

Quoted message said:

Quoted message said:

clock if it does not change the hour automatically when
daylight savings comes and goes??? So that I wake up at
exactly the same second every morning??? Now, that's
laughable!

The amazing thing to learn from this experience was that
NASA engineers don't need to get to work on time until a
few days after we non-NASA

folk

Quoted message said:

Quoted message said:

do! I guess their communications satellites don't need
to know the

correct

Quoted message said:

time until Monday, too. I thought it was Federal law
that required us

to

Quoted message said:

Quoted message said:

observe daylight savings, so why wouldn't the government
have it right? Maybe the government employee who is
responsible for setting their

official

Quoted message said:

clock was late getting to work to set it forward one
hour. Now wouldn't that be appropriate!!

Two comments:

1) Complex systems fail in complex ways.

2) Daylight savings time is a bogus idea. Take no notice
of it. It's for idiots!

I agree wholeheartedly.

Dave

"Benjamin Weiner" <[email hidden]> wrote in message
news:40772bb4$1@darkstar...

Quoted message said:

onefred said:

The amazing thing to learn from this experience was that
NASA engineers don't need to get to work on time until a
few days after we non-NASA

folk

Quoted message said:

Quoted message said:

do! I guess their communications satellites don't need
to know the

correct

Quoted message said:

Quoted message said:

time until Monday, too. I thought it was Federal law
that required us

to

Quoted message said:

Quoted message said:

observe daylight savings, so why wouldn't the government
have it right? Maybe the government employee who is
responsible for setting their

official

Quoted message said:

Quoted message said:

clock was late getting to work to set it forward one
hour. Now wouldn't that be appropriate!!

WTF are you talking about. "Federal law"? There are two
and a half states that don't use any Daylight Savings
Time at all.

Yes, but didn't they have to amend their state
constitutions to get around it? I don't recall exactly but
this sounds familiar.

Quoted message said:

I had never heard of "atomic alarm clocks" until now, and
a little Google research. Of course, they are not "atomic
clocks" in any meaningful sense. They're radio-controlled
clocks tuned to a time standard. If the maker of your
clock can't manage to make it update to WWV properly,
don't blame the government. What do you do if you're in a
place that gets bad reception on the time of the DST
switch - like a building with aluminum siding?

I don't know what NASA engineers prefer (NASA has nothing
to do with NIST or WWV, of course), but anyone who really
needs to know what time it is for serious purposes,
especially space-based, is using UTC anyway.

Quoted message said:

I am harboring really nasty feelings towards my alarm
clock and half of

me

Quoted message said:

Quoted message said:

wants to throw it into a brick wall, or run over it w/
my car, but my

other

Quoted message said:

Quoted message said:

half knows that this would be unreasonable.

It sounds perfectly reasonable to me. Get a clock that
operates in a known fashion and remember to set the time
your own self.

Wake-up on the wrong side of the bed this morning, Ben?

Dave

onefred <[email hidden]> wrote: [deletia]

Quoted message said:

Quoted message said:

Quoted message said:

The amazing thing to learn from this experience was
that NASA engineers don't need to get to work on time
until a few days after we non-NASA folk do! I guess
their communications satellites don't need to know the
correct time until Monday, too. I thought it was
Federal law that required us to observe daylight
savings, so why wouldn't the government have it right?

Quoted message said:

Quoted message said:

I don't know what NASA engineers prefer (NASA has
nothing to do with NIST or WWV, of course), but anyone
who really needs to know what time it is for serious
purposes, especially space-based, is using UTC anyway.

Quoted message said:

Wake-up on the wrong side of the bed this morning, Ben?

I guess you mean it as funny, but it ticks me off when
somebody makes a mistake like failing to set their clock to
the correct time because of an over-reliance on cheap
consumer electronics, and then goes on a rant about NASA
engineers and the government. Don't blame the government for
not getting you up in time.

Now if you want to blame anything on NASA _managers_, that
would be fine with me.

BTW, I had to wake up that morning to start (and score) an
MTB race, too. I went around the house at 10 pm the night
before setting the clocks forward. Even the ones in the car
(why are there _two_ clocks in my car? Don't ask).

"onefred" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

"Arthur Harris" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

onefred said:

But back to the atomic clock problem. Mine didn't
change to the

correct

Quoted message said:

Quoted message said:

Quoted message said:

hour until Monday morning!!! What is the point of
having an atomic

alarm

Quoted message said:

Quoted message said:

clock if it does not change the hour automatically
when daylight

savings

Quoted message said:

Quoted message said:

Quoted message said:

comes and goes??? So that I wake up at exactly the
same second every morning??? Now, that's laughable!

Perhaps your atomic clock works like mine:

It only checks once a day, around midnight. And since
the time changes at 2am, it doesn't correct until the
next night.

Bruce

Quoted post said:

Originally posted by Benjamin Weiner

Bonefred said:

The amazing thing to learn from this experience was that
NASA engineers don't need to get to work on time until a
few days after we non-NASA folk do! I guess their
communications satellites don't need to know the correct
time until Monday, too. I thought it was Federal law that
required us to observe daylight savings, so why wouldn't
the government have it right? Maybe the government
employee who is responsible for setting their official
clock was late getting to work to set it forward one hour.
Now wouldn't that be appropriate!!

WTF are you talking about. "Federal law"? There are two
and a half states that don't use any Daylight Savings
Time at all.

I had never heard of "atomic alarm clocks" until now, and a
little Google research. Of course, they are not "atomic
clocks" in any meaningful sense. They're radio-controlled
clocks tuned to a time standard. If the maker of your clock
can't manage to make it update to WWV properly, don't blame
the government. What do you do if you're in a place that
gets bad reception on the time of the DST switch - like a
building with aluminum siding?

I don't know what NASA engineers prefer (NASA has nothing to
do with NIST or WWV, of course), but anyone who really needs
to know what time it is for serious purposes, especially space-
based, is using UTC anyway.

Quoted message said:

I am harboring really nasty feelings towards my alarm
clock and half of me wants to throw it into a brick wall,
or run over it w/ my car, but my other half knows that
this would be unreasonable.

It sounds perfectly reasonable to me. Get a clock that
operates in a known fashion and remember to set the time
your own self. [/B]

Federal law mandates states observe Daylight Savings Time UNLESS the state legislature specifically votes to remain on Standard Time. If the legislature does nothing, the state goes to daylight savings time. The Federal law does have an escape clause that states at the western most extreme of a time zone often exercise-usually to avoid the problems of children travelling to school in the dark.

onefred wrote:

-snip my Atomic clock made me late for my race-

I like your tale a lot better than the guys who throw their
bicycles after a race and blame the mechanic.

--
Andrew the mechanic Muzi www.yellowjersey.org Open every day
since 1 April, 1971

I said:

... If the maker of your clock can't manage to make it
update to WWV properly, don't blame the government. What
do you do if you're in a place that gets bad reception on
the time of the DST switch - like a building with
aluminum siding?

On rereading the story, I saw that you had the opposite
problem - you did set the clock forward but it did get
reception and reset itself (at midnight, perhaps) to
standard time. That's extra annoying - just dumb firmware.
I'm definitely in favor of your running the clock over now.
Hell, my cheap VCR manages to compute daylight savings time
by itself from day, date, and year.

One too many posts to this thread from me, sorry.

Quoted post said:

Originally posted by Benjamin Weiner

BI said:

... If the maker of your clock can't manage to make it
update to WWV properly, don't blame the government. What
do you do if you're in a place that gets bad reception on
the time of the DST switch - like a building with
aluminum siding?

On rereading the story, I saw that you had the opposite
problem - you did set the clock forward but it did get
reception and reset itself (at midnight, perhaps) to
standard time. That's extra annoying - just dumb firmware.
I'm definitely in favor of your running the clock over now.
Hell, my cheap VCR manages to compute daylight savings time
by itself from day, date, and year.

One too many posts to this thread from me, sorry. [/B]

Dear Benjamin,

No, not too many posts--I'd hate to have
missed this last one.

Most of us aren't willing to type "oops," much
less "sorry."

Besides, it clarified the peculiar situation nicely
for those of us who still use sun dials.

Thanks for a good example.

Carl Fogel

onefred said:

"Arthur Harris" <[email hidden]> wrote in message

Quoted message said:

2) Daylight savings time is a bogus idea. Take no notice
of it. It's for idiots!

I agree wholeheartedly.

bah. i love daylight savings time. can't get enuf of it. i
want mandatory double year long daylight savings time.

.. more daylight after work in which to bike.

stuff the mornings, i'm not up then. dawn should be at 9am
.. when i start to think about waking up.
--
david reuteler [email hidden]

Ron Hardin said:

WWVB broadcasts a daylight bit starting at 00:00 UTC for
that day. The clock has to receive it, and then remember
it without acting on it for some number of hours until 2
in the morning local time; then set itself forward; and
then manage to avoid stumbling over the logic to achieve
this for the rest of the day.

(snip)

Quoted message said:

Ron Hardin [email hidden]

On the internet, nobody knows you're a jerk.

True. There's a second bit too. The combination of the two
tells precisely what's going on with DST .... i.e. gonna
come/go tomorrow. Something like that anyway; it's been a
while since I read the spec.

Some self-setting clocks do "phone home" (check NIST
transmissions) only once per 24 hours, so if your does, and
if recpetion is dodgy then, your clock clould fail to update
its time and/or respect the coming/going of DST. In certain
parts of the US WWVB is difficult or impossible to receive.

I have an Oregon Scientific RM-116E self-setter (it's a
tabletop alarm clock) and I *think* it checks in more than
once per day. Not sure.

Later I did my own version of a WWVB clock, and I designed
it to check in every hour. Overkill, I know, but in the 3-4
years it's been running I have never seen the wrong time
displayed.

"Benjamin Weiner" <[email hidden]> wrote in message
news:40774bfc$1@darkstar...

Quoted message said:

onefred <[email hidden]> wrote: [deletia]

Quoted message said:

Quoted message said:

> The amazing thing to learn from this experience was
> that NASA

engineers

Quoted message said:

Quoted message said:

Quoted message said:

> don't need to get to work on time until a few days
> after we non-NASA

folk

Quoted message said:

Quoted message said:

Quoted message said:

> do! I guess their communications satellites don't
> need to know the

correct

Quoted message said:

Quoted message said:

Quoted message said:

> time until Monday, too. I thought it was Federal law
> that required

us to

Quoted message said:

Quoted message said:

Quoted message said:

> observe daylight savings, so why wouldn't the
> government have it

right?

Quoted message said:

Quoted message said:

Quoted message said:

I don't know what NASA engineers prefer (NASA has
nothing to do with NIST or WWV, of course), but anyone
who really needs to know what time it is for serious
purposes, especially space-based, is using UTC anyway.

Quoted message said:

Wake-up on the wrong side of the bed this morning, Ben?

I guess you mean it as funny, but it ticks me off when
somebody makes a mistake like failing to set their clock
to the correct time because of an over-reliance on cheap
consumer electronics, and then goes on a rant about NASA
engineers and the government.

Hey, wait a second. NASA and other government employees
often are the object of ridicule and plesantry. It's meant
in jest. I don't sincerely feel that because someone works
for the government, they are stupid. Perhaps I just watch
too much late night satire.

Also, I've some cheap consumer electronics that work like a
charm. Not all of us can afford to buy professional caliber
stuff all of the time.

Quoted message said:

Don't blame the government for not getting you up in time.

[Oh God, give me strength...]

Quoted message said:

Now if you want to blame anything on NASA _managers_, that
would be fine with me.

Whoa. This an attempt at humor, Mr. Weiner? 'Cause you got a
giggle out'a
me.

Quoted message said:

BTW, I had to wake up that morning to start (and score) an
MTB race, too. I went around the house at 10 pm the night
before setting the clocks forward. Even the ones in the
car (why are there _two_ clocks in my car? Don't ask).

OK.

Dave