Discussion:
How many clock do you need?
(too old to reply)
Roy
2014-10-08 00:40:24 UTC
Permalink
"A man with two clocks is never sure." Actually if you are using
cellphones, you can never be sure.

I was on a road trip where we stayed in a motel. At checkin, the clerk
asked if we needed a wakeup call because the cellphones are unreliable.
The motel was about 200 yards from the state line and the timezone
change over between CST and EST . What your phone showed depended on
which tower is was using. Since the area was marginal for all Verizon
towers, the connection wasn't constant.

My wife and I compared our phones to each other and my wrist watch. It
was amazing to watch the phones change their time display. Some times
they agreed and sometimes they were different by an hour. When they did
agree, they could be both right or both wrong.
Keith Keller
2014-10-08 03:02:44 UTC
Permalink
Post by Roy
"A man with two clocks is never sure." Actually if you are using
cellphones, you can never be sure.
I was on a road trip where we stayed in a motel. At checkin, the clerk
asked if we needed a wakeup call because the cellphones are unreliable.
The motel was about 200 yards from the state line and the timezone
change over between CST and EST . What your phone showed depended on
which tower is was using. Since the area was marginal for all Verizon
towers, the connection wasn't constant.
Why not just set your phone to one time zone? My Android phone
certainly has an option to set a time zone (and the time, if really
necessary) instead of using the tower's.

--keith
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Jeff Liebermann
2014-10-08 03:38:41 UTC
Permalink
Post by Roy
"A man with two clocks is never sure." Actually if you are using
cellphones, you can never be sure.
Chuckle. People who live near time zone borders are used to such
differences.

However, if you're really picky, it also depends on if your cell phone
uses UTC or GPS time.
<Loading Image...>
At this time (pun intended), they're 16 seconds apart, and slowly
increasing:
<http://leapsecond.com/java/gpsclock.htm>
The clock software in most smartphones has provisions for compensating
for the difference. The offset is also transmitted as part of the GPS
data message. Most phones get it right, but a few (like my Droid X2)
manage to screw it up, as shown above.
--
Jeff Liebermann ***@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
David Kaye
2014-10-08 04:39:56 UTC
Permalink
Post by Jeff Liebermann
However, if you're really picky, it also depends on if your cell phone
uses UTC or GPS time.
<http://802.11junk.com/jeffl/crud/GPS-vs-UTC.jpg>
At this time (pun intended), they're 16 seconds apart, and slowly
Did you update your Windows time at the time you took the photo or are you
relying on Windows' once-weekly time update? I changed mine to reset 4
times a day. It can make a big difference.

I find that my current LG flip phone is synched to the NIST, or at least is
close enough that I don't notice a difference. My Windows machine is now
more accurate since I use an NTP client now that updates every hour or two.

Back in the day of "The Big 8", CKLW in Windsor Ontario, the DJs would
always give two time checks, Windsor and Detroit, since at that time there
was a difference; not sure if it was a daylight time difference or what
exactly.




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Jeff Liebermann
2014-10-08 07:10:31 UTC
Permalink
On Tue, 7 Oct 2014 21:39:56 -0700, "David Kaye"
Post by David Kaye
Post by Jeff Liebermann
However, if you're really picky, it also depends on if your cell phone
uses UTC or GPS time.
<http://802.11junk.com/jeffl/crud/GPS-vs-UTC.jpg>
At this time (pun intended), they're 16 seconds apart, and slowly
Did you update your Windows time at the time you took the photo or are you
relying on Windows' once-weekly time update? I changed mine to reset 4
times a day. It can make a big difference.
Yes. I updated it just before I took the photo. I can do the test
again and take another photo if you're not a believer. 16 second
difference between UTC and GPS times.

My desktop does drift around quite a bit during the typical day. For
example, when I run a backup that uses lots of CPU cycles, it will
loose a few seconds per day.
Post by David Kaye
I find that my current LG flip phone is synched to the NIST, or at least is
close enough that I don't notice a difference. My Windows machine is now
more accurate since I use an NTP client now that updates every hour or two.
The cellular networks are extremely accurate. They have to be or
things just don't work right. For example, for CDMA (Verizon/Sprint)
handoff between base stations to be seamless, the two base stations
need to be extremely well synchronized. I suppose it's the same with
the other cellular protocols. Such sync is normally done with GPS
receivers. In the distant past, it was done with SONET backhauls.
Post by David Kaye
Back in the day of "The Big 8", CKLW in Windsor Ontario, the DJs would
always give two time checks, Windsor and Detroit, since at that time there
was a difference; not sure if it was a daylight time difference or what
exactly.
Nope. Using Google:
<https://www.google.com/search?&q=windsor%20ontario>
<https://www.google.com/search?q=detroid+michigan>
The white box on the right both show identical "local time".
However, they might change daylight savings time on different days,
thus creating a 1 hr offset.
--
Jeff Liebermann ***@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
David Kaye
2014-10-08 19:17:24 UTC
Permalink
Post by Jeff Liebermann
Yes. I updated it just before I took the photo. I can do the test
again and take another photo if you're not a believer. 16 second
difference between UTC and GPS times.
This just doesn't make any sense. GPS and UTC should agree within
nanoseconds.
Post by Jeff Liebermann
My desktop does drift around quite a bit during the typical day. For
example, when I run a backup that uses lots of CPU cycles, it will
loose a few seconds per day.
Indeed. I'm surprised that the original PC architecture didn't sample the
RTC more than just at startup. At least the RTC doesn't drift
significantly.
Post by Jeff Liebermann
<https://www.google.com/search?&q=windsor%20ontario>
<https://www.google.com/search?q=detroid+michigan>
Maybe today, but I have CKLW airchecks from the 1960s where the DJs give two
different times for Windsor and Detroit.




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Jeff Liebermann
2014-10-09 00:30:11 UTC
Permalink
On Wed, 8 Oct 2014 12:17:24 -0700, "David Kaye"
Post by David Kaye
This just doesn't make any sense. GPS and UTC should agree within
nanoseconds.
Nope. See the UTC and GPS times at:
<http://leapsecond.com/java/gpsclock.htm>
"GPS time was zero at 0h 6-Jan-1980 and since it is not perturbed
by leap seconds GPS is now ahead of UTC by 16 seconds."

Don't assume that GPS and UTC are the only time systems available.
Here's a list of others:
<http://www.ucolick.org/~sla/leapsecs/timescales.html>

The real problem is that GPS time is based on counting cycles from an
atomic clock, while UTC is based on astronomical observations. Civil
time, which is based on UTC, is adjusted for leap seconds, while GPS
time is not.
<http://tycho.usno.navy.mil/leapsec.html>
--
Jeff Liebermann ***@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Bhairitu
2014-10-08 19:06:38 UTC
Permalink
Post by Roy
"A man with two clocks is never sure." Actually if you are using
cellphones, you can never be sure.
I was on a road trip where we stayed in a motel. At checkin, the clerk
asked if we needed a wakeup call because the cellphones are unreliable.
The motel was about 200 yards from the state line and the timezone
change over between CST and EST . What your phone showed depended on
which tower is was using. Since the area was marginal for all Verizon
towers, the connection wasn't constant.
My wife and I compared our phones to each other and my wrist watch. It
was amazing to watch the phones change their time display. Some times
they agreed and sometimes they were different by an hour. When they did
agree, they could be both right or both wrong.
Good reason to get rid of time zones altogether and just use UTC. It
would take about 10 years for the sheeple to adjust but it would
eliminate a lot of confusion. Time zones aren't for the Internet age
and are very retro 20th century.
David Kaye
2014-10-08 19:20:52 UTC
Permalink
Post by Bhairitu
Good reason to get rid of time zones altogether and just use UTC. It
would take about 10 years for the sheeple to adjust but it would eliminate
a lot of confusion. Time zones aren't for the Internet age and are very
retro 20th century.
China used 1 time zone stretched across 5 zones worth of territory. Maybe
this is why they have so many suicides. People have natural rhythms that
respond to light and darkenss. They want to wake up in the morning, eat
lunch at noon, and go do bad after dark. Changing those rhythms can be
extremely disturbing to people.




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Bhairitu
2014-10-09 00:23:07 UTC
Permalink
Post by David Kaye
Post by Bhairitu
Good reason to get rid of time zones altogether and just use UTC. It
would take about 10 years for the sheeple to adjust but it would eliminate
a lot of confusion. Time zones aren't for the Internet age and are very
retro 20th century.
China used 1 time zone stretched across 5 zones worth of territory. Maybe
this is why they have so many suicides. People have natural rhythms that
respond to light and darkenss. They want to wake up in the morning, eat
lunch at noon, and go do bad after dark. Changing those rhythms can be
extremely disturbing to people.
Those rhythms are somewhat individual too. For instance, my work
schedule pretty much through the late 80s was that of a club musician. I
worked at night arose late in the morning, ate a brunch not a breakfast.
To this day that rhythm seems still in play.

A study should be done to see if people gain weight after DST goes into
effect. My bet it does because they begin eating lunch at what is
effectively 11 AM and not NOON. There is a theory that when the sun is
high the digestive juices are also most prominent.

Scheduled eating throws the body off whereas eating when hungry and
drinking when thirsty is a better idea but don't tell the industrialists
that. It's their bottom line that counts.

Clocks are just numbers as is time. So noon would be a different number
crossing the globe.
David Kaye
2014-10-09 01:36:46 UTC
Permalink
I wrote...
Post by David Kaye
They want to wake up in the morning, eat
lunch at noon, and go do bad after dark. Changing those rhythms can be
extremely disturbing to people.
That's a HOOT! Go do bad after dark. Obvious where my mind was when I
wrote that...




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Keith Keller
2014-10-09 02:04:29 UTC
Permalink
Post by Bhairitu
Good reason to get rid of time zones altogether and just use UTC. It
would take about 10 years for the sheeple to adjust but it would
eliminate a lot of confusion. Time zones aren't for the Internet age
and are very retro 20th century.
The US hasn't even gone metric yet! It'd probably take 30 years just to
decide to start transitioning to UTC.

--keith
--
kkeller-***@wombat.san-francisco.ca.us
(try just my userid to email me)
AOLSFAQ=http://www.therockgarden.ca/aolsfaq.txt
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Thad Floryan
2014-10-09 18:27:34 UTC
Permalink
Post by Keith Keller
Post by Bhairitu
Good reason to get rid of time zones altogether and just use UTC. It
would take about 10 years for the sheeple to adjust but it would
eliminate a lot of confusion. Time zones aren't for the Internet age
and are very retro 20th century.
The US hasn't even gone metric yet! It'd probably take 30 years just to
decide to start transitioning to UTC.
Hi Keith,

The US Metrification Committee did exist and seems to have
been abandoned for anything dealing with the public.

I had a vague recollection of seeing dual English/metric speed
limit signs on I-280 between San Jose and Hwy 92 circa late 1970s
or early 1980s but I couldn't find any Google Images verifying
that.

What I did find was metric distance signs and that's what I now
remember seeing along I-280. An example can be seen here:

http://lamar.colostate.edu/~hillger/signs/

The 4th picture entry there (for Big Sur) shows exactly the kind
of metric signs I recall seeing here in the Bay Area. There are
other California signs on that page with dual miles/km -- scroll
down.

IIRC, the metric signs were removed after less than a year because
Americans couldn't figure out what they meant which is not surprising
since the average American seems to be a knuckle-dragging slack-jawed
LOL'ing fecebook-using dummy 100% absorbed in their dumb smartphones
as can be seen in this 12-picture sad commentary of our times:

http://dbagging.com/12-smartphone-douchebags/

As for UTC, I've been using that for decades in the XEphem program:

http://en.wikipedia.org/wiki/XEphem

http://www.clearskyinstitute.com/xephem/

This is one of 1000s of charts I've produced using XEphem using UTC;
this one documents the 2003 Mars event:

http://thadlabs.com/FILES/Mars_retro_2003.pdf 51kB
http://thadlabs.com/FILES/Mars_retro_2003.txt 14kB

Some other things produced using XEphem can be seen on my home page
(animation of ALL asteroids and a solar system animation for one
Saturn orbit of the Sun):

http://thadlabs.com/

You may get a kick seeing the "Clear Sky Charts" at the top right of
that page -- click anywhere on the thumbnail or text to get there.

Thad
Bhairitu
2014-10-09 18:29:22 UTC
Permalink
Post by Keith Keller
Post by Bhairitu
Good reason to get rid of time zones altogether and just use UTC. It
would take about 10 years for the sheeple to adjust but it would
eliminate a lot of confusion. Time zones aren't for the Internet age
and are very retro 20th century.
The US hasn't even gone metric yet! It'd probably take 30 years just to
decide to start transitioning to UTC.
--keith
UTC would be much easier to convert to than metric. Noon in the Bay
Area would be 20 hours UTC. And there might be a market for dual clocks
for a while.

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