UTC
In message 20050728.162059.104074939.imp@bsdimp.com, Warner Losh writes:
Within the respective zones created under the authority of sections
261 to 264 of this title the standard time of the zone shall insofar
as practicable (as determined by the Secretary of Transportation)
govern the movement of all common carriers engaged in interstate or
foreign commerce. In all statutes, orders, rules, and regulations
relating to the time of performance of any act by any officer or
department of the United States, whether in the legislative,
executive, or judicial branches of the Government, or relating to the
time within which any rights shall accrue or determine, or within
which any act shall or shall not be performed by any person subject to
the jurisdiction of the United States, it shall be understood and
intended that the time shall insofar as practicable (as determined by
the Secretary of Transportation) be the United States standard time of
the zone within which the act is to be performed.
I have not been able to find the actual regulations delegating this to
NIST (only statements to that effect on the NIST web site), so I'm
unable to tell how much deviation is allowed from the mean solar time
to still meet the statuatory langauge of 'based on'.
It may not be delegated to NIST, NIST may merely be advisory to DoT,
which USNO probably also is.
The other important bit is that ITU is an UN organization, so the
US Government decides who get to wave the USAs vote card and therefore
presumably also what they wave it for.
So even if NIST went wild and put the TF460 proposal in front of
7A, the USA may still not actually vote for that when it gets to
the plenipotential assembly.
I'm surprised nobody has found out where in the US the proposal
originated ? Was it DoD[1] ? DoT[2] ? DoE[3] ? NIST[4] ?
There must be something which can be done with a FoIA request ?
Poul-Henning
[1] likely in my mind. They have a war or two going on, they are
not in a position to take a couple of hours off to see what doesn't
work afterwards.
[2] Since, per above they're responsible for this area.
[3] Responsible for all the nukes, including the one on alert.
[4] I somehow doubt it. Why would they remove the one feature which
allows them to get a bit of publicity every so often ?
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Hi Poul,
Finally, my network access is back!
Poul-Henning Kamp wrote:
In message 42E813E4.4090001@erols.com, Chuck Harris writes:
[I split off this topic, it's interesting in its own right I think]
I must be very unusual, I fix modern TV's, radios, and other consumer
electronics doo-dads. It isn't generally economical to do what I do, but
it does keep me in touch with the bleeding edge of consumer manufacturing
techniques.
Right, but if you were a 7 year old kid, would you learn from it ?
There a few things that can be learned, one is what the various surface
mount components look like. Another is that there is actually something inside
that makes the set function . At 7, ideas that there may be gnomes inside
that do the work wouldn't seem too far fetched.
Shielding is another issue, and even the most micro electronic'd tv set
will still have an RF section that is inside a can. One can pop the top off of
the can, and see filters, etc.
And, of course, there are wires, connectors, speakers, and other gadgets
that are interesting.
The problem is that microelectronics obscure the basic circuit and
prevents you from poking around with anything but a few peripheral
capacitors which are mostly there for decoupling anyway...
I agree to a point, we are certainly heading to a time where the integration
will be so high that a TV set will be nothing but connectors, and this tiny
block of electronics that cannot be viewed at all. We aren't quite there yet
in the larger less expensive sets.
When I took a television apart, there were a schematic pasted on the
back panel, and I could trace the circuit and with a book about
radio reception in hand, I could follow the signals progress. I
could look at the schematic and figure out what happened when I
pushed this button and turned that knob.
I entered the playing field at about that time, and I can tell you the circuitry,
although it was visible, (and even point to point handwired) was so
economized that it wasn't at all obvious how it worked. Radios were a better
source of inspiration than TV sets.
If my kid takes a television apart, he can trace any wire with a
signal until it hits an integrated circuit and then what ?
It isn't the set that has squelched the interest. Around my house, there
are radios and test equipment of all vintages from vacuum tube, through
microelectronics.... And yet my kid doesn't even want to think about what is
inside. He was curious before he went to school, but after starting school,
with its mandatory computer, and internet use, he now couldn't care less.
For grins, I offered to give the 5th graders a lesson in magnetics and electricity,
and I brought in a home made motor, a home made loud speaker, an oscilloscope,
and sweep function generator, and a simple security board that I made for some
client. They kids and teachers were fascinated. My lecture was supposed to go
from 9am to 10 am, and because of all of the questions, they almost missed their
1pm lunch.
I still hear from my son's classmates about the time his dad came in to school.
The teachers were the ones that were really fascinated, as they had no idea
how motors and speakers really worked, and yet they were teaching a unit
on electricity and magnetism.
How can you teach what you don't know? I'd love to teach an elementary school
science course, I 'd gladly take time out of my day to do it. But with my MSEE,
I am not "qualified". You have to have a master's degree in education to teach.
-Chuck
Poul-Henning Kamp wrote:
[1] likely in my mind. They have a war or two going on, they are
not in a position to take a couple of hours off to see what doesn't
work afterwards.
The war in Iraq, though a pretty big thing for those who are in Iraq,
isn't taxing the DoD much at all. I live near washington, and Iraq and
Afganistan are not what is driving most of the work that goes on in the
DC area. You wouldn't even know that there was a war going on, if you didn't
already know.
-Chuck
The WSJ says that the UK still uses GMT. When the NASA person
called out "On my mark..." time during pre-launch activities,
it was specified as GMT.
What relationship does GMT have to UTx time? The hill in Greenwich
is now just a museum, right?
Bill Hawkins
GMT = UTC. A lot of old school folks in the Military and NASA were
schooled as GMT or ZULU time for UTC.
Bill Hawkins wrote:
The WSJ says that the UK still uses GMT. When the NASA person
called out "On my mark..." time during pre-launch activities,
it was specified as GMT.
What relationship does GMT have to UTx time? The hill in Greenwich
is now just a museum, right?
Bill Hawkins
time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
At 07:56 PM 7/29/2005, Brian Kirby wrote...
GMT = UTC. A lot of old school folks in the Military and NASA were schooled as GMT or ZULU time for UTC.
GMT is actually ambiguous, and in actual use can refer to either UTC or UT1. It predates UTC, and was used prior to the introduction of UTC. Here's an interesting article: http://www.apparent-wind.com/gmt-explained.html
In message 009801c5948e$b8802580$0500a8c0@darius.domain.actdsltmp, "Bill Hawkins" writes:
The WSJ says that the UK still uses GMT. When the NASA person
called out "On my mark..." time during pre-launch activities,
it was specified as GMT.
What relationship does GMT have to UTx time? The hill in Greenwich
is now just a museum, right?
The difference is that the UK government defines GMT and therefore are not
bound by the foibles of UTC if they don't want to be.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
I think we are on the same page, moduls some minor differences
which can easily be explained by some delta-T and delta-X:
I took apart old tube televisions in Denmark in the 1970ies.
How can you teach what you don't know? I'd love to teach an elementary school
science course, I 'd gladly take time out of my day to do it. But with my MSEE,
I am not "qualified". You have to have a master's degree in education to teach.
Yes, we're having the same issue my side of the pond: Somebody thought that
knowing how to teach would be enough, now we're finding out that knowing what
you teach is a big thing too.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
See one on eBay and was wondering about its function. Is this NTP server
that synchronizes to CDMA cellular?
It says; "Board only inside, no oscillator, unit is in working condition"
What say ye? Will this make a good enough NTP time source even without the
oscillator? What, where and how much would an oscillator cost?
Thanks,
Jack
From: Warner Losh imp@bsdimp.com
Subject: Re: [time-nuts] Re: UTC
Date: Wed, 27 Jul 2005 17:19:34 -0600 (MDT)
Message-ID: 20050727.171934.28808808.imp@bsdimp.com
Certainly. But what's your point? I don't see these utilities failing
if a second slips here or there. The one case where time is critical
is the power grid, and they keep their own time (Which, IIRC
approximates UTC).
The long term average of the power grid in the US is 60.000 Hz. Short
term variations from that can and do happen.
Actually, assume that the short-time frequency is most probably anything but
60 Hz (or 50 Hz, depending on where you are). The over and under-production of
electricity is the frequency control-means.
It is to make sure that the clocks run on time, on the average. It might be
better to say that the power grid approximates the SI second, since it has no
notion of which second it is (although the control infrastructure for the
grid most likely does).
Rather, you have on long term average a frequency control, but no phase
control.
My oldest counter had in standard edition the 50 Hz or 60 Hz power grid
frequency as reference frequency (using a phantastron frequency divider
circuit using a pentode and a triode) where as mine has the 100 kHz crystal
oscillator reference, when that was a luxuary. ;O)
Cheers,
Magnus