29 Years of the Digest ... founded August 21, 1981
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The Telecom Digest for July 10, 2011
Volume 30 : Issue 170 : "text" Format
====== 29 years of TELECOM Digest -- Founded August 21, 1981 ====== |
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Date: Fri, 8 Jul 2011 17:41:52 -0700 (PDT)
From: Wes Leatherock <wleathus@yahoo.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes
Message-ID: <1310172112.80007.YahooMailClassic@web111717.mail.gq1.yahoo.com>
--- On Thu, 7/7/11, Robert Bonomi <bonomi@host122.r-bonomi.com> wrote:
[ ... ]
> The NIST facility is amazingly accurate. They have 'smarts' on
> the server end that measure the round-trip latency to the user, and
> advance the 'tick' so that it arrives at the user's location at
> the proper instant. With quality software, one can set the system
> clock with sub- millisecond accuracy. If memory serves, the
> 'jitter' is around 15 _micro- second_.
This must be the one that you reach at www.time.gov. When you
click on your time zone it tells you to wait, which appears to be
while it is measuring the round trip latency. Then in a few seconds
the digital time (hours, minutes, seconds) appears in the box.
If it doesn't want to come up at www.time.gov there is also a
button to click at www.nist.gov, which brings up the same page.
The is also a timing pulse in the interstitial information on PBS
stations, as the instructions on video recorders often spell out in
detail.
Wes Leatherock
wleathus@yahoo.com
wesrock@aol.com
Date: 8 Jul 2011 10:38:07 -0400
From: kludge@panix.com (Scott Dorsey)
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: Battery power support today
Message-ID: <iv74of$11s$1@panix2.panix.com>
Robert Bonomi <bonomi@host122.r-bonomi.com> wrote:
>Dave Garland <dave.garland@wizinfo.com> wrote:
>>On 7/6/2011 3:49 PM, Robert Bonomi wrote:
>>
>>> Electric blankets are a non-issue, even relatively speaking. They are
>>> relatively low-power devices (i.e. around 150 watts) to start with, and
>>> that power is split across something like 20 or 30 separate wires running
>>> the length of the blanket. So you're looking at maybe 5-10 watts from
>>> each wire in the blanket, assuming it's all the way on.
>>
>>All the electric blankets I've seen had a single wire per control
>>unit, that ran in a serpentine fashion lengthwise. So the current is
>>the same everywhere (about 800 ma, if the blanket or side is 100W).
>
>And if there are 20 passes in the serpentine path, how many watts is
>each pass putting out? :)
Zero field leakage if you run the two conductors twisted together so the fields
cancel out. 100/20= 5 watts of heat.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Date: 09 Jul 2011 23:01:55 GMT
From: Doug McIntyre <merlyn@geeks.org>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: Battery power support today
Message-ID: <4e18dde3$0$74947$8046368a@newsreader.iphouse.net>
kludge@panix.com (Scott Dorsey) writes:
>Robert Bonomi <bonomi@host122.r-bonomi.com> wrote:
>>Dave Garland <dave.garland@wizinfo.com> wrote:
>>>On 7/6/2011 3:49 PM, Robert Bonomi wrote:
>>>
>>>> Electric blankets are a non-issue, even relatively speaking. They are
>>>> relatively low-power devices (i.e. around 150 watts) to start with, and
>>>> that power is split across something like 20 or 30 separate wires running
>>>> the length of the blanket. So you're looking at maybe 5-10 watts from
>>>> each wire in the blanket, assuming it's all the way on.
>>>
>>>All the electric blankets I've seen had a single wire per control
>>>unit, that ran in a serpentine fashion lengthwise. So the current is
>>>the same everywhere (about 800 ma, if the blanket or side is 100W).
>>
>>And if there are 20 passes in the serpentine path, how many watts is
>>each pass putting out? :)
>Zero field leakage if you run the two conductors twisted together so the fields
>cancel out. 100/20= 5 watts of heat.
In a perfect setup with no imperfections. But we don't live in a
pefect abstract world.
How much in real life with kinked wires, and not quite 100% matched fields?
Date: Fri, 08 Jul 2011 10:33:53 -0700
From: AES <siegman@stanford.edu>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes
Message-ID: <siegman-8A9965.10335208072011@bmedcfsc-srv02.tufts.ad.tufts.edu>
In article <op.vx9ss7w4itl47o@acer250.gateway.2wire.net>,
tlvp <tPlOvUpBErLeLsEs@hotmail.com> wrote:
> > Just for the record, a few days ago I found in a drawer one of those
> > Oregon Scientific battery-powered weather gadgets with a couple of
> > remote temperature gauges. Changed the batteries, set it on a shelf in
> > my office, within a day or so it had accurately self-synched it's date
> > and time to somebody's broadcasts out of the ether . (Except it won't
> > and I can't push its Year beyond 2004; it had been in that drawer for a
> > while.)
>
> Following the example of the y2k shenanigans I had to invent to retain the
> usefulness of an AT&T-branded "Computer telephone 8130" (nominated 'Computer
> Telephony Product of the Year' the year it came out late last century), you
> can get month, day, and date to come out just fine if you adjust the year
> to exactly 28 years ago -- not 2011 (which it won't do, you report), but
> 1983.
>
> (Or won't it accept 1983, either? The old 8130 happily accepted 1972 in
> 2000.)
My error: It now seems to have auto-set everything, including the year,
correctly. (Model number is BAR618HGA)
Date: Fri, 8 Jul 2011 22:08:14 +0100
From: Peter R Cook <PCook@wisty.plus.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes
Message-ID: <$A8tDkC+G3FOFwcs@wisty.plus.com>
In message <kqCdnfjrbeU204vTnZ2dnUVZ_hKdnZ2d@posted.nuvoxcommunications>,
Robert Bonomi <bonomi@host122.r-bonomi.com> writes:
>The NIST facility is amazingly accurate. They have 'smarts' on the
>server end that measure the round-trip latency to the user, and
>advance the 'tick' so that it arrives at the user's location at the
>proper instant. With quality software, one can set the system clock
>with sub- millisecond accuracy. If memory serves, the 'jitter' is
>around 15 _micro- second_.
This is a standard feature designed into the NTP protocol. It uses
Marzullo's algorithm to determine the round trip delay.
--
Peter R Cook
Date: Fri, 08 Jul 2011 18:25:33 -0700
From: Sam Spade <sam@coldmail.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: SLC96
Message-ID: <icWdnaSET_mTM4rTnZ2dnUVZ_sOdnZ2d@giganews.com>
My memory was certainly incorrect about SLC 96 concentration. I
reviewed the BSTJ link someone here was so kind to post. The "plain
vanilla" SCL concentration was 2:1, which I recall regulatory
authorities typically found as only a temporary solution.
But, the article went on to say that (for more $$$) concentration could
be avoided. I presume that is what our poster saw in in Apotos (or
whatever it is called) in the Santa Cruz, CA area.
I also believe that is what our esteemed moderator was alluding to aka NET.
Date: Fri, 8 Jul 2011 12:13:26 -0400
From: "Gary" <bogus-email@hotmail.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes
Message-ID: <iv7abn$p1q$1@dont-email.me>
"John Meissen" wrote in message news:20110707224723.9C29217F605@john...
> Probably just monitors WWV's transmission:
> http://www.nist.gov/pml/div688/grp40/wwv.cfm
>
> I've slowly been replacing all of the clocks in my house with ones
> that set themselves. It was interesting to see which ones failed
> when they changed the DST dates because they had hard-coded
> them. There's no reason to hard-code it because the DST status is
> part of the data stream.
I agree, the "ether" has to be WWV or WWVH. That's what all of these
"atomic" clocks we can buy for a few bucks use.
As far as DST goes, don't forget that Arizona and parts of Indiana
don't use DST. They stay on standard time all year. So, unless the
clock has a way of knowing if it's in such a location it will need
some sort of user input to tell it to use or ignore the DST flag.
Since the clock also has to be manually adjusted for UTC offset
(i.e. time zone), I can see why manufactures skimped on adding an
auto-DST option for the standard consumer "atomic" clocks. It was
probably left out of the first chip designed for these clocks and
nobody wants to spend the money to put it in. It looks to me like
Oregon Scientific uses the same chip in all their products, but I
could be wrong.
My favorite clock in my house is a rather old (maybe over 100 years)
Waterbury wind up pendulum clock; I think it's a school house model.
When I bother to fine tune the pendulum height and remember to wind it
regularly, it keeps pretty good time - staying within a minute or two
per day (relative to my "atomic" clock.) I do have to adjust the
pendulum every few months, I suspect due to temperature changes.
Anyway, it does quite well for something so old. They just don't
build them like they used too...
-Gary
Date: Sat, 9 Jul 2011 16:54:51 +0000 (UTC)
From: David Scheidt <dscheidt@panix.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes
Message-ID: <iva14r$a7m$2@reader1.panix.com>
Gary <bogus-email@hotmail.com> wrote:
:As far as DST goes, don't forget that Arizona and parts of Indiana
:don't use DST. They stay on standard time all year. So, unless the
All of Indiana has observed daylight savings time for six years or so.
--
sig 9
Date: 9 Jul 2011 16:01:36 -0400
From: kludge@panix.com (Scott Dorsey)
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes
Message-ID: <ivac30$p2d$1@panix2.panix.com>
In article <iv7abn$p1q$1@dont-email.me>, Gary <bogus-email@hotmail.com> wrote:
>"John Meissen" wrote in message news:20110707224723.9C29217F605@john...
>
>> Probably just monitors WWV's transmission:
>> http://www.nist.gov/pml/div688/grp40/wwv.cfm
>>
>> I've slowly been replacing all of the clocks in my house with ones
>> that set themselves. It was interesting to see which ones failed
>> when they changed the DST dates because they had hard-coded
>> them. There's no reason to hard-code it because the DST status is
>> part of the data stream.
>
>I agree, the "ether" has to be WWV or WWVH. That's what all of these
>"atomic" clocks we can buy for a few bucks use.
Actually most of them use WWVB, down in the VLF band, usually with a
small loopstick antenna that looks at the magnetic field rather than
the electrical field, so it can be physically small. WWVB is a big
win because the groundwave goes a long distance, so the propagation
time is both much shorter than more predictable than that of a skywave
at 10 MHz from WWV or WWVH.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Date: Sat, 9 Jul 2011 09:06:05 -0700 (PDT)
From: grumpy44134 <grumpy44134@gmail.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes
Message-ID: <2eb5bb03-c528-45ba-a853-017bee9734e4@m18g2000vbl.googlegroups.com>
> ***** Moderator's Note *****
>
> Please tell us which ones were able to handle the DST change.
This was what i found so far -
http://www.nist.gov/pml/div688/grp40/receiverlist.cfm
http://tinyurl.com/5wd39ro
***** Moderator's Note *****
I changed the second URL for readability: it's for a Google search,
but it was 570 characters long, so I used the tinyurl site to make
it fit better.
Bill Horne
Moderator
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