Hundreds of technical links without a lot of fanfare
This page is here for the benefit of all those who share similar interests. In
some of these areas I have no experience (Nauru); in others I have very
limited experience (aviation), and in other areas I have more experience
than enthusiasm (ham radio). However I have explored the internet
for information on these topics, and perhaps I can save someone else a little
This page has hundreds of links, and it has become so large that I have split it into
two separate pages. This page is mostly about electronic communications, and the
second page contains other interesting technical topics. All the topics for both
pages are listed below, and if you click on a topic that is not on this page, you will be
sent to the second page automatically. (How clever!)
At last count, there were 481 valid links on this page. Link checking is done periodically,
and the dead links are changed to HTML comments. If I
have missed a dead link, please let me know.
Some of the newest items have bold titles. That
was accidental, but I think I'll leave it that way.
I've seen this girl before -- in
a single frame of film leader. She was apparently well known to engineers at the BBC.
Martin Ellen wrote in to say, "This is the famous BBC 61A 'Flesh Tone Reference Chart' described
in great detail here."
Dave Buckley is quoted as saying, "The young lady on the make-up chart was a secretary in TV Training
Department (then based at Woodstock Grove, subsequently Elstree Centre
where we were the first department to move in) during the 1970's. Her
name was Lynn ??. I believe she was picked as she had won a Miss BBC
[Further update:] Lynn came third in a Miss Great Britain contest shown on TV and this may have been the
way she got the job of posing for the chart (which must have come in to use around 1976/77 at the earliest).
Update: High-quality reproductions of the Indian Head
Test Pattern are now available. They have been derived from the original artwork, and they
look great! Chuck Pharis really did a good bit of work restoring them. Every
TV station should have an Indian Head Test Pattern in the Engineering office. Order now!
The window pattern was mainly for testing DC response
in video circuits. If there was any smearing in the picture, then you knew there was a
problem with low-frequency response.
This is the good old EIA Linearity Chart
from 1961, also known as the ball chart.
In the 1970s, if your color cameras had registration problems, the ball chart would show them to you. You
see, the cameras had separate tubes for red, green and blue (RGB). After the RGB signals go through the
NTSC encoder, and sync is added, it is then called composite video. If you point your Norelco
PC-70 at this chart and the black circles have rainbows around the edges, you need to twist some knobs to
get the red, green and blue pictures to coincide. But it wasn't that easy -- the adjustments interacted
with each other, so it was all but impossible to make a perfect picture, especially if the cameras hadn't
warmed up yet. ("Hurry up -- we go on the air in ten minutes!")
Old glass slides from KRLD-TV are being transferred to computer-viewable form. The
old test pattern looks really good. See the photos at the bottom
of this page.
Other broadcast engineering topics, especially digital TV:
Read all about the EBS Authenticator
Word List, which was standard equipment at every broadcast
station, 35 years ago, along with a number of other old EBS documents. Also included,
at no additional charge, is speculation on my part about some potentially annoying features
to be included in the next generation of digital TV broadcasting.
Transmitter / Amp: An FM transmitter that plugs into a slot in your PC, so you can broadcast
your MP3 files all over the neighborhood. Of course, it's completely illegal in the U.S., but it
sounds like a lot of fun.
These are just notes I have collected while browsing for very bright LED products at affordable prices
(in quantities of 15 or 20 at a time). At the moment, the links in this section are shown in no
particular order. If some links are bold and others are not, it is only the result of the
mood I was in when editing the links. (Have I mentioned that 100% of the HTML code on this site is
hand-written with plain text editors?)
Read all about my experiences with long strings of
super-bright LED's! My great innovation was a method of
feeding 20 milliamps of
current through a group of about a dozen LED's connected in series, rather than
feeding them one at a time, each through its own dropping resistor.
Many consumers (like me) see nothing wrong with good old reliable incandescent bulbs, and object to the
recent mandatory moves that would outlaw them. This started under President Bush ("43"), so it doesn't
matter which party is in office, that's the direction we're headed if the public doesn't object.
More information about compact fluorescent bulbs can be
found here. I'm not a big fan, as you
Only very recently have LED "bulbs" shown up on store shelves, and unless you shop on the internet, the
prices are still quite high, and most of the products I've seen are spotlights and accent lights rather
than omnidirectional "bulbs." Drop-in replacements for ordinary light bulbs are hard to find, but
there is a company
called Luminosity LED offering
such a device already. Again, the internet is the marketplace for merchandise on the leading edge
White LED lamp market
brightens. White LEDs currently offer an efficiency of around 20 lumens (lm) per
watt, which is better than incandescent light bulbs, but not high enough to compete with
fluorescent lights that have an efficiency rating of from 60 to 100 lm/W.
There are about 729,000 licensed
hams in the US. But that number includes the licenses of a substantial number of deceased
individuals, since the licenses are good for ten years. It also includes huge numbers of
inactive hams like my wife and me, and people who have a license but have never been on the air, like
my son. (None of us have been on the air at any time in this
century.) FRS walkie-talkies do everything we need, so we got rid of our two-meter radios.
Even though the tests for ham operator licenses have been dumbed down considerably, in my estimation, there are many more
obstacles for the average person to avoid these days when operating a ham station. I'm not talking about
tower registration or rules about RF exposure limits. I mean the wide variety of interference sources
that share the radio spectrum. There are twice as many TV stations on the air today as there were
30 years ago, and probably three times as many FM stations. Not to mention cell phones, high-speed
digital signals and personal computers all over the neighborhood. Ham operators generally have to accept
interference without generating any, and that's not easy.
Get the lead out: What would electronics be without
solder? John Burke, the senior manager of Optichron, an electrical components manufacturer in
Fremont, Calif., [says], "There is absolutely no evidence that there is any reason for taking lead
out of solder. There was no reason to do it in the first place, the replacement
is ecologically more damaging, and, by the way, the replacement is less reliable."
Bibliography for Designing Lead-Free
Electronics. The higher processing temperatures of lead-free solders, along with
all of these new failure modes, have dramatically reduced the quality, reliability, and longevity
of RoHS-compliant electronics — produced since early 2006 — versus equivalent
tin/lead- based electronics that were manufactured from about 1950 through 2005.
The Editor says...
Newspaper articles about ham radio are relatively scarce, and accurate articles are quite rare.
This article is good, but most readers will be able to tell that the author doesn't have any first-hand
experience with ham radio.
Anti-lead laws fuel
"tin-whisker" fears. They've ruined missiles, silenced communications satellites and forced
nuclear-power plants to shut down. Pacemakers, consumer gadgets and a critical part of a space shuttle
have fallen victim. The culprits? Tiny splinters — so-called whiskers — that
sprout without warning from tin solder and finishes deep inside electronics. By some estimates, the
resulting short circuits have caused up to $10 billion in damage since they first were noticed in the
Interesting: Amateur Radio License Statistics,
including a long list of hams with
invalid zip codes. Apparently
it's possible to get a ham license even if your application shows that your Zip Code is 00000.
NATO Group Releases Report on BPL. BPL,
also called Power Line Telecommunications (PLT) in Europe, uses existing power lines for telecommunications with data
rates higher than 1 MBit per second. NATO said that since existing power lines were not designed for such
transmissions, "they will cause unintentional RF emissions which may adversely affect the established radio noise
floor directly, or by cumulative propagation from many such sources.
The Inevitable Death of Ham Radio: [The Red Cross already
has] enough communications capability to more than cover themselves. ... Cell phones, mutual aid repeaters and
Blackberries are replacing Ham Radio as the inter-agency communications glue.
N3ZI Kits: Including what appears
to be a very impressive DDS VFO.
One of my favorite old tubes was the 892R. The anode radiator
on this tube is a cluster of copper fins that weighs 41 pounds.
but until recently I had never seen a water cooled 892.
This data sheet shows both varieties.
Another variation was the GL892, good only to 1.6 megacycles.
Nortex Electronic Co. in
Fort Worth has recently closed, due to the death of the 84-year-old proprietor,
Lewis E. Cearly. Lewis was a cool old man. Both he and his store / museum will be
greatly missed by a number of people including myself.
Transmit Audio with a Laser Pen. Convoy! Originally,
a license was required for Citizens' Band radio, but masses of people simply broke the law
and operated without a license until the FCC was forced to bow to reality. Citizens'
Band radio became popular because of widespread resistance to the unpopular
55-mile-per-hour speed limit.
Editor's Note: I knew only
a few people who were into CB radio before 1974. One of them was my Driver Education
teacher (in the summer of 1970) who was very careful to obey all the rules about proper
identification and so on. It was only when the 55 mph speed limit went into effect
that 11 meters really became known as the "Criminal Band", and things like licensing
and station identification and power limits were universally ignored.
Silencing the Voice
of America: [Scroll down] As the article makes clear, the VOA service is marginal, at best:
it gets an audience of roughly 8 million people. But those 8 million are without any other news
source. And they can be relied on to spread what they hear on the radio throughout their communities and
networks, providing an invaluable check on the state radio monopoly. (India is a democracy, but it's not
always a nice one, and communal riots and massacres often go unreported on state airwaves.)
US in trouble over baby
babble. The US military is in trouble in Japan — but this time it's not low-flying
fighter jets or misbehaving Marines who are ruffling feathers, but infant babble transmitted over illicit baby
monitors. Japan's Internal Affairs and Communications Ministry has warned the 47,000 US forces based in
the country that the devices used by service personnel with young children interfere with local radio frequencies.
My GMDSS Operator/Maintainer license was issued on June 23, 2005. It looks very much like a ham radio
license. (Pictures at the bottom of this page.) A
search of the FCC database [on 6/23/2005] shows that there are currently 5201 GMDSS Operator
licenses, 404 GMDSS Maintainer licenses, and 377 GMDSS Operator/Maintainer licenses.
GMDSS replaces the old Morse code system for maritime distress messages and other urgent traffic. The
FCC database shows that there are currently 1919 active (unexpired) Radiotelegraph Operator licenses,
but this number is sure to steadily decrease. As far as I have
been able to determine, everyone who holds a Radiotelegraph Operator
license also has a ham radio license.
I have just finished two pages dedicated to a little-known FCC document from 1958
about the construction of Beverage antennas. This document is hard to find,
and once you find it, it's hard to read. So, as a public service, I have
manually transcribed the entire thing into HTML. (Attempts to use OCR programs
resulted in nothing but gibberish, so I had to do it the hard way.) The pages
of the original
are here but the new HTML version
Excellent! Why is 50 Coaxial Line so Special
Anyway? A mathematical analysis of power handling versus attenuation in coax lines. Lots
of calculus is involved, including a couple of symbols I've never seen before, but the bottom line is
Time signals and the science of precise time and frequency measurement:
You may have stumbled across this web page while searching for someone who mentions the Cesium resonance
frequency of 9192631770 Hz. As far as I know, nobody has mentioned that the nearest prime number
This just in: NIST
Unveils Chip-Scale Atomic Clock: The heart of a minuscule
atomic clock – believed to be 100 times smaller than any other
atomic clock – has been demonstrated by scientists at NIST, opening
the door to atomically precise timekeeping in portable, battery-powered devices
for secure wireless communications, more precise navigation and other applications.
Amateur Time Hackers Play With Atomic Clocks at
Home. Tom Van Baak's spare upstairs bedroom looks like a cross between the control center of a remote polar outpost
and the inner sanctum of a Victorian mad scientist. In reality, it's a home-built lab dedicated to the study of time.
One wall is stacked with a small museum's worth of old nautical clocks, thin slabs of quartz, vacuum tubes of unknown purpose and
a few metronomes.
saving time needs to be abolished. Here we go again with our annual exercise in silliness. At 2 a.m.
Sunday [11/4/2018] the absurdity known as daylight saving time ends. Unless you live in Arizona or Hawaii —
the only two states where daylight saving time is not observed — you will need to turn your clocks back an hour,
gaining the hour you lost when clocks moved forward March 11. You also don't need to worry about changing your
clocks if you live in the U.S. territories of American Samoa, Guam, Puerto Rico, and the Virgin Islands. But there's
not much time left to relocate there to escape the mandatory time travel the rest of must endure.
setting on daylight saving time? States consider alternative to clock-changing 'hassle'. Lawmakers in 10 states have
proposed legislation challenging what, for many, is a twice-a-year headache, and one they just endured again earlier this month.
The new bills would mostly have states pick a time ... and stay on that time. "Every time you have the spring forward or fall back,
you get in the coffee shops, churches and everybody's complaining about it and all of a sudden it dawned on me it is kind of a hassle,"
said Texas state Rep. Dan Flynn, who proposed a bill that would place the entire state of Texas on central standard time year-round.
Also in the news: Indiana
adopts Daylight Savings Time statewide. Indiana's governor on
Friday [5/13/2005] signed a law that will make the entire state recognize
Daylight Savings Time next year but whether the state will declare itself in the
Central or Eastern time zones is still up in the air.
Change: Energy Boon or Waste of Time? At 2 a.m. on March 11 the United States
will spring forward three weeks earlier than usual, as the country implements the first change to its time
standards since 1986. In 2005 Congress passed a mammoth new energy bill that includes a
controversial month-long extension of daylight saving time.
Saving Time Facts: Contrary to popular belief, no federal rule mandates that states or territories
observe daylight saving time. Most U.S. residents set their clocks one hour forward in spring and one
hour back in fall. But people in Hawaii and most of Arizona — along with the U.S. territories
of Puerto Rico, American Samoa, and the Virgin Islands — will do nothing.
daylight saving scam. Four years ago, Congress in its infinite wisdom extended daylight
saving time (DST) by a month, with the goal of saving energy. Lots of energy. The bill's
champion, Rep. Edward J. Markey, Massachusetts Democrat, said it would save consumers a generous
$4.4 billion over 15 years. Of course, Mr. Markey was just repeating what has long been
an established truism among policymakers: Setting the clocks forward in the spring saves energy
because people don't have to turn their lights on as much as at night. Just one problem.
While daylight saving time might "save" daylight, it doesn't appear to save energy. In fact, it
very well might do the opposite.
Railroads pushed the
uniformity in time across the United States in the late 1880s. "Welcome to Cleveland!" a train
conductor may have told passengers in 1890. "Set your watches ahead 33 minutes!" Travelers from
Cincinnati, however, would have been advised to move up 11 minutes. And anyone planning to catch
another train would have been warned to keep their own time and ignore the clocks of Cleveland. ... It didn't
matter until railroads started covering greater distances at faster speeds.
"Pardon Me, Soldier, but
Would You Happen to Have the Atomic Time?" "If GPS is disrupted or jammed, a CSAC could provide precise time to the GPS
receiver to enable rapid recovery or to protect receivers from GPS spoofing, a condition where false GPS signals are broadcast to fool
GPS receivers with erroneous information. The hope is that the Soldier wouldn't even know that his GPS is being jammed."
Cesium Atoms at Work: The U.S. Naval Observatory
operates about 70 cesium clocks, as well as other precision clocks like hydrogen masers, in 18 vaults
whose temperature and, usually, humidity are closely controlled in order to minimize perturbations by their
environment. (Warm vaults; cool pictures.)
Photo: Cesium-beam atomic clocks
at the U.S. Naval Observatory, 1984. Atomic clocks like these ones at the Naval Observatory are the basis for
establishing coordinated universal time (UTC), the most precise measurement of time used worldwide. The Naval
Observatory, in Washington, D.C., maintains a master clock based on readings from more than 60 atomic clocks.
USNO Alternate Master Clock. Although the purpose of the
AMC is to provide precise time in the event of a catastrophic failure of the USNO Master Clock in Washington, DC, its role
has expanded to include providing precise time to the Global Positioning System operated from Schriever
You've Got 25 Years
Until UNIX Time Overflows. The problem springs from the use of a 32-bit signed integer to store a time value, as a number
of seconds since 00:00:00 UTC on Thursday, 1 January 1970, a practice begun in early UNIX systems with the standard C library
data structure time_t. On January 19, 2038, at 03:14:08 UTC that integer will overflow. It's not difficult to
come up with cases where the problem could be real today. Imagine a mortgage amortization program projecting payments out
into the future for a 30-year mortgage.
Your local bank does not determine the official time of day,
even though it may have a time-and-temperature sign
or telephone time of day service on which many people rely. To
get the official time of day, call the experts:
(202) 762-1401 or (202) 762-1069 U.S. Naval Observatory, Washington, DC
(719) 567-6742 USNO, Colorado Springs, CO.
(900) 410-8463 U.S. Naval Observatory - distributed
exclusively by landlines to prevent satellite delay.
(It would be interesting to hear two of these numbers on a
conference call, to see if there is any difference.)
(303) 499-7111 WWV
(808) 335-4363 WWVH
(613) 745-1576 CHU (English)
(613) 745-9426 CHU (French)
South Africa: (012)-349-1576 and (012)-349-1577.
About 45 years ago, I heard that you could call any U.S. Air Force Base and ask
for Extension 3303, and you'd be connected to a WWV receiver. (Does anyone else
remember that?) It worked on the one occasion I tried it, in about 1969.
Sidebar discussion: I got interested in ham radio (and the study of the precise
time-of-day) back in 1967 because of WWV. I had tampered with my
new transistor radio in a successful attempt to move it into the shortwave bands,
and I ran across WWV, probably on 2500 kHz. Back then, WWV was identified
in Morse Code every five minutes. After learning the code, I got into ham radio,
and the rest of that story is
illustrated here if
For what it's worth,
federal law 15 USC §260: The
Secretary of Transportation is authorized and directed to foster
and promote widespread and uniform adoption and observance of the
same standard of time within and throughout each standard time zone. Apparently
this means that you're legally obligated to observe the correct time of day if you
transact business. (I've heard that federal contracting officers are required
to keep track of the time (when bidding closes on a contract) through
the Naval Observatory, just to be sure they're right about the time of day.
Recommended reading: Low-Cost
High-Accuracy GPS Timing (PDF document) This is an article about the extraction of precise
time (down to a few nanoseconds) and tremendous frequency stability from GPS for radio astronomy purposes.
NFS-220 plus is the newest of Brandywine's GPS Synchronizing clocks and utilizes a high
performance 16 channel receiver with automatic position-averaging that enables the best use of GPS
when operating in a fixed location.
GPS8 Plus: Low cost, full-featured GPS Time & Frequency unit with front-panel keypad and display.
Mike's Electric Stuff has information about a variety
of vacuum tubes and other things that combine glass, vacuum, and high voltages, including a whole page
about Nixie tubes.
Web sites of other Time & Frequency fanatics, also known as Time Nuts:
The Præcis Ct Low-Cost
Frequency and Time Standard: "Most precise time receivers require an antenna that must be
installed on the roof of your building, with good sky visibility. The Præcis Cf eliminates this
problem by synchronizing to within 10 microseconds of UTC by using signals broadcast from the
CDMA cellular telephone system."
It seems to me this would be ideal in an area with a high noise floor and lots of obstructions; for
example, in downtown Dallas.
Another related topic: The
Standard Meter. The U. S. Congress legalized the use of the metric system
in 1866 on the basis that one meter is exactly equal to 39.37 inches. In 1959
a number of English-speaking countries agreed that an inch is exactly equal
to 2.54 centimeters so that the International foot is exactly equal to 0.3048 meters.
Atomic clocks mark standard one-second intervals, and the date and time of each mark is assigned by
some other system. When a leap second is inserted, the clocks are not stopped for one
second. That's a fallacy commonly reported by the dumbed-down news media. The extra second
is assigned the time of 23:59:60, and normal counting resumes at the end of the leap second. The
leap second does not add one second to your life (as often reported), just as February 29 does not
add a day to your life.
Leap second overview Windows
10 will get better at telling time with new leap second support. There are two main sources of time: a whole
bunch of atomic clocks averaged together to produce International Atomic Time, and the astronomical time that comes from
measuring how long the earth actually takes to spin on its axis. This latter time, named UTC ("coordinated universal
time"), is used in science and engineering. For most purposes, it's the time reference that we want our watches,
clocks, phones, and computers to be set by. Because UTC is based on the Earth's actual spinning, it slowly falls behind
atomic time. Every time the gap is more than 0.9 seconds, an extra second is added to UTC — a leap
second — to bring the two back in sync.
The Editor says...
The people in charge of such things don't wait for the offset to reach 0.9 seconds. The leap seconds are inserted
when the difference (between UTC and UT1) is no more than about 0.6 seconds. Leap second events are planned and
announced months in advance and always occur at the end of June or the end of December.
Google turns on
free public NTP servers that SMEAR TIME. If the servers are as reliable as Google's DNS servers, they'll be
more than adequate. Google's also explained how its NTP servers will handle leap seconds, one of which will delay the
arrival of 2017 by a second. "No commonly used operating system is able to handle a minute with 61 seconds," Google
says, so "Instead of adding a single extra second to the end of the day, we'll run the clocks 0.0014% slower across the ten
hours before and ten hours after the leap second, and "smear" the extra second across these twenty hours. For
timekeeping purposes, December 31 will seem like any other day."
and why the leap second affected Cloudflare DNS. At midnight UTC on New Year's Day, deep inside Cloudflare's
custom RRDNS software, a number went negative when it should always have been, at worst, zero. A little later this
negative value caused RRDNS to panic. This panic was caught using the recover feature of the Go language. The net
effect was that some DNS resolutions to some Cloudflare managed web properties failed. The problem only affected
customers who use CNAME DNS records with Cloudflare, and only affected a small number of machines across Cloudflare's 102
data centers. At peak approximately 0.2% of DNS queries to Cloudflare were affected and less than 1% of all HTTP
requests to Cloudflare encountered an error.
Reaction to the article immediately above: Re: Cloudflare explains the leap second bug.
There is really no excuse for Cloudflare's problem with the recent leap-second. In 1969 and for many years afterward, I
worked on computer software that handled leap-seconds correctly. All we needed was about 2 month's advance notice that
a leap-second would occur; today, such notices are available much more than 2 months in advance. [...] Cloudflare is not
alone in having software developed by individuals who have little knowledge about the dynamics of time. The problem of
careless (ignorant?) programmers is even promoting plans to eliminate leap-seconds, which would mean a gradual (but generally
unnoticeable in a human lifetime) shift in the times of sunrise, sunset, and tides.
New Public NTP Servers Provide Smeared Time. Google says it has built support for the leap second into the time
servers that regulate all Google services. An anonymous reader shares a blogpost by Google: ["]No commonly used
operating system is able to handle a minute with 61 seconds, and trying to special-case the leap second has caused many
problems in the past. Instead of adding a single extra second to the end of the day, we'll run the clocks 0.0014%
slower across the ten hours before and ten hours after the leap second, and "smear" the extra second across these twenty
hours. For timekeeping purposes, December 31 will seem like any other day. ... ["]
finds its own way around leap second problem — by skewing time instead. Amazon will be dodging the usual
solution to the problems presented by the world's next leap second, ditching civil time for 24 hours and creating its own
version of time. [...] Instead of adding a second on June 30, for 12 hours on each side of the leap second, the company will
stretch out each second in AWS clocks to "1+1/86400 seconds of 'real' time", Barr added. That means for a 24 hour period,
Amazon will enter its own time and fall out of synch with Universal Coordinated Time (UTC) by as much as half a second.
Computers Will Deal with 2016's Leap Second by "Smearing Time". [Scroll down] This isn't a brand new
idea. Google's first came up with it in 2008, and other companies in similar positions have tried variations, though
the specifics vary. For the 2015 leap second, Amazon Web Services slowed its clocks by 1/86400 (.001157407%) for a day
before the jump, smearing the extra second over the preceding 24 hours so its clocks would be one second slow at the time of
the one-second jump. Another cloud company, Akamai, is doing the same thing this year, using a 24-hour smear.
Google's 20-hour smear is an outlier, but not due to any illusions that this method is superior. As Google's developer
page notes, the choice is to make things easy on Google's existing infrastructure, and the company proposes that everyone
adopt a standard noon-to-noon, 24-hour smear, with the leap second dead center, instead of on the end.
What's A Leap Second? Every now and then
a leap second is added to Coordinated Universal Time (UTC) in order to synchronize clocks worldwide with the Earth's ever slowing rotation.
This year's Y2K: 'Leap second'
threatens to break the Internet. The problem is that the computer software controlling
much of the Web doesn't play nicely with leap seconds. The previous leap second, which took place in
2012, brought down Reddit, Yelp (YELP), LinkedIn (LNKD, Tech30), FourSquare, Gawker and StumbleUpon, among
other sites and apps. Qantas' entire computer system went down for hours, forcing employees to check in
passengers by hand. The code for most Web apps is based on Unix, software that traces its roots to
1970 — two years before leap seconds ever existed.
New Atomic Clock Is So Precise Our Ability to Measure Gravity Constrains Its Accuracy. "The level of clock
performance being reported is such that we don't actually know how to account for it well enough to support the level of
performance the clock achieves," Andrew Ludlow, a physicist at NIST and the project lead on the organization's new atomic
clock, told me on the phone. "Right now the state of the art techniques aren't quite good enough so we're limited by
how well we understand gravity on different parts of the Earth." Before diving into the nitty gritty of what Ludlow and
his colleagues at NIST have accomplished, however, it will help to have some background on the nature of time and atomic
Older announcements: IERS Bulletin C. NO leap second will be introduced at the end of December
2012. [...] Bulletin C is mailed every six months, either to announce a time step in UTC, or to confirm that there will be no time step at the next
world preps for 'leap second' on June 30, Google says it's ready. Search giant Google
says that its systems are ready for the 'leap second' that the world will experience on June 30,
2015. Described as a sort of tiny leap year, a leap second lets the earth's rotation catch up
with atomic time, according to the Times of India. June's will be the 26th recorded leap second,
and the third since Google was founded in 1998. "By convention, leap seconds happen at the end of
either June or December," the search giant explained in a blog post.
"Leap second" bugs take out some prominent websites.
It was a rough weekend for the internet. While Friday's problems with Amazon Web Services and other sites could be chalked up to some wicked
thunderstorms, several sites went down Saturday for periods of time thanks to problems with the "leap second."
'Leap Second' Bug Wreaks Havoc Across Web.
On Saturday, at midnight Greenwich Mean Time, as June turned into July, the Earth's official time keepers held their clocks back by a single second in
order to keep them in sync with the planet's daily rotation, and according to reports from across the web, some of the net's fundamental software
platforms — including the Linux operating system and the Java application platform — were unable to cope with the extra second.
The Time Now: Time-related features with enhanced accessibility.
Years earlier... 2008 to be extended
by one second. Those eager to see 2008 come to a close will have to wait a second longer. A single
leap second will be added at the end of the year to accommodate a subtle slow-down in the Earth's rotation.
Tick tock ... tick: Extra
second added to 2008. Among the reasons for Earth's slowing whirl on its axis are the braking
action of tides, snow or the lack of it at the polar ice caps, solar wind, space dust and magnetic storms,
according to the U.S. Commerce Department's National Institute of Standards and Technology, another
timekeeper. By contrast, a leap day, February 29, occurs once every four years because a complete
turn around the sun -- our year with all its seasons -- takes about 365 days and six hours.
What is Earth Orientation? There are
various factors which cause the orientation of the Earth to change with time. Polar motion is caused,
in part, by large scale movements of water and changes in the atmospheric angular momentum. For example,
the yearly melting of snow and ice in northern Spring contributes to the annual term of polar motion.
It is also thought that large earthquakes and the embayment of water by dams and reservoirs might affect
polar motion, but this has yet to be quantitatively demonstrated.
Chile quake may have tipped
Earth's axis. The massive earthquake that struck Chile on Saturday may have shifted Earth's axis
and created shorter days, scientists at NASA say. The change is negligible, but permanent: Each day
should be 1.26 microseconds shorter, according to preliminary calculations.
Earthquake Shortened Days, Increased Earth's Wobble. Earth naturally wobbles slightly as it
spins, because shifting surface mass such as melting glaciers and moving ocean currents can throw the planet
off balance. Data from high-precision GPS instruments show that parts of Japan shifted by as much as
13 feet (4 meters) as the fault plates lurched due to the earthquake. This allowed scientists
to calculate how much Earth's overall mass distribution had shifted and thus how much the wobble was affected.
The shifting mass also affected the planet's spin rate, according to geophysicist Richard Gross, of NASA's Jet
Propulsion Laboratory in Pasadena, California.
The One-second War. As more and more
systems care about time at the second and sub-second level, finding a lasting solution to the leap seconds
problem is becoming increasingly urgent.
This is a roundabout way of saying the Windows
Time service makes no provision for leap seconds. How the Windows Time service treats a leap second:
After the leap second occurs, the NTP client that is running Windows Time service is one second faster than
the actual time. This difference is resolved at the next time synchronization.
complete list of area codes (alphabetical). There are 25 area codes
in Texas. I remember when there were only six. The explosion of phone
numbers occurred because every fax machine, cell phone, voice mail box and pager has
its own number, and every 15-year-old kid in town has a cell phone. Many
medium-sized businesses no longer have switchboard operators; they have PBX's
so you can dial any extension directly. And phone numbers are (apparently)
assigned in blocks of 10,000 to various phone companies.
If I were to guess, I would say Fort Worth is the largest city in
the U.S. which has not undergone a change of area codes. Or possibly El Paso.
The first digit of an area code is
never 0 or 1, and the second digit is never 9.
Area code 710 has been reserved for the United States Government, although no
lines - other than the single telephone number 710-627-4387 ("NCS-GETS") - had
actually been connected on this code as
of 2004* and
even that number requires a special access code to
use.* GETS stands for
the Government Emergency
Telecommunications Service, which is described in some
Telephones in the news
The Evolution of the Area
Code. I want to tell you about the controversy the Bell System's embrace of numeracy provoked — how resentful some people became
when their familiar method of making phone calls was taken from them. I want to tell you about why the change was necessary, and how it still informs
our conception of phone calls and text messages. I want to tell you about the future of the phone number.
Technology Facilitates Caller ID Spoofing. In
the last few years, Caller ID spoofing has become much easier. Millions of people have Internet telephone
equipment that can be set to make any number appear on a Caller ID system. And several Web sites have
sprung up to provide Caller ID spoofing services, eliminating the need for any special hardware.
Spoofing scams make
caller ID untrustworthy. Spoofing makes use of services that allow callers to disguise the number they
are calling from. ... The service is legal, and spoofing companies point out that even law enforcement agencies use
it as an investigative tool.
[Seems like a rather heavy-handed punishment to me. Wouldn't it make more sense to require the
phone companies to secure their systems?]
MPs urge action as
spooky caller ID-faking services hit UK. Communications watchdogs have today been pressed by MPs
to investigate a new service that allows people to fool caller ID systems into displaying a fake number, amid
fears it will be abused by ID fraudsters and other conmen. It's thought such trickery is currently legal
in the UK. So-called caller ID spoofing services have been available in the US for several years.
Caller ID and Spoofing: FCC Consumer
Facts. Caller ID service is susceptible to fraud. Using a practice known as "caller ID
spoofing," disreputable parties can deliberately falsify the telephone number relayed as the Caller ID number
to disguise the identity and originator of the call.
Comcast warns of *72 phone-forwarding
scam. The fraud involves an inmate calling a person collect and tricking the victim into
forwarding his phone to another number. The person at the other number then can make hundreds of
dollars in long distance calls that are billed to the victim's phone.
phones fade away at AT&T. The phone booth is a relic of an age nearly gone by.
On Monday [12/3/2007], the venerable AT&T announced plans to phase out its pay-phone business by
the end of 2008. The move affects AT&T pay phones in its traditional 13-state service area.
BellSouth, acquired by AT&T in 2006, had previously exited the business.
watch North Korean factory boss executed for 'making international calls'. A
North Korean factory boss accused of making international phone calls was executed by a firing
squad in front of 150,000 people. [North Korea's] citizens are banned from communicating
with the outside world, part of the regime's authoritarian policies seeking to prevent any
challenge to the iron-fisted rule of Kim Jong Il.
Verizon phones make an audible alarm when 911 is
dialed. Just the thing for those hostage and robbery situations — I don't think:
"The alarm is not ear-splitting, but it is loud enough to be heard at least several yards away." Verizon
claims the FCC requires this. The FCC says it's not that stupid.
New York Town Kills Cell Tower. In
a move that broadband advocates fear is part of an increasing trend, a small grassroots group forced the town
government in the Westchester County suburb of Lewisboro, New York to back out of a deal with the governing
board of a local church that had agreed to serve as a site for a cellular tower. The antenna would have
been mounted inside the church's steeple, making it rise about 50 feet higher into the air, and would
have been invisible to the surrounding area, which had long been prone to dropped calls and dead zones.
The Editor says...
It's too bad that all three sides couldn't lose. Here we have a church that is willing to
prostitute its steeple as a cell phone site. The church is hoping to profit by accomodating the
people who can't bear to live without continuous cell phone contact. Then there are the
"community" busybodies who want to meddle with other people's use of private property. They all
deserve each other.
T-Mobile Sues City of Olathe Over Proposed
Tower. T-Mobile Central is suing the city of Olathe to allow a 60-foot tower to be built next
to a church. The Gathering Place Pentecostal Holiness Church agreed to allow the cell phone company to
erect the pole, as long as T-Mobile added a beam that made the tower look like a cross. But city
planners objected to the plan on the grounds that it represents a sign not allowed in a residential
[Since when is a cross not permitted at a church?]
Incidentally, the earliest known appearance of the
word HELLO in
print is in a letter written by Thomas Edison dated August 15, 1877. In the letter,
addressed to T. B. A. David, president of Central District and Printing Telegraph
Company in Pittsburgh, Edison suggested that the word should be used to answer the
telephone. HELLO is
an alteration of the much older
Quoting from A Collection of Word Oddities and
Trivia: "It was believed for a while that Edison coined the word hello, but the word has
been found in print in 1826. It was used by Mark Twain in Roughing It (1872)."