An antenna is a transmission line terminated with an open circuit. (This IS a striaght-line - or bent in various ways - transformer.) The voltage at the end is quite high. If it's excited at its resonance, it is limited only by the losses from radiation, resistance, and surrounding materials.
Consider the "firefly" decorations once popular on CB antennas. 4.5 watts into 52 ohms produces 15 1/4 volts. A neon lamp requires about 90 volts to ionize and I think it's about 45 to sustain. Yet put one on the end of the antenna and it lights up merrily when you key the transmitter. No big illegal power amplifier required.
Repeat after me: 3 volts do not arc.
Sure it does, under a number of conditions.
You're thinking of STARTING an arc in air. For three volts the gap would have to be microscopic.
But when breaking a circuit with current flowing through it you end up with exactly that microscopic gap initially. Once the air is ionized the arc can be sustained by a very low voltage. And with any inductance in the circuit at all (even the stray inductance from the wiring) the voltage will climb to maintain the arc until the current through the inductor is finally brought to a halt by the reverse voltage. So the arc can be "pulled out" to significant lengths.
This is EXACTLY the mechanism that produces the voltage spike in the primary (and thus also in the secondary) of the transformer in a contact-point type auto ignition.
MythBusters looked into this. They built a chamber and filled it with various levels of gasoline vapors and then called cell phones that were in the chamber.
Now THERE'S a crock!
Ringing the cellphone will only create a spark if the vibarator motor is enabled or there's a defect in the insulation of the antenna exactly at the end of the conductor.
A much more likely source of ignition is a spark from the electrical contacts when opening a flip phone or hitting the answer button.
But even those are unlikely to create ignition unless the vapor concentration is just right AND there's a defect in the phone case.
How many different models of phone did they try? What defects did they induce in the phones? What surrounding metal (suitable for resonating if just the right dimensions and creating arcs at sharp points) did they supply? Did they EVER do anything to operate the phone buttons and flip-phone contacts? How many tests did they run, before leaving their audience with the impression that cellphone use while fueling is safe? Why did they dilute the number of tests by using "various levels of gasoline vapors" (i.e. mostly too rich or too lean to ignite) rather than creating an optimum explosive mix?
An alleged "debunking" of the alleged "myth" like this is very dangerous. Look how many posters here are now convinced that cellphones CAN'T light off gasoline vapors from tank filling. Imagine the number of watchers of that show that now believe the same thing, and will be using their phones while fueling.
If cellphones create one such fire a year in the next ten years, how many of those burn victims would have NOT been victims if they hadn't seen that show?
The conclusion was that a static spark from your coat on a dry day is FAR more dangerous than anything a cell phone can spit out.
Probably true - expecially in dry or cold climates. But the risk from static sparks is enormous, and likely to swamp ANY other ignition source (except maybe cigarette smoking while fueling). That doesn't make the risk from cellphones any smaller, or any less to be avoided.
The stats also show that women are "the cause" of more fires at the gas pump. Hey, don't blame me... it's just the stats, ma'am!
Nylon rubbing against cotton in a dry environment is a midget lightning storm, quite suitable for igniting gasoline vapor (or any other explosive vapor mixture). Women wear full-leg nylon stockings or pantyhose under loose cotton dresses MUCH more often than men. B-)
[...] Mythbusters [...] episode #2: [...]Can chatting on a cell phone while pumping gas cause the pump to blow up?
First you need an explosive mixture. With gasoline that's a rather strong concentration in air - present in a narrow region JUST OUTSIDE the gas pipe when filling without a vapor revovery system.
The you need a spark IN the explosive mixture. The spark can be VERY tiny. But it must be surrounded by the correct mixture, with a trail of the mixture back to the cloud of vapor emerging from the filler neck, through an open path large enough to propagate the flame without stealing its heat and quenching it (as passage through a metal screen with suficiently narrow holes will do).
Such sparks can occur on the breaking (and sometimes making) of any electrical contact inside the phone. But phones are pretty well sealed - especially the flexible circuit contacts under the buttons. (I'd be more concerned with the switch detecting the cover of a flip-phone.) You'd probably need a phone with a defect in the case - as well as holding the phone near the filler neck while filling for several seconds - to ignite gas fumes that way.
Another potential is arcing at the tip of the antenna (where the voltage is enormous) or the tip of a nearby object like a sheet-metal screw. (Even a near-invisible brush discharge would do the job.) Such screw tips are normally not found in the region around the filler neck where an explosive mixture is likely (both because they'd tend to savage the hands and clothing of people trying to fill the tank AND because they encourage static discharges, so the designers very carefully keep them away from the filler.) The tip of the antenna on a cellphone is normally imbedded in rubber, so no arc there unless there's a defect (like a pinhole) in the rubber. Also: Except for the old AMPS-system phones the cellphone signal is a rather broad spread-spectrum. This reduces its ability to excite a resonance in nearby metal leading to a high-voltage at the end of a conductor (like a screw point).
Note, however, that a cellphone doesn't have to be switched by the user to transmit. It sends a short burst every few minutes when it "checks in" with the local cell sites. An incoming call turns its transmitter on, increasing the opportunities to get any arcs it's producing into the explosive region as the user moves it around.
Third: If the battery came off you'll get a spark at its terminals as it disconnects. Again the caveat about getting an explosive mixture to the area of the spark with a path back to the vapor cloud.
Jamie and Adam "testing several explosive theories" on one segment of a show are hardly an exhaustive disproof. How many of the hundredish models of phone did they test? Did they arrange for a controlled concentration of gasoline at the phone, neither too rich or too lean, so it would actually ignite? Did they crack the phone cases in various ways to create an ignition path? Did they carefully make a pinhole in the rubber duckie antenna right at the end of the conductor?
Just like being hit by lightning or meteorites, gnition of vapors during fueling, from ANY source (even lit cigarettes!), is a rare event that nevertheless occurs when the conditions are JUST right. And getting the conditions right is hard - in part because automobile designers try to reduce its likelyhood. Millions of fillups occur daily, yet ignition is very rare. No offense to Jamie and Adam, but a few attempts to get it to occur while taping one segment of a show would be extremely unlikely to result in a fireball, e
I agree that North Korea is a threat, but it would be suicide on a national scale for them to launch a ballistic missile attack against the US.
It was suicide to fly aircraft into the World Trade Center, the Pentagon, and wherever the fourth one was headed (capitol hill? white house?). That didn't keep it from happening.
Yes, North Korea is a different culture. But that doesn't mean their leaders won't "push the button" if, for instance, their government is collapsing. (You KNOW they'll blame us for it, and if they're on their way out deterrence makes no difference.)
Then there are OTHER countries, with DIFFERENT cultures, that might have or at some point obtain missiles.
And rich individuals controlling terrorist organizations.
And the possibility that the missiles of countries who wouldn't use them as a policy move, might be misused by rogue military personnel or captured and fired by terrorist organizations or organized criminals. (Osama apparently shorted a bunch of stock in US financial institutions just before 9/11. Self-funding war, eh?)
If it was only to be used as a bargaining chip against the Soviet Union, why is the US still developing it, under the new label of National Missile Defense (NMD), when the Soviet Union doesn't exist?
Two words: North Korea.
Their latest missile can make it to everything but maybe the southern tip of Florida and the Keys.
Oh, right, the Bush administration says it's a way to defend against terrorists -- and we all know how likely it is that terrorists will use a complex ICBM when a nuclear device in a shipping container would be so much simpler
Something that I've been more than a little concerned about - given the big stack of COSCO containers at their Oakland facility, a similar one down in LA, and container-trains and trucks toting them all over the country.
(In case you're not familiar with it, COSCO is the Chinese Overseas Shipping COmpany, formerly known as the Chinese "Red Army".)
You can put a REALLY BIG H-bomb, a LOT of nerve gas, or even a small military unit with equipment and supplies, in a standard shipping container. The US recently intercepted six of 'em on their way to South America full of parts for military weapons. And it was clear there were more that got missed, since this was just the accessories.
Fortunately, you can easily spot nukes with a radiation detector. And the US has started stopping shipping far offshore for inspection.
It's a simple scam: Make up a false straw man claim by substituting the word "inventor" for "developer," "creator," or "father." Then point out that the victim didn't literally invent the item in question. If anybody calls you on it, look blank and insist that "inventor" is essentially a synonym for the real word.
Yep.
And what Al Gore did with respect to the internet was to push the legislation to open the net (which was limited to research, education, and military) to commercial use.
This got a lot of people connected.
Unfortunately, it gave spammers the argument that they were a legitimate commercial use. This makes it much harder to cut them off.
So if you want to slander Gore, just point out that what he REALLY did was legalize spam.
[...] the Alexis de Toqueville Institution [believes several absurdities, including] the "Star Wars" program was a good idea.
Gosh, Hemos. Last time I looked the Star Wars program had done EXACTLY what it was intended to do: Convince the Soviet Union / Russian Empire that it could no longer afford to play the superpower game. This led to its attempt to give the people JUST ENOUGH freedom to get some innovation done, and from there to its collapse without a thermonuclear shot fired.
Maybe the Star Wars program would never have been able to shoot down incoming ICBMs. Or maybe it would have. Or maybe it would have but not enough of them (and missing even one would ruin a lot of people's whole day). We'll never know. But it definitely ended the Cold War without having to fight WW III.
"Ultimate excellence lies not in winning every battle but in defeating the enemy without ever fighting." Sun Tzu would be proud.
Actually sounds like somebody trying to fix things
on
A Worm's Worm
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· Score: 5, Interesting
This is an all new low. Now virus programmers will have to make their virus's better so they dont get infected by another virus.
Actually, this sounds like somebody trying to make a disinfectant worm. Look at the description:
- It only infects infected systems, using a flaw in the previous infection.
- It cleans out the infection of the worm that it exploited, and several others.
It does open a new backdoor. But while that might be preparation for some future malicious action, it might also have been the author leaving himself a way to fix things if his initial worm got out with a destructive bug. (Of course it could be the worm cleaning up signs of previous infections in order to hide itself and thus head off other cleanups.)
I wouldn't be surprised to see, on further analysis, that it does other antimalware things (like fix the flaw the other worms used).
(Not to say that it IS somebody trying to fight virus with virus. But it might be interesting if it turns out that it is.)
I think everyone should go ultra secure, the best firewall ever... Disconnect from the net. It would make this all alot easier on us.
Which is exactly what the military does with some of its really secure stuff.
Now if we can just get the Microsoft users to emulate them. B-)
Animals ranging in size from squirrels to bears will camp in the road with impunity. Beeping will not help. Creeping forward will not help. This is why gun racks for trucks were invented.
If you're talking about the ones in the window: They were actually invented to deal with the concealed carry laws in certain states.
If you want to carry a gun in a car it has to be visible from the outside. Otherwise it's a "concealed weapon" because it's "concealed by the car". Thus the gun rack across the back window, where the guns are plainly visible.
(Don't tread on me. And if you're a peredator don't eat my livestock - or try to stick up my car. B-) )
By the way: At least one southwestern state had a law that required any gun carried in the car to be loaded. That's so the car's occupants can use the gun to prevent the theft of the gun by escaping prisoners and the like, in the regions where the nearest telephone or cop might be several hour's drive away.
erm, but it _is_ a bug. it is a bad CCA design that allows this exploit to be launched. this is not a radio jammer, it exploits the fact that CCA is not robust enough...
I.e. it takes advantage of the fact that the MAC holds off transmitting when it hears the channel is in use, delaying its transmission until the channel is sufficiently clear. So an attacker can use a low power signal to cause it to hold off indefinitely.
And this is perceived as a "bug", because it can be mounted with a small amount of power when completely blanketing the band would require much more.
In fact it's not a bug - because if the bad guy wanted to he could just use the higher-power alternative. This "bug" just makes it possible to do this with less power.
But another alternative attack exists which is even more effective and requires a similarly small amount of power, and would NOT be prevented by gutting the holdoff mechanism.
Consider what would happen if the Wi-Fi MAC were NOT "polite" and went ahead and transmitted despite the appearance of traffic on the channel. Its data would sometimes get through despite the described attack. But the attacker can instead sent a bursty signal that combines with the good guy's signal to inject more errors than the forward error recovery can correct. The result is corrupted packets which are dropped.
So instead of holding off the packets until the attacker shuts up, the transmitter throws them into the meat grinder and they are lost. Even worse, yes?
The only mitigating circumstance is that with this alternative the jammer must make his signal heard at the receiver, rather than the transmitter, of the packet to be blocked. But given that the conversation needs to be two-way to keep the link up, both ends are the "receiver" for the total conversation, it STILL works if he can only be heard by one end.
Further, "fixing" this bug means the "improved" Wi-Fi devices will NOT share the band well, either with other Wi-Fi devices or with non Wi-Fi users.
So I maintain that this is not a "bug", because the prescribed behavoir doesn't prevent jamming (just this PARTICULAR flavor of it, when another just as effective and low-resource is available), while improving the link quality in the absense of deliberate jamming and reducing the ability of the "fixed" version to share the band.
and the dash stands for......e! It's vaporware people!
I thought it said they were shipping samples now. The several-years business is about when they might be competitive as a general service laptop battery.
= = = = =
But that looks like pretty TOXIC vaporware.
Not that the other battery technologies don't contain toxic substances, of course. (Cadmium, for instance, is pretty nasty if you ingest it.) But high-energy storage devices like this are prone to catching fire if they develop an internal short. As a number of users of cellphones with Lithium batteries discovered not too long ago.
If a lithium-sulpher battery catches fire I'd expect it to emit a lot of sulphur dioxide. That's a serious poison gas and a really painful way to die.
how come "other people" are soooo smart in finding bugs in the system, than the system creators itself?
Because they never look.
This is NOT a "bug in the system". Being jammable is inherent in ANY radio based communication system.
Just as you can't hear and understand the person talking to you across the room when a pair of people are shouting in your ears or when another person with a similar voice is babbling nonsense at the same time, and you can't read morse code flashlight blinks sent by someone standing between you and the sun, so you can't receive and decode what a Wi-Fi card is sending you when another Wi-Fi card is transmitting "chatter".
The same is true on Cable TV modem signals (where a neighbor's chattering box jams your uplink), on 10-Base Ethernet (where you're all on one coaxial cable and a single chattering device is a constant collision), on broadcast radio and TV (where a nearby signal will wipe out or override and replace a distant one), radar, telephone party lines, hearing (meetings disrupted by the guy with the bullhorn), vision (strobe lights, searchlights, sombody standing between you and what you want to see), and so on.
Jammability is inherent in sharing a transmission medium with an additiona transmitter which is misbehaving, not some "bug" in any particular system.
how come "other people" are soooo smart in finding bugs in the system, than the system creators itself?
Who says they didn't know about it?
Jamming is EASY, and being able to jam any radio signal is a given. That's clearly understood by anyone who works with radio. (Spread spectrum techniques are harder to jam than narrowband, but not by much.)
Why is this suddenly the subject of news items, wringing of hands, and viewing-with-alarm? How can ANYONE POSSIBLY think this is a surprise?
The ONLY thing that's news is that somebody finally got around to doing it.
The last section modifies Section 1201(c) of title 17, a section that got much of its content from the DMCA. Basically, it guts much of this section by specifically allowing the use and distribution of DRM-defeating software if the goal is to enable fair use that is otherwise legal.
And the clause immediately before that similarly legalizes bypassing copy protection to make a copy if making the copy would be otherwise legal. (i.e. fair use would be legal, copy protection or no.)
There are lots of reasons. For example, a bus stop might have a timetable with one of these symbols next to each entry. You'd just hold your phone up to the one you want to check, and it would connect to the proper web page and show you where that bus is on its route and how long until it reaches your location. Instantly.
So why no print the URL in a human readable form, using a clean font that is a snap to OCR?
For your cellphone the result is the same. You scan the code and are instantly connected to the applicable website. Only the internal details are different: The cellphone (if it doesn't do the OCR itself) forwards the image to a server that OCRs it and returns (or redirects to) the appropriate URL.
But now you can ALSO:
- Enter it into your wi-fi equipped but scannerless laptop.
- Write it down to use later at some other terminal.
No special buttons to press or codes to enter, and with no expensive hardware needing to be installed at the bus stop.
Ditto. Does everything the barcode would do and more. And doesn't cut the human out of the loop.
Even an inch is too much.
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RFID MasterCard
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· Score: 4, Insightful
It's nice to say "you have to be within one inch of the reader for the card to be read", but WHERE is this limit built in?
Even an inch is too much. Pickpockets often have a "bumper" who distracts the target so he doesn't notice the touch on his wallet. Now the pickpocket can lift your card information by bumping into you in a checkout line.
Then a little careful observation as you enter your PIN and your account is toast.
"""there are too many, they can't get us all" is not a valid way to go about changing things, especially when the penalties are harsh like the penalties for FCC violations.""
1. actually it kind of is. it's one of the reasons civil disobedience can work.
Civil disobedience rarely works - and when it does it's because a big section of the power structure wants it to.
Re "too many microbroadcasters": Back in the '60s people thought that if enough people smoked dope and took other drugs it would saturate the justice system and lead to legalization of recreational pharmaceuticals. (Just as it was perceived had happened with liquor prohibition.) Four decades later we find that instead the government retooled for a self-funding "Drug War" on the model of the Spanish Inquisition and used it to debug legal tools that can be used for other forms of oppression.
If civil disobedience by the bulk of the largest generation in US history can't prevail, what chance do the relative handfull of small-broadcast operators have?
The poster children for Civil Disobedience are Ghandi and King.
Ghandi gets kudos because of the perceived success of his work in India. But a major fraction of the British Parlement already wanted to dismantle the empire, and especially to unload India as a colony that cost more than it paid. Ghandi gave them good PR for portraying their opposition as monsters and thus getting their way.
Very few people remember that, before he succeeded in India he tried the same approach in South Africa - with no success whatsoever. They also forget his prescription for what the Jews should do about the NAZIs: Commit mass suicide in protest.
As for the good Doctor Martin: Blacks got the vote at the end of the Civil War, but had it taken away by the Jim Crow laws. The freedom rides and the other passive resistance enabled LBJ to put one over on the generally pro-segregation Democratic party by passing the Civil Rights laws - but implementation of those were mandated by the courts to occur at "All Deliberate Speed" - which meant "never". What finally did the trick was the cities burning in '68. Immediately afterward the civil rights laws acquired some teeth and the blacks got the vote for real. WHAT a coincidence!
Then the media raised King to hero status - in order to eclipse the likes of H. Rap Brown, Malcom X, and Charlie Thomas. And the blacks have since been "helped" back into underclass status by "programs" that destroyed their family structure and educational opportunities - to the point that they actually peition the government to be futher disempowered.
Just like veterans got the vote after Shay's and the Whiskey rebellion, women after the temperance movement started smashing bars, and 18-20 year olds after the anti-Vietnam-War riots and bombings. Political power grows out of the barrel of a gun - and at the end of a club, and in a firebomb.
Passive resistance techniques such as civil disobedience are often a useful, and sometimes necessary, early step. They let you acquire the moral high ground. But passive resistance by itself doesn't prevail.
Ok... I understand why the RIAA wants to make more money off each track. There are only two or three good tracks on each CD. But to jack some prices up over what most new CDs are sold for in stores? How does that make any sense at all?
They're just hunting for the maximum profit price point.
What will get them to LOWER the prices is to show them that the demand is elastic and they'll get MORE money at LOWER price by selling more units. (I think that's the right way for them to go - but the market will determine it.)
So the way to show them that they're going in the wrong direction is to make their sales drop by more than the amount of the raised prices, so their total income drops.
They raised it from $.99 to $1.25? Buy LESS than four songs when you would have bought five. Enough less that the signal isn't obscured by new adopters.
If you still want to buy music online, for each new song you're thinking of buying, flip three coins, and if two come up heads NEVER buy it on line. (If it's something you REALLY WANT, pick the one you like least of your next three that come up "buy" and never buy THAT.) That way you'll drop to 5/8 of your previous purchase level.
And keep it up. A sudden and SUSTAINED drop in sales should get the point across.
Nope, it's not Microsoft bugs trashing the net. It's some asshole somewhere who thought it would be really cool to have lots of computers rebooting all the time (or whatever crap the latest virus does to your machine).
That's true. But it's also irrelevant.
Once the exploits are out there, the only ways to make them STOP trashing the net (short of taking out the machines) is to apply the patch. Blocking distribution of the security patch to unlicensed copies insures there will be a much larger number of infected machines chattering away than if it is open.
Selling millions of copies of software that is susceptable to infection and expecting them to remain uninfected is like laying out millions of uncovered petri dishes full of culture medium and expecting them to remain sterile. If nothing else, Microsoft bears some of the responsibility according to the doctrine of "attractive nuisance".
In case you're not aware of it: Consider a chemical company that keeps concentrated sulphuric acid in an uncovered, unfenced, outdoor tank that looks like a swimming pool. Is it the chemical company's fault if, some summer afternoon, some neighborhood kids jump in and/or push each other in? In US law: Absolutely!
By deploying a massively virus/worm susceptable system Microsoft has created an attractive nuisance. Yes the primary responsibility for damage when it is exploited rests with the exploiters. But when they "light a fire" that starts an ongoing process of consuming the neighborhood, it's Microsoft's responsibility to help put it out.
And it's in Microsoft's interest to do so, before somebody wises up and starts using the attractive nuisance doctrine to make them pay for the damage.
Its microsofts perogotive, theyre not in any way required to support pirated versions of their software, and why should they bother.
Because infected and unpatched instances of their software generally continue to operate for the user while clogging the net with viral traffic, serving as zombies for DDoS attacks and acting as spam forwarders.
This is damaging to legitimate customers of Microsoft's products, users of competitors' products, users of open-source products, and operators of the network infrastructure, as well as the users of unlicenced copies of their product.
This reminds me of a kid I knew when he was in high school, back in the Vietnam War era (when the internal security systems of the various levels of government in the US had gotten 'WAY out of control).
His use of a university's computer while a high school student (something he got started on as a guinea pig in a University program doing research on learning and teaching) had attracted the attention of the FBI.
A couple years later he decided to use the shiny-new FOIA to see what records the FBI and the state and local cops had on him. And while he was at it, he sent FOIA requests to several other agencies.
The first one he sent to the CIA was a classic self-referential hack: He requested their internal document describing their procedure for responding to FOIA requests. B-) (Obviously useful for generating the next round of requests, too.)
Needless to say the agencies involved didn't respond as required by the law. So with the aid of a Libertarian lawyer he started suing them. He won, and they eventually were ordered to give him what he asked for. Then they flaked on that, too, and he got a contempt citation and more court orders. Eventually he got much of his info (with big chunks blacked out). Then he sued them for his lawyer's fees and won that, too.
After a few iterations of this he was sitting on quite a number of interesting documents. So he started a newspaper to give them wider circulation and created a business of generating FOIA requests and publishing the results. This became quite popular with the CIA watcher, privacy advocate, private detective, and tinfoil-hat sets. Advertising revenue flowed in from such folk as buging and debugging equipment manufacturers.
At one point he got the petty cash records from a New York area CIA office. Items he found in it charged to one project (air compressor, flit guns, briefcase, auto exhaust system, washing a car) led to blowing the lid off a project to obtain information on how a biowarfare plague might spread in an urban environment by exposing the citizens of New York City to a "mostly harmless" bug that caused severe enough respiratory system symptoms that it could be tracked by hospital admissions. (Spread techniques included spraying subways with the bug from the gimmicked briefcase and spraying commuter traffic via the car's exhaust system.)
He also got hold of and published one year's version of the IRS procedures manual. And put out a pamphlet on how to use the FOIA. (Eventually he was enjoined from distributing either of these.)
Eventually the FOIA was modified to give the security agencies some loopholes against such requests.
Bob Dylan had something to say about this: "You have to pay to keep from going through these things twice." Also Thomas Jefferson: "The tree of Liberty must be watered, from time to time..."
He's still out there doing stuff like this, by the way. Last time he looked he had a web site dedicated to exposing personal information trading in the information age.
The above-mentioned kid was part of the Boomer's round. I guess now it's Generation X's (or maybe Y's) turn to pay some dues. (Sigh.)
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is the voltage on the antenna really enormous?
Absolutely.
An antenna is a transmission line terminated with an open circuit. (This IS a striaght-line - or bent in various ways - transformer.) The voltage at the end is quite high. If it's excited at its resonance, it is limited only by the losses from radiation, resistance, and surrounding materials.
Consider the "firefly" decorations once popular on CB antennas. 4.5 watts into 52 ohms produces 15 1/4 volts. A neon lamp requires about 90 volts to ionize and I think it's about 45 to sustain. Yet put one on the end of the antenna and it lights up merrily when you key the transmitter. No big illegal power amplifier required.
Repeat after me: 3 volts do not arc.
Sure it does, under a number of conditions.
You're thinking of STARTING an arc in air. For three volts the gap would have to be microscopic.
But when breaking a circuit with current flowing through it you end up with exactly that microscopic gap initially. Once the air is ionized the arc can be sustained by a very low voltage. And with any inductance in the circuit at all (even the stray inductance from the wiring) the voltage will climb to maintain the arc until the current through the inductor is finally brought to a halt by the reverse voltage. So the arc can be "pulled out" to significant lengths.
This is EXACTLY the mechanism that produces the voltage spike in the primary (and thus also in the secondary) of the transformer in a contact-point type auto ignition.
"googol" and "google.com" aren't even spelled the same! Gimme a break.
Damned right!
Especially since "google" was a word that described an extreme of looking, long before "googol" was coined.
MythBusters looked into this. They built a chamber and filled it with various levels of gasoline vapors and then called cell phones that were in the chamber.
Now THERE'S a crock!
Ringing the cellphone will only create a spark if the vibarator motor is enabled or there's a defect in the insulation of the antenna exactly at the end of the conductor.
A much more likely source of ignition is a spark from the electrical contacts when opening a flip phone or hitting the answer button.
But even those are unlikely to create ignition unless the vapor concentration is just right AND there's a defect in the phone case.
How many different models of phone did they try? What defects did they induce in the phones? What surrounding metal (suitable for resonating if just the right dimensions and creating arcs at sharp points) did they supply? Did they EVER do anything to operate the phone buttons and flip-phone contacts? How many tests did they run, before leaving their audience with the impression that cellphone use while fueling is safe? Why did they dilute the number of tests by using "various levels of gasoline vapors" (i.e. mostly too rich or too lean to ignite) rather than creating an optimum explosive mix?
An alleged "debunking" of the alleged "myth" like this is very dangerous. Look how many posters here are now convinced that cellphones CAN'T light off gasoline vapors from tank filling. Imagine the number of watchers of that show that now believe the same thing, and will be using their phones while fueling.
If cellphones create one such fire a year in the next ten years, how many of those burn victims would have NOT been victims if they hadn't seen that show?
The conclusion was that a static spark from your coat on a dry day is FAR more dangerous than anything a cell phone can spit out.
Probably true - expecially in dry or cold climates. But the risk from static sparks is enormous, and likely to swamp ANY other ignition source (except maybe cigarette smoking while fueling). That doesn't make the risk from cellphones any smaller, or any less to be avoided.
The stats also show that women are "the cause" of more fires at the gas pump. Hey, don't blame me... it's just the stats, ma'am!
Nylon rubbing against cotton in a dry environment is a midget lightning storm, quite suitable for igniting gasoline vapor (or any other explosive vapor mixture). Women wear full-leg nylon stockings or pantyhose under loose cotton dresses MUCH more often than men. B-)
[...] Mythbusters [...] episode #2: [...]Can chatting on a cell phone while pumping gas cause the pump to blow up?
First you need an explosive mixture. With gasoline that's a rather strong concentration in air - present in a narrow region JUST OUTSIDE the gas pipe when filling without a vapor revovery system.
The you need a spark IN the explosive mixture. The spark can be VERY tiny. But it must be surrounded by the correct mixture, with a trail of the mixture back to the cloud of vapor emerging from the filler neck, through an open path large enough to propagate the flame without stealing its heat and quenching it (as passage through a metal screen with suficiently narrow holes will do).
Such sparks can occur on the breaking (and sometimes making) of any electrical contact inside the phone. But phones are pretty well sealed - especially the flexible circuit contacts under the buttons. (I'd be more concerned with the switch detecting the cover of a flip-phone.) You'd probably need a phone with a defect in the case - as well as holding the phone near the filler neck while filling for several seconds - to ignite gas fumes that way.
Another potential is arcing at the tip of the antenna (where the voltage is enormous) or the tip of a nearby object like a sheet-metal screw. (Even a near-invisible brush discharge would do the job.) Such screw tips are normally not found in the region around the filler neck where an explosive mixture is likely (both because they'd tend to savage the hands and clothing of people trying to fill the tank AND because they encourage static discharges, so the designers very carefully keep them away from the filler.) The tip of the antenna on a cellphone is normally imbedded in rubber, so no arc there unless there's a defect (like a pinhole) in the rubber. Also: Except for the old AMPS-system phones the cellphone signal is a rather broad spread-spectrum. This reduces its ability to excite a resonance in nearby metal leading to a high-voltage at the end of a conductor (like a screw point).
Note, however, that a cellphone doesn't have to be switched by the user to transmit. It sends a short burst every few minutes when it "checks in" with the local cell sites. An incoming call turns its transmitter on, increasing the opportunities to get any arcs it's producing into the explosive region as the user moves it around.
Third: If the battery came off you'll get a spark at its terminals as it disconnects. Again the caveat about getting an explosive mixture to the area of the spark with a path back to the vapor cloud.
Jamie and Adam "testing several explosive theories" on one segment of a show are hardly an exhaustive disproof. How many of the hundredish models of phone did they test? Did they arrange for a controlled concentration of gasoline at the phone, neither too rich or too lean, so it would actually ignite? Did they crack the phone cases in various ways to create an ignition path? Did they carefully make a pinhole in the rubber duckie antenna right at the end of the conductor?
Just like being hit by lightning or meteorites, gnition of vapors during fueling, from ANY source (even lit cigarettes!), is a rare event that nevertheless occurs when the conditions are JUST right. And getting the conditions right is hard - in part because automobile designers try to reduce its likelyhood. Millions of fillups occur daily, yet ignition is very rare. No offense to Jamie and Adam, but a few attempts to get it to occur while taping one segment of a show would be extremely unlikely to result in a fireball, e
I agree that North Korea is a threat, but it would be suicide on a national scale for them to launch a ballistic missile attack against the US.
It was suicide to fly aircraft into the World Trade Center, the Pentagon, and wherever the fourth one was headed (capitol hill? white house?). That didn't keep it from happening.
Yes, North Korea is a different culture. But that doesn't mean their leaders won't "push the button" if, for instance, their government is collapsing. (You KNOW they'll blame us for it, and if they're on their way out deterrence makes no difference.)
Then there are OTHER countries, with DIFFERENT cultures, that might have or at some point obtain missiles.
And rich individuals controlling terrorist organizations.
And the possibility that the missiles of countries who wouldn't use them as a policy move, might be misused by rogue military personnel or captured and fired by terrorist organizations or organized criminals. (Osama apparently shorted a bunch of stock in US financial institutions just before 9/11. Self-funding war, eh?)
I could go on.
If it was only to be used as a bargaining chip against the Soviet Union, why is the US still developing it, under the new label of National Missile Defense (NMD), when the Soviet Union doesn't exist?
Two words: North Korea.
Their latest missile can make it to everything but maybe the southern tip of Florida and the Keys.
Oh, right, the Bush administration says it's a way to defend against terrorists -- and we all know how likely it is that terrorists will use a complex ICBM when a nuclear device in a shipping container would be so much simpler
Something that I've been more than a little concerned about - given the big stack of COSCO containers at their Oakland facility, a similar one down in LA, and container-trains and trucks toting them all over the country.
(In case you're not familiar with it, COSCO is the Chinese Overseas Shipping COmpany, formerly known as the Chinese "Red Army".)
You can put a REALLY BIG H-bomb, a LOT of nerve gas, or even a small military unit with equipment and supplies, in a standard shipping container. The US recently intercepted six of 'em on their way to South America full of parts for military weapons. And it was clear there were more that got missed, since this was just the accessories.
Fortunately, you can easily spot nukes with a radiation detector. And the US has started stopping shipping far offshore for inspection.
Try doing that with a missile.
It's a simple scam: Make up a false straw man claim by substituting the word "inventor" for "developer," "creator," or "father." Then point out that the victim didn't literally invent the item in question. If anybody calls you on it, look blank and insist that "inventor" is essentially a synonym for the real word.
Yep.
And what Al Gore did with respect to the internet was to push the legislation to open the net (which was limited to research, education, and military) to commercial use.
This got a lot of people connected.
Unfortunately, it gave spammers the argument that they were a legitimate commercial use. This makes it much harder to cut them off.
So if you want to slander Gore, just point out that what he REALLY did was legalize spam.
[...] the Alexis de Toqueville Institution [believes several absurdities, including] the "Star Wars" program was a good idea.
Gosh, Hemos. Last time I looked the Star Wars program had done EXACTLY what it was intended to do: Convince the Soviet Union / Russian Empire that it could no longer afford to play the superpower game. This led to its attempt to give the people JUST ENOUGH freedom to get some innovation done, and from there to its collapse without a thermonuclear shot fired.
Maybe the Star Wars program would never have been able to shoot down incoming ICBMs. Or maybe it would have. Or maybe it would have but not enough of them (and missing even one would ruin a lot of people's whole day). We'll never know. But it definitely ended the Cold War without having to fight WW III.
"Ultimate excellence lies not in winning every battle but in defeating the enemy without ever fighting." Sun Tzu would be proud.
This is an all new low. Now virus programmers will have to make their virus's better so they dont get infected by another virus.
Actually, this sounds like somebody trying to make a disinfectant worm. Look at the description:
- It only infects infected systems, using a flaw in the previous infection.
- It cleans out the infection of the worm that it exploited, and several others.
It does open a new backdoor. But while that might be preparation for some future malicious action, it might also have been the author leaving himself a way to fix things if his initial worm got out with a destructive bug. (Of course it could be the worm cleaning up signs of previous infections in order to hide itself and thus head off other cleanups.)
I wouldn't be surprised to see, on further analysis, that it does other antimalware things (like fix the flaw the other worms used).
(Not to say that it IS somebody trying to fight virus with virus. But it might be interesting if it turns out that it is.)
I think everyone should go ultra secure, the best firewall ever... Disconnect from the net. It would make this all alot easier on us.
Which is exactly what the military does with some of its really secure stuff.
Now if we can just get the Microsoft users to emulate them. B-)
Animals ranging in size from squirrels to bears will camp in the road with impunity. Beeping will not help. Creeping forward will not help. This is why gun racks for trucks were invented.
If you're talking about the ones in the window: They were actually invented to deal with the concealed carry laws in certain states.
If you want to carry a gun in a car it has to be visible from the outside. Otherwise it's a "concealed weapon" because it's "concealed by the car". Thus the gun rack across the back window, where the guns are plainly visible.
(Don't tread on me. And if you're a peredator don't eat my livestock - or try to stick up my car. B-) )
By the way: At least one southwestern state had a law that required any gun carried in the car to be loaded. That's so the car's occupants can use the gun to prevent the theft of the gun by escaping prisoners and the like, in the regions where the nearest telephone or cop might be several hour's drive away.
Why is this suddenly "news" in 2004 - when they STILL aren't talking about somebody actually DOING it
Shoulda RTFAed. So they're launching it from a railgun rather than high altitude and the may actually be working on it.
Railguns were all the rage back in the '60s/'70s, too, though I never heard of somebody combining the two weapons to make a surface-based device.
Terminal guidance on a railgun projectile. Now THAT's a mind-boggling concept!
I heard this puppy described back in the late '60s or early '70s - and not in a classified context, either. (Early L5 society meeting, as I recall.)
I'm trying to recall the name of it. "Javelin" or "Thor" or something like that.
Basic idea was a rod with steerable tailfins and guidance system, dropped from extreme altitude or orbit. Would turn a tank into a crater easy.
Why is this suddenly "news" in 2004 - when they STILL aren't talking about somebody actually DOING it, but just thinking about it?
erm, but it _is_ a bug. it is a bad CCA design that allows this exploit to be launched. this is not a radio jammer, it exploits the fact that CCA is not robust enough...
I.e. it takes advantage of the fact that the MAC holds off transmitting when it hears the channel is in use, delaying its transmission until the channel is sufficiently clear. So an attacker can use a low power signal to cause it to hold off indefinitely.
And this is perceived as a "bug", because it can be mounted with a small amount of power when completely blanketing the band would require much more.
In fact it's not a bug - because if the bad guy wanted to he could just use the higher-power alternative. This "bug" just makes it possible to do this with less power.
But another alternative attack exists which is even more effective and requires a similarly small amount of power, and would NOT be prevented by gutting the holdoff mechanism.
Consider what would happen if the Wi-Fi MAC were NOT "polite" and went ahead and transmitted despite the appearance of traffic on the channel. Its data would sometimes get through despite the described attack. But the attacker can instead sent a bursty signal that combines with the good guy's signal to inject more errors than the forward error recovery can correct. The result is corrupted packets which are dropped.
So instead of holding off the packets until the attacker shuts up, the transmitter throws them into the meat grinder and they are lost. Even worse, yes?
The only mitigating circumstance is that with this alternative the jammer must make his signal heard at the receiver, rather than the transmitter, of the packet to be blocked. But given that the conversation needs to be two-way to keep the link up, both ends are the "receiver" for the total conversation, it STILL works if he can only be heard by one end.
Further, "fixing" this bug means the "improved" Wi-Fi devices will NOT share the band well, either with other Wi-Fi devices or with non Wi-Fi users.
So I maintain that this is not a "bug", because the prescribed behavoir doesn't prevent jamming (just this PARTICULAR flavor of it, when another just as effective and low-resource is available), while improving the link quality in the absense of deliberate jamming and reducing the ability of the "fixed" version to share the band.
and the dash stands for......e! It's vaporware people!
I thought it said they were shipping samples now. The several-years business is about when they might be competitive as a general service laptop battery.
= = = = =
But that looks like pretty TOXIC vaporware.
Not that the other battery technologies don't contain toxic substances, of course. (Cadmium, for instance, is pretty nasty if you ingest it.) But high-energy storage devices like this are prone to catching fire if they develop an internal short. As a number of users of cellphones with Lithium batteries discovered not too long ago.
If a lithium-sulpher battery catches fire I'd expect it to emit a lot of sulphur dioxide. That's a serious poison gas and a really painful way to die.
how come "other people" are soooo smart in finding bugs in the system, than the system creators itself?
Because they never look.
This is NOT a "bug in the system". Being jammable is inherent in ANY radio based communication system.
Just as you can't hear and understand the person talking to you across the room when a pair of people are shouting in your ears or when another person with a similar voice is babbling nonsense at the same time, and you can't read morse code flashlight blinks sent by someone standing between you and the sun, so you can't receive and decode what a Wi-Fi card is sending you when another Wi-Fi card is transmitting "chatter".
The same is true on Cable TV modem signals (where a neighbor's chattering box jams your uplink), on 10-Base Ethernet (where you're all on one coaxial cable and a single chattering device is a constant collision), on broadcast radio and TV (where a nearby signal will wipe out or override and replace a distant one), radar, telephone party lines, hearing (meetings disrupted by the guy with the bullhorn), vision (strobe lights, searchlights, sombody standing between you and what you want to see), and so on.
Jammability is inherent in sharing a transmission medium with an additiona transmitter which is misbehaving, not some "bug" in any particular system.
how come "other people" are soooo smart in finding bugs in the system, than the system creators itself?
Who says they didn't know about it?
Jamming is EASY, and being able to jam any radio signal is a given. That's clearly understood by anyone who works with radio. (Spread spectrum techniques are harder to jam than narrowband, but not by much.)
Why is this suddenly the subject of news items, wringing of hands, and viewing-with-alarm? How can ANYONE POSSIBLY think this is a surprise?
The ONLY thing that's news is that somebody finally got around to doing it.
The last section modifies Section 1201(c) of title 17, a section that got much of its content from the DMCA. Basically, it guts much of this section by specifically allowing the use and distribution of DRM-defeating software if the goal is to enable fair use that is otherwise legal.
And the clause immediately before that similarly legalizes bypassing copy protection to make a copy if making the copy would be otherwise legal. (i.e. fair use would be legal, copy protection or no.)
There are lots of reasons. For example, a bus stop might have a timetable with one of these symbols next to each entry. You'd just hold your phone up to the one you want to check, and it would connect to the proper web page and show you where that bus is on its route and how long until it reaches your location. Instantly.
So why no print the URL in a human readable form, using a clean font that is a snap to OCR?
For your cellphone the result is the same. You scan the code and are instantly connected to the applicable website. Only the internal details are different: The cellphone (if it doesn't do the OCR itself) forwards the image to a server that OCRs it and returns (or redirects to) the appropriate URL.
But now you can ALSO:
- Enter it into your wi-fi equipped but scannerless laptop.
- Write it down to use later at some other terminal.
No special buttons to press or codes to enter, and with no expensive hardware needing to be installed at the bus stop.
Ditto. Does everything the barcode would do and more. And doesn't cut the human out of the loop.
It's nice to say "you have to be within one inch of the reader for the card to be read", but WHERE is this limit built in?
Even an inch is too much. Pickpockets often have a "bumper" who distracts the target so he doesn't notice the touch on his wallet. Now the pickpocket can lift your card information by bumping into you in a checkout line.
Then a little careful observation as you enter your PIN and your account is toast.
Not Mao, Lao.
This is a quote from the Dao Deh Jing, Lao-Tzu's classic philosophical treatise.
Don't be TOO hard on him. It was an "off by one" error. B-)
"""there are too many, they can't get us all" is not a valid way to go about changing things, especially when the penalties are harsh like the penalties for FCC violations.""
1. actually it kind of is. it's one of the reasons civil disobedience can work.
Civil disobedience rarely works - and when it does it's because a big section of the power structure wants it to.
Re "too many microbroadcasters": Back in the '60s people thought that if enough people smoked dope and took other drugs it would saturate the justice system and lead to legalization of recreational pharmaceuticals. (Just as it was perceived had happened with liquor prohibition.) Four decades later we find that instead the government retooled for a self-funding "Drug War" on the model of the Spanish Inquisition and used it to debug legal tools that can be used for other forms of oppression.
If civil disobedience by the bulk of the largest generation in US history can't prevail, what chance do the relative handfull of small-broadcast operators have?
The poster children for Civil Disobedience are Ghandi and King.
Ghandi gets kudos because of the perceived success of his work in India. But a major fraction of the British Parlement already wanted to dismantle the empire, and especially to unload India as a colony that cost more than it paid. Ghandi gave them good PR for portraying their opposition as monsters and thus getting their way.
Very few people remember that, before he succeeded in India he tried the same approach in South Africa - with no success whatsoever. They also forget his prescription for what the Jews should do about the NAZIs: Commit mass suicide in protest.
As for the good Doctor Martin: Blacks got the vote at the end of the Civil War, but had it taken away by the Jim Crow laws. The freedom rides and the other passive resistance enabled LBJ to put one over on the generally pro-segregation Democratic party by passing the Civil Rights laws - but implementation of those were mandated by the courts to occur at "All Deliberate Speed" - which meant "never". What finally did the trick was the cities burning in '68. Immediately afterward the civil rights laws acquired some teeth and the blacks got the vote for real. WHAT a coincidence!
Then the media raised King to hero status - in order to eclipse the likes of H. Rap Brown, Malcom X, and Charlie Thomas. And the blacks have since been "helped" back into underclass status by "programs" that destroyed their family structure and educational opportunities - to the point that they actually peition the government to be futher disempowered.
Just like veterans got the vote after Shay's and the Whiskey rebellion, women after the temperance movement started smashing bars, and 18-20 year olds after the anti-Vietnam-War riots and bombings. Political power grows out of the barrel of a gun - and at the end of a club, and in a firebomb.
Passive resistance techniques such as civil disobedience are often a useful, and sometimes necessary, early step. They let you acquire the moral high ground. But passive resistance by itself doesn't prevail.
Ok... I understand why the RIAA wants to make more money off each track. There are only two or three good tracks on each CD. But to jack some prices up over what most new CDs are sold for in stores? How does that make any sense at all?
They're just hunting for the maximum profit price point.
What will get them to LOWER the prices is to show them that the demand is elastic and they'll get MORE money at LOWER price by selling more units. (I think that's the right way for them to go - but the market will determine it.)
So the way to show them that they're going in the wrong direction is to make their sales drop by more than the amount of the raised prices, so their total income drops.
They raised it from $.99 to $1.25? Buy LESS than four songs when you would have bought five. Enough less that the signal isn't obscured by new adopters.
If you still want to buy music online, for each new song you're thinking of buying, flip three coins, and if two come up heads NEVER buy it on line. (If it's something you REALLY WANT, pick the one you like least of your next three that come up "buy" and never buy THAT.) That way you'll drop to 5/8 of your previous purchase level.
And keep it up. A sudden and SUSTAINED drop in sales should get the point across.
Nope, it's not Microsoft bugs trashing the net. It's some asshole somewhere who thought it would be really cool to have lots of computers rebooting all the time (or whatever crap the latest virus does to your machine).
That's true. But it's also irrelevant.
Once the exploits are out there, the only ways to make them STOP trashing the net (short of taking out the machines) is to apply the patch. Blocking distribution of the security patch to unlicensed copies insures there will be a much larger number of infected machines chattering away than if it is open.
Selling millions of copies of software that is susceptable to infection and expecting them to remain uninfected is like laying out millions of uncovered petri dishes full of culture medium and expecting them to remain sterile. If nothing else, Microsoft bears some of the responsibility according to the doctrine of "attractive nuisance".
In case you're not aware of it: Consider a chemical company that keeps concentrated sulphuric acid in an uncovered, unfenced, outdoor tank that looks like a swimming pool. Is it the chemical company's fault if, some summer afternoon, some neighborhood kids jump in and/or push each other in? In US law: Absolutely!
By deploying a massively virus/worm susceptable system Microsoft has created an attractive nuisance. Yes the primary responsibility for damage when it is exploited rests with the exploiters. But when they "light a fire" that starts an ongoing process of consuming the neighborhood, it's Microsoft's responsibility to help put it out.
And it's in Microsoft's interest to do so, before somebody wises up and starts using the attractive nuisance doctrine to make them pay for the damage.
Its microsofts perogotive, theyre not in any way required to support pirated versions of their software, and why should they bother.
Because infected and unpatched instances of their software generally continue to operate for the user while clogging the net with viral traffic, serving as zombies for DDoS attacks and acting as spam forwarders.
This is damaging to legitimate customers of Microsoft's products, users of competitors' products, users of open-source products, and operators of the network infrastructure, as well as the users of unlicenced copies of their product.
This reminds me of a kid I knew when he was in high school, back in the Vietnam War era (when the internal security systems of the various levels of government in the US had gotten 'WAY out of control).
..."
His use of a university's computer while a high school student (something he got started on as a guinea pig in a University program doing research on learning and teaching) had attracted the attention of the FBI.
A couple years later he decided to use the shiny-new FOIA to see what records the FBI and the state and local cops had on him. And while he was at it, he sent FOIA requests to several other agencies.
The first one he sent to the CIA was a classic self-referential hack: He requested their internal document describing their procedure for responding to FOIA requests. B-) (Obviously useful for generating the next round of requests, too.)
Needless to say the agencies involved didn't respond as required by the law. So with the aid of a Libertarian lawyer he started suing them. He won, and they eventually were ordered to give him what he asked for. Then they flaked on that, too, and he got a contempt citation and more court orders. Eventually he got much of his info (with big chunks blacked out). Then he sued them for his lawyer's fees and won that, too.
After a few iterations of this he was sitting on quite a number of interesting documents. So he started a newspaper to give them wider circulation and created a business of generating FOIA requests and publishing the results. This became quite popular with the CIA watcher, privacy advocate, private detective, and tinfoil-hat sets. Advertising revenue flowed in from such folk as buging and debugging equipment manufacturers.
At one point he got the petty cash records from a New York area CIA office. Items he found in it charged to one project (air compressor, flit guns, briefcase, auto exhaust system, washing a car) led to blowing the lid off a project to obtain information on how a biowarfare plague might spread in an urban environment by exposing the citizens of New York City to a "mostly harmless" bug that caused severe enough respiratory system symptoms that it could be tracked by hospital admissions. (Spread techniques included spraying subways with the bug from the gimmicked briefcase and spraying commuter traffic via the car's exhaust system.)
He also got hold of and published one year's version of the IRS procedures manual. And put out a pamphlet on how to use the FOIA. (Eventually he was enjoined from distributing either of these.)
Eventually the FOIA was modified to give the security agencies some loopholes against such requests.
Bob Dylan had something to say about this: "You have to pay to keep from going through these things twice." Also Thomas Jefferson: "The tree of Liberty must be watered, from time to time
He's still out there doing stuff like this, by the way. Last time he looked he had a web site dedicated to exposing personal information trading in the information age.
The above-mentioned kid was part of the Boomer's round. I guess now it's Generation X's (or maybe Y's) turn to pay some dues. (Sigh.)