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On Fri, 19 Mar 2004 01:32:03 GMT, Spehro Pefhany
wrote: On a different discussion point, picture the recent Spanish train bombings (10 set off.) Had the train installed cellphone signal blocking equipment most of those bombs would probably not have been set off. From the fact that few of them went off in the station, where they would have been far more effective, one may conclude that they were triggered by simple timers. Let's say three bombs went off at the station. If the other seven were prevented from going off that would still have been a significant victory against terror. Of course terrorists will always find other ways to detonate their bombs and the most effective method is still the suicide bomber, no technology sophistication there. Be forewarned. They will not remain the technology primitives they are today. In this escalating war new solutions will have to be found again and again. But in the meantime I think I have put forth a reasonable proposal that is cheap and easily implemented, to greatly reduce the opportunities for cellphone triggered bombs. More important, perhaps to reduce the enormous effort and costs to provide surveillance in public places. I like my idea of a built-in transponder chip that can be interrogated at check-out counters. A portable interrogator can be used to check abandoned packages from a safe distance without needing to know the cellphone call number. The Spanish rescue team found an unexploded bomb laden bag with a cellphone trigger and were very lucky that it didn't go off. |
I new you were an idiot. Plonk.
"KLM" wrote in message ... On Thu, 18 Mar 2004 18:12:08 -0800, "CW" wrote: The ideas are getting better but are you going to be the one to explain to people's families that it was for the public good that you were transmitting a signal designed to set off a bomb in a crowded place? It should get the terrorist and the couple of dozen people behind him waiting to get through the check point. I can't make out any logic in what you have written. Are you also plain English challenged besides being technology, legal knowledge and public policy challenged? |
"KLM" wrote in message
... On Thu, 18 Mar 2004 18:12:08 -0800, "CW" wrote: I can't make out any logic in what you have written. Are you also plain English challenged besides being technology, legal knowledge and public policy challenged? I can attest to his challenges with the last three. I posted this comment as a seperate header but it never showed up, so here is the deal on property rights and blocking cell signals again: Mostly one sea-lawyer's rant in this group, was that it is illegal to interfere with any radio signal, etc. That opinion is absent of understanding the intent of that law, or where it may be applied. On private property, one may install any device, counter-signal, shielding, etc that prevent or otherwise render inoperable any other signal that enters or tries to leave that property. There are reasonable exceptions, before the crazies ask what about a 1,000' balloon with radar reflector in your airspace right next to an airport. Get real. We're talking about a restaurant owner's right to make his interior airspace incompatible with cellular signals, and nobody can argue he doesn't have the right to do that, with or without notifying you of it. It's a courtesy if he tells you, tough luck if he doesn't. Similarly, the government regulates and (tries) to ensure the operability of public communications while mitigating unnecessary or malicious interference. Neither apply to a private property owner's right to have cell-phone signals blocked on his property. If he invites the public, some states might pass laws to require he notifies the public of that blockage, but neither is it the public's right to assume that is so. A locality could also decide it will prevent cell signals during any venue that takes place on property it owns or leases. It's reasonable, it's "legal", and it's happening. Before long, somebody will concoct a way to beat those blockers, probably by a jam-resistant receiver card that plugs into the phone's antenna. Then you'll have to check your gun and your cellphone with the maitri d'. ;-) Jack Virginia Beach |
Another ignorent one. This thred seems to be full of them.
"Jack Painter" uttered a bunch of useless crap. |
"KLM" schreef in bericht
... On Fri, 19 Mar 2004 01:32:03 GMT, Spehro Pefhany wrote: On a different discussion point, picture the recent Spanish train bombings (10 set off.) Had the train installed cellphone signal blocking equipment most of those bombs would probably not have been set off. From the fact that few of them went off in the station, where they would have been far more effective, one may conclude that they were triggered by simple timers. Let's say three bombs went off at the station. If the other seven were prevented from going off that would still have been a significant victory against terror. Of course terrorists will always find other ways to detonate their bombs and the most effective method is still the suicide bomber, no technology sophistication there. Be forewarned. They will not remain the technology primitives they are today. In this escalating war new solutions will have to be found again and again. But in the meantime I think I have put forth a reasonable proposal that is cheap and easily implemented, to greatly reduce the opportunities for cellphone triggered bombs. More important, perhaps to reduce the enormous effort and costs to provide surveillance in public places. I like my idea of a built-in transponder chip that can be interrogated at check-out counters. A portable interrogator can be used to check abandoned packages from a safe distance without needing to know the cellphone call number. The Spanish rescue team found an unexploded bomb laden bag with a cellphone trigger and were very lucky that it didn't go off. Forget it. You can't fight terrorism. You can only take away the anger/frustration that *feeds* it, which takes time and a lot of wisdom. A roll of duct-tape isn't going to fix anything. -- Thanks, Frank. (remove 'x' and 'invalid' when replying by email) |
A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing on Usenet? CW says... You can try to ratioanlize it as much as you want. The willfull electronic interference of a radio service is a crime. You need to stop saying things like "is a crime" when posting to Usenet, a medium that is worldwide. Also, the following web pages may help you: Bottom vs. top posting and quotation style on Usenet http://www.cs.tut.fi/~jkorpela/usenet/brox.html Why bottom-posting is better than top-posting http://www.caliburn.nl/topposting.html +What do you mean "my reply is upside-down"? http://www.i-hate-computers.demon.co.uk/ The advantages of usenet's quoting conventions http://homepage.ntlworld.com/g.mccau...ks/uquote.html Why should I place my response below the quoted text? http://allmyfaqs.com/cgi-bin/wiki.pl...bottom-posting Quoting Style in Newsgroup Postings http://www.xs4all.nl/%7ewijnands/nnq/nquote.html -- Guy Macon, Electronics Engineer & Project Manager for hire. Remember Doc Brown from the _Back to the Future_ movies? Do you have an "impossible" engineering project that only someone like Doc Brown can solve? My resume is at http://www.guymacon.com/ |
Active8 says... Someone else seems to think the T's aren't using DTMF. Does the phone answer itself? The B*s*c St*mp that decodes the DTMF cam also look for a ring and answer the phone. Terrorists hire engineers and technicians. Countermeasures that any random sci.electronics.design participant can defeat are a waste of effort. -- Guy Macon, Electronics Engineer & Project Manager for hire. Remember Doc Brown from the _Back to the Future_ movies? Do you have an "impossible" engineering project that only someone like Doc Brown can solve? My resume is at http://www.guymacon.com/ |
KLM says... I like my idea of a built-in transponder chip that can be interrogated at check-out counters. It has a fatal flaw. Al, the terrorists have to do is to buy a couple of hundred of the current cell phones that lack the chip and store them away for making bombs with. -- Guy Macon, Electronics Engineer & Project Manager for hire. Remember Doc Brown from the _Back to the Future_ movies? Do you have an "impossible" engineering project that only someone like Doc Brown can solve? My resume is at http://www.guymacon.com/ |
On Fri, 19 Mar 2004 05:54:13 GMT, KLM wrote:
On Fri, 19 Mar 2004 01:32:03 GMT, Spehro Pefhany wrote: On a different discussion point, picture the recent Spanish train bombings (10 set off.) Had the train installed cellphone signal blocking equipment most of those bombs would probably not have been set off. From the fact that few of them went off in the station, where they would have been far more effective, one may conclude that they were triggered by simple timers. Let's say three bombs went off at the station. If the other seven were prevented from going off that would still have been a significant victory against terror. Of course terrorists will always find other ways to detonate their bombs and the most effective method is still the suicide bomber, no technology sophistication there. Be forewarned. They will not remain the technology primitives they are today. In this escalating war new solutions will have to be found again and again. But in the meantime I think I have put forth a reasonable proposal that is cheap and easily implemented, to greatly reduce the opportunities for cellphone triggered bombs. More important, perhaps to reduce the enormous effort and costs to provide surveillance in public places. I like my idea of a built-in transponder chip that can be interrogated at check-out counters. A portable interrogator can be used to check abandoned packages from a safe distance without needing to know the cellphone call number. The Spanish rescue team found an unexploded bomb laden bag with a cellphone trigger and were very lucky that it didn't go off. Objections of others partially aside, you're getting close to a workable idea. If a few of the off the shelf trak phones had to be recalled or exchanged for new ones, any old ones the T's stockpiled would be worthless. The RFID systems could be set up to either cover a small area like a turnstile or a larger area depending on how you wanted to go about implementing security for a given loacation. The problem to overcome is that we don't want to set one off in a crowd, so we don't want it to ring in response to the RFID interrogation. We also don't want an invasion of privacy, so a generic RFID response would be the solution. We also don't want the thing detonating from the interrogation with people around and that's the biggest prob. You have to admit only one person at a time into the area. That's not too bad. It's common courtesy to stand back from someone using an ATM so maybe a few feet will do. Like in a bank line. I don't imagine the T's will want the thing detonating at the check point either, so they'll probably have that figured out and an inspection of the phone should reveal anything suspicious. I think the real problem is the human factor. When baggage handlers make $15/hr and get full union benefits, while the security contractor pays his monkeys minimum wage, you have apathy. This is no BS, it's serious. Back in the 80's after the Berlin disco bombing and a few other attacks, people were talking a lot about security. And talking is about all they did. I went through the security check at the Atlanta airport and after being admitted into the so-called secure area I had to go to the bathroom so I asked where it was. Damned if it wasn't outside the secure area. I went out through an unckecked passage and came right back in. No one bothered checking me. Last few times I went through a metal detector, I set it off. The first time, the guard checked me with the wand and suggested it was my shoes or the jacket zipper, but didn't ask me to remove them. The second time (a month later) I went through, the same guard was there. I just pointed to the shoes and the zipper and I was in. Friggin' apathy. Maybe he remembered that the wand didn't indicate a big enough chunk of metal, but that jacket fit just about right to conceal a Glock. -- Best Regards, Mike |
"Spehro Pefhany" wrote in message
... On Fri, 19 Mar 2004 01:08:01 GMT, the renowned KLM wrote: On a different discussion point, picture the recent Spanish train bombings (10 set off.) Had the train installed cellphone signal blocking equipment most of those bombs would probably not have been set off. From the fact that few of them went off in the station, where they would have been far more effective, one may conclude that they were triggered by simple timers. Best regards, Spehro Pefhany Yes, that is correct - at least that's what was said on the news channels here in the UK. The Spanish bombs were triggered by mobile phones set on alarm at 7:39am IIRC - the phones didn't even have to have SIM cards in them. No signal jamming equipment could have prevented them from going off. cheers, Costas |
I read in sci.electronics.design that KLM wrote (in
) about 'Cellphones and Bombs', on Fri, 19 Mar 2004: To the objections from other posts; of course a determined terrorist will always get through. Who can stop one who is willing to blow himself up. If he acts entirely alone, like the one who blew up the gay pub in London, no-one, unless by chance - nail-bomb in Brixton. But anyone who confides in others is vulnerable to infiltration, and there's a lot of that going on, you can be sure. -- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory. The bad news is that everything is prohibited. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk |
In article ,
Costas Vlachos wrote: Yes, that is correct - at least that's what was said on the news channels here in the UK. The Spanish bombs were triggered by mobile phones set on alarm at 7:39am IIRC - the phones didn't even have to have SIM cards in them. No signal jamming equipment could have prevented them from going off. Ah - the modern equivalent of the classic alarm-clock timing mechanism. Modern digital watches would work about as well. As to the idea of jamming cellphone frequencies: even if physically practical, and even if the government would authorize widespread distribution of devices which jammed a licensed radio service (doubtful IMO since the cellphone companies paid $$$ for their licenses and would doubtless fight it in court), it would only move the problem elsewhere. There are far too many radio frequency bands, and far too much commonly-available equipment which could be modified to allow for remote detonation control over moderate distances. Garage door openers with rolling-code security, portable radios of all sorts, etc. could all be incorporated into a scheme for remote- controlled mass murder by those whose inventiveness and skills outweighs their ethics and humanity. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
"KLM" wrote in message ... On Thu, 18 Mar 2004 16:53:28 -0800, "CW" wrote: Do you know what the word ILLEGAL means? It is very obvious that you are ignorant of the technical details and I am not going to be your electronics teacher. It is illegal for a reason. Terrorists are using cellphones to kill and maim hundreds of people and you are maintaining that unrestrcted CP use is a god given inviolable right. Nope. He's simply pointed out, quite correctly, that willful interference with a legitimate radio service is very , very illegal, and it is so for some very good reasons. Besides, "jamming" cell phones is a stupid and ineffective idea anyway. You can't reliably "jam" such things within a limited area (which is one reason for the laws in question - to RELIABLY jam phones within an area that IS under your legal control, you MUST create signals that will cause interference OUTSIDE that area. Hence, don't do it.) A far better plan is to simply shield the area in question from ANY RF transmissions - easily and relatively cheaply done, and will cause no legal or other hassles, or unintended interference. And you can still bring in any RF-based info you DO want - TV, radio, etc. - via a cable. Bob M. |
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"KLM" wrote in message ... Why not include a circuit in every cellphone that will cause the answer bell to ring when anyone carrying a cellphone crosses one of these interrogators. Maybe have the circuitry activate a different ring tone or ring pattern from the normal call ring. Its extremely short range and won't interefere with normal cellphone use. Simple - again, the strong likelihood of interference with cell phones AND other legitimate services. Plus the rather obvious fact that it won't achieve the desired goal; once these things were placed into service, it would be trivially easy for a "cell phone bomber" to disable their phone's ringer. Or to cause a dummy ringer (the one that doesn't have to do with the bomb) to go off and thus defeat the security. You really should learn a bit more about how these things work before proposing supposed "solutions" to the supposed "problem." Bob M. |
KLM wrote in message . ..
On Thu, 18 Mar 2004 13:00:55 -0800, "CW" And cellphone signal blocking is localized, short range, same as WiFi. Put up a sign to that effect in your business premise. Those who feel they must have their cellphone access 24/7 can always step outside the door or avoid the place. That business will survive because there are a miniscule number of 24/7 cellphone freaks. Anyway the use of cellphones while driving is banned in many states in the US and worldwide. What is so different in banning their use in selected public places. The only difference is that signal blocking is applied universally in that defined building area, and without having intrusive checks being made on anyone to effect compliance. To prevent the use of cellphones ANYWHERE kills an industry, I want to be able to use it everywhere, OK handsfree in a car. If the terrorist intention is to damage industry, economy, then yes. Else live with the danger. JP |
"Reg Edwards" wrote in message ... I AM old enough to remember the pre-war and the phoney-war impressions of the population of the cities of Birmingham and Coventry about the capabilities of the Luftwaffer. It was "They'll never get this far." At the same time the citizens of Cologne, Hamburg, Berlin and Dresden were saying much the same thing. Whath they found out was that they don't have to ALL get through. |
"Bob Myers" wrote in
: "KLM" wrote in message ... On Thu, 18 Mar 2004 16:53:28 -0800, "CW" wrote: Do you know what the word ILLEGAL means? It is very obvious that you are ignorant of the technical details and I am not going to be your electronics teacher. It is illegal for a reason. Terrorists are using cellphones to kill and maim hundreds of people and you are maintaining that unrestrcted CP use is a god given inviolable right. Nope. He's simply pointed out, quite correctly, that willful interference with a legitimate radio service is very , very illegal, and it is so for some very good reasons. Besides, "jamming" cell phones is a stupid and ineffective idea anyway. You can't reliably "jam" such things within a limited area (which is one reason for the laws in question - to RELIABLY jam phones within an area that IS under your legal control, you MUST create signals that will cause interference OUTSIDE that area. Hence, don't do it.) A far better plan is to simply shield the area in question from ANY RF transmissions - easily and relatively cheaply done, and will cause no legal or other hassles, or unintended interference. And you can still bring in any RF-based info you DO want - TV, radio, etc. - via a cable. Bob M. Spot on, thats whats used where possible in sensitive buildings in the UK. The use of CP's for these purposes has been going on for 30 years at least. It's not new and various means to counter it have been tried with various success. There's a tendancy to assume these people are stupid as well as socially corrupt. Not true. The IRA for instance used cp's in the 70's and 80's bombing of London and the mortar attack on 10 Downing street while the cabinet was in session. The IRA's technique was to use two cell phones and a sequence of calls to arm and trigger the weapon. Once the bomb was placed and the phone was on and receiving signal the bomb was also set to go off if the phone was switched off or the signal lost - as it would be if the area was 'jammed'. Jamming the phone service could actually set the thing off where the planter wanted it to be. Not a good idea. As an aside, given that Bush has started his war on terrorism, terrorists and all that support them, does that mean he's going to pursue all those who have and still do support the IRA and 'the cause' who where almost entirely funded from the US? |
Reg Edwards wrote:
"At the same time the citizens of Cologne, Hamburg, Berlin and Dresden were saying much the same thing." Yes. Hermann Goering boasted early in the war that his name was mud if bombs fell on Berlin. Later in the war as Hermann scurried for shelter he was heard introducing himself as "Herr Mud". Best regards, Richard Harrison, KB5WZI |
Forget it. You can't fight terrorism. You can only take away
the anger/frustration that *feeds* it, which takes time and a lot of wisdom. A roll of duct-tape isn't going to fix anything. Those are very wise words. Thats *IS* exactly how it is. Unfortunatly the big terrorist Bush wants to have war everywhere, so he can sell weapons, and will make unrest everywhere. His men are now in Siria, perhaps also in Taiwan, Bush was talking today of 'world is at war' well, that for sure is what he is directing every possible energy towards. So my hopes of this realization being realized so to speak are not great. Only chance we have, in our lives, is to enjoy this moment given to us, NOW, there are no guarantees for the future, and the past is gone. There are however people in this world trying to make people realize that peace in an inner experience, your own choice so to speak, and atainable, for example my Guru www.maharaji.org. So, as long as there is a way out, we are free :-) JP |
(The Captain) wrote in message . com...
Dave Shrader wrote in message news:Xu36c.33004$po.292953@attbi_s52... John Michael Williams wrote: SNIP However, the first radios transmitted sparks, so in principle it should be possible to transmit near a long wire separated by a small gap from ground or another wire and get a small spark. So, I decided to try an experiment. SNIP There is one other potential source for a spark that you did not investigate. A make/break contact in a switch causes sparks when opened. The US Military specifies special shielded switches for their explosive, gas vapor, etc., environments. So, it is possible that pressing the PTT or the ON/OFF switch causes the necessary spark. Remember the Apollo ground fire. A switch/spark caused an oxygen explosion. Actually, anyone who has worked in the offshore oil industry will be familiar with the concept of intrinsic safety. This requires that no electronic instrument shall be able to ignite a mixture of air and inflamable vapour or gas. All handheld radios used on rigs are intrinsically safe, making them far more expensive than the standard variety. I very much doubt that cell phones are buit to intrinsicly safe standards, and under those circumstances I would certainly not feel safe near someone yacking while filling. So, an interesting querstion is; does your phone conform to UL requirements for intrinsic safety? And if not, why are you using it in an area where an explosive gas air mixture is possible? Cap Actually, a former maritime safety engineer Emailed me about this. However, he could not locate the law or regulation which defines "intrinsic safety". If you can find a law or regulation governing operation of a transmitter around a gas pump, please post it. I have no idea how UL testing would pertain to a battery operated device incapable, itself, of electrocuting anyone. However, the battery eliminator which I have (but did not use in the experiment I described) is UL approved. On the safety issue, the same engineer also told me he was able to create visible sparks with a 100 W transmitter, holding the antenna near a piece of metal. However, for the following reason, I suspect the sparks were because his transmitter was earth-grounded: The handheld CB I used had a completely insulated rubber antenna and of course had no ground connection. I replaced the rubber antenna with a telescoping metal one. I then keyed the transmit button (as above) in the dark, while trying to get a spark by bringing the tip near a 1 m x 1 m aluminum 1/4 in plate (ungrounded). I could see nothing, although touching the metal caused the CB's power out bar to indicate a drop in power. The plate should have been an effective AC ground at ~27 MHz. So, neither induction into a wire nor electrical direct contact seems likely to make a visible spark, with a 5 W CB transmitter. I would only expect a 100 mV or so spark anyway, which would be hard to see. So, I'm not convinced that a cell phone could cause a spark, either. I agree that key closure sparks might be possible internal to the device, and that neither it nor a cell phone would be likely to have been designed to suppress a flash from such a source. However, the issue I have tried to address here is a spark from the RF, not from generic electrical causes. I don't doubt that gasoline vapor is inflammable in a generic sense. John John Michael Williams |
"Costas Vlachos" wrote in message ...
Yes, that is correct - at least that's what was said on the news channels here in the UK. The Spanish bombs were triggered by mobile phones set on alarm at 7:39am IIRC - the phones didn't even have to have SIM cards in them. No signal jamming equipment could have prevented them from going off. cheers, Costas I ma not sure abou that other phone, in a backpack, it rang, and that is how they found it. So it MUST have had a sim card. When I heard that news, I knew they would get the guys in hours. One look at that sim, and a look at the telco's logs, and you have the whole network:-) It proves these guys are really dumies in that stuff. Nevertheless very very dangerous. JP |
Jan Panteltje wrote:
Forget it. You can't fight terrorism. You can only take away the anger/frustration that *feeds* it, which takes time and a lot of wisdom. A roll of duct-tape isn't going to fix anything. Those are very wise words. Thats *IS* exactly how it is. Actually, we fought nazi terrorism during WWII and won. Seems to me it would be more appropriate to say: "The fight against terrorism is a never ending war unless we take away the anger/frustration that *feeds* it." -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil wrote,
Jan Panteltje wrote: Forget it. You can't fight terrorism. You can only take away the anger/frustration that *feeds* it, which takes time and a lot of wisdom. A roll of duct-tape isn't going to fix anything. Those are very wise words. Thats *IS* exactly how it is. Actually, we fought nazi terrorism during WWII and won. Seems to me it would be more appropriate to say: "The fight against terrorism is a never ending war unless we take away the anger/frustration that *feeds* it." -- 73, Cecil http://www.qsl.net/w5dxp Actually, we used terrorism against the Nazis, the Japanese, and the Italians in WWII and were very satisfied with the results. We also paid people like Osama Bin Laden to terrorize the Russians when they invaded Afghanistan and were again very satisfied with the results. Moreover, we were quite happy to see Saddam Hussein terrorize the Iranians and the Kurds when it suited our interests. We were not pleased to have these dogs turn on us, however, and so we're now engaged in a war on "terrorism." That's code. What we mean by it is not that we're against terrorism, since we are capable of using it ourselves when the need arises, but against being terrorized. 73, Tom Donaly, KA6RUH |
"David Williams" wrote in message
... Changing laws and changing behaviour is *exactly* what they want. **** them. The only thing you can do is report suspicious packages at train stations etc. Other than that, just ignore the *******s and get on with your life - if you do anything else they have won. If you're scared then they have won. That's why it's called TERRORism. Look at the odds - if you're not scared of crossing the road you shouldn't be scared of terrorism. hear hear |
"Cecil Moore" wrote in message
... Terry Given wrote: dont they have a nice monument though? Terry, what the heck are you doing awake at 2am tomorrow? -- 73, Cecil http://www.qsl.net/w5dxp questioning my own causality? |
On Fri, 19 Mar 2004 10:29:15 +0100, "Frank Bemelman"
wrote: Forget it. You can't fight terrorism. You can only take away the anger/frustration that *feeds* it, which takes time and a lot of wisdom. A roll of duct-tape isn't going to fix anything. I agree with you 100%. But its an emotional subject I avoid assiduously as any argument that says the Arabs and the Muslims have good reason to feel the way they do will invite very angry flames from a sector of shoot-em-all-first Americans. For crying out loud, even Americans who hold this view (Arabs and Muslims have valid grievences) have been intimidated into silence by their own side. Until the American right wing come around to dealing with the root causes of why people are willing to blow themselves up to take out their enemies, suicide bombings will continue. The issue is intimately linked with what's going on in Israel. Again I refuse to get caught in the middle as one will be mauled by both parties whatever one says. Was it Mercuto who said "Pox on both Houses" in Romeo and Juliet? Exactly my feelings. ------------------------------------- I originally used the term CP signal blocking and there were off-the-shelf equipment openly available for sale some years ago. It blocks signals to your establishment, eg. inside a restaurant, in specific frequencies only I believe. I presume the signal blocker does not block signals outside the premise for that would be clearly illegal. It does not jam signals with dirty noise that intereferes with the safe operation of other electronic equipment which is also clearly illegal. In any case the suggestion for cellphone signal free areas is just a suggestion. Of course it wouldn't stop CP triggered bombings for they will just plant them elsewhere. But at least there is a chance that the more high value target - a very crowded place in a high profile establishment - may be spared. |
On Fri, 19 Mar 2004 07:29:27 -0500, Active8
wrote: We also don't want the thing detonating from the interrogation with people around and that's the biggest prob. You have to admit only one person at a time into the area. That's not too bad. It's common courtesy to stand back from someone using an ATM so maybe a few feet will do. Like in a bank line. I did consider this objection. The interrogation will be done going into a designated area (eg. sports stadium, train station where other waiting to go in can wait some distance away. If I recall this (checks going in) was done for the Superbowl and were not backpacks and other bags banned? So have them enter a blast cage (to catch the sharpnel mostly) or something like that for RFID interrogation. The idea is not unlike the airport metal detector gate check. Once they are in they are presumed to be safe. So perhaps have similar "interrogation gates" for people entering a pedestrians only shopping area, or to Times Square for the New Year bash. We are dealing with only one threat - CP triggered bombs. Therefore, please think small and figure if it is worth doing. I am not trying to protect the whole world. |
On Sat, 20 Mar 2004 02:28:56 GMT, KLM wrote:
On Fri, 19 Mar 2004 07:29:27 -0500, Active8 wrote: We also don't want the thing detonating from the interrogation with people around and that's the biggest prob. You have to admit only one person at a time into the area. That's not too bad. It's common courtesy to stand back from someone using an ATM so maybe a few feet will do. Like in a bank line. I did consider this objection. The interrogation will be done going into a designated area (eg. sports stadium, train station where other waiting to go in can wait some distance away. If I recall this (checks going in) was done for the Superbowl and were not backpacks and other bags banned? So have them enter a blast cage (to catch the sharpnel mostly) or something like that for RFID interrogation. The idea is not unlike the airport metal detector gate check. Once they are in they are presumed to be safe. So perhaps have similar "interrogation gates" for people entering a pedestrians only shopping area, or to Times Square for the New Year bash. Simple. Drop precast, steel reinforced entryways in the street. We are dealing with only one threat - CP triggered bombs. Therefore, please think small and figure if it is worth doing. I am not trying to protect the whole world. -- Best Regards, Mike |
"John Woodgate" wrote in message ... I read in sci.electronics.design that CW wrote (in ) about 'Cellphones and Bombs', on Thu, 18 Mar 2004: You can try to ratioanlize it as much as you want. The willfull electronic interference of a radio service is a crime. Did you read the part of my post about signal blocking? I thought not. Go back and try again. If a terorist is going to strike, he is going to strike. The Department of Homeland Paranoia is not going to be able to do anything about it. I am ALMOST old enough to remember a similar idea held in UK and Europe before WW2, that 'the bomber (aircraft) will always get through'. The RAF pretty well disproved it. OTOH, the Eighth Air Force did pretty much prove it. Unfortunately, they didn't always come back. Ed wb6wsn |
"Roger Gt" wrote in message om... "Active8" wrote : Roger Gt wrote: : "Paul Burridge" wrote : : Jim Thompson wrote: : : : :I was struck by a thought when I heard the latest Palestinian : :terrorist trick is to send a kid through the border with a : back-pack : :bomb triggered by a cell phone.... : : : :The Israelis should get a telemarketer's speed dialer and : constantly : :dial away... boom... boom... boom... : : : :ROTFLMAO! : : : : Yes, I'm rolling on the floor laughing at all these deaths, too, : as : : I'm sure we all are. : : Huh? : He seemed to be laughing at the lame Idea! I also thought it : funny that anyone would try something which would almost totally : wipe out the cellular phone service for the entire country... : : does a 200 station phone room with auto-dialers all calling one : state wipe out POTs? WTH are *you* talking about? Gee - Primitive! Not a Telephone guy I guess...... The last autodialer I worked on was a Dual DS3 line unit with a router. 2 times 864 lines wide. A few of those would really choke a network! So YOU are one of the SOB's who create those things? Ed wb6wsn |
"Ben Bradley" wrote in message ... In rec.radio.amateur.antenna, ( I suppose this is on RRAA because cell phones have antennas ) sci.electronics.design,sci.electronics.basics, Jim Thompson wrote: Of course, in the USA, one could put the cell number on the national DO-NOT-CALL list, then only an "illegal" telemarketer would trigger the bomb. Bombers might figure ways around this (especially if they search Usenet), such as a cellphone answering circuit and a "dee tee em eff" decoding circuit. I wouldn't want to spell it out for them... ...Jim Thompson They may not be as illiterate as you suggest; perhaps Pig Latin could offer sufficient encryption: Eeday eetay emyay effyay. Ed wb6wsn |
See my post titled Intrinsic Safety -- Guy Macon, Electronics Engineer & Project Manager for hire. Remember Doc Brown from the _Back to the Future_ movies? Do you have an "impossible" engineering project that only someone like Doc Brown can solve? My resume is at http://www.guymacon.com/ |
John Michael Williams says... Actually, a former maritime safety engineer Emailed me about this. However, he could not locate the law or regulation which defines "intrinsic safety". If you can find a law or regulation governing operation of a transmitter around a gas pump, please post it. The National Fire Protection Association’s (NFPA) National Electrical Code (Article 500, NFPA 70) defines Hazardous Locations as those areas "where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings." NFPA-NEC Intrinsic Safety ratings detail the specific Hazardous Location in which an electrical device can be used without fear of electrostatic discharge that may cause an explosion. The classification that applies to auto fuels a Class I: Gases, vapors and liquids - Group D: Hydrocarbons, fuels, solvents, etc. - Division II: Not normally present in explosive concentrations (but may accidentally exist). Other standards that apply to Intrinsic Safety a ANSI/UL 913 Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, and III, Division 1, Hazardous (Classified) Locations US Mine Safety and Health Administration (MSHA) Mine Wide Monitoring Systems (MWMS) Program: MSHA ACRI2001 - 30 CFR Part 18, Part 23 CENELEC/EN European Standards for electrical apparatus for potential explosive atmosphere General requirements EN 500 14 [IEC 60079-0] Increased safety "e" EN 500 19 Intrinsic safety "i" EN 500 20 [IEC 60079-11] [BS 5501 part 7] Canadian Standards Association (CSA) C22.2 No. 157-92 ANSI/ISA RP 12.6 Wiring Practices for Hazardous (Classified) Locations Instrumentation - Part 1: Intrinsic Safety Factory Mutual Research Corporation (FMRC)? American Society for Testing and Materials (ASTM)? Also see: http://www.crouse-hinds.com/CrouseHi...afe/insafe.cfm http://www.ascojoucomatic.com/images...f1/V1005gb.pdf http://www.mtlnh.com/datashts/sensors/Sen%20Specs.pdf http://www.msha.gov/S&HINFO/TECHRPT/...ICAL/imisf.pdf http://www.gexcon.com/index.php?src=...HBcontents.htm http://www.electrona.se/pdf/tp_1110_3.pdf http://www.ieee-pcic.org/archive/pcic98.pdf -- Guy Macon, Electronics Engineer & Project Manager for hire. Remember Doc Brown from the _Back to the Future_ movies? Do you have an "impossible" engineering project that only someone like Doc Brown can solve? My resume is at http://www.guymacon.com/ |
Jan Panteltje says... it rang, and that is how they found it. So it MUST have had a sim card. My cellphone rings without any simm card. All I have to do is to set the alarm clock function. -- Guy Macon, Electronics Engineer & Project Manager for hire. Remember Doc Brown from the _Back to the Future_ movies? Do you have an "impossible" engineering project that only someone like Doc Brown can solve? My resume is at http://www.guymacon.com/ |
I read in sci.electronics.design that Ed Price wrote
(in 12W6c.19644$uh.12711@fed1read02) about 'Cellphones and Bombs', on Sat, 20 Mar 2004: "John Woodgate" wrote in message ... I read in sci.electronics.design that CW wrote (in ) about 'Cellphones and Bombs', on Thu, 18 Mar 2004: You can try to ratioanlize it as much as you want. The willfull electronic interference of a radio service is a crime. Did you read the part of my post about signal blocking? I thought not. Go back and try again. If a terorist is going to strike, he is going to strike. The Department of Homeland Paranoia is not going to be able to do anything about it. I am ALMOST old enough to remember a similar idea held in UK and Europe before WW2, that 'the bomber (aircraft) will always get through'. The RAF pretty well disproved it. OTOH, the Eighth Air Force did pretty much prove it. Unfortunately, they didn't always come back. The idea was that there was *no effective defence** against bomber aircraft, and it is that which is false. OTOH, there was no effective defence against V2 rockets at the time. Luckily, they were developed too late to prevail. -- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory. The bad news is that everything is prohibited. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk |
Guy Macon http://www.guymacon.com wrote in message ...
Jan Panteltje says... My cellphone rings without any simm card. All I have to do is to set the alarm clock function. Yes, that works here too. Even when the thing is off! But what I ment is that I got the impresion it was really ringing, like they dialed it, and for that you need a SIM. Of cause if you had the phone, a look in the flash would reveal much of what they had done (likely some card was in it for testing). Probably we will not hear details for obvious reasons. But again, do not blame it on cellphones, if these were not available they would use something else I am sure. In fact the phone gave them away! We will have to live with the danger. I missed an IRA bomb by one minute years ago in London, just clearly remember the thought 'shall I go have a cup of coffee in that Wimpy (coffee bar), or go back to the office (tube across it)'. We had to go for a production to Italy next day or so, and had a lot to do (was working in London in that time). So I took the tube back to the office, whan I arrived there it was on the news that a IRA bomb was in that coffee shop. So, dangers surround us all the time, why we move, and how we move, our timing, be concious. JP |
On 17 Mar 2004 12:02:15 -0800, (John Michael
Williams) wrote: However, the first radios transmitted sparks, so in principle it should be possible to transmit near a long wire separated by a small gap from ground or another wire and get a small spark. There were few spark transmitters mounted in automobiles. They were just too inefficient, big, and clumsy to be functional. Transmitters in vehicles really didn't start until tube type transmitters became popular. The problem was that the typical mobile radio used a dynamotor (motor-generator) combination to generate the necessary high voltages. With the radio and dynamotor mounted in the trunk of the vehicle, there was a good chance that gasoline fumes would accumulate in the trunk of the vehicle and be ignited by the spark from the dynamotor commutator. See the photo of the 80D at: http://www.telmore.com/ka1nvz/old_tw...ola/49-59.html The dynamotor is the black cylinder near the handle. The 140D was twice as big and heavy. Back in the 1960's, my 1960 Ford Falcon had an assortment of Motorola 80D and 140D radios in the trunk. I experienced a small explosion in the trunk ignited by the dynamotor. I had filled up the gas tank at the local gas stop (for 19 cents per gallon). Warm weather caused it to expand and leak vapour into the trunk. Key the transmitter, the dynamotor starts, sparks, and boom. I then attached a 1.2 m monopole antenna to an oscilloscope. This antenna has a Schottky hot carrier diode and impedance matching resistors builtin. Lovely. A harmonic generator. Any reason you want lots of harmonics? Shottky diodes or any other non-linear device, do not belong in antenna matching circuits. It's home made, but it's probably as good as any other wire about that long. Wrong. Optimum for CB is either a 1/4 wave monopole (102 inches) or two of them to form a half wave dipole. So, first conclusion: To get even a 1 V spark would take a wire at least 9 m long, all somehow kept within 1 m of the transmitter. Thus, it appears it is not feasible to create a hazardous spark with a CB at a gas station. Find a 4 watt flourescent light. Attach a 1/4 wave antenna to your 5 watt CB radio. Transmit. Hold lamp in hand and touch the end of the 102" antenna. It will light when you talk. (Note: With AM modulation, you only get 5 watts when you yell into the microphone. Without modulation, you only get about 2.5 watts of RF). Now, ask yourself what voltage is required to light the flourescent lamp. In order to get a spark, you need to generate enough voltage to ionize the air between the contacts. That's about 20KV/inch. If we eliminate the antenna, 5 watts of RF into 50 ohms will generate: P = E^2 / R E = 16v rms E(peak) = 1.4 * 16 = 22 volts The gap necessary to create an arc with 22 volts is: 22V / 20,000V/in = 0.001 inches Kinda small, but given a microscope, a 1 mil spark gap will arc. Of course the VSWR protection circuity in the transmitter will instantly shut down the transmitter when it arcs, but that takes a few millisec. Notice that this is a voltage phenomenon, and is not dependent upon the power level. Therefore, an antenna that offers a voltage step-up will generate a higher voltage. However as the antenna is in the air and nowhere near a close enough ground to arc, it doesn't matter. If there's gonna be any arcing, it will be between the xmitter output and the base of the antenna. The typical mobile FM transmitter of the day (1960's) cranked out between 15 and 150 watts. Most were around 75 watts. Run the calcs again for 75 watts and see if the gap is more reasonable (I'm lazy). The next question is how much heat is necessary from the arc to ignite the gasoline vapour. I'll leave that as an exercise for when I have more time to burn. Gotta get back to lying and cheating on my taxes. -- # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060 # 831.336.2558 voice http://www.LearnByDestroying.com # # 831.421.6491 digital_pager AE6KS |
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