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Science Technology

Another Reason to be Annoyed by Cell Phones 427

lotussuper7 writes: "This story at newscientist (free, no registration, unlike the NY Times) has some insight into the amount of RF you may be getting from all those cell phones people around you are using. Might be time to buy a cell phone jammer."
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Another Reason to be Annoyed by Cell Phones

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  • ECM (Score:4, Insightful)

    by shaldannon ( 752 ) on Friday May 03, 2002 @04:49AM (#3456051) Homepage
    Would you really want someone jamming *your* important calls? I wouldn't, and turnabout is definitely fair play. Besides which, jamming someone's phone is a DoS. Most people get rather upset over that sort of thing...

    If you don't like cell phones, then go find somewhere that doesn't have them.
    • Re:ECM (Score:2, Interesting)

      by fallacy ( 302261 )
      If you don't like cell phones, then go find somewhere that doesn't have them.

      Given the current popularity of mobile phones, you'd be hard pushed to find a "phone free zone".

      Besides, the argument (and I suppose it's exactly that at the moment until we get solid uniform proof) is that it's damaging to one's health. Using that analogy, would you tell non-smokers to find a smoke-free zone or put up & shut up?

      Besides, mobile phones are not limited to RF poisoning: something which hasn't been mentioned is the damage to train users' ear drums when the entire carriage errupts in a shouting match of "ARE YOU STILL THERE? HELLO? HELLO?..." when the train goes through a tunnel...
      • that it's damaging to one's health

        I'm not an RF expert but I am a physicist. As far as I know radiation can damage your cells in two ways:

        a) Direct heating
        b) Ionization

        The latter one is easy to dismiss by elementary physics. Unlike in the gamma radiation, the photons of the cellphone microwave radiation simply don't carry enough energy to damage the DNA strands. Hell, microwaves pack less punch per photon than the infrared (heat) radiation!

        The heating argument is more difficult to deal with. In general, the power of the RF field is again far too weak to heat your brain significantly (=more than the temperature varies naturally). However, if several fields overlap in a certain way (a standing wave forms inside your skull), then I guess there might be a possibility for an interference "hotspot" to form. Again I think this is very unlikely. Even a small head movement or the movement of the radiation source will change the geometry and thus the interference inside your head.

        Quite frankly I am surprised by the anti-cellphone mentality in this thread. Most of it seems to come from experiences with annoying cellphone users. However, that's not a problem with the cellphones. That's a cultural problem. People simply have not learnt the proper etiquette yet.

        Where I live the cellphones have practically replaced the landline phones. If the adaptation of the cellphones continues at this rate, there will soon be a one cellphone per citizen -- and that includes the minors. When the use is this widespread, the people in general know how to switch their phones to silent mode for meetings, movies and concerts. Having your cellphone ring, for instance, in the middle of a movie is socially extremely bad behaviour. If you start talking on your phone in the theatre, you will get thrown out -- either by the theatre staff or by the rest of the audience.

    • Re:ECM (Score:5, Insightful)

      by rbeattie ( 43187 ) <> on Friday May 03, 2002 @07:27AM (#3456372) Homepage
      If you don't like cell phones, then go find somewhere that doesn't have them.

      You can't escape them, so stop trying...

      My great-grandfather was annoyed by cars. My grandfather was annoyed by the TV. He never like it except when he was watching it. My parents are annoyed by call waiting and so I still get busy signals. My wife is annoyed by cell phones. I'm sure my children's mega-PDA-communicator-multimedia-device will get on my nerves too.

      Buy you know what? That's technology. Get used to it.


  • Yeah, that'll help (Score:5, Insightful)

    by koreth ( 409849 ) on Friday May 03, 2002 @04:50AM (#3456055)
    Might be time to buy a cell phone jammer.

    Reduce your exposure to RF emissions by carrying around a powerful RF transmitter! Sure, that'll do the trick.

    • by ComaVN ( 325750 ) on Friday May 03, 2002 @05:11AM (#3456101)
      In addition to that, all cellphones will start transmitting at full power when they cannot reach the base station. Sounds like jamming is a really bad idea indeed.
      • Not to mention the fact they are illegal in a number of countries
        • Not to mention that it's also thoroughly antisocial, and potentially dangerous - what if someone genuinely needs to make an urgent call, maybe a medical emergency, and some moron has a jammer on?
      • So don't jam. Snatch the offending pieces of technology and beat the users about the head with them. Worked for Suge...

    • From the little I know about GSM jamming devices, jammers do not jam by simply blanketing the GSM band with a very powerful signal. Instead they use a low-powered signal to spoil the control link transmission from the base stations to the GSM handsets, so that the GSM will not be able to set up a call connection. The phone will continue to try and connect to a base station, using short bursts of emission at high power, but on average these bursts are of much less power than an ongoing call, especially in a train (shielding cage, and often far from base stations).

      Here [] are some specs and details of such a jamming device.
      • especially in a train (shielding cage, and often far from base stations).

        Trains are usually very close to base stations, I don't know where you live, but here in metro Melbourne GSM coverage is probably better than normal along train lines (except some underground railway lines). The reason - to provide coverage to the often very crowded trains.
    • by Unanimous Backward ( 569494 ) on Friday May 03, 2002 @07:51AM (#3456438)
      Another reason jamming is a bad idea, other than that it will increase your exposure to RF by a factor of several times, the FCC having you thrown in prison/fining you large sums of money, is: if people do start carying around portable jammers, "ECM", the phone makers will have to start making ECCM phones, such as Spread Spectrum, possibly with other antijam features. Then the amount of power your little annoyance device will have to put out will go up enormously.

      How much RF will you soak up when you have a device in your pocket that will have to put out a 50-100 watt RF spike into every 1 khz of a 50-100 MHz wide frequency BAND? Your ass will melt. Besides: you're not soaking up that much RF from other people's mobiles, not compared to what they do, and if I were you I wouldn't worry so much about a few watts from a tower: if you want something RF to cry about, how about that 50+ kHz wide 50 MEGAWATT radio station that you live only a few miles away from, that's blasting you much harder than a tiny little cell phone tower. Sheesh!

      I will agree with you, though, if you say a no-phone section ought to be created in resteraunts. You don't just drop your pants and crap on the floor at a restaurant, do you? No, you get up and excuse yourself and go to the bathroom. That's what people should do when the get or have to make a call in a busy social situ. Plus, all CP's should have a silent ringer.

      Indeed, if you're in a restaurant, and someone starts gabbing and laughing on a cellphone right at his table, just go over to his table, pull down your pants, and take a shit right on his table, (preferably in his food, or his lap). When he says "hey!" Tell him, that that is what he is doing to your meal by yacking on his phone while you're trying to eat.

      Just a suggestion anyway.

      • So, what's the difference between talking on a mobile at a restaurant and talking to your dinner companion ? I don't get this argument at all.

        Some say it's because they talk louder on a phone than they do in normal conversation, but I don't see that - if a person is loud on the phone, then usually they are loud in face to face conversation too.

        The annoyance of mobiles for me is the stupid ringtones. SET THEM TO VIBRATE people. I do use my phone quite a bit, but nobody ever hears it ring, nd I speak in a normal face to face conversation volume so it doesn't annoy people.

      • Bull. The frequency matters. Microwaves interact with water in a way that generates heat. That's why we shouldn't stick gerbils in the microwave. Cell phones use microwaves. FM radio does not. Having 50,000 Watts coming from a radio tower has not been shown as a danger.

  • I'd be more worried about the cumulative effect of loads of commuters repeating the mantra..
  • by ishark ( 245915 ) on Friday May 03, 2002 @04:55AM (#3456067)
    The article looks like it's just a simulation of what may happen (with some microwave propagation tool), it would be more interesting to perform a measurement (I'm sure that the railways can "lend" a wagon for one day to the experimentalists) and really see what's going on...
    It could be much less serious (or much more....).
    • The article looks like it's just a simulation of what may happen (with some microwave propagation tool), it would be more interesting to perform a measurement

      Yes, and this is so much like the anti-RF crowd: "Let's conduct a simulation because we wouldn't understand a hard measurement if it hit us over the head." This policy began with the flawed assumptions of Wertheimer and Leper, who made one of the first studies indicating that powerlines might cause Lukemia. The problem was that they didn't measure the actual radiation --they assumed it would be propotional to the class of powerlines near each house. Wrong.

      This policy of simulate instead of measure has continued to this day. And those who do measure often get it wrong. You see, none of them are RF engineers. One study using lab rats actually exposed the lab rats to 10 times the radiation level they thought they were using. Our esteemed researchers forgot to take the metal cage in to account...

      The anti-RF crowd are mostly a lot of believers who think they have indentified a statistically insignificant danger and now they're looking for a theory to back it up. Instead they find statistical artifacts and use these spurious correlations to get more funding. The only known hazard of RF radiation are heating effects. Those who discover anything else deserve a Nobel Prize, if for nothing else, PHYSICS!

  • over here in The Netherlands, mobile phone jammers are illegal. I think this is not too strange, considering the millions payed for GSM frequencies, and the billions payed for UMTS frequencies. No one except the license holder of these frequencies may broadcast on them.
  • "Might be time to buy a cell phone jammer."

    No thanks, my cell phone came with a free's called AT&T wireless service ;-)
  • by geoffsmith ( 161376 ) on Friday May 03, 2002 @04:59AM (#3456079) Homepage
    While everyone else is getting brain cancer, I've been wearing my Aluminum Foil Deflector Beanie [] for years.

    Just a myriad of uses for these things...

    Websurfing done right! StumbleUpon []
  • Get your multi frequency digital cell phone jammer here [], or just skip the sissy stuff and build a disruptor [].

  • "Tsuyoshi Hondou, a physicist from Tohoku University in Sendai, Japan, who is currently working at the Curie Institute in Paris, says Japanese commuter trains are often packed with people surfing the web on their mobile phones."

    Ok, I am gonna ask a naive question here. I live in Hotlanta (or Atlanta, but if you have been here you know what I mean) and I have taken good ole MARTA enough. However, I have not seen anyone using a cellphone to surf the web. (Or maybe there is some new method of websurfing by putting it to your ear that I don't know about) I think this is because of two reasons....

    1) have a fancy phone, you increase your chance of getting jacked, and MARTA ain't the safest rail system.

    2) just not big in the southern US.

    Anyone care to prove or disprove my thoughts? We all know cell phone advances occur at a much higher rate in EU, so is this a legitimate concern? Seems to me we got too many other things to worry about other than a stupid cell phone, but that's just my opinion.
    • "Tsuyoshi Hondou, a physicist from Tohoku University in Sendai, Japan, who is currently working at the Curie Institute in Paris, says Japanese commuter trains are often packed with people surfing the web on their mobile phones."

      Ok, I am gonna ask a naive question here. I live in Hotlanta (or Atlanta, but if you have been here you know what I mean) and I have taken good ole MARTA enough. However, I have not seen anyone using a cellphone to surf the web. (Or maybe there is some new method of websurfing by putting it to your ear that I don't know about)

      NTT Docomo (the Japanese PTT) offers a thing called "I-mode", basically stripped HTML 4 (cHTML) with GIF pictures only that can be viewed on phones with nifty color screens. I-mode has also been launched in The Netherlands, and I think in Germany as well (by KPN Mobile and E-Plus).

      I-mode, unlike WAP 1.x, uses GPRS (packet service) by default, and handsets are required to display 256 colors. The mobile versions of TCP/IP and HTTP used (yes, I know, mobile versions, why change a winning team?) in current I-mode are the same as in WAP 2.0 though. The main difference then is in the markup language (cHTML vs. WML) and the color thing, though the newer handsets do GPRS, color and WAP 2.0 (including WML).

      Since neither WAP nor I-Mode use real HTML, these Japanese people aren't surfing 'the' web, but rather a subset. Of course it helps that not many Japanese actually have a desktop computer that is hooked up to the net (what with being a pretty rocky country, running cables isn't cheap).

  • Meanwhile.. (Score:2, Interesting)

    by Lord Bitman ( 95493 )
    a slightly more intelligent person, having the same hypothesis, just went in and measured the fucking thing, rather than coming up with some bullshit math and explanations of how it /MIGHT/ happen. Where the hell is the proof? I don't buy it, that this guy came up with such great mathmatical proof and NEVER EVEN FUCKING TESTED IT.
    Some nerdy slashdotter want to head out and measure it themselves while this jackhole is sitting there with a pencil? Please post your results.
  • by Gordonjcp ( 186804 ) on Friday May 03, 2002 @05:14AM (#3456110) Homepage
    People are worried because of the word "microwave". A mobile phone cannot produce any great amount of RF heating, for a few simple reasons.

    A microwave cooker uses a very high power magnetron (usually >500W), directed in a narrow, focused beam, into a resonant cavity (the oven itself) from a distance of around 6". Furthermore, the oven uses a specific frequency, much below which RF heating is much weaker, and you need a lot more power (somewhere around 2.45GHz).

    Now, a mobile phone uses around 1 or 2 watts *peak*. In normal use, it won't go above 500mW rms, otherwise the batteries would last only a few minutes. Not only that, but the antenna is designed to spread the signal over a wide area.

    Mobile phone cell towers are also pretty much safe - although they use a much higher power than phones (15W or so, IIRC) they tend to be stuck up on high poles, well away from people. Inverse Square Law, anyone?

    Here in Scotland, we recently had a series of large protests about siting cell towers near schools. The protesters were mainly middle-class mothers, from supposedly posh parts of Glasgow. Damn near all of them had sunbed tans. I'd take my chances with a mobile phone cell tower before I'd risk skin cancer from a sunbed...
    • I just want to say, the power transmitted by the radio and television station net, is 100 times larger than the one for mobiles, Just to give you people a comperasion. Before you start worring about the mobile telephone network, demolish 99% radio transmitters first.
    • So what you're really saying is that you didn't read the article, what with the

      both reflection and the cumulative effect of the radio waves were taken into consideration, the resulting electromagnetic field in a train carriage could exceed the maximum exposure level recommended by the International Committee for Non-Ionising Radiation (ICNIRP).

      and the

      Hondou's calculations show that it is possible to exceed ICNIRP exposure limits if 30 people, each with a mobile phone that emits radio waves at a power of 0.4 watts, all use their phones at the same time. The peak power a mobile phone is allowed to produce is two watts.

    • by rneches ( 160120 ) on Friday May 03, 2002 @02:44PM (#3458752) Homepage
      I've heard this kind of stuff over and over again - and alarmingly often from people who ought to know better (physics teachers, engineers, et cetera). The next time someone starts to tell you about cell phones giving you cancer, here's what you should tell them.

      My cell phone (the ubiquitous Nokia 3360) is a TDMA phone that operates in the IS-54 (800 MHz) and IS-136 (1.9 GHz) bands. Now, 1.9 GHz sounds like a big, scary cancer-causing number. So let's see if it really is.

      First of all, we need to know how radiation causes cancer. We'll just assume it's electromagnetic radiation, since cell phones definitely do not emit anti-protons, neutrons, muons and other shit like that. There's no way in hell a battery the size of a Triscut can generate reaction energies high enough to produce hadrons or leptons, so we can forget about them. (Well, actually, with a big capacitor you might get a few, but you're already getting showered with cosmic rays, and the pathetic little fart of hadrons you'd get out of a cell phone battery wouldn't count for didly squat.) The cancer-causing mechanism for electromagnetic radiation is fairly simple. In order to be dangerous, a photon (the electromagnetic force carrier particle) needs to carry enough energy to ionize (chemistry parlance for "fuck up") something important. It doesn't really matter how many photons you're slinging around, since it's the frequency that determines the energy of a single quanta.

      So, what is our hypothetical candidate cancer-causing quanta going to have to inonize to do the deed? Well, DNA of course. It's going to have to cause a genetic mutation. Because of the way photons interact with matter, they are most likely to be absorbed by electromagnetically contiguous objects of sizes roughly equal to their wavelength. The reasons are deeper than this, but suffice it to say that a photon is "smeared" over an area about the size of its wavelength. Since you can't absorb part of a quanta (that's why they're called quanta, after all), you have to have a thing big enough to soak up a whole particle about the size of the wavelength. In this way, everything is, or is made of, antennae. To cause a mutation, you have to have a photon whose wavelength is about equal to diameter of a DNA molecule. Actually, the ideal length of an antenna is a quarter the wavelength of its intended optimal frequency, so we'll say the wavelength we're looking for is four times the diameter.

      So, as I said, my cell phone operates at 1.9 GHz, or 1.9 billion cycles per second. What's the wavelength? Well, wavelength is the period times the speed of light. The period is the the inverse of frequency, so :

      3*10^8 / 1.9*10^9 ~= 0.16 M

      That's about the length of your hand, give or take a thumb. One quarter of that is about 4 cm - about the length of your thumb, give or take a nail. Now ask yourself this question: How big is your DNA?

      If your DNA is built out of atoms the size of rasins, you might have something to worry about. The diameter of the DNA helix is 2 nm and the vertical rise per base pair is 0.34 nm. If you want a photon that will be able to reliably zap DNA, it needs to have a wavelength _smaller_ than 8 nm. The probability that a photon will be absorbed by a given object decreases with respect to the difference between the size of the object and the wavelength of the photon according to the standard deviation. So what's the probability that a given photon spewing out of my cell phone is going to fry some of my DNA? Well, we're a factor of five million away from the optimal wavelength. I'd say it's pretty fucking unlikely.

      But wait a second - what's kind of radiation has a wavelength of 8 namometers? Well, we do the opposite to find the frequency :

      3*10^8 / 8*10-9 = 3.7*10^16

      That's in the ultraviolet range. Surprise, surprise!

      So, what can we conclude from this? Well, since a cell phone has a transmission power of less than a watt and a wavelength the size of your thumb, it's not going to do jack shit to your DNA. Nada. Zilch. In other words, THERE IS NO WAY CELL PHONE RADIATION CAN GIVE YOU CANCER!!! I'd be more inclined to beleive that the plastic in the earpiece causes cancer.

      You're several orders of magnitude more likely to contract cancer as a result of proximity to a 100 watt incandecant light bulb. It's got a much, much higher output, and its frequency range is thousands of times higher.

      So relax, enjoy your wireless technology, and wear your SPF-30.

  • by MosesJones ( 55544 ) on Friday May 03, 2002 @05:24AM (#3456129) Homepage

    Radiation found to be harmful, largest Radiation source found to be the Sun, blow up the Sun advises Slashdot.

    Scientists claim radiation can be use to kill cancer, carry more mobile phones advises Slashdot.

    Living in City can lead to lung disease, move to the country advises Slashdot.

    Living in country results in lower salaries, move to City advises Slashdot.

    Car pollution causes Global warming, buy bigger cars advises Slashdot.

    Is there a risk from this RF, yup, is there more of a risk from people driving while using a mobile than from this... oh boy yes. Is there a risk from Coal fired powerstations from radiation... oh wow yes.

    Passive Mobile phone usage, Caligormia to legislate.

  • It seems to me (Score:2, Interesting)

    by zurmikopa ( 460568 )
    that instead of doing all these calculations to determine what the amount of RF radiation might be that one might instead actually go on to one of these trains and take measurements?
  • Idiotic (Score:5, Informative)

    by Gromer ( 9058 ) on Friday May 03, 2002 @05:31AM (#3456152)

    Why does everybody still take this stuff seriously? Read the article- all this study does is establish that you get exposed to more RF radiation in a crowded train car than you do in other places. The scary part only comes in when it brings up these "international guidelines" which such exposure may exceed. Who established these guidelines, and how? The article does not say anything beyond the name of the organization, but I note that its name makes it sound like an independent, non-governmental organization- so this could be effectively anybody smart enough to give themselves a clever-sounding name

    The idea that RF transmissions will kill you or cause cancer has a long and ugly history of bad science concealed by calculated emotional appeals. It was basically started by a guy whose wife (who used a cell phone a lot) died of brain cancer, from which he concluded that cell phones cause cancer. Most of the "science" that has been done on this issue is basically the same idiotic reasoning dressed up in white lab coats. It is highly likely that the organization setting this 'standard' is in fact one of the lobbying groups associated with the anti-cell-phone movement.

    Consider- radio waves are extremely low-energy- far below the threshold necessary to break molecular bonds, which is how genuine cancer-causing radiation works. Thus, if RF waves do cause cancer, the mechanism by which they do this is A. different than for other sorts of radiation, and B. totally unknown.

    Plus, as has been pointed out a million times, a 'jammer' is a device which drowns out a signal by emitting a much more powerful signal of its own, not by magically making the other signal go away. If RF waves give you cancer, the jammer will give you cancer faster.

    • Re:Idiotic (Score:2, Informative)

      by yo303 ( 558777 )
      Well, the jury is still out.

      We know that cell phones (and other radio broadcasting equipment) emit radiation that is harmful to living beings at high power. The current theory is that this radiation at lower powers are not harmful.

      But let's look at this. There are many dangers that radiation causes, but the one that concerns most people is cancer. What is the mechanism for radiation causing cancer? An ionizing radiation particle strikes the DNA inside the nucleus of a cell, causing a mutation that causes the cell to go into a state of uncontrolled cell reproduction. It just takes one initial cell to mutate to make a tumor.

      Of course for this to happen, the radiation has to strike the DNA in exactly the right place. Your cells contain a lot of error-checking, so it is extremely unlikely for a single photon to make this happen. That is why scientists say you need a high dose of cell phone radiation to get cancer. But cancer has always been a probability game. You can get cancer from swallowing a single molecule of benzene, if it finds its way into the nucleus of a cell and attaches itself to the right place in your DNA. In the same way, a single cell phone call can give you cancer -- it's just not that likely.

      Lower power radiation does not mean lower power photons coming from the antenna. It means less photons per second leaving the antenna. They are the same photons - the energy of a photon depends only on its frequency (E=hv, energy = Planck's constant times the frequency.) If a lot of photons of a certain frequency can give you cancer, so can just one.

      I am an electrical engineer, but sometimes I think that a hundred years from now, people will look back on what we're doing in these times the same way we look at the coal-burning pollution at the start of the industrial revolution. We're crazy!!

      We are bathing ourselves in RF! Not only do we wrap all of our houses in wiring that transmit 60Hz radiation, we broadcast in every known frequency that we can - AM, FM, television, cell phones. (AM is especially bad - so much of the power is wasted in the carrier.) Companies fight over unused parts of the spectrum - they can't wait to send cancer-causing photons into our bodies!!

      Using electrons and photons to transmit information (at relatively low levels) is one thing. A century from now they will look back and be surprised that we used electricity - in all its lossy, inefficient, cancer-causing glory - to transmit energy from one place to another. That's just a bad idea. (A lot of people are looking at hydrogen, extracted from water through electrolysis, as a clean way to transport energy)

      Of course, as has been mentioned, modern living exposes us to all kinds of health risks. Personally, I will keep driving my benzene-spewing car and using my radiation-emmitting cell phone until the next thing comes along.


      • Re:Idiotic (Score:3, Informative)

        There are many dangers that radiation causes, but the one that concerns most people is cancer. What is the mechanism for radiation causing cancer? An ionizing radiation particle strikes the DNA inside the nucleus of a cell, causing a mutation that causes the cell to go into a state of uncontrolled cell reproduction. It just takes one initial cell to mutate to make a tumor.

        It's not just the intensity of the electromagnetic radiation. Cell phones emit non-ionizing radiation. Each photon has much less energy than the UV, X-ray, and gamma ray photons that can cause cancer.
        • Re:Idiotic (Score:2, Insightful)

          by supertsaar ( 540181 )
          And also, I'd like to add that the idea that cancer can be caused by just a single mutation caused by a single hit (yes, that's called 'the single hit hypothesis') is not very popular anymore. Most people agree there has to be some acumulation of damage before things go bad enough to produce cancer. That would explain why your risk of getting cancer increases as you get older, for instance. Have look here [] for some concepts.
      • Your description of the mechanism by which radiation causes cancer, and of the quantum nature of radiation are both entirely correct. The only problem is that RF radiation is non-ionizing. In other words, an individual photon in the radio frequency band does not have enough energy to induce a chemical change in any molecule. Consequently, as you note, even enormously strong RF waves cannot cause chemical changes, because they just consist of more (low-energy) photons. Thus, the traditional cancer-causing mechanism for radiation does not apply to RF. The only known physiological effect of RF radiation is thermal- if you absorb an RF photon, your body heats up by that amount. However, you will notice that you don't need to take off a sweatshirt to use a cell phone- the thermal effects of that amount of RF radiation are miniscule to nonexistant, so that's no good as a mechanism either.

  • by Geek Boy ( 15178 ) on Friday May 03, 2002 @05:32AM (#3456157)
    Sounds like all the more reason to use a car instead! That way we can justify building more roads!
  • Last I heard, and this was for analog cellular, the max watts was 3 watts for car phones and those huge phone bags that no one uses anymore, and handhelds was 600mw. And that is PEAK power. The cell tower will most often instruct phone to drop its output power depending on signal strength.

    So where does the author get 2 watts from?

    And what about digital, which is what most phones use now. Don't they operate at even lower power?

  • OK - so let's get geeky about this. Why do we need to broadcast continuously to disrupt mobile phones. Why not listen for outgoing packets and emit a nice big rf chirp when the base station tries to handshake.

    Benefits -

    prevents users dialling out
    prevents users accepting calls
    low rf power requirements
    reasonable battery life
    difficult for law enforcement to track down

    Disadvantages -

    more difficult to design

    Any final year electronics students looking for an interesting project??

    • by artg ( 24127 )
      There was a thread on sci.electronics on this a while ago - one suggestion was that a jammer should imitate a base station. Operating at low power, it would fail to complete the call negotiation. The phone would then try again, but always at low power because the base was close at hand.
  • by Anonymous Coward
    It's amazing how everyone is suddenly an expert on microwave radiation isn't it ?, and how we all know the results of exposure to raditation because we've seen documentaries about nuclear reactor accidents, and because, we've seen cartoons that show that all you have to do to turn into a big eyed green monster is get exposed to a little radiation.

    The media would have us believe that radiation is an evil thing that destroys and mutates anything it touches.

    So let's just be a little more scientific here shall we, and find out a bit about what EM radiation really is.

    Electro-magnetic radiation is a term referring to the radiated field (ie, moving energy) of all types of electro-magnetic waves, from completely benign low-energy stuff like the radio waves your tv and radio receive, to quite nasty stuff such as gamma radiation. The difference is the amount of energy (and hence frequency) involved, and what happens to matter when exposed to those energies.

    A large portion of the EM spectrum contains radiation that is of such a low frequency that the most it could do is impart some heat (okay, maybe a lot of heat) into your body. Anyone who has ever stood outside in the sun (yeah I know, I'm talking to a bunch of IT geeks who have probably never gone outside), will have noticed that it feels quite warm. You may not realise you've just experienced what it's like to be exposed to infrared radiation.

    Look around, and bask in the knowledge that without the radiation we call visible light hitting the back of your eyes, you wouldn't be able to see a damn thing out there.

    Now go back inside, turn on your TV and enjoy the television signals that are propogating through your house and are being converted into a very weak electrical current by the aerial on your TV, which is then hugely amplified so that you can watch a cartoon about mutant ninja turtles who live in a sewer.

    When you fall and break your leg, you get carried off to the local hospital, where they radiate your leg with a high-energy radiation commonly called x-rays. When they do this, they cover the parts of your body they don't want to radiate with layers of lead, since lead is a cheap and dense atom and tends to absorb most things that hit it. This provides a shielding affect, which is good, because x-rays *are* dangerous if you are exposed to them for too long.

    The reason that x-rays and gamma rays are dangerous, and radio waves and visible light are not, is that high-energy radiation contains sufficient energy to break the bonds within an atom, and can knock off electrons - creating a charged atom (known as an ion).

    To say that another (simpler) way, ionising (ionizing for americans) radition is a dangerous thing to play with, since the cells in your body are not designed to operate well when charged. This is not to say that they will 'mutate' and your skin will turn green. More likely is that those cells will die and if you continue to be exposed to the radiation source, your body will be unable to produce new cells fast enough to replace the dead ones. Organs will shut down and stop functioning, and eventually your body will die from specific failures that I don't need to get into here.

    Non-ionising radiation does not contain sufficient energy to break nuclear bonds, and thus is pretty safe to be around (The world would be a boring place without visible light).

    Having said that, it's not entirely accurate to say that all non-ionising radition is safe - because it can destroy cells by heating them past the point that they can operate at. Anyone who has stayed out on the beach too long will be well aware of the danger of ultraviolet light, which is a non-ionising form of radiation, and thus does not destroy cells at an atomic level, but simply heats them up and burns them.

    Fortunately the human body is capable of dealing with this, and the deeper layers of your skin produce a dark compound that is quite good (but not perfect) at absorbing UV radiation. Most people have seen this happening, and call it a sun tan.

    This is not *quite* the same as the infra-red radiation that comes from say an oven or heater - that too can burn your skin, but since it has a different level of energy, and thus frequency, the exact manner that damage occurs.

    What may surprise many people is that MICROWAVE radiation (1ghz - 100ghz) is also non-ionising. The damage it can cause is thermal, just like UV, radio, tv, infra-red, and ultra-violet radiation.

    Microwave ovens work at 2.4ghz by *heating* whatever it is that you put in it. The reason they are shielded is that the makers don't want to cook the people standing outside the oven. If you were stupid enough to stick your hand in a microwave oven and turn it on, your hand would suffer a similar fate to as if you had put it in a fire or over a bunsen burner.

    Incidently, 802.11b wireless networking works at around 2.422ghz - the same freqency that your microwave oven works at, but at a much lower power level, which is why you won't even feel a warm spot on your hand if you stuck it in front of the aerial.

    GSM cellphones operate at 980Mhz, 1800Mhz, and 1900Mhz, depending on what type of network you are on. Those frequencies are at the end of the 'radio' part of the EM spectrum and the beginning of the 'microwave' part. Bear in mind that the term 'microwave' is simply referring to the size of the wavelength, and covers frequencies in the range 1Ghz to about 100Ghz.

    Don't just take my word for it - check for youself. Google knows all, but I'll give you a few starting points:

    There's a nice clear diagram showing where the different energies (types of radiation) fit in to the EM spectrum on nasa's site: 1/ emspectrum.html

    And there's a good explanation of ionising and non-ionising radiation here:,,sid9_ gc i775674,00.html

  • by forgoil ( 104808 ) on Friday May 03, 2002 @06:23AM (#3456246) Homepage
    Ever seen one of those wireless phones you have at home? So you can run around the house while speaking in it. Got any idea how strong that signal is? How often it transmits signals?

    Or what about wireless ethernet for that matter...

    We need science, and we need to know what is dangerous and what is not. But these reports, or the reports about the dangers of potato chips, is not especially valid yet. I belive that two independant studies has to be made before you can draw any conclusion, and both of them has to live up to certain scientific standards.
  • by cybergibbons ( 554352 ) on Friday May 03, 2002 @06:55AM (#3456302) Homepage
    As someone who has been in a few large substations, and near to high power transmitters, they do have effect on your body. You feel dizzy and ill after being near to these sites - there are no two ways about this. Many others claim this as well.

    Phones may not do this to such a great extent - but open up one of the many "monkey drum" microwave dishes found all over the place in the UK, and the USA as well I should imagine. What do you find? A conventional cooking microwave magnetron. Ok, slightly different, and usually of a lower power.

    Radar can produce huge bursts of power - and round radar sites, there are exclusion zones to stop you receiving a dose large enough to make you infertile or even kill you. Precision Approach Radar can be very dangerous in this respect due to the fact that the frequency and power used are dangerous, the dishes are located at ground level, and some of them can rotate 360 degress in seconds (the unit has to realign when different runways are used, and if you are in the way). Yes, this is an extreme case... but it still shows something.

    I think that dismissing RF as safe because it doesn't cause ionisation or heating is stupid. In the same way as smoking was once viewed as safe, and that skin cancer has only been noticed very recently. Often our bodies do not behave in the ways which we think they should. I just think we should wait to see all the evidence before we jump to conclusions.

    Surely electric currents in the brain are affected by RF? Do we know if this is bad or not? People also die when they are using their phone and can't pay full attention to the situation they are in.

    Other issues are that when many radio waves are in a small space, they do not always combine to produce the same frequencies. Harmonics and other frequencies are generated, so saying that the frequency that the phone transmits is not dangerous doesn't mean the area is. Powers can also mount up.....

    And jammers tend not to be high power - they disrupt the signal in a more clever manner. Although in the short term, the phones will transmit with more power, people will turn them off or the phones will stop trying so regularly.

    I don't have a mobile. I don't want one mainly for the reason I don't want to be conctacted when someone doesn't know where I am. Landlines tend to be cheaper as well.
    • Other issues are that when many radio waves are in a small space, they do not always combine to produce the same frequencies. Harmonics and other frequencies are generated, so saying that the frequency that the phone transmits is not dangerous doesn't mean the area is.

      Adding multiple frequencies together will NOT create any new frequencies.

      If that was the case - all the radio stations would result in so many extra frequencies that'd we'd barely have any usable radio spectrum for anything else.

      • Resonance in a physical cavity will result in high frequencies being produced.

        Reflections cause a change in wavelength, and hence also in frequency.

        Signals such as these in FM broadcast are not affected in such a way, as they are of low amplitude.

        The Raman effect causes energy to move to otherwise higher or lower frequencies (I cannot remember which).

        So it is perfectly possible for many thousands of components to be produced in the space close to the mobile that have significant power to affect other devinces.

        I also did not say "adding multiple frequencies". The interaction between signals is far more complex than addition in the real world.
  • Dont you just love the feeling that that little phone by your reproductive bits is blasting away as hard as it can because it got surrounded by metal, and now it's all reflecting around back at you?

    Mmmm, my lunch wasnt cooked when i brought it in with me this morning....

  • What about CB radio? (Score:2, Interesting)

    by boltar ( 263391 )
    Back in the days when CB was popular people frequently ran "burners" that upped the power to 10s if not 100s of whats. Now if someone had one of them in their car, truck or house next to you
    imagine the radiation you'd be absorbing then. Surely all truckers would have cancer by now?
    Sure its a much lower frequency but I can tell you
    from persojnal experience (I once held an aerial that was transmitting by mistake) that even SW
    radio can heat you up quite considerably!
    • by GigsVT ( 208848 )
      There's this thing called the inverse square law. I am a ham radio operator, and I can legally operate 1500 watts on most ham bands (including 2.4Ghz), right from my roof., and my neighbors can't say shit.

      1/d^2 where d is the distance. Say you measure power at one foot. The power at two feet will be 1/4 of the power at one foot. At 4 feet from the radiator, it will be 1/16th of the power. At 50 feet, it will be 1/2500th of the power at one foot, at 100 feet, 1/10,000th.
  • by Tim Colgate ( 519024 ) on Friday May 03, 2002 @07:12AM (#3456334) Homepage
    From the article, Tsuyoshi Hondou came to his conclusions by getting a plan of a train carriage, calculating ratio of window to metal area and using this to work out the proportion of microwave radiation reflected inside the carriage. He then calculated how radiation from several phones would add together. He concluded that the resulting EM field could exceed ICNIRP guidelines.

    The problem is, there is no mention of any real-world measurements being taken. Maybe the model is fundamentally flawed. Maybe having people in the carriage causes the signals to be attenuated more quickly than the model allows for. Maybe the metal of the carriage is not a perfect reflector. Maybe there is destructive interference between phones like the fading on AM radio stations in the evening etc. After all, if too much of the radiation were bouncing around internally, not enough would get out to allow the phones to work at all.

    • I was thinking the same thing. The article needs some sort of data (or even an illustration of the model he used) to give us some sort of idea what scenario he built. I'm imagining the model is just a bunch of free-floating cell phones in a geometrically perfect (i.e., no dents on the walls) carriage. If he created a model that placed a human head on one side of each cell phone, and accounted for other things (movement of the carriage would create a doppler effect for the phone signals, right?) his results might carry some weight. As it stands now, we have no idea how he arrived at this conclusion. Or what, in actual numbers, that conclusion is.

      I'd say it's worthy of doing a real study though with real people, multiple tests with certain percentages using cell phones and even an empty "control" carriage. But if there really was a huge amount of radiation in there, we would have noticed two effects: a.) It's too tough to get a signal with all that radiation, and b.) There would be a lot more birth defects in the past few years.

  • "Might be time to buy a cell phone jammer."

    This reminds me a scene from Spaceballs [], where Lone Star (Bill Pulman []) fires a pot of raspberry jam at Dark Helmet's (Rick Moranis []) radar.

    "Raspberry. There's only one man who would dare give me the raspberry: Lone Star!"

    If you covered someone's mobile in jam, that'd stop them using it. Only while they stopped to smash your face to a pulp, mind, but it'd stop them none the less.

  • by Mathness ( 145187 ) on Friday May 03, 2002 @07:26AM (#3456369) Homepage
    when one can use a cheap and long known device, a Faraday cage.

    As for the train, the only area not covered is the windows, adding a fine mesh of wire (inside the glass) and connect it to the body off the train, and you have an effective mean of shutting down most of the mobile phone emmision, they only remaining is the mobile phones trying to reach a base station.

    If people travel a certain amount of time, say 20 minutes or more, they are likely to turn off the mobile phone since there is no access until they get off the train. And they will save some power on the battery (not as big a problem as it used to be though).
  • no one else has mentioned this. in the article the guy says that in his calculations he factored in that 30 people were using the phone in the one train car. not that the phone is on, but that 30 people are USING thier phones. here in sweden anyway i notice 1 or 2 people actually using thier phones while in the train car. not 30 people simultaneously.
  • by Restil ( 31903 ) on Friday May 03, 2002 @08:25AM (#3456511) Homepage
    But if every extremely vocal teenybopper with a cellphone and unlimited minutes suddenly develops cancer and DIES.... I'm supposed to feel SAD about that... right?

    It was nicer back in the day when it cost 30 cents per minute to use your cell, and thats if you were only making a local call. A lot of people had them, but nobody used them unless they HAD to, and even then they kept the conversations short and to the point. There was no fear of idle chitchat while in a movie theatre.

    And no offense to women, but they're abusive phone users. This is nothing new. But before cheap cell phones, they were isolated to their own homes and didn't seem too compelled to share their hours long conversations with the rest of the world. But now, go into any large grocery store and I can almost certainly guarantee you that there will be at least ONE woman in there gossiping up a storm with someone over the cell, almost completely oblivious to the world around her. Its worse when they drive.

    So hey, I'm all in favor. LET the phones cause cancer. Hell, make them even MORE dangerous. And the louder the user speaks, make it emit more radiation. Its the perfect way to rid the world of the people that seem to dedicate their lives to annoying others.

  • by Mulletproof ( 513805 ) on Friday May 03, 2002 @08:51AM (#3456597) Homepage Journal
    First, I don't see all these supposive people dropping dead from RF over-exposure via cell phones. Maybe it's just me, or maybe it's one giant conspiracy. Right. Second, I think the person who has the most to worry about is the user. We're not talking second hand smoke here. The power at range just isn't significant to harm a 3rd party. Third, your worried about cellphones when you probably drive through a myriad of high intensity EM fields everyday!? Take a florecent light and walk under some high-tension power lines one of these days. Or put one in a mirowave. I'm sure you'll find the effect enlightening. Funny how a cellphone doesn't produce either of these effects, but it just happens to be everybodies whipping-boy of the day. I love it.

    And you actually want to jam cell phone calls? I hope those people get their asses sued off the day somebody tries to phone in a life threatening injury but can't. If you have the right to jam my phone, I must have the right to slash your tires to keep from annoying me. I can't wait until they make jamming triangulators so they can find you, beat your sorry butt down and break your little toy. heh.

    Ironically, I'm betting your little jammer will produce more EM radiation than a cellphone. I used to work on EA-6b Prowlers [] in the navy and you're going to have a tough time jamming without generating an equal or greater amount of power than the source. That, and the greater the range, the more power it'll require. Have fun irradiating yourself, chumps.
  • This story at newscientist (free, no registration, unlike the NY Times)

    Yes, but the entire edition of the New York times is available for free, whereas only contains teasers from the print edition ( []).
  • at rap (or hiphop these days) stars (and Mr. T) that wore 10-15mile worth of gold chains around their neck didn't you? they were smarter after all. you still don't get it? gaussian cage around their head. who's laughing now ;) run forest run ... to the nearest jewellry store. or just dig into wife's dresser.
  • Just go onto trains with the proper equipment (if he's so adept in this field, he'd have access to it, right?) and MEASURE the amounts? I'm suspicious of any research that's so purely existent on the back of an envelope, especially when the researcher has eschewed an easy opportunity to test the real world.

Any sufficiently advanced technology is indistinguishable from a rigged demo.