Another Reason to be Annoyed by Cell Phones

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."

Comments

This is really nonsense.

[Gordonjcp]

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...

Re:hmm

[pe1rxq]

Microwave is RF.....

Microwave is simply an indication for the wavelength of a certain type of RF.
Your normal microwave oven works by emitting an RF signal at 2.45GHz

Jeroen

Idiotic

[Gromer]

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.

cancer at 1.9 GHz, and other myths

[rneches]

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.