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Cell Phone Radiation Chart
BjB writes "CNet has an interesting article on Cell phone radiation. More interesting is that they've included a chart of the radiation levels that various models of cell phones produce. They've even gone through the trouble of showing the highest and lowest on separate pages. It's lovely to see that your cell phone is #2..." Mine is in the middle of the pack... course, I'm not exactly reassured by that fact.
OK, here's one to ponder - _IF_ there are health effects from cellular phones, is there any difference between the "GSM" ones and the "CDMA" ones? Here's why I ask:
1. Cel phones do not emit what is traditionally called "ionizing radiation" (UV, X-ray, gamma ray) - photons with enough energy to knock electrons out of atoms and break chemical bonds. Yes, this type of radiation causes cancer. No, cel phones do not emit it. Period.
2. My cel phone does, however, emit some radiation at a frequency that is capable of effecting electrochemical changes in biological molecules. Specifically, the power LED and LCD backlight emit photons of visible light that interact with my retina. The energy per photon of this radiation is roughly 1/2 of that of the UV at the low end of the "ionizing radiation" spectrum. Let's say a wavelength of 500 nm for "visible", 250 nm for "ionizing". (energy per photon is proportional to 1/wavelength)
3. The "interesting" radiation from the phone is at a frequency of approx. 3 GHz. This gives a wavelength of 10 cm, or 100,000,000 nm. In other words, the energy per photon is 200,000 times less than that of visible light and 400,000 times less than that of "ionizing" radiation.
4. I know that microwave ovens cook food. A cel phone uses a lot less power than a microwave oven. Consider this - it would hurt to stick your hand in a toaster for 5 minutes. That's infrared / visible radiation, with a higher energy per photon than your microwave. Does that mean that all infrared and visible radiation is harmful? Does it mean you will burn your brain if you sit next to a candle? Our bodies contain a lot of water, which has a high heat capacity. We also have circulating blood and an evaporative cooling system which allows us to regulate our temperature. Thermal radiation is only a problem at intensity levels which overload our body's regulating systems.
5. So the question now is, what's left in cel-phone radiation that could cause cancer or other biological effects? This is where I would be interested to hear the opinions of people who know more about these areas:
- Biological systems are quite sensitive to the shape of molecules. Microwave ovens heat food by exciting certain rotational/vibrational modes of water molecules. Is it possible that some interesting biological molecules are tuned so that microwave photons can distort their shape or alter the rate of some chemical reaction?
- Electric or magnetic fields. Instead of the quantum picture of individual photons, consider the classical picture of an electromagnetic wave. A time-varying magnetic field will induce electric currents in a conductive medium. The magnetic field itself will exert a force on moving electrons (Hall effect). Cel phones are easily capable of interfering with nearby electronic devices - some phones make the picture on computer monitors jump around, or produce audible pops and buzzing from cheap radios. The human brain is a rather delicate electrical system. Is it totally unaffected by the same levels of EM fields which interfere with electronic appliances? [I don't know the answer here]
6. If there are any actual interactions according to this last point (which to me seems to be the most likely, _IF_ there's anything there at all), shouldn't the effects be more pronounced with GSM phones than with CDMA ones? As you can see from technical references such as this one, GSM phones use "Time Division Multiple Access" where each one transmits pulses of radiation in a narrow frequency band. Conversely, CDMA phones transmit over a wide frequency range. Given the same total amount of energy being transmitted, a narrower bandwidth means a higher peak intensity of electric and magnetic fields. Therefore, wouldn't the GSM ones be more likely to cause adverse non-thermal effects in surrounding devices?
I'd agree that the ratings as written are silly, but the report missed some key facts that affect the biological impacts that each phone can have.
In particular, they ignored the extremely important factor of modulation method. Comparing raw "power output" figures for CDMA and TDMA is more like comparing apples and rocks than even apples and oranges. TDMA (and TDMA-based systems like GSM and its ilk) use a wideband, high-power transmission rigidly slotted in time. This by necessity produces a train of extremely sharp rise-time/fall-time RF power spikes that appear, at least in some studies, to have potential harmful effects on nearby biological systems. Every study that has shown a correlation between RF and potential health problems has been with either analog (which has higher radiated power in general) or TDMA/GSM digital systems. Even analog systems seem to be safer than TDMA because thier continuous modulation lacks the sharp spikiness that seems to be part of the health problem.
CDMA is fundamentally different in its physics because the RF signal is both much lower power and *continuously* spread across the entire frequency band, thus, no spikes. (CDMA is a direct sequence, not frequency-hopping, spread spectrum system.) This is just what Claude Shannon said would happen: if you spread the information out over the frequency domain, the power required to propagate the signal falls dramatically. In fact, CDMA signals are very much like background noise, which is why they were first used for secure and stealthy military communcations syustems. (The direct sequence "spreading sequence" in CDMA is evan called a PN, for "pseudo noise" code. There are a set of these codes called "gold codes" that are all orthogonal to one another, and obviously, the ones you want to use to maximize cell capacity.)
Finally, not all systems are power agile, as Bruce suggests - CDMA is, and developing the ability for the handset to be able to adjust and coordinate its power output in real time with the base station was probably the most difficult part of the engineering that went into making CDMA a commercial reality. (It was certainly responsible for CDMA's rocky and slower start in the market than the brute-force TDMA approach. Power agility is a nice-to-have for battery life in a TDMA system, but it's a gotta-have in a CDMA system of any significant density.)
It's obvious there's quite a lot we don't know about the effects of RF exposure on living things, but there's more than a little evidence to suggest that high power analog and sharp, very fast high-power spikes *may* be hazardous, so why not opt for an alternative that is likely much safer?
This is my frustration with Handspring over their (finally) perfect implementation of a phone for integration with a PDA - it's only available in GSM CancerPhone form. I'd buy one in heartbeat if I could get it with a CDMA radio.
And no, for the record, I do not work for Qualcomm or any other CDMA company - it's just better technology, and a couple of years ago, I bothered to do the research to find out the facts, as best we know them today. I also have decided, unlike some notables like Richard Branson, that carrying and using a wireless phone is worth the risks - but I made sure I understood the nature of the risk I was taking on before I accepted it.
(As an aside, I personally think all the people, even here on slashdot, decrying the "danger" of phone use while driving are luddites - there was a similar argument about the "obvious" dangers of car radios back inthe 1920's. Fortunately cooler heads prevailed...)
"The future's good and the present is nothing to sneeze at." - Roblimo's last
BZZT. Go back to Philosophy of Science 101.
In science, the burden of proof is upon the one making the claim.
You claim that there exists a radiation hazard from cell phones. This is a falsifiable, testable claim, and is properly within the domain of science.
Yet the studies do not support your claim.
A scientist would reject the claim as being unsupported by the evidence. Until your side of the debate can come up with the evidence, your claim is invalid.
You further fail to understand the point by going on to say:
> the claim that microwaves can't do anything because they are not ionizing radiation is at best doubtful.
> How do we know that there isn't a chemical substance in the brain which resonates at the frequencies of these transmitters and which will selectively absorb energy
>from them causing a breakdown of the chemical from selective heating?
Because:
(i) The burden of proof is on you. If you believe such a substance exists, please derive its chemical properties (easy enough to do given the requirements of a resonance frequency matching the cellular band), and dissect a few rat brains and show it to us.
(ii)Please explain how such a substance could exist in such concentrations in the brain as to be heated several degrees above (due to the miniscule wattage of cell phones) ambient body temperature, and explain how this heating would be "bad" compared to the normal heating and cooling of the body by 1-2 degrees throughout the course of the day.
(iii) Occam's Razor. Our theories of how brains work are supported by our notions on nonionizing radiation and do not require the invocation of Substance X. Your theory requires the invention of Substance X to explain something that doesn't show up in the data. Why should we choose your theory, which invokes a substance (existence of which is unverified even by you!) expressly for the purpose of saving your theory?
> To say "Its safe because I don't see any way it could be dangerous" is pretty arrogant.
(iv) Argumentum ad hominem and back to burden of proof again. Your argument smacks of "How do we know the moon isn't made of green cheese? I mean, apart from the small areas of moon we explored in the 60s. We haven't been to all the square footage of the moon, to say that none of it is made of green cheese is arrogant!
For starters, I spent the last two years working in Motorola's Cell Phone division, working with Cell Phones and Base Stations. Cell phones really do work like that. There is a base station determined time window at which base stations are required to check registration for new phones in the coverage area. If this window is small, the base stations have to check up the mobile phones more often which involves far more frequent Base Station and Mobile communication, even for phones that are powered on but not in use! The plus side to a smaller window is that the mobiles power up (and down) much faster.
:)
As for the body's electrical field and the impact of other electrical fields on it... The theoretical answer is that equipment exists that measures the strength and homogeneousness of a person's electrical field. Cancer patients and other people in poor physical health have much weaker fields, and the fields tend to be distorted and patchy. In contrast, pregnant women have much larger, "fuller" fields. There was an art exhibit done on this, actually, contrasting the outputted electrical field pictures of people based on their health in life. You could probably find information on this online with a google search.
Anyway, the point is that putting any strong electrical field inside of the body's electrical field causes distortions, and this is a "bad" thing. I don't know if it's bad enough to cause cancer, but it's bad enough to cause a headache.
If you want an empyrical test, try this. Plug in a laptop computer, turn it on, and make sure the power saving mode is OFF, so it should stay on for a while. Start up some CPU intensive program like PoV. Find a quite place for it and take a nap with your head on the laptop. See how you feel in an hour or two. High power usage laptops should illustrate better, of course. Hopefully that will be scientific enough to satisfy your own curiosity. (You did want a real scientific experiment, right? You're not closed minded...
-Ted
Pass it on.
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
I would also like to see the following charts, which are just as valuable as this chart:
The relative levels of the magnetic fields from major credit cards.
The amount of electromagnetic radiation ("Oh no! Radiation!") given off from popular brands of flashlights.
The level of "cooties" my wife's purse gives off.
--
Sometimes it's best to just let stupid people be stupid.
Cells phones adjust their output power DYNAMICALLY.
The closer to cell tower, the LOWER the power.
A true model the actual output power, in the field, is well beyond
the scope of a simplistic measurement based on FCC filings.
What is listed is based on peak power and has little or NO correlation to
actual radiated power while the cell phone is in use.
The important part about this is not the radiation moniker, but the EMF label. There are many enzymes in your body (this includes, for most people, their brain) that contain transition metals in their active sites. Moreover, these transition metals have magnetic moments which can be affected by a magnetic field. Therefore, important catalytic activities can be hindered by magnetic activation (or deactivation) of this metal.
Also, most of the molecules in your body that are biochemically interesting are chiral. This means that they have a configuration that for all intents and purposes reacts anisotropically to EM things like polarized light and magnetic fields. A quick search through the ACS publications will show you results of chiral molecules reacting preferentially in magnetic fields.
Mind you, this post doesn't endorse the notion that EMF fields cause cancer, but merely suggests possible mechanisms to the condition. Because, on the other hand, we live in a huge magnetic field everyday...the one produced by the planet we live on. (of course the local strength is probably smaller than the one made by the phone next to your head-or nads if you use the ear/mic attachment and keep it in your pocket)
Also, your phone changes its power depending on how much is necessary to reach the cell base. If you are close to the cell and in line-of-sight, your phone will emit less RF.
And nobody's mentioning the most important factor, the inverse square law. Exposure decreases as the square of distance - which means don't hold it up to your head if you're worried, use a headset or a roof antenna on your car.
Bruce
Bruce Perens.
Oh wait... what exactly is the difference between a rat in a lab and working in a cubicle under flourescent lights surrounded by monitors, phones, power lines, and CPU's?
-m
As for the suggestion that the phone be housed in a Faraday cage, uh, wouldn't that kinda defeat the purpose of a cell phone?
Bottom line. Not everything with the word "radiation" is bad for you. Don't believe the hype, believe the physics.
(For that matter, not everything with the word "nuclear" is bad for you either. But that's another story.)
I've seen a study like that too. The rats were arrayed in tubes around a transmitter. Some more rats were arrayed without a transmitter, and still more rats were allowed to run free in their cages. The conclusion was that restraining rats in tubes causes all sorts of health problems.
Friends don't help friends install M$ junk.
Just a thought.
________