NEWS: WIFI - Children at risk from 'electronic smog'

NEWS: WIFI - Children at risk from 'electronic smog':

Sir William Stewart, head of the Health Protection Agency in the U.K., wants a probe on whether the use of Wi-Fi in schools poses any danger on students. Such action is also being sought by the Professional Association of Teachers - the group has called on Secretary of State for Education Alan Johnson to launch an official investigation into the issue. Current figures indicate that wireless networks are now deployed in over half of primary schools and four-fifths of secondary schools in the country.

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Reply to
aljuhani
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[sigh] Someone needs to recharge their Clue Card and go shopping again for more clues to reality.
Reply to
DTC

DTC

Can you please supply the full technical backup to your response. I for one would be very intrested in your point for point rebuttle.

Reply to
That Bloke

From the article referenced above:

Now *that* inspires confidence in their skills at analysis! Move over, Ted Stevens, you have competition!

Reply to
BakersT

I was deeply involved in the question of the bio hazard effects of RF/EMF from cell phones in the mid 90's. Given that the power levels from wifi are a fraction of that from cell phones and are at a frequency where the SPF (specific absorption factor) is very poor and that the typical distance from a wifi AP is a meter or more vis 1 or 2 cm from hand held cell phone the impact is neglable. (less than the EMF generated by a jogger running east/west in the earth magnetic field.)

BTW there were similar claims made with regard to honey bee deaths in the USA. Something I found very interesting in that bee stings were a major danger when I was climbing radio towers in the 70 and 80's as bees would build hives in the cable races right under the antennas for some high power transmitters..

Reply to
NotMe

Anyone who knows anything about RF Exposure knows that at the power levels an assess point operates at even at 2.4Ghz won't ever hurt you unless you happen to be sitting right on the antenna and even then.... Once you get a few inches away there really isn't that much to worry about.

Adair

Reply to
Adair Witner

"That Bloke" hath wroth:

Oh, that's easy enough. 2.4GHz Wi-Fi uses the same frequency as a microwave oven. The average Wi-Fi access point and client belches about 35 milliwatts. When you get about 10,000 of these dangerous Wi-Fi devices together in one place, you have the equivalent power of a microwave oven with the door open.

This can easily happen at conventions, rock concerts, hotels, and Burning Man, which goes far to explain the vacuous stares and burnt out look of the attendees. This can also happen at schools, where each student brings their Wi-Fi enabled PDA, laptop, game machine, or robot. Get enough of them together and the combined transmit power will cook what's left of their brains after the skool gets done with them.

There's also the danger of having students use their computers to contradict the teachers. Given Wi-Fi and internet access, any student can look up the topic on Wikipedia, and contradict the dogma spewn by the instructors. This tends to create a credibility challenge, which the instructors are not equipped to deal with. Little wonder the teachers are protesting Wi-Fi at skool. (Incidentally, I did this a few times in grade schools, except I used borrowed reference books.)

Another danger is Wi-Fi enabled cheating on exams. Ad-Hoc wireless networks are easily established and can greatly facilitate the exchange of test questions and answers. Again, the instructors are not equipped with sniffers and direction finders in order to deal with the thread. Little wonder they want to ban Wi-Fi. (Incidentally, I did this in grade school, except I used Morse Code and ham radio.)

Finally, there's a real danger that the administration might notice that students are learning more from the internet than from the instructors. Online instruction is nothing new, but constitutes a serious threat to the teaching establishment. It's conceivable that the subject might be taught online, with the instructor in absentia. (I did this in college by tape recording the boring lectures.)

Whether Wi-Fi will cook the brains of the students, or constitute a threat to public instruction as we know it, will remain to be seen. However, I can be certain that the teaching establishment will not go down without a fight, in a futile effort to retain the status quo in the presence of progress.

Reply to
Jeff Liebermann

"Adair Witner" hath wroth:

Perhaps some calculations would be more definitive. See:

First, a typical access point or client radio. 0.035 watts 2.2 dBi dipole 20 ft radius area of interest 2400 MHz Include ground reflections That yields a safe radius of 0.16 ft = 2 inches.

At the other extreme, is the high power base with a common patch or panel antenna. 0.400 watts 8.0 dBi patch 20 ft radius 2400 Mhz Include ground reflections That's safe to 0.79 ft = 10 inches.

Actually, that's rather conservative because the Wi-Fi xmitter is NOT generating full power at all times. The transmitter is pulsed on and off at a rate set by the traffic requirements. It never gets even close to 100% duty cycle. Therefore, the *AVERAGE* xmit power is considerably less than the 35mw or 400mw I'm using.

Yeah, unless you sit on the antenna, you're safe.

The effects of RF exposure appear to cumulative over long periods of time. For example, before I got involved in the RF business, I had a full head of hair, a full bank account, and a generally positive attitude. After many years of exposure to RF, the hair is falling out, the bank account depleted, and the attitude is decidedly pessimistic. Obviously, this was all caused by RF exposure.

Reply to
Jeff Liebermann

The other interesting thing is that up until this came out, all the research, etc. , was on how to stem the tide of bees getting killled off by a virus that was spreading. Now this comes along and all of a sudden the virus isn't talked about any more. Interesting.

Reply to
Kurt Ullman

Kurt Ullman hath wroth:

Pesticides, a fungus perhaps, possibly a virus, or all of these:

As always, the deep pockets get the blame for literally everything.

Searching Google using "cell phones cause" yielded 10 million hits. Cell phones can asllegedly cause auto accidents, headaches, cancer, dead bees, world wide hunger, airliner crashes, gasoline explosions, computer illiteracy in Japan, cell mutations, stunted cell growth, etc. Never mind that the incidence of brain cancer has been essentially constant for many years, while cell phone usage has increased astronomically. If they were related, the curves would track each other.

Incidence of brain cancer:

My comments on RF safety and such:

The radio towers I used to climb in the 60's had a mild bee problem. Bees just love the inside of fiberglass radomes, outdoor racks, cable trays, and poletop boxes, for hives. I've only been stung a few times. One nice thing about the bees is that we didn't have to do much about site security. No sane person would break into a building or cabinet full of bees.

Reply to
Jeff Liebermann

The auto accidents is well established and they can cause headaches (largely when the spouse goes up side of your head with one-g).

While I don't have any reason to think otherwise, cancers of the induced type are cumulative and the advent of cell phones that you put next to your head are (in these terms) relatively new. I think you can shoot the link down from a technical point of view quite effectively, you probably have to wait another 10+ years before you can put a stake in it epidemiologically.

Reply to
Kurt Ullman

Uh, microwave ovens have door interlocks, so opening one turns off the transmitter.

Reply to
Bob Willard

Further this is about Mobile Phones and RF from Saudi Medical Journal2004 ; Vol. 25 (6): 732-736:

"The extensive use of mobile phones has been accompanied by public debate on the possible adverse effects on human health. The concerns relate to the emissions of radio frequency (RF) radiation from the mobile phones and the base stations that receive and transmit the signals. There are 2 direct ways by which health could be affected as a result of exposure to RF radiation. These are thermal (heating) effects caused mainly by holding mobile phones close to the body and also as a result of possible non-thermal effects. Mobile phones may cause adverse health problems such as headache, sleep disturbance, impairment of short term memory and more seriously significant increases in the frequency of seizures in epileptic children, brain tumors and high blood pressure amongst users of mobile phones. In addition, mobile phones can cause discomfort, lack of concentration, dizziness, worm on ear and burning skin"

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-aljuhani

Reply to
aljuhani

Kurt Ullman hath wroth:

Baloney. Cumulative effects might be possible if there were a static group of potential victims that was being studied. However, the class of potential victims (i.e. all the increasing number of cell phone users) has increased dramatically in the same time span. It has increased sufficiently for used cell phones and dead batteries to be classified as an environmental waste hazard. Unless you expect RF radiation exposure to be contagious, require a carrier, or is self-limiting, where the mechanisms are quite different, cell phone use and brain cancer should track.

However, I will grant that the decrease in SAR (specific absorption rate) may balance the increase in cell phone usage. There may also be non-linear threshold effects. However, if these were the case, one would expect to see some variations in the brain cancer rate. There have been none. The curve is flat.

What you're suggesting is very common in research, where the mantra "more research is necessary" is traditionally added to any research report. 10+ more years of throwing money at a problem that doesn't exist isn't very useful. However, paranoia and statistical ineptitude are powerful political motivators. Maybe add a cancer research tax fund to our cell phone bills and be done with it?

Reply to
Jeff Liebermann

I don't believe cell phones - or any other very low-level RF - causes cancer, but your premise is wrong.

If low-RF causes cancer, then like any other low-level environmental carcinogen, it won't start showing its effects for two or three decades. The effect lags the cause considerably.

We won't know for probably at least ten more years if there's a connection. (Well... I know.... I have Cingular, and there's almost NEVER a good connection! Oh... wait! That's not what we're discussing.....)

LLoyd

Reply to
Lloyd E. Sponenburgh

Bob Willard hath wroth:

Sorry. I wasn't specific enough:

When you get about 10,000 of these dangerous Wi-Fi devices together in one place, you have the equivalent power of a microwave oven, with the door open, case partially disassembled, the door interlock bypassed with creative wiring, an external antenna attached to the magnetron probe, and pointed at the intended victims.

If you need instructions or a recipe for microwaved students, I think it can be found under cannibal resources.

Reply to
Jeff Liebermann

But most cancers that are related to such thing (not "naturally occurring" for lack of a better term") have dose-response relationships. The longer you smoke the more lung cancers you see. Asbestos and radon are both more likely with longer exposures than with shorter ones. Most chemical cancers same way. *IF* (real big if) cell phones are going to cause cancers by the ways suggested, then you have to wait out lag times, because they will be there.

It has

Right, they should track, but not right away because the damage with cancers are related to long-term exposures. Their relative waste hazard has little to do with their health hazard within the context of their use. .

May (or may not be) just that the cases haven't started showing up yet. Look at the timeline with women and lung cancer, for example, where they started smoking in increasing numbers, but the spike in lung cancer in women did not begin until 20 years later. Cancers work that way.

What you are suggesting is very common when discussing epidemiology, not understanding that cancers and other diseases don't just pop up.

Reply to
Kurt Ullman

Well said!

Also well said!

Reply to
RWEmerson

Kurt Ullman hath wroth:

So, how long do you want to wait? In 1985, there were about 600,000 cell phone users in the world. Today, there are about 2.5 billion cell phones in the world in use:

That's about 15 years (my guess) since cell phones became sufficient numerous to be statistically significant for cancer research. The original 600,000 users should have developed brain cancer by now, especially after perhaps 22 years of exposure. Look again at the brain cancer incidence graph. Flat, no increase, since 1984.

Asbestos and radon are both cumulative, which explains why they're exposure related. So are all ingested carcinogens. However, the last time I checked, the human body cannot store RF. It might store some temporary heating, but that's very short term.

It should have shown up by now, since widespread cell phone use started in approximately 1985. There is the possibility that vehicle accident fatalities induced by cell phone use exactly balances the increase in cancer rate. However, autopsy results on accident fatalities does not show a high incidence of brain cancer.

Is 10 years enough for tracking? If so, we should have seen an increase in brain cancer from the 1985-1995 users of cell phones. We haven't.

I meant that to demonstrate the large number of cell phones currently in use (and discarded).

Wrong. The tiny spike in about 1990 was caused by improvements in cancer screening methods that improved early detection. As I recall, it showed up for both men and women. As a result, more lung cancers were identified on introduction. The curve dropped immediately afterwards:

Incidentally, lung cancer testing statistics are somewhat of a crap shoot because the tradition chest x-ray generates large numbers of false positives. The false positives tend to appear in the statistics reported by doctors, while little effort is made in removing these false positives from the statistics when more invasive tests show that it's not a cancer. The few that I've seen tracked end up getting classified as "spontaneous remission" which is a nice term of a bad cancer diagnosis.

Incidentally, if you need some entertainment value, and have a 24dBi barbeque dish antenna, you might try pointing it at the sun. The dish diameter is roughly 1 square meter. The total power delivered by the sun is about 1000 watts per square meter.

Very little of this is at 2.4Ghz, but your wireless client or access point should show a measureable increase in noise level when pointed at the sun. I'm late for lunch or I would calculate the noise power. Anyway, there's probably more radiation at 2.4GHz coming from the sun, than from a nearby wireless client. (I'll grind the number later).

Reply to
Jeff Liebermann

On Sun, 29 Apr 2007 17:13:52 -0700, Jeff Liebermann wrote in :

Entertainment value of your comments aside, computer-based and on-line education have thus far been found to be pretty much a flop in serious studies. The latest is a new report from the Department of Education which concludes that most education software does not boost test scores. Teachers are far, far more effective.

Reply to
John Navas

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