New Report

13 posts by 5 authors in: Forums > CWTS - Enterprise Wi-Fi Fundamentals
Last Post: June 6, 2011:

    This study is important, as it comes from the WHO, who usually are not known for "over-dramatising" things.

    It will be many years before some of the effects of prolonged useage of cell phones "shoved up against the side of the head" become properly known. Same thing as with tanning beds. It took years for proper data to show up illustrating that prolonged useage can be dangerous. When tanning beds first came out ( still electromagnetic radiation, just a different part of the spectrum ), the consensus was "oh, they're fine, just the same as sunshine". Wrong.

    Cell phones are a "necessary evil". Nearly all of us have to use them during our daily lives.

    Common sense should guide us though. Remember that you have an active radio transmitter shoved against your head. Anyone who gives a cell phone to children needs to re-think that. When children are developing, their skull density is quite low.

    Do you really need to use that phone to make that "urgent call" to tape Dancing With The Stars ? Will the earth collapse if you don't call Bob to tell him how great the Braves were last night ?

    In other words, try to minimize the number of calls per day to only those that are "essential". Texting is a much better option, as the device is held away from the head, usually, and transmission time is short.

    Cell phones are an integral part of the day to day work of anyone involved with Wi-Fi. Catchy ads and sleek marketing make them out to be "just the same as any electronic device". They are not. They are RF transmitters. Once again, I have seen no evidence that Wi-Fi poses any threat to users who do not have the AP beside their heads ( have seen that a few times in office cubicles ).

    Laptops. Sat hunched over a laptop all day ? Your body WILL change shape over time to accommodate that, including your spine. Ever wonder what is causing that pain in your wrists/shoulders/neck ? If you can, try to have a docking station, where you can sit up properly and have the monitor at eye level. Yes, it's not always easy. Carpal tunnel surgery ? Load of nonsense. Doctors do not properly understand how muscles and tendons work. When a muscle is overused ( through weightlifting or working with a mouse/keyboard ) in the case of wrist/forearm muscles, two things happen: it becomes shorter in length through contraction, and it becomes fatter in diameter ( due to extra muscle mass ). That is what happens to the tendons as well ( though to a lesser degree than the muscles ). So, when you have been keyboarding for years, the tendons that go into the wrist become slighter thicker than before. They pass through a hole called the carpal tunnel. It has a ligament across it called the transverse carpal ligament. Underneath that is a nerve called the median nerve. Tendons get thicker and press against the nerve...carpal tunnel syndrome. Doctors don't even look at the cause, but rather the symptom ( as a bad engineer would do ). They then cut the ligament to make more room. WRONG !! ( They wanted to do that to me before I started studying the actual cause ). Increase the length of the tendons/muscles back to their original length, and that will help/cure it. Also, the median nerve starts at the brain and works it's way down the arms to the wrist. If you have a piece of cable on a radio link, you know that if someone presses against that cable ANYWHERE from the source ( transmitter ) to the destination ( input to antenna ), attenuation/VSWR can occur. This means that although the most likely cause of Carpal Tunnel is due to increased size of the tendons/muscles, if there is an impingement due to tight muscles in the upper arm, say, then that could cause it as well. At the clinics I used to go to when I was ill, I never once saw a case of Carpal Tunnel that could not be fixed without surgery.

    For those of us keyboarding and texting all day, try some wrist and finger stretches. You would be amazed at the number of Wi-Fi folks who are living off pain killers and muscle relaxants, because they don't want their co-workers/bosses knowing they are in pain.

    Have a look at your co-workers hunched over laptops around you. Do you think that the human body was designed to sit like that ? There are consequences.....


  • Dave,

    One of my best friends died from brain cancer. He was one of the first persons in L.A. to be seen with a phone permanently attached to his head (or so it seemed).

    When people tell me there is no danger in holding Bluetooth or Wi-Fi radios to their heads. I ask them a question:

    "If I modify a microwave oven to work with the door open, and set the power extra low, would you stick your head in there for a short time while I turn it on? "

    There answer is NO of course.

    Their mood changes quickly when I tell them it's the same frequency as their newest appendage.

    Of course it's not the same thing exactly - but I still don't carry a cell phone or anything like it. I get enough microwaves in my job.

  • Wirelesslanman

    Sorry to hear about that.

    Your analogy is right on the mark. I too rarely use a cell phone for voice calls, except when I absolutely have to....on the road etc ( otherwise landline phone ....still a few around.....on speaker/on the desk , Skype, text, e-mail etc )

    A few months ago, I asked two friends of mine, one an engineer, the other a salesman to try and make a note of how many voice calls they made in a typical day, then to check and see which calls "absolutely had to be made". In others words, business/efficiency would be affected by not making them.

    They both got a big surprise. Once I explained what is literally going right through their brains and eyes, they have cut down drastically on "phone glued to the head".

    Unfortunately, most folks are not aware of any of this. Just got back from our local supermarket. Dozens of people pushing trollies with phone to head ( or worse, trapped in between the head and shoulder with head tilted.....nerve compression...not good ) going on about what's for dinner, how little Bobbie's baseball game is going etc.

    "If there were dangers, we'd know about it !!" "Millions of people are using them, TVs don't kill us do they ?"

    "No dear, they don't. But they're on an entirely different frequency band, and the physiological effects are totally different....."

    Alas, with all the shiny bright colors and buttons and gadgets and sleek ads and "celebrities using them", even if absolute proof came out about the long term effects, I don't think it would matter one little bit, as people would say "I just can't live without mine !!....Do you hear me !!.....I just couldn't live without it"

    "Yes, I'm sure that if your useage was cut down, your whole life would collapse around you....."

    We were once told that cigarettes were actually good for us......

    Unfortunately, the common sense method of using cell phones only when necessary has died and is six foot under, never to be seen again.


  • Don't you folks understand dB math at all?

    A microwave oven is at 1,000 Watts and a WiFi device is at 30mw that's 3/100's of a Watt.

    So the WiFi device is 1/30,000 as much as the Microwave oven.

    Now ask the same silly question again - "would you put your head next to a Microwave oven that is set to 1/30,000 of it's power" - most people can't even fathom or understand such a small number.

    Now I agree that sitting, hunching over, and not being ergonomic is dumb, but there is more power coming off of many other things around you than the minuscule amount from WiFi.

    Talking about this is akin to people who waste their money on the lottery - ie. a tax on the stupid.

    Harsh enough for you?

    I personally don't feel comfortable (physically) with holding a phone in my hand by my head and use a noise-canceling headset any time I'll be on a long call, and I also despise when folks can't seem to put down their phone when doing normal things like shopping, driving, at the movies, etc.


  • Keith,

    It may be a silly question, but people still hesitate on the question when they're asked it a second time.

    Long after we're gone, it will be shown how much microwaves do or do not affect our bodies.

    Granted, low-level Black Body (microwave) radiation has been around forever, but not at millwatt+ levels.

    Look at all the things people and governments have said were safe - asbestos, agent orange, etc.

    Time will tell.

    In the meantime, just don't try to call me on my cellphone.

  • From one half of ?You Folks?:

    Firstly, yes I do understand dB math, having used it every day for the last thirty years in the design of countless successful satellite and radio links worldwide. I also use advanced mathematics in the calculation of antenna design variables using integral calculus, as well as probability theory in rainfall and realiability calculations. I have also used triple integrals in some antenna design cases.

    Wirelesslanman and I are not some spotty kids working at Circuit City.

    ?Harsh enough for us ??.

    No, just unpleasant and uncalled for.

    Wirelesslanman was merely using an analogy. He made no mention of power levels whatsoever.

    As regards your comments on power levels, take the following as an example.

    Intelsat Standard A earth station, 32m in diameter, G/T of say 40.7 dB per degree kelvin in Bahrain, say . Distant station, say, Intelsat revised A, at, Goonhilly England. 36 MHz transponder, IS 7 spacecraft. 20, 2.048 Mbps IDR carriers operating at a BER of say 10 ( minus 6 ). All the remaining data can be found on the Internet. You can use your dB calculations to work out the PFD over the physical surface of the parabolic reflector.

    Between the panels that make up the reflector, there are tiny gaps. Some of the Tx energy ?leaks?from those gaps. The calculated amounts referred to by some of the telecomms carriers were so small as to be considered ?barely measureable? and ?well within safety limits?.

    I spent years working with such antennas. We had a team of riggers whose job it was to work on the back on the antennas performing maintenance such as panel adjustments and de-rusting etc. Those guys were told that the ?tiny, tiny amounts of leakage? posed no threat to their well being. The problem is that damage to human tissue from radiation ( electromagnetic or otherwise ) is cumulative. They were hanging off the back of a 105 foot antenna, with their eyes close to the gaps. Of the small group that I knew ( half a dozen ), one died from brain cancer, one died from various tumours in his neck and face, one had an eye removed from a very nasty type of cancer, and another was seriously ill with cancer when I last spoke to him ( years ago). There were other rigging groups whom I have been told have had similar problems, but I have no first hand experience of them.
    Human physiology and ?resistance?to radiation of various types varies dramatically in human beings. We have seen this in cases such as Chernobyl where workers of approximately the same size had dramatically different results from exposure to approximately the same levels of radiation. Yes, I do understand the difference between ioninizing and non-ionizing.

    I have worked with the US Navy at many locations, and many of the old radiomen will tell similar stories about radar techs etc.

    You mentioned about power from other things being at higher levels. That is often the case, but the key here is frequency. There is a world of difference between someone sitting near a TV set ( yes, TV sets do radiate ) and having a Bluetooth headset at 2.4 GHz right by your ear.

    Could it be that say ten years of continuous use of a Bluetooth headset pumping a signal through your brain and eyes has no effect ? Of course. Could it be that there is some risk ? I would say possibly, under certain circumstances. We simply do not know enough about the effects.

    Again, I cannot see any evidence that the power levels from wireless routers, APs etc are anything to worry about.

    Having any GHz or UHF device operating for long periods right beside my ear/eyes ?.that?s a different story.

    Dave Hutchieson BSc ( Hons ) MIET

  • Dave,

    I've got the utmost respect for your experience and skills - you've done some great podcasts with me in the past and I can easily tell your intelligence and abilities.

    I'm just a bit tired of weak science and sensationalist journalism trying to scare the public. Like parents worried about having WiFi in schools, while at the same time talking on a cell phone. Or RCA announcing a Wireless Cell Phone Recharging system at last year's CES charging off of WiFi Access Points...

    I'm sure there are lots of folks who've been harmed by being too close to radar, large antennas, etc. But haven't heard of anyone, anywhere, anytime being harmed by WiFi... Yet it makes for shocking journalism.

    Of course, I could be totally wrong - I've been there many times in my life - But I just haven't seen any real science supporting these fears of WiFi.

  • Keith

    The only thing I was trying to raise was the report about mobile phones, as opposed to Wi-Fi. I too believe that the levels emitted by Wi-Fi systems are perfectly safe.

    Mobile phones are another issue. The jury is still out on that one. However, as we still do not know enough about the long term effects, prudence would say that we should not have them "glued to our ears all day long", as I see almost every day around me at shops etc. When that phone is "pressed against the head", it's not much distance to the brain and other soft tissues. I use a mobile phone, but I rarely use it for more than a few minutes when I have it "against my head".


  • Keith the major health issue with low power RF devices is not the absorption of RF waves, but from the effects of the EMI, you know the same force that allows you to go outside on moonless night and light up some fluorescent tubes by standing under high voltage power lines. Nevermind the fact that 2.4GHz is used in microwaves because it resonates a molecule of water really well. People are over 80% water, right? Your side of the argument, is it has to be proven ?scientifically? and ?peer reviewed?, and while that is important look at who has funded all the studies that say mobiles are safe, Moto, Nokia, Verizon; all companies whose bottom line depend on RF safety being relegated to the level of wackjob crazy conspiracy nuts, right; and without ever looking at the few non-RF industry studies that while not 100%, definitely show statistically an increase in cancer and health problems from mobiles. The French are taking down cell antennas from schools and hospitals. So the next question should be what about the guy on his wifi mobile all day? RF radiation is still radiation, and long term exposure to any of it is not good for you, look at guys who have spent years near RF transmitters, not the antennas, they just look old and worn out, just like guys working 8-10 hours a day in a nuke plant, old before their time and just plain exhausted.

  • Personally, I don't really see a problem with the classification given by the WHO. The examples given by Wlanman and dave1234 make a lot of sense but, strictly scientifically speaking, are anecdotal at best. Essentially, they are the perfect example for clarifying the difference between correlation and causality. Yes, all the people in the examples did work on radar/antennas/RF-rich environments, and yes, they all had major health issues, but that is correlation only. Studies would need to be done to actually prove causality (ie. mobile phone signals actually cause the damage and not some other source that also happens to be present but unaccounted for).

    By classifying mobile phone signals the way they have, the WHO has hopefully helped stimulate/foster some scientific research to help lend some weight to the anecdotal evidence we have. This is a good thing since, again, strictly scientifically speaking, they will never technically be able to prove the theory that mobile phone signals cause cancer. When it comes to theories, you can do experiments to support them or you can disprove them. Trying to prove a theory scientifically is a fools errand since you can never possibly test or account for all variables and scenarios.

    The other option would be to run under the assumption that mobile phones signals do not cause cancer and then wait for someone to prove that theory wrong. Given the results of being wrong, in this scenario, I tend to think this is a bad idea. I'm not saying we need to assume carcinogenic qualities in every new technology, just that after a certain amount of anecdotal evidence it would be foolish not to take a closer look. The worst that happens is we are right, the best that happens is we are wrong.

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