Radiation Danger zones around Wifi and other personal communication Devices

By Norm Ryder.

All electrical and electronic equipment emit Electromagnetic Radiation (EMR), fortunately most devices do not emit high levels of EMR. The ones of prime concern are those that emit radio signals. These include but not limited to: Cell Phones, Cordless Phones, Laptop, Tablets, Baby Wireless Monitors, Wireless Routers. The laptop this is being written on emits approximately 25 milivolts per meter (Electric Field) when turned on, 25 more when the charger is plugged in and regularly over 1000 milivolts when on Wifi. To determine the Power Density would would also need to measure the amps per meter (Magnetic Field). Few radiation meters measure the Amps per meter. These regular meters calculate the amp reading based on established physics when the measurements are in the far field or at a distance from the source.

Yes this is a topic that few of us are aware of or understand on first reading. More explanation of the physics of Radio Frequency is in Cell Tower Siting Considerations. An excerpt on Near Field Radiation is in the pdf accompanying this article. The full booklet is available on request by contacting worksafe@sios.ca .

The radiation field around a transmitting device is divided into 3 primary zones: the Near, Far and a zone that is called the Intermediate or Transition zone – a blend of the other 2.

figure A1 - General antenna field regions
Safety Code 6 (SC6) Radio Frequency Exposure Compliance Evaluation Template (Uncontrolled Environment Exposure Limits) Industry Canada Technical Note-261

In the near field Spectacular peaks and Valleys of radiation intensity can occur, the radiation pattern is considered to be difficult to model if it is possible to model it. In the Radio Frequency Tool Kit For Environmental Health Practitioners by the BC Centre for Disease Control (BCCCDC) the near field zone is referred to as chaotic. In his zone both Industry Canada (IC) and the BCCDC specify both the Electric Field and Magnetic Fields must be measured in several locations to obtain the true power density readings.

The extent of the danger zones around an emitting device is determined by a series of calculations based on the frequency (wavelength) and size of the antenna. Additional confusions can be introduced by interference from other sources, reflected energy, stored energy and antenna design and imperfections to name a few of the other sources of complexity that may possibly exist.

The Danger zone around a cell phone can be consider to be in the order of 0.1 m and greater if the phone is using wifi. A cell phone antenna – even ones on roof tops over 12 meters to the extreme danger limit and 50 meters to the high danger zone. Larger antennas or higher frequencies could extend these distances considerably. A home wifi router the minimum distance to the extremely dangerous zone limit 0.1 and to the highly dangerous zone 0.3 meters (1 ft). For a laptop assume distance in excess of 1 meter and 4 meters respectively.

Excerpt Cell Tower Siting Considerations

7 thoughts on “Radiation Danger zones around Wifi and other personal communication Devices

  1. This may be what the experts say, but I am affected by cell phones from even 15 feet away. There are supposed danger zones and actual ones. The scientists are supposing.


    • Thanks for your comment
      I agree, the effects for many including me are felt at a much greater distance. The zones I am referring to are the areas where a simple power density measurement does not give the whole picture. When one is in the far field zone a simple measurement of the volts per m or amps per meter is all that is needed to determine power density, closer to the source the measurements become more complex.


  2. Dear,
    Would you please quote the source about the body voltage caused by Wi Fi. This source is very important to persuade people and make them trust it, if there is scientific source quoted.
    Thank you very much !


  3. Thanks for this Norm – Every time I am on the computer for longer than 10 mins. at a stretch my ears feel like I am descending in an airplane. Pressure, deafness and also my parotid glands swell slightly. I also get vision problems as if my eye muscles are seizing up. Have you heard of others with these strange symptoms? I only have them when I am on the internet around Wi Fi at home or when I use the library computers but also my landlords have Wi-Fi installed in their home upstairs. I don’t own a cell-phone or any other high-tech gadgets because I am afraid for my health.


    • Not sure what in my article you are referring to re “body voltage”. The voltage I am referring to is “voltage in the air”, If you look at most country standards for allowable limits – in addition to power density values they also refer to maximum volt per meter and amp meter values. Power density is the product of the 2 values.


    • Avoiding sources of EMR is becoming more and more difficult. Many others note the same physical problems you noted, however most refuse to even consider the possibility they are caused by radiation. The best thing you can do is keep talking to people about the problems ans lowly many will realise some problems they have may be radiation related.


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