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Beware of this test; it does not give you a reliable answer!

Microwave Oven Radiation Leakage – cell phones do not provide an adequate test!



A friend sent me an email with a message about testing for leakage in microwave ovens with a cell phone. Beware of this test; it does not give you a reliable answer!

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Microwave ovens and cell phones work with electromagnetic waves. Visible light, X-rays, and heat radiation also are electromagnetic waves. However, they are all working with substantially different wavelengths – and that makes for a great difference between them.

The Electromagnetic Spectrum

The electromagnetic spectrum (ES) covers a large range of wavelengths as shown in the figure below. From the most energetic (shortest wavelength) gamma rays to your AM radio transmissions they cover some eighteen orders of magnitude alone. However, there is no theoretical limit on either end of the spectrum.
 Spectrum of electromagnetic waves with bands of commonly used wavelengths
Fig. Spectrum of electromagnetic waves with bands of commonly used wavelengths (the inverse of frequencies) and their use.

Microwave Ovens

Microwave ovens (MOs) operate at a wavelength of approximately 0.1 m (4 inches) that is around the borderline between radar and FM radio transmissions. That wavelength is readily absorbed by water molecules and results in the heating of your food placed in the MO. To prevent leakage of the microwaves to the outside, your MO has a screen embedded into the glass window that absorbs any radiation which might otherwise get outside. You can see the screen and its open spaces quite clearly when the inside of your MO is illuminated; they are about 0.3 cm (1/8 inch) wide. It’s also easy to understand that such screens prevent leakage of the MO’s 4-inch wavelength radiation to the outside. Some early MO models had insufficient radiation protection, inadequate screens or leakage protection around the door and allowed some minor radiation leakage. However this problem has long been solved and all MOs have had adequate protection for many years already.

Cell Phones

Modern cell phones (CPs) or other mobile devices for verbal or text communication, for surfing the internet and similar activities are operating on much shorter wavelengths (much higher frequencies) than microwave systems. They typically use wavelengths of 0.01 m or shorter (0.1 inch), which is in the middle of the radar band or even closer to the infrared end of the spectrum – see the figure. Of course, electromagnetic waves of such short wavelength are not absorbed by the common MO screens, as they can readily pass through their holes. So, let’s put all that information together and actually test it with cell phones.

Cell Phone Test

I was lucky to get hold of an “ancient” cell phone, about 17 years old and still in use, let’s call it CP-1. A second cell phone, CP-2 is of a much more recent make. I undertook the following tests: I placed phone CP-1 inside the MO and tried to call it from CP-2. CP-1 did not respond. I placed phone CP-2 inside the MO and tried to call it from CP-1. CP-2 did respond. That’s exactly what you should expect if everything is working properly. The older phone (CP-1) is operating on a longer wavelength that is close enough to the one of the microwave oven and, therefore, the signal sent to it was absorbed by the screen. In contrast, CP-2 which operates on a shorter wavelength did receive the signal as that was not retained by the screen. Obviously, the result of the cell phone test of your MO depends very much on the operating frequency (or wavelength) of your cell phone. Therefore, it cannot tell you if your MO has any radiation leakage or not; in order to determine that, you need to perform another simple experiment, the MO test.

MO Test

The MO test tells you whether or not your microwave is leaking radiation. It requires two identical (small) glasses. Fill each to the same level with water of the same temperature. Then place one inside your MO and hold the other outside your MO near the door surround. Start your MO and run it for 60 seconds. The water in the glass in your hand should remain at the same temperature but that inside the MO should be close to boiling. Unless you notice otherwise, it shows you that your microwave oven is just fine.


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Dr. Klaus L.E. Kaiser -- Bio and Archives

Dr. Klaus L.E. Kaiser is author of CONVENIENT MYTHS, the green revolution – perceptions, politics, and facts Convenient Myths


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