We would like to draw your attention to negative influence of radio relay links and terrestrial base stations for satellite communication onto humans. We will mostly speak about frequency range above 5 GHz.

One often says that such systems can only transmit signal from point to point and therefore they are safe for humans.

In reality, radiation is usually concentrated in a cone (width of antenna pattern can be, for example up to 3 degrees). Often the systems can work without interruptions if even a person gets into the cone. Let us estimate power flux density at a distance of 20 m with 40 dB antenna gain and radiation power of 10 W. We get 20 W/m2. This is a very powerful exposure (the ICNIRP norm allows only 10 W/m2). Of course, people are rarely exposed to such powerful influences, but the ALARA-principle (precautionary principle) is often violated. Just imagine, such ''safe'' system can produce 80 µW/m2 at distance of 10km while the ALARA-principle permits only10 µW/m2 (it was suggested by many independent researchers). There are about 18000 transmitters of the radio relay links in Finland at present. But Finnish Radiation and Nuclear Safety Authority (STUK) nothing writes about the radio relay links. Of course, the STUK has replied on our questions by e-mail. It has written that the radio relay links are used in Finland but they are safe for humans. We assume that the STUK is using norms of the ICNIRP; nevertheless the STUK itself often speaks about ALARA-principles and even publishes ALARA-newspaper. But you can see from our examples, that radiation from the radio relay links and the terrestrial base stations of satellite communication can be dangerous, both in terms of existing guidelines and in terms of the ALARA-principles. We asked the researcher from the STUK if their institute had measuring devices for radio relay links in microwave range. Response was: ''The STUK has no such means of measurement.'' Of course, one may buy part of measurement devices (e.g. Spectrum Analyzer from Rohde & Schwarz, up to 67 GHz, price is about 100 000 ?). Additionally one must buy some directional antennas, a station for computations and a preselector if one wants to do precise measurements. We assume that the station and the preselector do not currently exist (at least for civilian applications). The entire system will cost far more than 1 million ?.

Usual people could use a relatively cheap broadband measurement device (often called: detector, RF meter, power meter, monitor, etc). Some of such devices can work even in extremely broadband frequency range 0.0001?100 GHz. Unfortunately the devices can warn only about extremely strong radiation (e.g. typical threshold is around 5 W/m2=5 000 000 µW/m2). But one must clearly understand that these broadband devices do not indicate many dangerous signals (remember, that PACE has suggested threshold only up to 1000 µW/m2).

There are many dangerous signals in the microwave range, but often even Radiation and Nuclear Safety Authorities have no possibility to measure dangerous radiation in this range.

People need good protection from this dangerous radiation. For these reasons the most part of the radio relay links should be replaced by using optic fiber and FSO (Free-space optics) devices. As for the terrestrial base stations of satellite communication, users (especially in the Nordic countries) should get clear guidance on the safe use of these systems.


Georgiy Ostroumov, Ph.D., Eva Jansson, F.M., Finland



More about the theme:

http://www.buergerwelle.de:8080/helma/twoday/bwnews/search?q=microwave+radiation
http://omega.twoday.net/search?q=microwave+radiation
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http://www.buergerwelle.de:8080/helma/twoday/bwnews/search?q=ALARA
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http://www.buergerwelle.de:8080/helma/twoday/bwnews/search?q=STUK
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http://www.buergerwelle.de:8080/helma/twoday/bwnews/search?q=ICNIRP
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http://www.buergerwelle.de:8080/helma/twoday/bwnews/search?q=Ostroumov