Subject: (Lundquist) Reply to questions about RF] (fwd)
Date: Mon, 26 Apr 1999 050912 -0500 (CDT)
From: "Roy L. Beavers" <rbeavers@llion.org>
To: emfguru <rbeavers@llion.org>
--------------------------------------------------
......More good info here about the relevant factors when discussing
radio frequency interaction with cells...... As Marjorie says here,
"a whole course could be taught in reponse to Mark's questions."
Roy Beavers (EMFguru)
rbeavers@llion.org................
...It is better to light a single candle than to curse the darkness...
.................PEOPLE ARE MORE IMPORTANT THAN PROFITS...............
---------- Forwarded message ----------
Date: 25 Apr 99 21:42:47 MDT
From: MARJORIE LUNDQUIST
To: markrowe@northrock.bm
Cc: rbeavers@llion.org
Subject: Reply to questions about RF]
Mark, radio frequency EMF refers to a portion of the electromagnetic spectrum
used for radio transmissions. Its definition may have changed a little over
the past half-century, but basically, assuming it to include the microwave
frequencies, it runs from about 100 kHz to 300 GHz. I'm not sure about FM
radio, but commercial AM radio frequencies have wavelengths that are, roughly,
about a mile long. (This long wavelength makes them penetrate buildings
readily, which is why you can receive stations on your radio inside your
home.)
Microwave frequencies have much shorter wavelengths (higher frequencies: 300
MHz to 300 GHz) with lengths in centimeters or even millimeters. The
microwave frequencies are usually considered to be part of the RF range of
frequencies (I have defined RF here to include microwaves) although some
people prefer to think of them as separate, in which case the RF range is
below the microwave frequency range.
There are important practical differences between AM commercial radio (which
is in the high-kilohertz/low-megahertz frequency rage, I believe) and the
microwave frequencies that cellular phones use (above 800-900 MHz) both from
an electrical engineering perspective, and in terms of the way they interact
with mammalian bodies. (The way you design a transmitter is very different,
and the health effects of the radiation on mammals are very different, too.)
The basic equations of electromagnetism are the same, no matter what the
frequency, but the natural unit of length is the wavelength, and this can vary
from a couple of miles to a fraction of a millimeter, which is a very large
range, in terms of human experience.
Suppose you are listening to a commercial radio station, the transmitter of
which is 9 miles away, operating at a frequency having a wavelength of 3
miles; then you are three wavelengths away from the transmitter. For
comparison, suppose you are three wavelengths away from a microwave
transmitter operating at a frequency such that the wavelength is two cm; then
the distance from that transmitter to your body is 6 cm, or slightly less than
2.5 inches, about the distance from a cellular phone transmitter to the user's
head, when it is in use.
In the case of the AM radio, your whole body is in the same field, for all
practical purposes; in the case of the cellular phone, a small portion of your
head is in this region, with other parts of your body being much greater
distances away (in terms of wavelength).
There are similarities in the two situations I mentioned -- two different
situations where living tissue is 3 wavelengths away from the transmitter --
but there are also differences.
Einstein got a Nobel Prize for a paper published in 1905 explaining the
photoelectric effect: it contained the equation E=hv (the "v" here is
supposed to be the Greek letter "nu" representing the frequency) which says
that the energy of a photon is proportional to its frquency, the constant of
proportionality being Planck's constant "h". A photon is a quantum
(indivisible packet or bundle) of electromagnetic energy. At microwave
frequencies, electromagnetic energy comes in larger "bundles" than at
commercial AM radio frequencies. One way tissues are damaged is to absorb
energy from EM radiation; at microwave frequencies the minimum amount that can
be absorbed is larger than at lower frequencies. When EM energy is absorbed
from microwave radiation, the absorption of a photon delivers a comparatively
large amount of energy; but if the radiation comes from an AM radio broadcast,
the photon delivers a smaller amount of energy, because the frequency is
lower.
Also, there is evidence to suggest that some diseases are frequency specific;
change the frequency, and the disease that result from exposure will change.
Others may not depend very much on frequency, so that you can develop the same
illness, no matter specific frequency you are exposed to (over a limited but
perhaps wide range; for example, there are lots of different cancers, and a
wide range of frequencies is probably able to cause some type of cancer; but a
specific type of cancer may be caused by only a narrow frequency).
Another factor has to do with the properties of the biological matter, and
how these relate to frequency. There is resonant absorption of energy
when the dimensions of a material entity are the same as the wavelength of
the radiation. The height of adult human beings is about 5.5 feet, so our
bodies will interact resonantly with radiation having this wavelength.
There are other significant dimensions within living tissues: the size of a
biological macromolecule, or a chromosome, for example. These are so small
that they would interact resonantly with microwaves, not with AM radio
frequencies.
If you are wondering why AM and FM commercial radio broadcast radiation is not
harmful, the answer is: It is harmful, but the harm is spread out over large
areas, so one has at look at statistical data to "see" the evidence. I have
seen such evidence and wanted to write a paper, but at the time I was in the
midst of a foreclosure, and I lost an enormous amount of my things, including
the matearial for several papers I wanted to write. (I remind you that no one
has ever paid me to do research in this area, so I had major practical
problems that interfered with my bringing my research to the publication
stage.)
With microwave radiation, the injuries are serious and are concentrated in a
relatively few people. With AM radio, they are milder and are spread out over
a comparatively large population.
The "service area" of a commercial broadcast radio station will vary with its
power, but will probably have a diameter of something like 100-250
wavelengths. The "service area", or cell size, of a cellular radio system may
be similar in terms of wavelength, but instead of being 100-250 miles, as for
a commercial radio station, it will be a lot smaller because the wavelength is
much smaller. I don't know just what the size of a "cell"
is, but I do know that the "cell" size is smaller for systems that operate at
2 GHz than for those that operate at 900 MHz; and the smaller "cell" size
means that more towers are needed to "blanket" an area of given size.
You ask about the differences in health effects between cellular phone
radiation and commercial broadcast radiation. There are indeed major
differences, but there are also some similarities. For example, I am
satisfied that both exposures (to analog cell-phone signals, or to AM
broadcast signals) can produce an increase in the cancer rate. Nervous system
tissue is the most susceptible, as a general statement, but cancers in other
tissues seem more likely to occur with microwave radiation than with AM radio.
However, it will be easier to associate microwave radiation with cancer than
radiation from AM radio with cancer, so we are likely to have evidence that
microwave are carcinogenic before we have evidence that lower-frequency analog
radio signals are carcinogenic.
(The severity of the health effects seems to diminish as the frequency goes
down.)
Another reason we have not seen adverse health effects from commercial
broadcast radio is that no one has been looking for such effects. What I
found, I found by accident. Microwave radiation has been suspected as being
hazardous for 45 years, and has been rather intensively studied, by
comparison.
All RF, including microwaves, travels in straight lines. Some frequencies can
be "bounced off" the ionosphere, but I don't think this happens in a
well-designed cellular system. (This, I think, is what Roy meant when he
referred to radio waves bending around the earth's curvature.)
A whole course could be taught on the basis of your questions, Mark. I hope I
have helped to give you some insight into the answers. Basically, the main
reason microwaves are so much more hazardous than other radio frequencies is
that, because of their short wavelength, they can interact disruptively with a
great many molecules and subcellular structures in biological tissues that the
much longer commercial AM radio-waves are unable to interact with -- at least,
not to the same degree. -- Marjorie
====================================
"Mark" wrote:
Marjorie,
I mailed those newspaper cuttings to you.
I put out the following questions to Roy. If
you have time I'd be interested in your explanation.
Mark:
Question Roy,
This seems dumb. How does Radio Frequency
EMF differ from that emitted by AM/FM radio
transmitters which have been around in large
quantities for 50 years. Two follow up questions:
1).Why do we need so may more towers for cell phones
than we ever did for radios (after all every house and
car has a radio which always have worked pretty well)
2) Is there likely to be a different impact on health
form cell phone towers compared to ordinary
old fashioned radio transmission towers, which have
been around long enough to permit meaningful
statistical epidemiological studies.
Roy's answers:
Question Roy,
>This seems dumb. How does Radio Frequency
>EMF differ from that emitted by AM/FM radio
>transmitters which have been around in large
>quantities for 50 years.
>
>[....No substantial difference in terms of possible EMF effects, if
>any..... However, keep in mind that the possible effects of the first
>75 to 100 years of the radio/ELF age were slow to become a significant
>factor in our environment. And we were not "watching" for effects in
>terms of health consequences. The last 25 years, approximately, are a
>different story. The exposures have **exploded** within our environment
>during that period (approximately) and we (mankind) have begun to "notice"
>health effects -- starting with the Russians about 25-30 years ago.....]
>
>Two follow up questions:
>1).Why do we need so may more towers for cell phones
>than we ever did for radios (after all every house and
>car has a radio which always have worked pretty well)
>
>[.....Cell phones operate in line-of-sight (straight line) frequencies.
>They don't "bend" around the earth's curvature the way old fashioned radio
>frequencies do -- that take advantage of "scatter" effect in the
>atmosphere.....]
>
>2) Is there likely to be a different impact on health
>form cell phone towers compared to ordinary
>old fashioned radio transmission towers, which have
>been around long enough to permit meaningful
>statistical epidemiological studies.
>
>[.....Not likely to be IN MY OPINION.... However, keep in mind my
>comments to your first question ... and, keep in mind that we do not
>yet have much evidence about (possible) different effects of the many
>different frequencies of the EMF/EMR spectrum....... It is possible that
>human cells react differently to the different wave-lengths. That could
>mean different end-consequences in a health sense. In fact, it could
>mean that some frequency bands are virtually harmless -- as a few
>'knowledgeable' (about EMF/EMR) scientists have speculated.......]
>
My follow up:
Thank you. Those questions suddenly struck me.
I am still surprised that there is such a big difference
between the frequencies as regards the requirements
for numbers of towers. If the cell phone EMF
is absorbed more by objects
i.e. requires line of sight transmission then that is
reason enough to be more concerned because
humans are objects. Cell phone transmissions are
a more concentrated directional flow of energy.
When blocked by an object it transforms and the
question is what effect does that transformed energy
have on the body?
Mark.
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Reprinted with permission of Roy Beavers, http://www.feb.se/EMF-L/EMF-L.html