Subject: (Curry) (Addo) Cellular tower next to residence (fwd)
Date: Thu, 27 May 1999 092724 -0500 (CDT)
From: "Roy L. Beavers" <rbeavers@llion.org>
To: emfguru <rbeavers@llion.org>
--------------------------------------------------
......Bill Curry has written a nice paper which elaborates on
my brief statement below and which summarizes much of the current
"knowledge" regarding possible cell tower measurements and risks....
It provides another good example of the complicated (and probably
"health hazardous") "Blue World" we are being submerged into -- without
the PUBLIC'S knowledge or permission.....
Many of you will want to save this...... I have edited it minimally from
Bill's original..... (Goal: to encourage easier reading....)
Roy Beavers (EMFguru)......
rbeavers@llion.org.......
.....It is better to light a single candle than to curse the darkness.....
EMF-L web-site can be found at:
EMF-L archives can be found at: (soon to be available)
...................PEOPLE ARE MORE IMPORTANT THAN PROFITS.................
---------- Forwarded message ----------
Date: Wed, 26 May 1999 23:35:41 -0500
From: "Bill P. Curry"
To: "Roy L. Beavers"
Subject: Re: (Addo) Cellular tower next to residence (fwd)
Roy and Patrick:
(Roy, if this is too long for the Guru list, just send it on to Patrick.)
No one can say what precisely is a safe distance or a safe radiation power
density. Most governments, unfortunately, follow the lead of the US in
decreeing that anything that does not produce either ionization or thermal
(heating) effects in the body tissues is safe. This flies in the face of a
decade of research that shows there are more subtle effects. For example, at
radiation levels similar to cell phone radiation, DNA breakage in blood from
rats has been observed by Henry Lai and his colleagues at the Univ. of
Washington. You can view dramatic slides of some of Lai and Singh's results
on Stewart Fist's web site www.electric-words.com. Jerry Phillips has done
similar studies on cells taken from humans. In addition, Martin Blank and
Reba Goodman at Columbia University have shown that biological cells,
confronted by certain types of electromagnetic fields, go into a protective
mode and emit what are called Heat Shock Proteins, just as cells that are
threatened with heat damage do.
These [examples] are relatively low frequency electromagnetic fields, but
the range of greatest sensitivity of the cells to
the electromagnetic fields (0-500 Hz) includes the audio frequencies by which
human speech is able to modulate the much higher cell phone carrier wave
frequency (about 830 MHz for analog phones and about 1600-1900 MHz for more
modern PCS phones and similar types of phone. Also, phones that are based on
the European GSM phone technology are pulsed at about 220 Mhz - right in the
middle of the cell-sensitive spectral region. Each pulse length is about half
a second. (There are also phones of other technologies that pulse at a
different rate.)
Several other investigators have found that some electromagnetic fields
can affect flow of ions across cell membranes and also
can suppress the production of the brain hormone melatonin - one of the most
potent natural cancer fighters. Further 4 separate laboratories have
demonstrated the ability of certain electromagnetic fields to render
ineffective the cancer fighting properties of both melatonin and tamoxifen.
If you will look at Robert Bedard's web site: www.wave-guide.com, you will
find many useful bits of information - including a table compiled by Cindy
Sage that shows a number of biological effects and the levels of radiation
exposure that produced these effects. The next step is to estimate the
radiation coming from the antennas you mentioned to see whether any of these
published biological effects are likely to occur in your situation.
If you can, try to find the manufacturer and model number of the antennas
that are being used in the cell phone tower you mentioned. Antenna
manufacturers list their products on the Internet by model number. From
such a catalog you can find the gain of the antenna, the antenna pattern
(which shows how the antenna gain varies as you depart from the direction
of maximum gain - so that you can
know whether the people you are concerned about are in a high emission
direction).
Some manufacturers also tell you how much the radiation pattern
will be tilted toward the ground - usually 0 - 6 degrees, but sometimes more.
As close as your parents-in-law are to the antenna, it may well be the case
that the primary radiation pattern will pass over their home and reach the
ground at a more distant location, but you can tell how far (horizontally)
away from the antenna the radiation will reach the ground, if you know the
antenna characteristics.
To estimate the radiation density at a particular location you need to ask
the following questions: 1) How high is the antenna off the ground?, 2) How
high is the observation point off the ground?, 3) How far (horizontally) is
the observation point from the antenna?, 4) How much power does the
transmitter put into one communication channel? 5) How many communication
channels will be active at the same time?, 6) What type of antennas are
there?, 7) How many antennas are there?, 8) Are there any reflective surfaces
in the neighborhood of the antennas? If you have even partial answers to most
of these questions, you can use the formulae in the FCC web pages in the
document OET-65 to estimate the radiation density. Alternately, if you will
gather the information above and Email it to me, I will carry out the
calculations for you.
Now, a word of explanation about these questions: 1, 2, 3) As I previously
stated, the radiation may be above the heads of the people you are concerned
about, if the antenna is sufficiently high. In any case, you need both the
heights and horizontal distances of both the observer's position and the
emitting antenna's position to be able to compute the slant distance between
the antenna and the observer.
The radiation power density diminishes as the inverse square of this
distance. 4, 5) A communication channel is an increment of the total
frequency range that is allocated to a particular type
of cellular phone system. The total power emitted by a base station
transmitter may be divided into many channels. For example, if the power into
one channel is 50 watts, and there are 50 channels emitting simultaneously - a
typical configuration in a metropolitan area - the total emitted power will be
2500 watts. 6)
If you can get an engineering drawing or a copy of the permit
application made by the service provider, you may be able to get the name of
the antenna manufacturer and the model number of the antenna. If you cannot
get this information, you will need to do some observations. If the
transmitting antenna is a straight pole - a monopole antenna - the radiation
will be emitted (approximately) equally in all directions. Sometimes license
applications will state that the cell phone tower is a monopole structure -
even if the antennas are not monopoles. Don't be confused. The word monopole
is used both for structural description of a cell phone tower and for
description of the electrical characteristics of an antenna system.
If you see a group of rectangular pieces laid out perpendicular to each
leg of a triangle, then the antennas are panel antennas or sector antennas
(alternate names for the same thing). The usual configurations of sector
antennas are 2, 3, or 4 antennas on each leg of a triangle. When there
are 2 or 3 antennas on a triangle leg, only one of these will be a
transmitting antenna - the rest will be receiving antennas. If there are
4 antennas, there will be 2 transmitting and 2 receiving antennas.
Because there are three legs of the triangle, the radiation pattern from
these antennas will have 3 broad lobes in
the horizontal plane and much narrower lobes in the vertical plane. If you
know the antenna model number, you can get (from the Internet) an antenna
pattern for each plane. [Antenna patterns] are polar plots of the antenna
gain in decibels. They show how much the gain falls off as you depart
from the direction of maximum gain. To get the antenna absolute gain, you
have to divide the gain in decibels by 10 and then raise 10 to the power
equal to the result of the division.
For example, if the antenna gain in decibels is 13,
you must raise 10 to the 1.3 power to get the absolute gain - in this case 20.
Some antennas go as high as 16.5 decibels. This means that the absolute gain
is 10^(1.65) = 45. This is a high gain, but not at all unusual. The absolute
gain is the ratio of the emission in a given direction to the emission that
would occur (for the same total power) if the emission were equal in all
directions.
Antennas with gain focus the radiation into specific directions
at the expense of decreasing the radiation in other directions. The effective
radiated power of a cell phone base station (in a given direction) is the
product of the power into a single channel times the number of simultaneously
active channels times the antenna absolute gain (in the given direction) times
the number of antennas that are radiating in the same direction. The
radiation density at a given position equals the effective radiated power
divided by (4 pi times the square of the slant distance). If there are
reflective structures near the antenna, this result must be multiplied by an
empirically determined factor stated in OET-65.
The procedures I have described above give you an idealized estimate. To be
really sure of the radiation density where the people about whom you are
concerned live, you really should get some competent engineer to measure the
RF field strength (in milivolts per meter) or radiation power density (in
microwatts per square centimeter). One can convert from one type of such
measurement to the other. Ultimately, you will want to compare the estimated
or measured radiation power density to the chart that shows different
biological effects at various power densities. The same chart also correlates
biological effects with different SAR levels. This is a radiation dose
measurement. SAR means specific absorption ratio, and it refers to the amount
of power absorbed by one gram of body tissue.
-------------------------------
Roy L. Beavers wrote:
>
> ......We don't have good answers for this question, do we.....
> Primarily because those responsible for protecting the PUBLIC health
> are "looking the other way" when it comes to searching for the answers.
>
> Nevertheless, perhaps some of our regular readers would like to provide
> the benefit of your experience.....
>
> Roy Beavers (EMFguru)......
> rbeavers@llion.org.......
> .....It is better to light a single candle than to curse the darkness.....
> EMF-L web-site can be found at:
> EMF-L archives can be found at: (soon to be available)
> ...................PEOPLE ARE MORE IMPORTANT THAN PROFITS.................
>
> ---------- Forwarded message ----------
> Date: Wed, 26 May 1999 12:57:01 +0200
> From: Patrick Addo
> To: Rbeavers@llion.org
> Subject: Cellular tower next to residence
>
> Dear Roy,
>
> I am quite worried about a cellular tower located about 10 meters from
> the house in which my parents-in-law live with some of their children
> and grandchildren. In fact the tower is located in an area where they
> spend most of the day and so the family comes to a distance of less
> than 5 meters from the tower for a good part of the day.
>
> Could someone advise as to what safe distances and time spent in the
> vicinity of these towers should be and what health hazards these
> people are likely to be exposed to. What should be done to save these
> people should it be necessary.
>
> Hope my queries would be answered
>
> Patrick
>
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--
----
Bill P. Curry, Ph.D. |Physics is fun.
EMSciTek Consulting Co. |Trying to make a living!
22W101 McCarron Road, |Phone: (630) 858-9377
Glen Ellyn, IL 60137 |Fax: same, but require prior notice
Home page: http://www.EMSciTek.com
____________________________________________________
| Analysis, experiment design & software development |
| for engineering and the physical sciences |
----------------------------------------------------
Archive provided courtesy of WaveGuide, http://www.wave-guide.org
Reprinted with permission of Roy Beavers, http://www.feb.se/EMF-L/EMF-L.html