Subject: (Curry) (Burmaster) cell-phones modus operandi (fwd)
Date: Mon, 19 Oct 1998 203310 -0500 (CDT)
From: "Roy L. Beavers" <rbeavers@llion.org>
To: emfguru <rbeavers@llion.org>
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---------- Forwarded message ----------
Date: Sun, 18 Oct 1998 19:24:04 -0500
From: "Bill P. Curry"
To: "Roy L. Beavers"
Subject: Re: (Burmaster) (A. Philips) cell-phones modus operandi (fwd)
Roy and Tim,
These are my semi-educated guesses in regard to the questions you
asked: 1) There are several web sites that advertise some kind of cell
phone shield. The one that I finally bought for my wife's phone was
Phone Shield (TM), even though it only reduces emission by a factor of 2
or so. I bought it because they included hard test data from an
independent laboratory in their advertisement. It only shields the ear
piece, but that is the closest to the brain, and the ear piece also
emits more radiation than any other part of the phone except the
antenna, itself. I think the cell phone manufacturers are quietly
trying to "plug" this radiation leak now - without, of course, admitting
that it was ever a problem. 2) The testing done on the Phone Shield
supposedly included whether its use would cause the phone to go to
higher power emission, and the results indicated no significant increase
in total emission resulting from use of the shield. 3) Alasdair's
suggestion that cell phone use should be minimized is excellent, and my
wife and I try to follow this advice. We are both in our sixties, so
the potential adverse health impact of cellular phones on us is probably
significantly less important than it would be on a young person. I
think that probably the most vulnerable individuals are young women of
child bearing age, especially young pregnant women. 4) Radiation from
the earpiece is dangerous because it is relatively intense and is
emitted only about a centimeter from the brain. If the microwave
generating apparatus and antenna are located remotely from the user, the
incident radiation intensity on the user will decrease with distance
from the emitter to the user according to the inverse square law. Thus,
putting the transmitter/receiver and antenna somewhere away from people
is a good idea, even if you have to have a long cable from the unit to
the earpiece and mouthpiece. If properly connected, the cable to the
headpiece should not deliver any microwaves to the user - only audio
signals. The cable is likely to be significantly longer than the
antenna, so it shouldn't act as a very good receiving antenna, even if
not properly grounded and shielded. Essentially, it can't receive
significant amounts of microwave energy as long as it is significantly
longer than 1/4 wavelength. For 1 Ghz radiation, a wavelength is 30 cm
and 1/4 wavelength is 7.5 cm, and this is about the length of an
extendable antenna from a cell phone. I think the best type of
installation is one mounted permanently in a car with hands off
microphone and speaker (for automobile safety as well as user health).
Many real estate agents (and other people who need mobile phones in
their routine business use) have this kind of installation, but most of
us don't. 5) My worst qualms about shields for cell phones arise from
the fact that, in the absence of proven damage mechanisms, we have no
hard evidence of what is a safe level of radiation - hence, we don't
really know how to design an adequate shield. Dr. John Goldsmith (in
one of his papers) says that biological effects are negligible below
about 2 microwatts per square centimeter, but that is probably near the
background level in most of the industrialized world.
When I first got into cell phone controversies, I intended to use my
knowledge of how to compute the fields inside a layered, spherical
object illuminated by electromagnetic waves to design a viable, wearable
shield (cap or hat) for cell phone users. I even got an encouraging
reception for submitting this as a Small Business Innovation Research
proposal to the National Cancer Institute. It seems not all the NCI
officials follow the party line that "there are no significant health
effects!" What stopped me cold was 1) there are already too many
(probably doubtfully effective) shielding devices already on the market
and 2) I couldn't establish what the shielding criterion should be - how
low a level to which I should attenuate the radiation. If I ever
develop a shield I want it to be effective, not just realize a profit
from people's paranoia!
--
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
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Reprinted with permission of Roy Beavers, http://www.feb.se/EMF-L/EMF-L.html