Subject: (Curry) (Fist) (Lundquist) Scientific publications (fwd)
Date: Tue, 27 Apr 1999 032248 -0500 (CDT)
From: "Roy L. Beavers" <rbeavers@llion.org>
To: emfguru <rbeavers@llion.org>
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......Note Bill's reference to the "harmonics" below. We haven't talked
about that for a while. I say -- Amen, brother!!! The harmonics may be
a more serious threat than some of the fundamental frequencies..... That
depends, of course, upon whether future research ever establishes that
'frequency' or 'wave length' is a critical metric in the occurrence of
biological effects.......guru......
---------- Forwarded message ----------
Date: Mon, 26 Apr 1999 22:05:07 -0700
From: "Bill P. Curry"
To: "Roy L. Beavers"
Subject: Re: (Fist) (Lundquist) Scientific publications (fwd)
Roy and Stewart,
I think a significant factor that may be being ignored in the SAR debate
is the need to reproduce near field conditions experienced by humans. I
don't know how well the phantoms do this. I have been told that a human
head present in the reactive near field of the phone spoils the Q (quality
factor) of the phone antenna.
Q is the ratio of stored energy to radiated energy. The energy is largely
stored in the induction field of teh antenna, and Q spoiling
reults in loss of energy each cycle. A human head drains off some of the
stored energy in each radiation cycle, and this causes the phone to go to
higher power to make up for the lost energy. Since I attempted to make
measurements on a cell phone in the near field - but just outside the reactive
zone - I have found in subsequent attempts, that the phone does indeed vary
its power when the distance to the measuring instrument is varied. This
complicates the problem of getti ng accurate measurements. Note, however, the
significance of the human head being in the reactive near field. Clearly this
causes a signifcantly greater hazard to the phone user than would be expected
on the basis of the FCC mandated far field tests - especially since the
resulting impedance mismatch can result in radiation of significant amounts of
higher harmonics.
The third harmonic of 0.835 GHz is 2.5 GHz - microwave oven frequency. From
the permittivity and conductivity data measured from cadavers, you can
calculate the abssorptivity of tissues - especially brain tissue. I have done
this, and the absorption coefficient for brain tissue increases by a factor of
three between these two frequencies. The implication is that the third
harmonic (if sufficiently intense) will probably cause more biological damage
than the fundamental frequency.
Roy L. Beavers wrote:
>
> ---------- Forwarded message ----------
> Date: Sun, 25 Apr 1999 17:24:07 +1000
> From: Stewart Fist
> To: "Roy L. Beavers"
> Subject: Re: (Lundquist) Scientific publications (fwd)
>
> Majorie says:
> > While I didn't explicitly say so, I have flown in the face of electrical
> > engineers, because they insist that the SAR, all by itself, is a valid measure
> > of exposure.
>
> Of course we all know that the SAR is not a "measure" at all, except in
> phantom (mock-up plastic, etc) heads. It is an estimate in live humans, and
> that estimate has proven so wrong so many times.
>
> Om Gandhi (who was co-convenor of the 1991 IEEE committee which set exposure
> standards) has just released a new paper showing that 800-900 MHz cell phones
> have exceeded the 1.6 W/kg per gram-of-tissue limit in SAR. This is outside
> the IEEE exposure guideline.
>
> His older paper in 1995 showed that with 900MHz cellular handsets - SAR
> estimates (based on modelling) varied from 0.16 to 0.69Wkg, and for the brain,
> from 0.06 to 0.41Wkg
>
> Back in 1986. Gandhi exposed rats to intermitten levels of 2.45GHz at
> 2.5mW/cm2 and studied the behavioral and physiological effects. At
> levels down to 0.7W/kg he observed that " the microwave exposed rats showed a
> lower efficiency in the number of lever-presses emitted for the food pellets
> delivered." Note: this is the opposite of Preece's raised reaction times (to
> a degree).
> -------
> Just to fill this out: Two other experimenters have done estimates also (apart
> from Kuster, etc)
>
> Dimbylow and Mann 1994 used a vertical or lateral antenna, and suggested
> 3-4Wkg averaged over 1gram. Their estimate for the meninges and the surface of
> the brain is about 25% of this. [DOES ANYONE HAVE A GOOD ABSTRACT OF THIS]
>
> Excell 1998 says higher values up to 4.2Wkg rising to 8.2Wkg at 1800MHz, based
> on MRI.
> [I'D APPRECIATE AN ABSTRACT OF THIS ALSO]
>
> --
> Stewart Fist - writer and columnist
> See http://technology.news.com.au/opinion/
> http://www.abc.net.au/http/sfist/ (some archives)
> http://www.electric-words.com (main archives)
> 70 Middle Harbour Road, Lindfield, 2070, N.S.W, Australia
> Phone +61 2 9416 7458 Fax +61 2 9416 4582
--
----
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
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----------------------------------------------------
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