Subject: Re Brief comment about 60-Hz fields (fwd)
Date: Wed, 3 Dec 1997 195045 -0600 (CST)
From: "Roy L. Beavers" <rbeavers@mail.llion.org>
To: emfguru@hotmail.com
--------------------------------------------------
Hi everybody:
Stewart Fisk (message forwarded below) is a technical and science writer
in Australia. He also has his own web-site at
As I follow all of this discussion about the relative "guilt" of RF versus
ELF frequencies ... I continue to think of a suggestion I offered earlier:
Does "mother nature" see any difference in the two? She did not "create"
the EMR "band" delineations..... Man did! In terms of "natures"
characteristics, those "man-made" distinctions are wholly artificial ...
existing only in the mind of man!!!
Are we not becoming guilty of assigning characteristics to those bands
which "mother nature" knows nothing about and could not care less???
At this point in time, it seems to me that we have no basis at all to
declare that ANY of the EMR frequencies are "safe" ... while pointing
the finger of guilt at others as "unsafe."
Based on the very small "tip of the iceberg" that research has revealed so
far -- the evidence "strongly suggests" that ***ALL of the EMR frequencies
appear to be capable of biological activity (at exposure levels that are
occuring in the environment)*** ... and therefore (until we find otherwise)
they must ALL be regarded as equally suspect!!!
Stewart has some very worthwhile thoughts below, too......
Cheerio.......
Roy Beavers (EMFguru)
rbeavers@llion.org..............http://www.feb.se/EMF-L/EMF-L.html
................................It is better to light a single candle ...
than to curse the darkness...............................................
---------- Forwarded message ----------
Date: Thu, 04 Dec 1997 09:28:51 +1100
From: Stewart Fist
To: "Roy L. Beavers"
Subject: Re: Brief comment about 60-Hz fields (fwd)
It seems to me that so many systems combine both radio-frequency (very high
frequency) and low frequency (50 to 500 Hz) that it is hard to distinguish one
problem from the other. GSM cellular phones, for instance, have their main
radiation in the 900 million cycles region, but pulse the power at 217 times a
second, so both components exist.
These phones appear likely (from current research) to be more damaging to
cells than the steady-state AMPS handsets that don't have the low-frequency
component -- which appears to implicate the 217 Hz. However, we must be
careful about such assumptions. GSM phones output their power in very short
bursts, so the actual power-density of a GSM phone radiation at the time of
impact on a cell is about 8 times as high as a AMPS for the same time-averaged
power output.
So it could well be a power-density problem, not a frequency one.
But Marjories claims about the R/F level on power lines appears to me to be
quite fallacious. If the levels she believes to be there actually exist, then
I should easily detect them with a scanner placed near to any household power
line -- since, to be of any threat, they would need to be well above the
current background level of free-space radio transmissions that any radio
picks up. I can't find them, and so in the absence of evidence, I don't
believe they exist. R/F has real problems passing through power line
transformers, and generally they need to add special circuits to get this to happen.
Also, Marjorie says in a letter to me:
> Here is another point you may not be aware of: while the strength of
> 50/60-Hz fields falls off gradually with increasing distance from the line,
> the strength of the RF field declines very abruptly. This means that, for
> all practical purposes, there is a hazardous RF field around the line out
> to a certain distance, and then virtually zero hazard at greater distances
> from the line. In other words, even when there is power line carrier on a
> power line, there is a hazard only when people are "too close" to the line
>--meaning they are within the hazardous "sheath" of RF around the line.
This is just not so -- in fact, it is the opposite of the practical evidence.
Electric and magnetic fields (unless blocked) all fall off by steady amounts
depending on the inverse square law. And R/F fields, by their very nature,
travel very long distances with very little power. A 100 watt (the power of
an electric light bulb) transmitter on a satellite can distribute television
signals right across the whole 3 million square miles of Australia, from a
height of 38,000 km. Imagine how 'bright' this would be if it were a
light-bulb. Infinitessimal.
In fact the main problem with satellite radio reception is that you need a
large parbolic reflector dish just to collect enough signal to get the
electronic power up above the intrinsic radiation levels, resulting from the
electronic motion of the copper molecules in the wires. Even then you must add
a special low-noise amplifier directly behind the dish - because even a meter
or two of wire would produce so much radio-noise from the movement of the
molecules, that the television signal would be grossly degraded.
Until recently they needed to keep these low-noise amplifiers frozen by liquid
nitrogen to keep the molecular movement to a minimum, so that it didn't
degrade these minute signals.
So radio signals of this (and other) kind are characterised by their
extraordinary low power and yet long carrying distance, with a perfectly
calculatable (square of distance) progressive drop off in power-densities over
distance.
There may be a biological threshold which causes a "zero hazard at greater
distances" but I doubt that biological systems are like this. Some people are
usually far more susceptible than others, so each would have a different
threshold. And in the case of cancers, we certainly have multiple causations,
so every person is an individual once again, because of their past chemical
and radiation exposures, age, DNA, etc.
--
Stewart Fist - technical writer and columnist
See: http://www.australian.aust.com/computer/cmpcols.htm
http://www.abc.net.au/http/sfist/ (some archives)
http://www.electric-words.com (main archives)
All my stuff is for distribution if you want.
.-
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