Subject: LFA Sonar / radio & microwave - ear damage (Karow)(Murphy)..
Date: Thu, 18 Nov 1999 035812 -0600 (CST)
From: "Roy L. Beavers"
To: emfguru
--------------------------------------------------
.......A nice informative response to Hans questions..... Deserving of
your attention......
Roy Beavers (EMFguru)
roy@emfguru.com
.....It is better to light a single candle than to curse the darkness.....
NEW!!! Website
...................People are more important than profits.................
---------- Forwarded message ----------
Date: Thu, 18 Nov 1999 00:34:30 -0600 (CST)
From: christian a murphy
To: "Roy L. Beavers"
Subject: Re: LFA Sonar / radio & microwave - ear damage (Karow)..
On Wed, 17 Nov 1999, Roy L. Beavers wrote:
>
> FYI....... courtesy of..
>
> Roy Beavers (EMFguru)
> roy@emfguru.com
>
> .....It is better to light a single candle than to curse the darkness.....
> NEW!!! Website
> ...................People are more important than profits.................
>
> ---------- Forwarded message ----------
> Date: Wed, 17 Nov 1999 17:03:45 -0800
> From: Hans Karow
> To: "'rbeavers@llion.org'"
> Subject: LFA Sonar / radio & microwave - ear damage
>
> Roy,
>
> re: LFA Sonar / US Navy
>
> I checked and read http://www.oceanmammalinst.org/mgpaper.html
> which is very interesting and concerning.
>
>
> Can anyone help me to give some clarification>
> 1 Can Low Frequency Active Sonars (referring to above mentioned article,
> see web site) be classified within the ElectroMagnetic Spectrum, as are the
> electromagnetic fields (power line- and microwave frequencies)?
No sonar is acutally sound, which is a vibraton of whatever substance the
wave is traveling through. In air it is the air molecules that are moving
and in water it is the water molecules that are moving. But there must be
some physical substance for the wave to travel through. No sound is
possible in a vacuum.
Electromagnetic waves on the other hand, do not require a physical
substance to move through. There have been several theories of what it
does move through but what ever it is it has no mass. This is why you can
recieve radio waves through a stone wall. This same wall, however, will
block the shouts of somone outside.
Succinctly: A sound wave is something physical. If it has a large enough
magnitude it can knock you off your feet. An electromagnetic wave is not
physical. If it is powerfull enough it can effect the molecules in your
body but it really can't push you over in the same way a sound wave can.
> 2. What is a comparative sound of 110 - 120 dB, can humans hear it?
----------------------------------------------------
Humans can definitely hear that. That is a measure of the magnitude of the
wave. It is basically how loud the sound is. Just to give you a rough idea
of noise level the sound in the cabin of a jet plane is about 80 dB. See
below for a discussion of what a dB is.
----------------------------------------------------
> 3. What does dB stand for? Could you give another sample for dB (in
> Dummies' language), like using the water hose to demonstrate Voltage,
> Current, Power, Conductor etc.
--------------------------------------------------
dB stands for decibel and it the logarithm of the ratio of the amplitudes
of two waveforms. The equation is dB=20*log(A/B). When it is said that a
sound has a certain dB, it must be compared to some standard. You can
check out the web site
http://www.Point-and-Click.com/Campanella_Acoustics/faq/faq.htm
for more information about these standards.
The important thing is that when you are comparing two sounds in decibels,
because of the logarithm, A FACTOR of TWO in dB implies a FACTOR OF 10 in
the actual amplitude. So an 120dB sound has 3.2 times the amplitude
of an 80 dB sound.
> 4. What is the human's ear range in dB? Below AND above that range, are
> you aware of any possible damage/negative side effects to the ear? If there
> are negative effects to the human ear, what are they?
Above 85 dB you should use hearing protection (about the sound of a
lawn mower on grass) at 100 dB is considered dangerous. At these levels
the sound can actually destroy the ear and with it the ability to hear.
(this is from the above web site)
Sound can have additional effects that I am not well versed in. When I
listen to CD's on headphones I get a headache as well as feel sick to my
stomach. I do not know if this is a low or high frequency noise effect but
sound can effect you in adverse ways. I think these effects are very
dependant on the frequency (pitch) of the sound. Low frequency sound has a
very low pitch, depending on the frequency too low for us to hear. It is
sometimes possible to feel it in your body, however. You can get the
effect from good sized radio speakers.
> 5. If I assume that the dB range is within the human hearing range, which
> frequencies within the electromagnetic field (within our EMF/EMR debated
> issue) are you aware of that can cause adverse effects to the human ear?
> What are the effects in case you are aware of? .
As above you cannot really compare sound and emf radiation. I do not know
of any direct damage to the ear from EMF's prehaps somone else does? The
cavities of the head can, however, act as resonant cavities for EMF. When
I was studying Ham radio stuff I was told you had to be careful not to use
too high a power hand held radio because you can cook you eye balls and
not even know it because they don't have the appropriate sensors there.
>
> 6. What about the ears of domestic animals (cats, dogs, horses, cows: any
> known studies that report about negative effects or damages to their ears
> caused by
> a) Low Frequency Active Sonar
> b) radio/micro waves.
All I really know about this is that animals can hear sounds higher that
what we can. This is the idea behind the "silent" dog whistle wich is only
silent to our ears as we cannot hear it. By dogs can. It does not,
however, mean sound of that frequency does not have an effect on us, we
just can't hear it.
So I hope this is somewhat helpfull.
Christian Murphy
> If there are studies available, please give references.
>
>
> Thank you, Hans.
>
> PS.: It is us, who have to dig up and present the already existing but
> hidden information about EMFs/EMRs' adverse health effects to the ignorant
> & biased industry/government!
>
Archive provided courtesy of WaveGuide, http://www.wave-guide.org
Reprinted with permission of Roy Beavers, http://www.emfguru.com