[Cliffdwellers] RF Exposure

Sat, 11 May 2002 15:09:57 -0400

Hmmmm.... the basic premise was that sub 30mHz frequencies were not
particularly harmful at reasonably low duty cycles.  I would concur that the
typically very low duty cycle of CW in even the 10M band is verrrry low
exposure.

A lot of studies have been done over the years by the US gov't, health
organizations, the FCC, NIH, radio makers, cell phone makers, and power
industry groups.  Most have been subject to audit and peer review --  and
passed.

EVERY amateur should become informed and knowledgeable about RF exposure.
You will eventually be challenged by the 'public', your neighbors, and even
family - some of whom use supermarket tabloids as reference materials and
think Rosie O'Donnel is a 'consultant'.
------------------------
RF exposure is generally not a factor for amateurs on HF.  However, the
typical 2M/.70cm ragchewer with an HT has a couple of watts (3-5X or more a
portable cell phone's output) on rather high duty cycle (50/50), right next
to their ear....  me thinks this should encourage another study...  We've
been telling folks that radio is 99% reception and 1% emission, but the rag
chewers don't hear the message because they won't let the key up long
enough.
-------------------------
The cell phone makers went to great lengths to counter claims that exposure
to low power/high freq emissions are safe.  A recent video entitled 'How
safe are cell phones" made by one of the manufacturers for its sales staffs,
did in my opinion more to raise suspicions than satisfy the detractors.
Until recently, this entailed 600mw/800mHz 100% duty cycle emissions for, at
most, a few hundred minutes a month.

These studies were done back when the typical cell user was on 100 - 200
minutes a month.  Today, with the carriers providing 3500 -> 4000 minutes
(~60 hours) of evening long distance at higher frequencies (up to 1.9gHz
PCS), these same concerns are about to surface again.   There are even some
1 -> 2W cellular hand sets sold in the US for PCS/1.9gHz usage.  That's
exponentially a larger exposure than 100W at 14mHz with the antenna 40'+
distant from the operator.  Even Vox on cell use only lowers the duty cycle
to ~50% for non-packet type cell phones.

HOWEVER, WE'RE NOW LIVING IN THE SOUND-BITE ERA.....

Amateur radio needs to be prepared, with subtle materials and non-legalese
documents, for the next 11PM news article about a phone user with a brain
tumor.  There are now about 40 Million cell phone users in the US.  This
will reach well into the mathematical probabilities of mating up cell usage
with health problems.  The public doesn't understand the premise that:

   All burglars have tools.  However, all tool owners are not burglars.
   All drunk drivers have cars.  However, all car owners are not drunk
drivers.
   All shooting victims were shot.  However, all gun owners don't shoot
people......
                I think you get the picture.

I had neighbors at our second home who were somewhat brainwashed by other's
CC&Rs stating that they were designed to 'protect the health' of residents.
I even needed to persuade folks that radio reception was not a factor.
These are the same type of folks that line the outside of their microwave
ovens, toasters, and TV sets with tin foil.  One of the local 'rules police'
members (an elderly woman) even wrapped all her household power cords with
foil to stop low frequency waves... she saw it in a supermarket tabloid.
Add that to the typical 'herd mentality', and you have runaway, irrational
fear.  Most people don't read beyond the headlines or dig into the story
beyond the 2 minute soundbite by the TV talking head....  Most people aren't
even informed enough to vote intelligently, but that's a subject for another
reflector list.

73
Frank

<<---  END OF MESSAGE --->>
----- Original Message -----
From: "Alex" <[email protected]>
To: "W2WU" <[email protected]>
Cc: <[email protected]>
Sent: Saturday, May 11, 2002 12:39 PM
Subject: Re: [Cliffdwellers] RF Exposure

> W2WU wrote:
> >
> > Rule of thumb any power < 50 W @ HF represents no problem. 73 W2WU
>
> Except when it comes to magnetic loops/small transmitting loops. I found
> a RF exposure study on this type of antenna that was quite interesting.
> I'll post it if I can find it again.
>
> 73s,
> --Alex
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