[Lowfer] LF radiation hazards

[DTX]

Some URLs that looked promising to me on a cursory reading.

A couple of points to bear in mind:  There are many places worrying about
the effects of HF and lower VHF radiation exposure, because A) the human
body seems vulnerable in this region and B) it is relatively easy to create
5KW of HF and efficiently couple it to free space ;-)

And many formulae will take the mathematically easy way out and do
calculations on far fields, usually thought of as 1/3 WL or more from the
"point source."  Your whole town may be inside the near field for LF, right?

However, the information and calculators below are (I think) fairly good
starting points, give insight, and tend to verify that power levels of watts
at 170kHz to antennas you can erect in a city or populated county with
building codes and inspectors doesn't even tickle the low end of these RF
exposure charts.  Still, I would not stand 4 or 5 ft from a ground level
Hi-Q loading coil and point my finger at the connection to the antenna wire
saying "This is the point of highest danger" while it was being fed a few
hundred watts either ;-)


http://www.arrl.org/news/rfsafety/hbkrf.html

http://www.arrl.org/news/rfsafety/hbkrf.gif

http://www.remote.arrl.org/news/rfsafety/eval/

http://www.state.ma.us/dph/rcp/122.pdf this one is 90% lawyer words, but
half way thru there is some useful data and formulae.

http://n5xu.ae.utexas.edu/cgi-bin/rfsafety.cgi  put in numbers, cranks out
answers.  The exposure limits do track frequ variations.  1000 watts, 0dbi
antenna, 170kHz is safe by a factor of 8 at 5ft.  At 5Mhz it is not 100%
safe.  And no, I have no idea where you will find a 0dbi antenna for
170kHz<G>.

http://www.paulbunyan.net/users/jcrisman/  so informational links and a
downloadable MPE (Max Permitted Exposure) calulator.

http://www.sss-mag.com/rfsafety.html has links to many places of
information.

Gary WA6DTX

----- Original Message -----
From: "Eric Smith" <eric@willow.nutstreet.net>
To: <lowfer@mailman.qth.net>
Sent: Sunday, May 18, 2003 9:57 AM
Subject: Re: [Lowfer] LF radiation hazards


> On Sun, 18 May 2003, Lyle Koehler wrote:
>
> > As far as I know ...
>
> Thanks, Lyle.  This dispels somewhat images I had of bubbling vitreous
> fluid merely from being in my backyard.
>
> So far the only burn I've received (that I know of :) is the one I
> got when feeling of the 2-watt resistor I was using to test my amp
> ... ouch!
>
> 73
> Eric, KD5UWL
>
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