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Re: RF biological hazards? (fwd)
---------- Forwarded message ----------
Date: Sun, 3 May 1998 09:49:39 -0700
From: Jim Lux <jimlux-at-earthlink-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: RF biological hazards? (fwd)
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: RF biological hazards? (fwd)
> Date: Saturday, May 02, 1998 3:28 PM
>
>
>
> ---------- Forwarded message ----------
> Date: Sat, 2 May 1998 10:34:59 EDT
> From: Homer Lea <HomerLea-at-aol-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: RF biological hazards? (fwd)
>
> In a message dated 5/1/98 7:38:07 PM Pacific Daylight Time,
tesla-at-pupman-dot-com
> writes:
>
> > > that "skin depth" in people was several tens of cm at a few MHz,
>
> I have always taken "several" to be at least 4 so we are talking about 16
> inches or more. Sounds like more than the thickness of most bodies?????
>
> jim heagy
>
In fact, this is why there is some concern about radiation in the high UHF
frequencies. You are talking about frequencies where the size of the object
is comparable to the wavelength, and so simple models, like field strength
(applicable for wavelength>>size) or bulk absorption (applicable for
wavelength<<size) may not be relevant.
There has been a lot of work in the last 10 years using conductive models
shaped like heads (and bodies) and actually measuring (or using
computational techniques) the power densities. A hot (no pun intended) area
for this research has been with respect to cell phones, wavelength about a
foot and about a watt, close to the head.
I might add that even with these measurements there still isn't a whole lot
of data on the actual effect of the RF power, except for thermal effects.