RF safety --Re: TC discharge... safe or not

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

In an RF safety class a few years back, the instructor cited some anecdotal
reports of apparent RF injuries from folks working with aircraft on the deck
of an aircraft carrier. They reported minor to moderate pain in wrists and
ankles.  After much testing for mechanical and repetitive stress injuries,
to no avail, the working theory is that the workers got RF internal injury.
They would be standing on the deck, touching the aircraft. The deck of a
carrier is a "RF rich" environment, and they concluded that the RF currents
were flowing through their hands/arms/body, and feet (capacitively coupled
at hands and feet.. they're wearing gloves and shoes).  The resistance of
the wrist and ankle joints is much higher than other parts of the body, due
to the large fraction of bone, relative to everything else.  They figured,
after some computation, that the RF heating inside the joints caused the
pain. Unlike the usual RF exposure scenario, where you worry about bulk
absorption, or actual shocks, the body was serving as a path from an antenna
(the plane) to the ground. (note that a ground wire on the plane wouldn't
necessarily fix things, being comparable in length to a wavelength).

A cautionary tale, and one that is relevant to tesla coiling, since it's a
similar sort of injury mechanism.  One should also be aware that prolonged
exposure to loud impulsive noises can cause discomfort injuries, due to
microlesions forming in tissues absorbing the acoustic pulse energy.  This
is more an issue standing next to a cannon or something, but, given the high
power in some TCs, potentially something of interest.

 > Original poster: "Barton B. Anderson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>
 >
 > Early on, I got a little too close to the sparks running about 5kw or so.
 > I'm not sure if I was actually hit or not, but definitely within inches. I
 > was holding my arms up trying to see if I could feel a charge the nearer
 > and nearer I got to the coil without actually getting hit (NEW COILER
 > STUPIDITY). A day or two later, my arm was in a very deep pain. I would
 > describe the pain as similar to bursitis or arthritis. It was quite
 > annoying, painful (a deep ache), and lasted about a week or so. I have no
 > doubt my arm was subjected to RF currents and did a bit of cooking (by
 > either an unseen/unfelt attached spark or coupled in someway to pass
 > currents through my arm).
 >