"garigue" wrote in message
news:jSjCd.19888$wu4.13273@attbi_s52...

"Jim - NN7K" wrote in message
m...
Not to mention safty concerns- like those FCC rules for hams in the KW
class- minimum safty standards - and those at 100 FEET, not in front of
your face ! Also, those have rarely had great swr readings when
measured. Most likely a combonation of these concerns-- Jim NN7K


Years ago there was a very interesting letter from a real old timer who
put
a telephone element across the output of his transmitter .. He was having
a
voice QSO with another ham for the first time.. He does not remember
what
happened but woke up on the floor. The RF had caused some intercranial
changes and this fellow was fortunate enough to make it alive. I remember
years ago giving SW diathermy transcranial for Alzheimer's with capacity
plates at either ear. I would not want to do that again but it was
standard
practice. It is really amazing what tissue heating feels like with those
RF
fields ...... adds a new meaning to the phrase ..."a warm feeling within".

73 Tom Popovic KI3R Belle Vernon Pa



A couple of anecdotal experiences.

Back about 15 years ago, I was doing some high-power RF exposure testing on
a cruise missile. I had a 300 watt TWT amplifier feeding an X-band pyramidal
horn antenna through waveguide. I went into the chamber to rotate the
antenna polarization, and put my left hand across the antenna aperture. I
immediately thought it was strange, as warm air was blowing out of the horn.
But that was impossible, since the horn had a mica window across the throat!
Duh, I had left the amplifier turned on! So I can report that tissue heating
is an almost pleasant experience (very short term!), quite akin to the
warm-air hand dryers found in some washrooms.

I also recall reading a letter to an RF trade journal, where an experimenter
was relating his experience on a WWII research project. His team of four was
working on waveguide hardware design, observing high-altitude, high-power
breakdown problems. He related that the team had set up a horn antenna
within a large glass bell-jar (so that they could pump it down to altitude).
The horn faced horizontally out of the jar, and the team set up a small
telescope just outside the jar so that they could look down into the horn
throat and feed to observe arcing. He said that they would change observers
when their face got too hot!

Ed
wb6wsn