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Something new about antennas??




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From:  terryf-at-verinet-dot-com [SMTP:terryf-at-verinet-dot-com]
Sent:  Friday, June 05, 1998 9:08 PM
To:  tesla-at-pupman-dot-com
Subject:  Something new about antennas??

Hi All,

        Tonight while making measurements with an antenna I noted an
interesting thing.  With a scanner antenna connected to my scope and a
current probe on the second channel I found the following:

        With the antenna feed directly to the scope (no 50 ohm termination)
the antenna picked up a signal proportional to the voltage from the coil
(the D or electric flux density field from Maxwell's equations).

        With the antenna feed to the scope with a 50 ohm termination inline,
the antenna picked up the current being projected from the coil (the J or
current density field from Maxwell's equations).

        These two measurements were 90 degrees out of phase as would be
expected.  A small arc from the terminal confirmed the phase.
        
        I should write another paper on this but I am a little "papered out"
at the moment :-)  I am now starting to see the big picture of the fields,
currents, and such in Tesla coils.  I have been studying field theory's and
they are very key to our work.  I never was very good at field theory but I
am sure learning about it now! :-)  I'll have more to say later.  I have
been up late the last few days and the mind is starting to numb!

Later,

        Terry Fritz