TESLA ON ANTENNAS

                       By Jerry Burling, SBE 4311

During the course of his experiments with Electromagnetic energy,
Tesla developed some theories on the distribution and propagation
of different types of waves including Hertzian waves.  His
experiments concluded that a Hertzian antenna operates much more
efficiently when the impedance of the antenna is very high; the
higher the better in most cases.  If one consults the Radio
Amateur's Handbook from the ARRL, it would appear that a trans-
mitter does not care what the length of an antenna is if it is
over 8 wavelengths long.  It will load into an 8 wavelength, or
longer, antenna and the loading, and especially the tuning,
controls seem to have no effect, since the lengthy antenna is now
mostly voltage oriented.

By consulting an impedance table, one can clearly see that as the
impedance elevates, the current drops and the voltage increases.
This might explain why a 5/8's wave antenna is superior over a
simple quarter wave ground plane.  Not only is there more antenna
surface area to radiate, or capture, electromagnetic signals but
the voltage, at the top end, is higher making it a more efficient
radiator over the quarter wave.

Tesla wound special coils to drastically increase the impedance
of his antenna to where the voltage was in the neighborhood of
25 million volts.  These coils were bi-filar wound to completely
eliminate (or as much as possible) any distributed inductance or
capacitance.  He made a switching arrangement to where he could
switch his special voltage increasing coils into the system using
the same antenna and feed line.  All other factors, including the
transmitter power level, were equal.  Feeding the system with 500
watts, the voltage on the antenna was so high that during periods
when the humidity in the air was high, the antenna crackled and
popped and sometimes a blue corona appeared around it.  But
according to Tesla's data, a radiator of this type was much more
efficient than a simple half wave balanced dipole fed in the
center with a 600 Ohm delta feed line.  He ascertained that, since
the voltage on the antenna was so high, he was not only
transmitting Hertzian waves but scalar waves as well.  The
Hertzian signal level, at the receiving point, from Tesla's high
voltage antenna when compared to a standard antenna feed system,
was much higher and the signal to noise ratio was much improved.
This author's experience, with shunt versus series fed broadcast
antennas, has been that although the shunt system matches and the
power is successfully transferred to the antenna with a very low
SWR, the series antenna, with an insulator at the base of the
radiator, seem to radiate with more efficiency.  Series antennas
seem to have a higher voltage at the end of the radiator than the
shunt system.  This would seem to support Tesla's theory that
electromagnetic waves are mostly voltage and that they travel
much more efficiently when their voltage is very high.