RadioBanter - View Single Post

March 20th 06, 03:32 PM posted to rec.radio.amateur.antenna

wrote:
You keep trying to drag something from a self-resonant helice into a
loading coil discussion.

My 75m bugcatcher coil is self-resonant around 6.7 MHz so it
meets the minimum requirement for a Tesla coil at 6.7 MHz.
4 MHz is 60% of the Tesla coil self-resonant frequency. The
coil is known to possess a 90 degree delay at 6.7 MHz. That
would make the delay ~60 degrees at 4 MHz. Dr. Corum suggests
a 15 degree limit for the lumped-circuit model.

The two are nearly at opposite extremes in behavior, but even at that
the self-resonant helice can be analyzed with standar L/C analysis.

Unfortunately, that's not true. One cannot assume the
presuppositions of one's model without proof. The "standar L/C
analysis " assumes the delay through a coil is zero, i.e.
faster than light. The delay through a self-resonant coil
is known to be 90 degrees. That "standar L/C" model is
invalid at the self-resonant frequency where the coil
is acting like a 1/4WL open-circuit transmission line
stub.
--
73, Cecil http://www.qsl.net/w5dxp