Richard Fry wrote:
On Jul 1, 11:53 am, Roy Lewallen wrote:
But a helically-wound radiator *is* a naturally resonant radiator if
wound to make it so. It just isn't straight.

That is true, but a resonant, helically-wound, electrically short
radiator does *not* have the radiation resistance of a straight, self-
resonant radiator of about 1/4 wavelength -- which can make a large
difference between the two forms in the amount of available energy
radiated vs. that lost in the r-f ground system.

RF

Guess I just don't understand how a resonant, helically-wound antenna is
"electrically short". Suppose you helically wound an eighth-wave
vertical in such a way that it was resonant. Its physical length is an
eighth wavelength. What would its "electrical length" be? That is, how
"electrically short" would it be?

How do you determine what the "electrical length" of a vertical or
dipole is? Does a loading coil at the base alter the "electrical
length"? Does an L network at the base?

Roy Lewallen, W7EL