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I0OJJ > ANTENN 01.07.10 23:03l 26 Lines 1056 Bytes #-5797 (0) @ WW
BID : 48980I0OJJ
Read: GUEST
Subj: Re: language and antenna gain
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Sent: 100701/2028z @:I0OJJ.ILAZ.ITA.EU #:6167 $:48980i0ojj
Richard Fry wrote:
> On Jul 1, 11:53 am, Roy Lewallen <w...@eznec.com> 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
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