[Antennas] resonance

Sat Dec 17 11:57:33 EST 2005

Robert Lay (W9DMK) wrote:
> Dear Frank,
>> You are correct about the behavior of the real component
> of antenna impedance as a function of height above ground
> (for resonant dipoles).
>> Just out of curiosity, I wonder why you are concerned
> about it.

I am not really concerned. I am more interested in what 
others think they know about the subject. So far I still 
have not seen a clear answer to the original question. Does 
the impedance remain resistive when the antenna height is 
varied?
>> To me, the more interesting phenomenon is the fact that
> depending on wavelength over diameter of conductor, the
> length of the dipole is generally not 1/2 wavelength at
> resonance. It's always shorter than a half avelength -
> more so with thicker wire. In other words, with real 
> thick wire, it would be real short - like 0.4 wavelength.
> Ain't that a hoot?

No, that is just a missapplication of the formula for 
determing length of wire antennas. I am pretty sure there 
are correction factors to be considered for 'thick' dipoles.
Regards,
Frank Kamp
K5DKZ