[Antennas] resonance

Sat Dec 17 11:34:57 EST 2005

Steve wrote:
> Resonance is actually a function of the antennas
> electrical length. The fact that the exact center of a
> half wave dipole is purely resistive at resonance is a
> happy coincidence. It is possible (common actually) to
> have a resonant antenna who’s feed point isn’t purely
> resistive or even close to the 75 ohm value of a dipole.
> For instance if you were to keep the length of the dipole
> exactly the same and tap it at a point other than the
> exact center the feed point wouldn’t be purely resistive
> or anywhere near 75 ohms but the antenna would remain
> resonant.

How would you know that it remained resonant? How would 
you test that? The only test I have is to verify 75 ohm 
resistive impedance at the center with the antenna 1/4 
wavelength above electrical ground.
I figure if it cant be verified, it may not be true 
regardless of how logical is sounds.
Regards,
Frank Kamp