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Old May 26th 06, 05:32 PM posted to rec.radio.amateur.antenna
Roy Lewallen
 
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Default converting from dipole/inverted vee to beam



Jerry Martes wrote:
"Buck" wrote in message
...
I have a wire dipole and an inverted Vee each cut to resonance on a
desired frequency. I would like to add a reflector and/or a director
(one at the time) to make each one a beam. Will adding the reflector
and/or director change the resonant frequency, or just the impedance?

Thanks
Buck
n4pgw

--
73 for now
Buck
N4PGW


Hi Buck

Isnt Resonance defined as the frequency where the Impedance has *no*
reactance? Wouldnt that imply that the resonant frequency of the antenna
will always change if its impedance changes?
Can you *ever* change one without changing the other?


You're correct about the definition of resonance.

Buck's statement would have made more sense if it the last words were
"just the resistance", and that's likely what he meant.

Sure, you can change the impedance without changing the resonant
frequency -- a transformer will do that, for example. At resonance, the
resistance will simply be a different value.

But to answer Buck's question, adding another element will almost
certainly change both the resistance and reactance at the feedpoint, and
therefore the resonant frequency.

Roy Lewallen, W7EL