Paul,
When you say "bandwidth" I presume you mean "VSWR bandwidth".
The Resistive component of the feedpoint impedance of a dipole varies
relatively slowly with frequency either side of resonance, but the
Reactive component varies much more quickly; so it's the rate of change
of the Reactive component which largely determines the VSWR bandwidth.
The rate of change of the Reactive component is closely linked to the
size of the conductor - the "fatter" the conductor, the slower the rate
of change of Reactance, and the wider the bandwidth.
Hope that helps.
Steve G3TXQ
On 03/02/2011 21:10, Paul wrote:
I have been asked a question about why the diameter of the conductor of
antenna effects the band width.
This question came up while in a discussion with a guy that had built a
80 meter dipole out of a semi ridged copper tubing 1/2 diameter. One of
the newer hams in the discussion was very curious and interested in the
subject.
I remember learning about this many years ago, but was totally unable to
enplane the subject. I know this group is the best repository of
knowledge. So your feed back is greatly appreciated. I will forward
your replies onto the interested ham.
Thanks,
Paul K.
WA0BAG
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