That slow change of the resistive component and rapid change of the
reactive component is much more prominent if you look at the parallel
admittance than the series impedance.
73, Jerry, K0CQ
On 2/3/2011 3:41 PM, Steve Hunt wrote:
> 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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>>
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