[TenTec] OT Kind of. ?? about wide band antennas

[Dave Edwards]

Huh.....I was just trying to explain that to my wife the other day!!!

----- Original Message ----- 
From: "Dr. Gerald N. Johnson" <geraldj at weather.net>
To: <tentec at contesting.com>
Sent: Thursday, February 03, 2011 5:30 PM
Subject: Re: [TenTec] OT Kind of. ?? about wide band antennas


> 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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