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Re: At which point do we take the value of impedance to tune an antenna?

 

Hi Roger,

This is an (educational) presentation, not a paper. My talks are always for radioamateurs and this formula is best known. This triggers the audience to listen before it gets more 'complicated' :-)

If you look into this presentation a few pages more, the complex impedances are explained and shown. Even the 40+j30 and SWR=2.

73

Arie PA3A

Op 4-8-2022 om 18:30 schreef Roger Need via groups.io:

On Thu, Aug 4, 2022 at 05:32 AM, Arie Kleingeld PA3A wrote:

Lets put it simple without too many formulas. There has been a lot of
math to come to the SWR formulas but we can think about it.
Lots of things to tell about that subject. The following might be
interesting for you:


Arie,

Thank you for posting your paper. I suggest that you correct the text below to state that this formula is only true when the reactance X is 0. I have seen on many occasions people thinking that the magnitude of impedance |Z| can be used in this formula. For example if the complex impedance is 40 + j30 then |Z| =50 and the SWR is 2.0 (when the reference impedance is 50 +j0 ohms). Someone misusing the formula would think |Z|/50 = 1.0 for the SWR which is incorrect.

Roger
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