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Re: KX3 ATU

Posted by Matt Maguire on Sep 19, 2012; 5:34am
URL: http://elecraft.85.s1.nabble.com/KX3-ATU-tp7495809p7562962.html


On 19/09/2012, at 2:48 PM, vk4tux <[hidden email]> wrote:

> Don, When you say "The ATU will tune the antenna to an acceptable SWR", you
> are contradicting yourself, because as you rightly said the tuner does not
> change the antenna feedpoint swr.

It is clear from the context that Don meant the ATU will tune (ie. match) the antenna *system* to the radio, where the antenna system consists of the ATU, antenna and connecting feedline considered as a single unit. This of course does not mean that the VSWR is 1:1 everywhere within that system.

The theory predicts that the measures VSWR will be constant along a *lossless* feedline. As you point out, practical feedlines do have losses. This will include I^2.R copper losses, but there can be losses from other sources as well, such as dielectric losses. Often such losses will be modelled as some sort of equivalent series resistance.

73, Matt VK2ACL
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