Posted by
Phil Salas on
Nov 05, 2009; 12:18am
URL: http://elecraft.85.s1.nabble.com/K3-SWR-Accuracy-reprise-tp3943810p3949281.html
Transmission line theory (and therefore the Smith Chart info) IS correct.
Transmission line length DOES transform the impedance, but not SWR. So you
may be changing the impedance to something that your tuner can tune when you
add coax length, but you are not changing the SWR by adding coax - other
than the change due to coax loss which is negligable for short lengths.
Now I do agree that different SWR meters probably read differently when the
SWR is the same but the impedances presented to the two SWR meters are
different.
Phil - AD5X
----- Original Message -----
From: "Steve Ellington" <
[hidden email]>
To: "Phil & Debbie Salas" <
[hidden email]>; <
[hidden email]>
Sent: Wednesday, November 04, 2009 5:59 PM
Subject: Re: [Elecraft] K3 SWR Accuracy - reprise
> The first statement is correct. Length of coax will transform impedance
> and cause SWR meters to read differently.
> I've seen this Smith Chart reference before and it makes no sense. You can
> certainly use your feeder to "match" your antenna. Of course, if SWR
> meters didn't care what the impedance is then yes, it wouldn't matter
> where you put it along the line but such is not the case.
> Steve
> N4LQ
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