[Elecraft] K3 SWR Accuracy - reprise

[Steve Ellington]

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
N4LQ at carolina.rr.com
----- Original Message ----- 
From: "Phil & Debbie Salas" <dpsalas at tx.rr.com>
To: <elecraft at mailman.qth.net>
Sent: Wednesday, November 04, 2009 5:53 PM
Subject: Re: [Elecraft] K3 SWR Accuracy - reprise


> "How long is the coax between the LP100 sensor and the K3? This can have
> a significant impedance transformation impact as you go to higher
> frequencies, leading to a different indicated SWR at each end."
>
> The impedance changes, but not the SWR.  Looking at this on a Smith Chart,
> you can see that you just rotate around a constant SWR circle.  Minus coax
> losses of course, which are negligable when we're talking a few feet at 
> HF.
>
> Phil - AD5X
>
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