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Re: [TowerTalk] 75ohm cable

To: "towertalk@contesting.com" <towertalk@contesting.com>
Subject: Re: [TowerTalk] 75ohm cable
From: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 19 Jul 2010 22:39:17 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
>True, but the additional loss in the coax depends on the matched loss 
>and the additional loss (in the line) due to SWR.  With a low loss line, 
>it's miniscule, but if using RG8 on 440 it could be substantial.  

WRONG!  The additional loss due to mismatch does NOT depend on the 
matched loss. It depends ONLY on the mismatch at the load. In fact, the 
higher the MATCHED loss, the less that mis-match matters. One of the 
things that the Smith Chart teaches us is that loss causes the SWR to 
converge toward 1:1 (and the impedance at the TX to be equal to Zo. The 
more matched loss, the faster it converges. 

73, Jim K9YC


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