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[TowerTalk] Fwd: Resonance is over rated

To: towertalk@contesting.com
Subject: [TowerTalk] Fwd: Resonance is over rated
From: hanslg@aol.com
Date: Tue, 11 Aug 2009 00:54:30 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
 


 


 

Isn't the discussion really what a good antenna system is all about?

To my knowledge it is important to get as much power in the radiating part as 
possible or have as little losses as possible in the rest of the system.

1) If you have a coax cable, especially if it is long (or lossy, same thing) 
you want to minimize the SWR as that leads to minimum loss in the cable.

2) You want to have as high ration of radiating resistance to ohmic resistance 
in you radiating element as possible also to minimize you losses.

A dipole is a good example of a radiator with (usually) high ration 
radiation/ohmic resistance. (If you use a steel wire or a very thing Cu wire 
well ...) A 6" nail is rather useless as radiatior (but I can tune it though).

In my humble opinion you place the best antenna tuner as close to the antenna 
you can and tune it up so you have as low SWR as you can in your feed cable. If 
you, like me, use a low loss ladder feed to your antenna you can move the tuner 
closer to your radio shack (convenience if nothing else) without loosing to 
much power in the system.

It is not the radiating element that has to be in resonance (my opinion) it is 
whatever a coax is feeding (and your TRX for that matter, as that "likes" 50 
Ohms load). I have been using longwires, short and long verticals and even 
aluminum ladders as antennas with relaively good result, but I have always used 
a tuner at the TRX end to insure my TRX "sees" the correct load.

Hans - N2JFS


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