Towertalk
[Top] [All Lists]

Re: [TowerTalk] Resonance is over rated

To: Towertalk e-Goups <towertalk@contesting.com>
Subject: Re: [TowerTalk] Resonance is over rated
From: Steve Hunt <steve@karinya.net>
Date: Fri, 07 Aug 2009 11:08:54 +0100
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Antenna efficiency (as opposed to antenna system efficiency) has little 
to do with resonance, but a lot to do with its radiation resistance 
relative to its loss resistances.

A resonant dipole with a feedpoint impedance of 70+j0 which includes 
copper losses of 1 ohm has an efficiency of 69/70=98.6%.  A non-resonant 
dipole with a feedpoint impedance of 70+j1000 has exactly the same 
efficiency - 98.6% !!

And just to end with some nonsense: a monoband antenna can only be 
resonant at one spot frequency - so don't speak into the mic, or press 
the key, because those sidebands you generate will be on frequencies 
where the antenna isn't resonant :)

73,
Steve G3TXQ



_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>