[TowerTalk] wire antenna question

[Blair S Balden]

Well, I suppose my understanding was not quite right.  I had assumed that, if you could get the load impedance to a value of 50 ohms (when using 50-ohm coax), you would get a 1:1 SWR.  I thought this is how antenna tuners and matching networks worked, by inserting the appropriate amount and type of reactance to arrive at 50 ohms, or as close to it as possible.

I had reasoned that if my resonant dipole had an impedance of less than 50 ohms, with the resulting SWR, I could reduce the SWR by changing the length, thereby "unbalancing" the reactive component and raising the total impedance to 50 ohms.  

Apparently, I need to study this further.

Thanks to all who commented.

73,
Blair NP2F
 

----- Original Message -----
From: Jim Brown <jim at audiosystemsgroup.com>
Date: Friday, November 14, 2008 6:46 pm
Subject: Re: [TowerTalk] wire antenna question

> On Fri, 14 Nov 2008 23:37:41 +0000, Steve Hunt wrote:
> 
> >Minimum VSWR:  Freq = 21.03 MHz, Z = 101.1 - j16.64, VSWR = 2.09
> >Resonance: Freq = 21.13 MHz, zZ= 112.2+j0, VSWR = 2.25
> 
> >The "anomaly" occurs because the VSWR is being  referenced to 
> something 
> >significantly different than the resonant impedance of the antenna;
> 
> Here's yet another situation where 75 ohm coax would be a better 
> choice than 50 
> ohm coax. 
> 
> 73,
> 
> Jim K9YC
> 
> 
> 
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