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Re: [TenTec] SLIGHTLY OT

To: tentec@contesting.com
Subject: Re: [TenTec] SLIGHTLY OT
From: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Reply-to: geraldj@weather.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Fri, 08 Apr 2011 16:25:12 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
Perhaps it would be more useful to connect the ends through coils that 
would bring the antenna nearly to resonance on 160 and by their choke 
(neglecting distributed C to make into traps which may not be a perfect 
assumption) effect disconnecting the added wire on the higher bands. The 
choke will be more effective on 80 through 30 than 20 through 10 meters 
because the distributed will likely make the choke series resonant 
somewhere in that range and above that resonance it looks capacitive. 
I'm sure I've read about such chokes in Pat Hawker's antenna topics volume.

73, Jerry, K0CQ

On 4/8/2011 3:46 PM, Steve Hunt wrote:
> Art,
>
> If you mean extending the ends off at 90 degrees to the main dipole at
> the 25ft/30ft level, that's fine. Just think of it as adding end
> capacity loading to an electrically short dipole. The important thing is
> that it raises the resistive component and drops the capacitive
> component of the feedpoint impedance - both of which significantly
> reduce the VSWR and loss on the open wire.
>
> But note that we are focussing on 160m here - there will be a "knock on"
> for the other bands which will likely be detrimental. On the higher
> frequency bands there will be much more current in those low extensions
> than there is on 160m, and that means the "effective height" of the
> antenna will be lower.
>
> 73,
> Steve G3TXQ
>
>
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