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Re: [TenTec] 160 M antenna

To: "'Richards'" <jrichards@k8jhr.com>, "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Subject: Re: [TenTec] 160 M antenna
From: "Rick - DJ0IP / NJ0IP" <Rick@DJ0IP.de>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Fri, 8 Nov 2013 09:28:16 +0100
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
I would do the same thing I have been doing for 30 years and the same thing
I have told you to do many times:

        DO WHAT YOUR FRIEND SUGGESTS!

Go look at my Inverted-L picture again.
There is no difference in the theory between the Vertical and Inv.-L when it
comes to matching and efficiency.
I am doing EXACTLY that.

I make the antenna about 15% longer and shorten it electrically with a
capacitor.
This raises the feedpoint impedance to 50 Ohms (in the ideal case).
Unfortunately I made mine too long and it is at 73 Ohms, so my SWR is 1.5:1.

Your friend is SPOT-ON!

73
Rick


-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Richards
Sent: Friday, November 08, 2013 9:18 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] 160 M antenna

Interesting commentary, Ken.

I DO have a 40m ground plan with 65 radials.   And it has that textbook 
38 ohm low SWR you mention.   It seems to work swell... but your comment 
suggests it could be better.

A friend suggested I make it slightly taller and add some capacitance until
it presents a an inherent 50 ohm load.  (I think that is what he said...
let's assume HE said it right, if this is not a good idea... and presume I
remember it wrong...)


     So - What would YOU do with my antenna to make it  work better?


(This is NOT an argument - it is a very serious question to me.)

--------------------  K8JHR -----------------------

------ Original Message ------
From: "Ken Brown" <ken.d.brown@hawaiiantel.net>

A quarter wavelength vertical over an excellent ground counterpoise system
has an impedance of about 37 ohms. If you don't need a matching device to
get a 1:1 SWR at the resonant point, then it is likely you have about 13
ohms of loss resistance (the kind that produces heat, versus radiation
resistance, the kind that produces a radiated signal) that added to the 37
ohms of radiation resistance makes a perfect match to your 50 ohm coax. Very
convenient. Not very effective. What would you rather have? A low SWR or a
stronger signal? Many hams have chosen (perhaps unwittingly) a low SWR.

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