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Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals

To: tentec@contesting.com
Subject: Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals
From: Jim Brown <k9yc@audiosystemsgroup.com>
Reply-to: k9yc@arrl.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Fri, 27 Jan 2012 13:08:52 -0800
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
On 1/27/2012 11:41 AM, Steve Hunt wrote:
> Jim,
> What "bugs" me most about this issue is that it isn't Rocket Science -
> simple application of Ohm's Law will give you the answers.


> Some may think that's an insignificant difference and that we are
> "nit-picking"; but now imagine you are running a long length of that
> ladderline at high VSWR based on an Antenna Book loss prediction of 2dB
> - would you be happy if you discovered that the real loss was at least
> 4.8dB? Or that what you thought was a 4dB loss was actually nearer 10dB?

Exactly my point as well.  One option that smart engineers always 
consider for very long runs are open wire lines. Anyone who has had the 
opportunity to visit one of the WW!! vintage HF broadcast and 
communications stations or a high power AM broadcast transmitter has 
seen LOTS of open wire lines feeding rhombics, Sterba curtains, vertical 
radiators. Some are/were balanced, and some are/were in a coaxial 
configuration. They are typically supported on rigid poles with a 
U-shaped bracket and insulators at the top. In a typical coaxial 
configuration, there might be four closely spaced parallel wires 
functioning in parallel as the center conductor and four or more wires 
at much wider spacing surrounding the center conductor as the shield.

73, Jim Brown K9YC
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