[TowerTalk] Double Coax Feed

[Bill Coleman AA4LR]

On 10/5/00 10:34, ValErwin@aol.com at ValErwin@aol.com wrote:

>Like any good ham, I got some of this stuff and used it to keep 
>from having to tye-rap  the coax over the entire length.  The result was 
>excellent! I used this antenna on 10-80M, QRO, for a period of 5 years until 
>I moved. This double coax approach also worked out very nicely for ham shack 
>access from the outside world.

This works as a balanced feeder, but has no other advantages. It doesn't 
have the near lossless properties of open wire, instead you have the same 
amount of loss as ordinary coax. 

The one recommendation I would make for this type of installation is the 
same one I make for a remote balun: use solid dielectric coax. Since the 
feedline is part of the conjugate-matched antenna system, reactive loads 
might appear that could induce high voltage points on the coax. Solid 
dielectric coax has a higher breakdown voltage than foam. 

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@radio.org
Quote: "Boot, you transistorized tormentor! Boot!"
            -- Archibald Asparagus, VeggieTales


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