[TowerTalk] Shunt fed tower

[Bill Coleman AA4LR]

On 3/31/00 1:06 PM, Jan Ditzian at ditzian@alltel.net wrote:

>
>This topic has probably appeared here before, so if someone can just
>send me to the right month and year to look at past articles, I will be
>satisfied.  I am interested in shunt feeding my 50-foot tower, but it is
>guyed, and the guys are not insulated.  I assume that it is necessary to
>insulate them, especially if I want them to act as a capicatance hat,
>but I would like confirmation.

I am also interested in shunt-feeding my soon-to-be 48 footer. Please 
post responses to the list.

In my case, the tower will be bracketed and not guyed.

As I understand it, shunt feeding consists of two parts: a) getting a 
good radial field down to improve radiation efficiency and b) properly 
matching the tower with a gamma or omega-match.

I've gamma-matched delta loops by trial-and-error (made easy with an 
antenna analyser), is there any way to compute the length, size and 
distance of such a match, or at least get in the ballpark?



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


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