[TowerTalk] Detuning a tower .... was Open-wire transmission line

[David Gilbert]

Hi, Joe.

Detuning a tower and shunt feeding a tower seem to be essentially the 
same mechanism except for whether there is a feed or not, and I've often 
wondered why running a wire down the center of a tower wouldn't create 
the same coaxial section as surrounding the tower with multiple wires.  
Has anyone successfully tried this?  I couldn't find much of anything by 
searching online.

Take care es 73,
Dave  AB7E



On 1/2/2024 7:17 AM, Joe Subich, W4TV wrote:
>
>
> A tuned skirt is a detuning kit.  In essence, the skirt is a coaxial
> section while a single wire is an open wire line.  They work the
> same way short one end, tune the open end with the appropriate
> reactance (capacitor).  If one knows the Zo of the line section,
> determining the starting capacitance is straightforward.
>
> I would prefer a three or six wire skirt for detuning simply because
> it is easier to calculate the effective diameter(s) of the triangular
> tower section and the skirt.  Any errors should be systematic and
> the *ratio* of the two diameters will be consistent.  However, either
> the single wire (loop) or skirt will work to detune a tower.
>
> 73,
>
>    ... Joe, W4TV