[TowerTalk] 40m 4el KLM - replacing linear loading with coils

[jimlux]

On 4/28/20 7:08 PM, Michael Tope wrote:
> Yeah, I was expecting the two-coil design to have better VSWR bandwidth. 
> Did you compare the radiation resistance of the two designs? I would 
> expect the one coil design to have a lower radiation resistance.

> 
> Perhaps the lack of difference in the VSWR bandwidth of the two designs 
> explains why the Cushcraft 402CD/XM240 designs go to the trouble of 
> using capacitance hats after the loading coils.

capacitance hats make the current distribution more uniform along the 
element - that helps with gain as Dave just pointed out.

A sort of ultimate version is a tesla coil - uniformly loaded, with big 
capacitance on each end, with the "element" being a tiny fraction of a 
wavelength.  It's a parallel LC circuit.

Of course, a TC is a terrible radiator.



> 
> 73, Mike W4EF..............
>