[TowerTalk] Carolina Winsome and vertical radiator question

[Joe Subich, W4TV]

> But of course, if you put a 4:1 voltage balun at the feedpoint the
> braid isn't connected directly to either leg :)

Which is why the Carolina Window did not use a voltage balun <G>.  I
believe it used a basic *auto-transformer* - or that's what the one I
autopsied a few years ago looked like (I had the PVC housing of a CW160
DMU fail after several years in the Florida sun).

At one time the Carolina Windom "story" indicated the feedpoint DMU
was designed to force unbalanced current and "force" vertical
radiation.  That would be consistent with an autotransformer instead
of a voltage balun.  However, the fixed length of the vertical radiator
would almost certainly result in different "vertical" components from
band to band.

73,

   ... Joe, W4TV


On 2015-01-25 3:32 PM, Steve Hunt wrote:
> The proportion of current that flows back down the shield compared to
> that which flows into the attached dipole leg will depend on the
> relative impedances of those two paths. In the case of a half-wave fed
> one third from one end, the two leg impedances are almost identical:
> 319Ω/-87.7 degrees for the short leg and 334Ω/+72 degrees for the long
> leg in a 132ft dipole I modelled. That suggests there'd be little
> difference whichever side you connected the braid.
>
> But of course, if you put a 4:1 voltage balun at the feedpoint the braid
> isn't connected directly to either leg :)
>
> Steve G3TXQ
>