[RFI] Computer RFI problem

[ka5s@earthlink.net (Cortland Richmond)]

Now, that IS interesting! Does NEC tell us that there isn't an end-null 
in an end-fed half-wave's's near field? Is the coupling purely capacitive 
to the adjacent feedline conductor? 

Cortland

> [Original Message]
> From: Ian White, G3SEK <G3SEK@ifwtech.co.uk>
> To check this more carefully, I put together a highly simplified EZNEC 
> model of a typical "no radials" vertical, and then tried the effects of 
> running the feedline either straight downwards or away horizontally.
> 
> I assumed a perfect choke at the feedpoint, so that induction was the 
> only way for current to get onto the feedline. I also assumed a 
> half-wave resonant feedline, which is pretty much the worst possible 
> case.
> 
> On calculating the maximum current induced onto the feedline, it really 
> didn't make much difference at all whether the feedline ran straight 
> downwards, horizontally or at 45 degrees! The straight-downwards case 
> was worst, but only by about 20%.