[RFI] Computer RFI problem

[Ian White, G3SEK]

Rob Atkinson, K5UJ wrote:
>I'm seeing a reiteration of an earlier message with no explanation.
>Perhaps I have misunderstood what is meant by "...dropping it [the 
>feedline] down vertically in line with the main antenna element..."
>I have pictured a feedline dropping away _below_ a vertical radiating 
>element, in line with it,

Yes, that's correct. The main antenna element goes vertically upward 
from the feedpoint. The coax goes vertically downward from the 
feedpoint. A straight vertical line, extending upward from the ground, 
would pass first through the coax and then through the antenna element.

All this seems to me to be the normal usage of the term "in line 
with"...

> and having no part parallel to the same radiator.

Sorry, I don't understand that.

> The excerpted description above could easily refer to a feedline 
>parallel to the radiating element

If you mean that the feedline runs upward alongside of the radiating 
element, that is "parallel to" but *not* "in line with".


>although I have no idea why anyone would feed an antenna in that 
>fashion.  However that would indeed result in a great deal of coupling 
>it seems to me.  Otherwise, I wish to have this explained to me please. 
>Thank you very much.

I hope that helps.

-- 
73 from Ian G3SEK         'In Practice' columnist for RadCom (RSGB)
                            Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek