Tom Rauch wrote:
I think I know what you meant, but I'm not sure I agree with that
picture. RF that is accidentally picked up doesn't need to flow
anywhere. It isn't a bucket of something we have to pour out somewhere.
Sorry, Tom, but it is precisely that! Kirchhoff's Law applies
rigorously inside the shack: whatever RF current comes in, must have
some path out again. If it didn't have, it wouldn't come in.
(There are some exceptions, particularly on the higher bands where
wiring lengths inside the shack are a significant fraction of a
wavelength; but they don't overturn the basic principle. Particularly on
the low bands, I've measured a good balance between incoming and
outgoing currents.)
I do agree that feedline chokes are needed on almost all antennas, and
they should always be the first thing you try. But they may only be part
of the solution.
In some situations (which may not apply to you personally, Tom, but they
do apply to some others) it may be necessary to choke both the entry
path *and* the exit path to get a complete solution.
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
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