Thread: FM antenna
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Goofball_star_dot_etal
 
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On Sun, 26 Jun 2005 17:04:04 -0400, "Robert Morein"
wrote:


"Goofball_star_dot_etal" wrote in message
...
On Wed, 22 Jun 2005 20:56:44 -0400, "Robert Morein"
wrote:


. Therefore, it
picks up more signal, which can cancel with that received by the nominal
antenna.


********! (7)
It is a balanced transmission line which is matched to the balanced
300ohm folded dipole. The fields associated with the twin conductors
of the feeder cancel in the far field. It cannot radiate/recieve
itself if it is properly balanced.

The cancellation is not perfect, because the conductors are not coincident.
In the 60's and 70's, twinlead used as antenna feed was a major cause of
ghosting, which is a multipath related effect.


LIke I said, plastering it into walls is not ideal. . .

"The twinlead from a folded dipole is part of the antenna system
itself." seems clear enough and wrong.

Your belief that the far field cancels is based upon the analysis of a
point-source dipole, which is merely a theoretical tool.


If it leaked it would be lossy. Coax is convienient.