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TopBand: Matching transformmers

To: <topband@contesting.com>
Subject: TopBand: Matching transformmers
From: N6DX@aol.com (N6DX@aol.com)
Date: Tue, 17 Sep 1996 20:26:54 -0400
Gentlemen,
Please allow me to comment on another "universal truth" that ain't quite so.
 Despite publication in ON4UN's authoritative book on Low Band antennas the
ideal transformer for a Beverage antenna is not an autotransformer as
recently described.  Due to significant surface wave ground loops induced in
feed lines for Beverages, especially if they are long, are a big cause of
spurious signal reception.  It wasn't until I isolated the windings of the
transformer did I remove all the garbage.  My method is to use the tri-filar
winding for only the secondary.  The separate primary (50 ohm) winding is
wound with small diameter coax with the end center conductor attached to the
shield at the beginning of the winding.  This not only isolates any
circulating ground currents but provides a Faraday shield between the
windings.  After getting them all working I was surprised to see how similar
the signal levels and how quiet they became.  This may be not as critical
over good ground but out West our ground is extreemly poor and irregular.
Good luck.  Let me know any results to this suggestion.  On 160 receiving is
everything!

Darrell, N6DX@aol.com

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