[TowerTalk] To get a truly balanced antenna feed

[Ian White]

Thanks for the reference, Paul.

73 from Ian GM3SEK


>-----Original Message-----
>From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
>Paul Christensen
>Sent: 25 June 2016 16:08
>To: towertalk at contesting.com
>Subject: Re: [TowerTalk] To get a truly balanced antenna feed
>
>>"Moving on to "How might you measure CM current or line balance?" I'm
>afraid the two-ammeters method is only the roughest of checks. Because
it
>only measures the overall magnitudes of the currents in the two legs,
it is
>only capable of detecting gross levels of unbalance. A more accurate
>measurement must also take account of the differing phases in the two
legs.
>The simplest method would indeed be to pass the line through a large
>toroid,
>and extract a sample of CM signal on a terminated secondary winding."
>
>Ian,
>
>http://www.wz5q.net/index/shack_data/tuna.htm
>
>Have a look at WZ5Q's work where he monitors both line current and
phase
>with toroidal sample loops (scroll to the bottom of the page).  Note
that he
>takes scope phase measurements directly at the tuner output.
>Measurements
>made at a point further along the line may yield a different result if
>there's unintentional line coupling to close objects.    Still, it
shows an
>awareness of the line balance performance issue.
>
>Paul, W9AC
>
>
>
>
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