Posted by
W8JI on
Jul 23, 2010; 6:00pm
URL: http://elecraft.85.s1.nabble.com/Balun-Questions-tp5328810p5330610.html
<<
This sounds really similar to a lot of plans that I've seen... One
other piece that I've noticed on many of these that no one seems to
ever mention is that the two 1:1's are usually wound in opposite
directions on each half of the core... I'm assuming this helps to
reduce the coupling between the two 1:1's? Also I'd be interested to
hear people's thoughts on this "improved balun"... Seems to be an
attractive solution. It only pictures the schematic here and I kinda
picture it as being wound similarly but you wire one of the turns on
one of the feeds from "out" side to "in" side. Essentially the ends
of the wires would fold back over the core to get to its location>>
If you are talking about two cores in the balun, and each core wound with
half turns and then flipped with a transposed winding, everyone who has
measured the fancy winding concludes it does nothing overall except move
things around.
If you are talking about winding two 1:1 baluns on a single common core and
using that to make a 4:1 current balun, I can guarantee you that will not be
a balun. It will unbalance any balanced load placed on the balun's balanced
terminals. Each transmission line transformer has to be on its own
independent core. They cannot share a common flux path.
73 Tom
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