On 9/6/2010 11:43 PM, John Smith wrote:
On 9/6/2010 5:44 PM, John Smith wrote:


This is even an improvement over the more common baluns you find around.
The balun show is a 4:1, consisting of two bifilar windings, one bifilar
on each side of a single toroid. It is shown in Fig. 4 and text
describes its' construction and working. There is even a graph showing
performance across a wide bandwidth. This design can be expanded to a
9:1 by simply using two trifilar windings in place of the two bifilar
windings, and making proper connection of the windings.

http://www.home.earthlink.net/~chris...k4to1Balun.pdf

I suspect a gain in performance would be had with most, if not all,
antennas in common use. And, as the text points out, grounding the
correct side of the secondary series windings will allow the balun to be
used as an UNUN.

Regards,
JS

Actually, I used 9:1 when I should have used 16:1. For a 9:1, you would
still construct the balun with the trifilar windings. However, the
"last" two windings (one from each side) would be tapped, roughly, on
1/2 of their turns and these two points used to supply the 9:1 output point.

Regards,
JS