John Popelish wrote:
The beads I am suggesting are over an inch in diameter and over an
inch long. A half watt would barely raise their temperature
noticeably above ambient. And they will fit over coax that is a half
inch in diameter. There are other shapes that are more cost effective
for smaller diameter coax. 28B0591-200 has a .23 inch hole, but is
1.38 inches long, with a .591 inch OD. A half watt won't warm that
one very much, either. And it costs only $.76 each, if you buy 10 of
them.

My point was that there are cheap long form factor toroids available
now, that weren't available when W2DU designed and described his BalUn.

My point is dollar for dollar multiple turns always wind up being a
better investment. That's because impedance approximately follows the
square of the passes through the core.

Also, a string of beads is a terribly inefficient use of ferrite
materials. If you double the expense of the balun by doubling the
number of beads, you only double the common mode impedance.

But it spreads the heat out, and doesn't require you to kink the coax,
which makes it last longer in the weather.

I've never once had cable fail from being wound on cores. I can't
imagine why someone would need to kink the cable.

The only part of the cable that significantly increases CM impedance is
the part inside the core window. Why care how tightly the cable is
pulled against the core outside??

73 Tom