I am having a heck of a time locating a source of good information
on
how to make an effective common mode filter using the snap-on type
ferrite beads such as available at RAdio Shack.

Someone needs to characterize those beads.
What is the one-turn choking impedance at
10 MHz?


That is a good point. I'm not even sure of the vendor of the numerous
split beads I have on hand. The ferrite is about 1/2" thick, 1" in
diameter, and a 5/8" hole diameter. Don't know the material. The
plastic housing is labeled " F / R " with the slant bar being a
lightning bolt, and the part number is: 80640* . (that's an asterisk
after the zero.)

Ed