On Fri,1/30/2015 2:49 PM, Jim Garland wrote:
But, like I said, maybe I'm not following something.
Right -- you are not. First, you don't understand what common mode is.
Second, you don't understand the choke. A ferrite common mode choke
STARTS OUT as a lossy inductor, but one with shunt capacitance. This
forms a very low Q resonant circuit (typically 0.4), and thus a very
broad resonant peak. It is the resistance around resonance that forms an
effective common mode choke.
I've discussed this in considerable detail in tutorial form in
k9yc.com/RFI-Ham.pdf and some of that material has been added to the
ARRL Handbook. There's also a pdf of the slides that go with an RFI
tutorial that I've done for several ham clubs. It's on my website --
k9yc.com/publish.htm I suggest that you study these two pieces. It's
far too much work (and probably boring for many readers of this list)
for me to post it here.
73, Jim K9YC
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