On Fri, 08 Oct 2010 11:14:13 -0400, John Ferrell wrote:

I have been faithfully using a coil of coax as a common mode choke for a
while without any idea if it is really doing any thing.

Googling turns up more url's than I can follow. I would appreciate any
suggestions as to how might measure the effects of the common mode
choke. 30 to 17 meters is my favored range of operation. I have a pretty
well equipted shack.
John Ferrell W8CCW

Here is one of the better papers I've found on this subject.

www.audiosystemsgroup.com/RFI-Ham.pdf

Danny, K6MHE