One of the most vexing issues for contesting hams can be RFI. The causes of RFI are many as are the fixes. So determining the cause of the overload on other peoples equipment and what a viable solution could be is a difficult task.Jim Brown, K9YC, has a 60-page pdf file available for download called "A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing."Jim just recently updated the document as well, including "a major update to the Choke Cookbook, based on extensive measurements of these chokes."This is a handy reference to have and we should all take advantage of the great knowledge and work being shared from a guy that really knows this stuff.Scot, K9JY