Bill - An effective common-mode choke can be made with 17 turns of RG58-coax wound on to an Amidon FT240-31 core. See: www.karinya.net/g3txq/chokes/ GL - Steve WB6RSE On Sep 29, 2014, at 9:49 AM, Cqtestk4xs--- via Topband <topband at contesting.com> wrote: What do you think? Bill K4XS