Non - You can contact RF Parts. They have a number of single winding RF chokes, and may have an appropriate item or substitute http://www.rfparts.com/choke.html#highrf w9gb > Does anyone know of a source for the 1 mh RF chokes used in the SB-220? > These are RFC 4, 5 and 6 on the schematic and the Heath part number is 45-4. > > Thanks, > > Bob W6VY