On 1/30/2012 5:33 PM, Silvio M. Martín LW9EOC wrote: > As I can remove noise entering through the ground? and how to isolate the > shield?
A common mode choke, made by winding many turns of the coax around a ferrite core, would help. The best core to use is Fair-Rite mix #31, and you want at least 14 turns through a 2.4-inch outer diameter toroid for 160M. 7-9 turns through a big one-inch inner diameter clamp-on will work. Study http://audiosystemsgroup.com/RFI-Ham.pdf for details, a discussion of how and why this works, part numbers of useful ferrite cores, and a list of known good sources in the US. See the Fair-Rite website for a listing of international distributors. 73, Jim Brown K9YC _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
