Heres the thread: http://elecraft.365791.n2.nabble.com/K4HD-filter-physical-format-td7652442.html#a7652506 Up to 3 filters per receiver. 73 Lou, W0FK ----- St. Louis, MO "The difference between stupidity and genius is that genius has its limits." Albert Einstein -- Sent from: http://elecraft.365791.n2.nabble.com/