Yes, they do. Elecraft presents it's position on the term "Roofing Filter" here: http://www.elecraft.com/K3/Roofing_Filters.htm where the "protective" function is emphasized. Bob NW8L On Thu, Oct 28, 2010 at 5:37 PM, Wes Stewart <n7ws at yahoo.com> wrote: > Unfortunately, they do. Personally I dislike the term. >