On 4/29/2013 5:37 PM, Karl W4KRL wrote: > I think it is more correctly a notch filter. Yep, I use one as a 'wave trap' in my crystal set. Richard -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://amrad.org/pipermail/tacos/attachments/20130429/5c739522/attachment-0001.html>