I played with the filter programs a little and here is what I found to be one possibility. The main problem with the direct conversion receiver is the LO signal goes in the antenna and overloads the front end. A dual conversion would eliminate this problem. I have a box full of 25.125Mhz crystals so that is what I'll be playing with. The receiver will be from 0 - 20 Mhz. First a filter for the front end.