My Band Pass Filter board has had problems with the 3 upper filters showing low (35dB) upper side rejection. I just determined a simple fix. Connect the digital and RF grounds together near U1(this should be the only place they are connected). Add a .1uF bypass from U1-14 to ground. I made a new set of measurements last night and posted them on my bpf page of my web site. Look in the left pane for "measurements". The upper side rejection of all filters is now more than 50 dB with some >60 dB.
Dave - WB6DHW <http://wb6dhw.com>
