There was discussion of "Tuning clicks" before. My Raduino had this and also the jitter on the last digit. I would describe it as a rustling noise rather than clicking. I tried caps around the 7805 regulator but the noise was still there. What made the noise inaudible was a series 10ohm and a 2200uF electrolytic to ground in the supply to the Raduino. (Values as available in my spares box.) Small 104 caps had no effect. It is a power supply problem. The DDS takes 78ma, as much as the rest of the receiver. Presumably when the DDS frequency changes, there are several milliseconds of much higher power demand.
Like Mark, I think my bandpass filter might be off frequency. The rx seems much more sensitive at 7.5MHz than at 7.0. Next step is to test the tx side and I can more easily then plot the bandpass filter response.
