Try removing C18 on the LPF-Control or grounding the receive pins on the TR switch.? I think the feedback is getting in through U1 & U8.? Maybe the control logic is not correct.
On Mar 21, 2025, at 3:10?PM, jerry-KF6VB <jerry@...> wrote:
?No progress on my oscillation problem. I figured maybe it was external feedback from the LPF to the BPF. So I tried moving the BPF farther away from the LPF...no difference. Then I disconnected the BPF entirely & replaced it with an SMA barrel...no difference.
I noticed that a few of my SMA connectors were fraying where the cable joined the crimp. Peeled off a bit of insulation and soldered them to the crimp ferrule.
