wanted to add some comments as i trouble shoot this same issue before i was a part of this IO group.
I had this exact issue and it was VERY bad, huge birdies on the waterfall and very high level of noise at the target frequency.
i noticed the major noise ( for my sbitx V3 at least) was from the flat display ribbon getting close to the radio board. while the radio was on i could move it closer or further away and recreate the issue. if i gently formed it (bent it) away from the radio board the noise dropped of considerably.? i re-organized all of the cables to "encourage" the display ribbon to stay away from the radio board.?
but the but big improvement came when i added aluminum tape to the display ribbon to act as a shield. same tape that is used for shielding on guitars (pretty much the same as the aluminum foil tape for duct work) and covered the aluminum tape with electrical tape so it can not short anything. I was concerned this could cause some capacitance on the ribbon and thus display issues but , no,? no issues to be found.?
Wow what a difference.? i can crank the IF to 100 without getting the noise anymore.??
after reading the comments form this thread i am going to open it back up and add the solutions you have found as well, thank you for sharing all your findings.?
hope this helps someone, W9BLW
