My pings are just like that. The trolling motor interference comes and goes but I can live with it. In fact the final install will not be on a trolling motor so that's not an issue. The pings though when the other unit is running is a huge issue since the final install will be next to another transducer.
Which other sonar and transducer is causing the pings? You might want to try changing the frequencies on the other unit to see if that helps. Also play with the Noise Reduction settings on the PS21.
Smokercraft Phantom 202 Yamaha F115/Merc 9.9
Garmin 7610xsv/GT51M-TM/Panoptix PS21/LiveScope
Why am I hanging out here when I could be fishing.....
Which other sonar and transducer is causing the pings? You might want to try changing the frequencies on the other unit to see if that helps. Also play with the Noise Reduction settings on the PS21.
It's an Onix and I've tried every setting I can think of. I'm going to try the shaft mount for the panoptix this weekend if the 100% chance of rain goes away.