^ I've used that exact same one. Didn't work for me. Though come to think of it now, there's a twist....
1) I used it between the GPS output and the SM10 input, to try to get rid of the buzz from GPS. Initially, was putting the GPS into the GL2Way CB 2nd radio input, the noise was enough to always trigger the CB RX and suppress all bike audio. Next, tried the GPS via that isolator into the SM10 aux input, still triggered the SM10 aux audio suppression but just some of the time, not all of the time. I'm not using either of those now, have the GPS tied into bike audio via the INT and AUX circuits.
2) I guess I could / should try that on the input between the Sena Goldwing 5-pin DIN adapter and the SM10. Maybe it will do the trick on the Sena charging ground loop, if not the one via the GPS. I'll probably try that in the near future.
How do you have it hooked up Rambler358?
BTW, the plug on my isolator is too fat to go into the weird little Sena weatherproof sockets. I wound up grinding some rubber off the isolator, though using one of the ancillary Sena cords as a jumper is probably a smarter idea.