Ran into this with running a 998 and a 597. I put a pc11 power cable on the 597 and an rf choke on power wire also. Pc11 has a choke built in but the other one helped more. I still fet a little interference when running both units at same to e by no more trolling motor Interferenxe. I turn the sonar off on my 998 and use it for fps when I'm up front watching the 597.