Well I've been fishing with my grandpa and talked him into splitting a lowrance elite 5 hdi and the sonar and downscan are pretty grainy. I messed with all the settings that people suggest. I've been told by a dealer that we could have a bad transducer. My grandpa wired this thing up while I was working and he spliced into the trolling motor wire going to the battery. I have tried to tell him that is the problem but I'm looking for more expert input