Just put on a brand new terrova on the boat. Hooked up the us2 to my 597ci HD di unit. Shows good sonar readings (I know di will not work, just hid those views) but the depth jumps all over the place. I can manually set depth a few feet past what I know the depth is and receive good sonar returns, but the depth is constantly jumping all over the place. Restored defaults once already. Any tips?