I have a helix 10 mega SI unit, I have the mega transducer on the boat and also a 2D transducer attached with the Y cable for depth reading at hi speed. I am
confused about which of the transducers is used for depth at idle speed/ I assumed that all depth reading would come from the 2d ducer. I say this because I can put my hand under the 2D ducer at idle and no change I put my hand under the mega ducer and depth goes crazy so reading is coming from the mega. At on plane speed I get depth but is has to be coming from the 2D ducer. In sonor settings I have the mega imaging ducer selected Is this correct?