Looking at the depth displayed, it seems inaccurate. I connect the unit either to my bow trolling motor transducer or console wires which connects it to a transom transducer.
How do I know if either is showing the correct deoth especially the transom mount seeing as how the transducer is flush to the boat bottom which is a few feet below the surface. The Tr.M. transducer connected to the motor is also lower than the surface by about 2'.

What I did recently was to mark my anchor rope with zip ties every foot to a depth of 8' to test accuracy. Should be able to try it soon. I got to be careful getting close to rocky shallow bottoms when using the gas motor not knowing if the depth is 4' or 2'.