This is an area of coverage at the edge of the cone, usually near the bottom, where fish cannot be detected. It is common to all sonar units. This zone exists on flat lake bottoms as well as at the edges of a piece of structure as the angler moves up and down the breakline. The dead zone sometimes accounts for fish that are caught but not seen on the sonar screen. It means that at times you must fish structure and not just fish seen on sonar.
Bill Diedrich is a retired Minnetonka math teacher with a love of fishing electronics.
