Turning on the A-Scope
The a-scope is a vertical flasher along the right side of the full-screen sonar view. This feature expands the most recently received sonar data so that it is easier to see. It can also be helpful for detecting fish that are close to the bottom.
NOTE: This feature is not available on all sonar screens.
From the full screen page, select .
Diameter of the sonar cone at the present depth