Sonar Technology Cone Angle

Cone angle describes how wide the sonar beam spreads as it travels from the transducer into the water. A wider cone covers more area but produces less focused detail. A narrow cone covers less area with greater precision. Understanding cone angle helps you interpret what your fish finder is actually showing and how much of the water beneath you is being scanned.

The cone angle is directly related to frequency. A 200 kHz transducer typically has a cone angle around 20 degrees, covering a circle roughly 7 feet wide at 20 feet of depth. A lower 83 kHz beam might spread to 60 degrees, covering far more area. Imaging frequencies at 455 kHz and above use very narrow beams, sometimes just a few degrees wide, which is what allows them to produce such detailed structural views.

A wider cone means you will see more fish passing through the beam, but each fish will appear on screen for longer because it stays within the detection zone. This can make it appear that there are more fish present than there actually are — a single fish crossing through a wide cone at slow boat speed will create a large arch. A narrow cone shows fewer fish but represents their actual location more accurately.

Most transducers list their cone angles in the specifications for each frequency band. When comparing models, consider how you fish. Wide cones work well for general scanning and finding schools. Narrow cones are better for precision marking of individual fish and structure.