Transducer CoverageThe area covered by the transmitted sound waves is determinedby the cone angle of the transducer and the water depth. The widecone angles (40°) associated with low frequencies (50 kHz) providea large coverage area for finding fish within a coverage width thatis approximately 2/3 of the water depth. However, this also meansthat wide cone angles produce less bottom detail and resolution. Asshown in the drawing on the near right, the 40° cone angle producesa coverage area of approximately a 20-foot diameter circle at a 30-foot depth.The narrow cone angles (10°) associated with high frequencies (200kHz) provide better bottom resolution and crisper detail, but cannotshow a large coverage area for finding fish. The 10° cone angleprovides a coverage width that is approximately 2/10 of the waterdepth. As shown in the drawing on the far right, the 10° cone angleproduces a coverage area of approximately a 6-foot diameter circleat a 30-foot depth.Dual frequency mode combines both frequencies to get the bestcoverage area and contour/depth readings.40° Cone Angle (50 kHz)CoverageDiameter Depth10° Cone Angle (200 kHz)CoverageDiameter DepthGPSMAP 376C Owner’s Manual 113SETTING UP AND USING SONAR > U NDERSTANDING SONAR
