Garmin Fishfinder 100 BLUE Owner's Manual

Also see for Fishfinder 100 Blue: Specifications

On the Water31On the WaterTransducer CoverageTransducer CoverageThe area covered by the transmitted sound waves is determined by thecone angle of the transducer and the water depth. The 50kHz frequencyprovides a 40° cone angle, with a coverage width that is approximately 2/3of the water depth. As shown in the sidebar, the 40° cone angle (50kHzfrequency) approximately covers the area of a 20 foot diameter circle at a30 foot depth. The 200kHz frequency provides a 10° cone angle, with acoverage width that is approximately 2/10 of the water depth. As shown,the 10° cone angle (200kHz frequency) approximately covers the area of a6 foot diameter circle at a 30 foot depth.When using the Fishfinder 100 Blue in ‘Dual’ frequency mode, the unittransmits both 50kHz and 200kHz signals at the same time. The ‘Dual’frequency capability of the Fishfinder 100 Blue allows the user to havea large coverage area and still retain good bottom resolution. When in‘Dual’ frequency mode the unit uses the 200kHz to display detailed bottominformation, keeping “Dead Zones” to a minimum, and the 50kHz signalfor the large coverage area.Fish returns from the 50kHz and 200kHz beams will appear differentlyon the display. The 50kHz beam tends to show longer fish returns thanthe 200kHz beam. The examples below show simulated fish returns at50 and 200 kHz.200kHz - 10˚ Cone Angle72" coverage at 30'50kHz - 40˚ Cone Angle20' coverage at 30'50kHz 200kHz