Garmin 190-00683-00 Manuale Utente

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Transducer Coverage
The area covered by the transmitted sound waves is determined 
by the cone angle of the transducer and the water depth. The wide 
cone angles (40°) associated with low frequencies (50 kHz) provide 
a large coverage area for finding fish within a coverage width that 
is approximately 2/3 of the water depth. However, this also means 
that wide cone angles produce less bottom detail and resolution. As 
shown in the drawing on the near right, the 40° cone angle produces 
a coverage area of approximately a 20-foot diameter circle at a  
30-foot depth. 
The narrow cone angles (10°) associated with high frequencies 
(200 kHz) provide better bottom resolution and crisper detail, but 
cannot show a large coverage area for finding fish. The 10° cone 
angle provides a coverage width that is approximately 2/10 of the 
water depth. As shown in the drawing on the far right, the 10° cone 
angle produces a coverage area of approximately a 6-foot diameter 
circle at a 30-foot depth. 
Dual frequency mode combines both frequencies to get the best 
coverage area and contour/depth readings.
40° Cone Angle (50 kHz)
Coverage 
dameter
Depth
10° Cone Angle (200 kHz)
Coverage 
dameter
Depth
GPSMAP 378/478 Owner’s Manual 
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