Garmin GPSMAP 276C User Manual

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
Diameter
Depth
10° Cone Angle (200 kHz)
Coverage
Diameter
Depth
100 GPSMAP 276C Owner’s Manual
SETTING UP AND USING SONAR > UNDERSTANDING SONAR

Garmin GPSMAP 276C Specifications

General

Sport (fitness, running)	No
Marine (chartplotters, sounders)	Yes
Routes quantity	50
Tracks quantity	20
Number of waypoints	3000
Form factor	Fixed
Product color	Gray
I/O ports	NMEA 0183
Antenna type	Detachable
Display resolution	480 x 320 pixels
Headphone outputs	1
Battery life (max)	15 h
Sustainability certificates	RoHS

Weight and Dimensions

Depth	48 mm
Width	145 mm
Height	81 mm
Weight	385 g