Understanding Side Imaging - Humminbird 797c2 GPS Chartplotter Operation Manual

531519-1_A - 797c2_Man_Eng.qxp 11/6/2006 5:50 AM Page 8

Understanding Side Imaging

It is important to understand how Side Imaging technology produces the
display. The images you see on the display are produced using sonar
technology. The special transducer produces three distinct beams – one beam
facing down and two beams pointing out to the side. These "side beams" are
aimed at right angles to the path of the boat and, unlike the "down beam"
which provide conical coverage, the side beams provide coverage which is very
thin front to back, yet very wide top to bottom.
The narrow aspect (front to back) of the beam illuminates a small strip of the
bottom perpendicular to the direction of the boat. Each time the unit "pings",
a strip of data representing all the echoes received by the transducer, are put
together on the display to form the image that you see. The rows closest to the
boat icon at the top of the display are the most recent sonar data. The
information is scrolled down the screen as new data, drawn at the top of the
screen, becomes available.
455 kHz provides maximum coverage with 180° total beam width
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