Humminbird 987C SI COMBO manual Understanding Side Imaging

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WhiteLine® highlights the strongest sonar returns in white, resulting in a distinctive outline. This has the benefit of clearly defining the bottom on the display.

UNDERSTANDING SIDE IMAGING

It is important to understand how Side Imaging technology produces the display available on the 900 Series™. 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.

262 kHz provides maximum coverage with 180° total beam width

	Side Imaging
	262 kHz - Maximum Coverage
84o	20o	84o
262 kHz		262 kHz
	200 kHz

74o

50 kHz

180º Total Coverage

The side beams can be operated at one of two frequencies: 262 kHz or 455 kHz. Selecting 455 kHz produces the sharpest image while selecting 262 kHz provides greater bottom coverage area. It is important to understand that when the boat turns, the strips to one side will begin to overlap and the strips on the other side will fan out, providing some distortion to the image. Side beams look out 240 feet, with a depth limitation of 100 to 150 feet, depending on the contour of the bottom. Please see the Side Imaging Sonar Tutorial at www.humminbird.com for a more detailed explanation.

Your Side Imaging transducer also provides traditional sonar imaging at 50/200 kHz. Total coverage under the boat is 180°.

455 kHz provides highest resolution with 160° total beam width

Side Imaging

40o	20o	40o
	74o 200 kHz
455 kHz		455 kHz

50 kHz

160º Total Coverage

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