Humminbird 365i manual 110

Grayscale The use of varying shades of gray to represent the strength of the sonar signal on the display. Traditionally, the strongest sonar signals a re represented in black, and progressively weaker signals are represented in progressively lighter shades of gray.

Noise The unintentional, external sound waves that interfere with the optimal operation of sonar. Noise appears as random “dots“ on the d isplay and is caused by a varie ty of sources. Many Humminbird® products have a Noise Filter menu setting that allows the user to clear the screen ofnoise that is difficult to eliminate (also, see Troubleshooting).

Pixels The “picture elements“, or small square blocks, that make up the image onthe LCD. Measured as a v ertical by horizontal number (i .e. 6 40V x 32 0H), this k ey specification typically indicates t he quality of r esolution. In fishfinders, the total resolution (vertical multipliedby horizontal) is often less important than the “Vertical Pixel“ resolution because a greater number of vertical pixels provide finer resolution of targets detected by sonar. Sonar informationon the horizontal axiscan vary greatly, depending on boat speed and the Chart Speed setting.

Power Output The amount of sound energy emitted into the water by the transducer’s transmitter. Poweroutput is measured using either RMS (Root Mean Square) or P-T-P (Peak- to-Peak) measurement systems. Either method is acceptable, but it is important when comparing power outputs, to make sure that the same measurement system is being used for both outputs, because P-T-P numbers are 8 times higher than RMS numbers. Greater power output allows the sonar signal to penetrate through weeds and thermoclines,reach deeper depths and operate more effectively in noisy environments, such as when theboat is running at high speed.

Pulse Width (Pulse Length) The length of time that a sonar sound burst is transmitted into the water.Shorter pulse widths provide better target separation, but cannot travel to great depths. Longer pulse widths provide better depth penetration, but result in poorer target separation.Humminbird® varies pulse width based on depth to optimize both target separation and depth performance. See TargetSeparation.

Second Return Describes the appearance of a second sonar return below the primary sonar return (bottom contour) at exactly twice the true depth. The second return is caused by the same sonar energy bouncing off the bottom once, rebounding to the water surface and then travelingback down to the bottom to be reflected again. Second returns are more common in shallow water and over hard bottoms; it is possible to see a third sonar return under some circum stances. The sec ond return provide s use ful info rmation to help determine bottom hardness, as areas with harder bottoms will generally create a second return. The second eturnr can be used as a guide to set Sensitivity when in shallower water.

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