Humminbird 1197C SI warranty 181, Receiver See Transmitter

531617-1_A - 1197c_ManE.qxp 11/6/2007 4:40 AM Page 181

Glossary Sonar Terms

Pixels: Pixels are the "picture elements", or small square blocks, that make up the image on the LCD. Measured as a vertical by horizontal number (i.e. 640 V x 320 H), this key specification typically indicates the quality of resolution. In fishfinders, the total resolution (vertical multiplied by horizontal) is often less important than the "Vertical Pixel" resolution. See Pixels, Vertical.

Pixels, Vertical: Vertical Pixels are a number of vertical picture elements in a single column on an LCD display. A greater number of vertical pixels provide finer resolution of targets detected by sonar. Essentially, a vertical distance (the depth), when divided by a larger number, breaks that distance into smaller samples, each representing a smaller area and thus providing more detail. In fishfinders, vertical pixels are more critical than horizontal pixels because the horizontal axis of the display represents time, or history. Sonar information on the horizontal axis can vary greatly, depending on boat speed and the Chart Speed setting. A greater number of horizontal pixels show more sonar history that the boat has passed through. On many models, Humminbird® provides the most vertical pixels to provide a better display resolution. See Chart Speed and Pixels.

Power Output: Power output is the amount of sound energy emitted into the water by the sonar transmitter. Power output 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 the boat is running at high speed.

Pulse Width (Pulse Length): Pulse Width is 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 Target Separation.

QuadraBeam PLUS™: QuadraBeam PLUS™ is a Humminbird® sonar configuration that uses four sonar beams for a more detailed bottom image. QuadraBeam PLUS™ uses the DualBeam PLUS™ configuration for downlooking, and also adds two additional beams to look to the left and right. The sonar beams pointing to the left and right provide the ability to spot fish and structure over a wide 90° area, and to identify on which side of the boat they are located. See DualBeam PLUS™.

Quick Disconnect Mount: The Quick Disconnect Mounting system is an exclusive Humminbird® feature that permits the unit to be easily removed from the mounting base by pressing a release button, and re-installed by simply snapping it back into place. All cable connections are made when installing, so that no separate wiring connections are required. Additionally, the mount offers 90° tilt and 360° swivel capability to adjust the viewing angle of the unit as you move about the boat.

Real Time Sonar: Real Time Sonar is a Humminbird® technology that delivers ultra-fast sonar transmitter/receiver operation and results in a more detailed instantaneous view of what is under the boat. The Real Time Sonar window is a vertical band at the right side of the display that shows the instantaneous sonar return from the transducer at a particular instant. The RTS® Window menu option permits the user to adjust the window to show the full sonar signal return, or just a narrower band that indicates intensity using grayscale. Real Time Sonar relies on very fast Sonar Update Rate (Ping Speed). See Sonar Update Rate.

Receiver: See Transmitter.

Second Return: The Second Return is a term that 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 traveling back down to the bottom to be reflected again. Second returns are more common in shallow water and over hard bottoms; it is actually possible to see a third sonar return under some circumstances. The second return provides useful information to help determine bottom hardness, as areas with harder bottoms will generally create a second return. The second return can be used as a guide to set Sensitivity when in shallower water.

Sensitivity: Sensitivity is a user feature that adjusts the sensitivity of the sonar system to show more or less detail in the water. Higher sensitivities are often preferred, however, when the water contains debris (silt, storm debris, etc.) and it can be difficult to pick out targets. Conversely, if sensitivity is set too low, relevant targets may be missed.

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