84 GPSMAP 392/398/492/498 Owner’s ManualU SING SONAR > FLASHER PAGEFlasher PageThe Flasher page provides an almost instantaneous return of whatis below your boat. This page can show depth, fish, bottom content,and structure. When you use the Flasher page, you can adjustthe Range, Gain, Color Gain, Frequency, and Scroll settings. Seepage 79 for information about these settings and how to changethem.Flasher PageUnderstanding the Flasher PageThe most intense, constant signal on the Flasher Page is the actualdepth and bottom:• A soft bottom (such as silt or mud) creates a signal that isnarrow and more faint.• A hard bottom (such as sand or rock) creates a signal that iswider.The colors indicate the different strengths of the signals. If youunderstand a bit about how sonar works, you can better understandwhat you see on the Flasher Page. Remember, three-dimensionalspace is appearing on a two-dimensional screen. The circular areaof the bottom becomes a wide mark on the screen and fish insidethe transducer beam can be any color and in any position, includinginside and beyond the bottom mark. The colors indicate thedifferent strengths of the signals. This can be roughly correlated toa position inside the beam. Red being the center most part, orangethe area around, and green the outer edge of the beam. Targets (forexample, fish) with larger surface area appear more red; and targetswith less surface area appear orange, and green for the smallestitems.
