Garmin GPSMAP 276C Owner's Manual

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Contents

Using the Sonar PageWhen combined with a GSD 20 Sounder Module, your GPSMAP276C becomes a powerful fishfinder/flasher with the Sonar Page.If a GSD 20 is attached, but the unit does not detect a transducer,a “Sonar Turned Off” message appears across the Sonar Page. TheSonar Page appears only if a GSD 20 has ever been attached orwhen the unit is in Simulator Mode.The middle of the page contains a right-to-left moving sonar imageof the water beneath your boat. Items appear as they pass under yourtransducer. Those items on the right side of the screen are closer toyou than those on the left. Along the right side of the screen is anadjustable scale that reflects the depth of the area being shown. Thetop left corner shows the adjustment option, the depth, and the watertemperature.Sonar PageThe sonar returns show as red (strongest), then orange (strong),yellow (medium), green (weaker), and blue (weakest). The FishSymbols option allows you to view the actual sonar data, a fishsymbol or a combination of both. When the unit is set to Dual, theappearance of the fish symbols changes. Fish symbols from thecenter of the beam (200 kHz) are solid (or narrow arches), but thereturns from the edges of the beam (50 kHz) are hollow (or widearches).The sonar display can also be set to show a split screen view of azoomed portion of the sonar, bottom lock (display scaled from thebottom up), or a combination of these options. For example, youcan choose to show dual frequency at a 2X zoom (Dual 2X) on onehalf and normal range dual frequency (Dual) on the other half. Thecurrent display mode appears at the bottom of each sonar display.Read the “Understanding Sonar” section beginning on page 97 formore on information about sonar.Adjusting the Sonar PageUse the Adjustment menu to access the settings and features mostcommonly used on the Sonar Page. Ten main adjustment optionsare available: Range, Zoom, View, Gain, Target Level, Whiteline,Frequency, Depth Line, Noise Reject, and Scroll. Use the ROCKERand ENTER keys to make all adjustments. The currently selectedoption appears in the upper-left corner.90 GPSMAP 276C Owner’s ManualSETTING UP AND USING SONAR > U SING THE SONAR PAGE