Using the Sonar PageWhen combined with a GSD 21 or GSD 20 Sounder Module, yourGPSMAP 376C becomes a powerful fishfinder/flasher with theSonar Page. If a GSD 21 or GSD 20 is attached, but the unit doesnot detect a transducer, a “Sonar Turned Off” message appearsacross the Sonar Page. The Sonar Page appears only if a GSD 21or GSD 20 has ever been attached or when the unit is in SimulatorMode.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 112 formore on information about sonar.10 GPSMAP 376C Owner’s ManualsettIng uP And usIng sonAr > usIng the sonAr PAge
