How Sonar Works | Humminbird 737 GPS manual

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How Sonar Works

Sonar technology is based on sound waves. The 700 Series™ Fishing System uses sonar to locate and define structure, bottom contour and composition, as well as depth directly below the transducer.

Your 700 Series™ Fishing System sends a sound wave signal and determines distance by measuring the time between the transmission of the sound wave and when the sound wave is reflected off of an object; it then uses the reflected signal to interpret location, size, and composition of an object.

Sonar is very fast. A sound wave can travel from the surface to a depth of 240 ft (70 m) and back again in less than 1/4 of a second. It is unlikely that your boat can "outrun" this sonar signal.

SONAR is an acronym for SOund and NAvigation Ranging. Sonar utilizes precision sound pulses or "pings" which are emitted into the water in a teardrop-shaped beam.

The sound pulses "echo" back from objects in the water such as the bottom, fish and other submerged objects. The returned echoes are displayed on the LCD screen. Each time a new echo is received, the old echoes are moved across the LCD, creating a scrolling effect.

When all the echoes are viewed side by side, an easy to interpret "graph" of the bottom, fish and structure appears.

The sound pulses are transmitted at various frequencies depending on the application. Very high frequencies (455kHz) are used for greatest definition but the operating depth is limited. High frequencies (200kHz) are commonly used on consumer sonar and provide a good balance between depth performance and resolution. Low frequencies (83kHz) are typically used to achieve greater depth capability.

The power output is the amount of energy generated by the sonar transmitter. It is commonly measured using two methods:

•Root Mean Square (RMS) measures power output over the entire transmit cycle.

•Peak to Peak measures power output at the highest points.

The benefits of increased power output are the ability to detect smaller targets at greater distances, ability to overcome noise, better high speed performance and enhanced depth capability.

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Humminbird 737 GPS manual How Sonar Works, Peak to Peak measures power output at the highest points

Contents

Atic Thank You Table of Contents Key Functions Views Menu Tab Accessories Menu Tab How Sonar Works Peak to Peak measures power output at the highest points DualBeam Plus Sonar QuadraBeam SonarWideSide Sonar With optional-purchase WideSide transducer How GPS and Cartography Work Software UpdatesMulti-Media Card MMC/SD Slot With optional-purchase GPS Receiver Soft Bottom RTS Real Time Sonar Window 83 kHz, Wide Beam Hollow Fish SymbolWhat’s On the Display Sonar views ViewsSonar View Real Time Sonar RTS Window Understanding Sonar HistoryBottom Presentation Freeze Frame Sonar Zoom View Sonar Zoom View Big Digits View 200/83 kHz Split Sonar ViewCircular Flasher View Big Digits View 200/83 kHz Split Sonar View Side Beam View Screen Snapshot ViewMaking a Screen Snapshot Screen Capture View Bird’s Eye View WideSide View Chart View with Active Cursor Chart View without Active CursorCombo View Depth Waypoints, Routes and Tracks Viewing Cartography Save, Edit, or Delete a Waypoint Add a Waypoint Target or Trolling Grid Chart View with Grid Key Functions POWER/LIGHT KeyView Key Info Key WAY Cursor Control Key Accessory BusMark Key Goto Key Presence or absence of a transducer Powering Up the UnitMenu System Normal Operation Start-Up Options MenuSystem Status Simulator GPS Diagnostic View Accessory TestExit PC Connect mode by powering the Fishing System off Sonar X-PressTMMenu To adjust the SideSide WideSide transducer WideSide view only To adjust the Upper Range To adjust the SensitivitySensitivity Upper Range Side Beam Range Chart SpeedLower Range Bottom View Cancel NavigationBottom Range Bottom Lock Waypoint Name Navigation X-PressTM MenuOnly with an active cursor on a waypoint To view the Waypoint Name Submenu Save Current Track Cursor to WaypointClear Current Track Save Current Route Sonar Window Remove TargetRemove Grid Delete Image Screen Snapshot X-Press TM MenuDelete All Images Sonar Menu Tab Fish ID+TM Beam SelectTo use Beam Select Highlight Beam Select on the Sonar main menu Zoom Width Fish ID SensitivityKHz Sensitivity Advanced WideSide Sensitivity KHz BalanceDepth Lines Advanced with WideSide transducer Max Depth Surface ClutterNoise Filter Water Type To change the Water Type settingTransducer Select Navigation Menu Tab Waypoints Current TrackSaved Tracks Routes Chart OrientationNorth Reference Grid Rotation Map Datum Track Min DistanceCourse Projection Line Export All Nav Data Chart Detail Level Chart Menu TabMap Borders With optional-purchase GPS Receiver only Spot Soundings Lat/Lon GridSet Simulation Position Set Map Offset Depth Alarm Alarms Menu TabFish ID Alarm To change the Depth Alarm setting Temp Alarm Low Battery AlarmOff Course Alarm Arrival Alarm Alarm Tone Drift AlarmSetup Menu Tab To change the Drift Alarm setting Units Depth User ModeUnits Temp Units Distance Restore Defaults Triplog ResetSelect Readouts Advanced, Sonar view only Temp Offset Depth OffsetSpeed Calibration Position Format Date Format Time FormatNmea Output Sonar Using Screen Snapshot Accessories Menu TabViews Menu Tab To Change the View Status of Any View To view screen snapshots TroubleshootingTo make a screen snapshot Screen Snapshot must be enabled Finding the Cause of Noise Display Problems Specifications Series Fishing System Accessories Sonar Terms Glossary 100 102 Receiver See Transmitter 104 GPS & Navigation Terms 108 Contact Humminbird