Garmin GPSMAP 296 Transducer Coverage

SETTING UP AND USING SONAR > UNDERSTANDING SONAR

Transducer Coverage

The area covered by the transmitted sound waves is determined by the cone angle of the transducer and the water depth. The wide cone angles (40°) associated with low frequencies (50 kHz) provide a large coverage area for ﬁnding ﬁsh within a coverage width that is approximately 2/3 of the water depth. However, this also means that wide cone angles produce less bottom detail and resolution. As shown in the drawing on the near right, the 40° cone angle produces a coverage area of approximately a 20-foot diameter circle at a 30- foot depth.

The narrow cone angles (10°) associated with the high frequencies (200 kHz) provide better bottom resolution and crisper detail, but cannot show a large coverage area for ﬁnding ﬁsh. The 10° cone angle provides a coverage width that is approximately 2/10 of the water depth. As shown in the drawing on the far right, the 10° cone angle produces a coverage area of approximately a 6-foot diameter circle at a 30-foot depth.

Dual frequency mode combines both frequencies to get the best coverage area and contour/depth readings.

Coverage
Coverage			Depth
Diameter			Depth
Diameter
				Coverage				Depth
				Coverage
				Diameter
				Diameter

40° Cone Angle (50 kHz)

10° Cone Angle (200 kHz)

GPSMAP 296 Pilot’s Guide

129

Contents

Page Page INTRODUCTION About This Manual Marine Mode Pages Main Menu Setting Up and Using Sonar Appendix Table of Contents Page Warning WARNING: Caution result in injury or property damage Cleaning the Unit Storing the GPSMAP Immersing the Unit in Water GETTING STARTED Unit Overview Information about Charge Mode Adjusting the Backlight and Volume Viewing GPS Status With the GPS Tab Receiver Status GPS Tab Options GPS Tips Learning About the Keypad PAGE Key QUIT Key ENTER/MARK Key MENU Key Understanding Terms Selecting Options and Entering Data GPSMAP 296 Databases MapSource Detailed Maps Starting Simulator Mode Entering a New Location BASIC OPERATION IN AVIATION MODE Aviation Mode Page Sequence PAGE To switch usage modes: Creating a Direct To Show Details Select Approach Select Route Find Land Points Viewing Details for the Destination Viewing Frequency Restrictions Aviation Nearest Categories Selecting a Nearby Point as Your Destination Viewing Details for a Nearby Point Viewing Communication Frequencies Viewing Airspace Alert Information Viewing Additional Airspace Information Setting Airport Criteria Selecting an Approach To select an approach for the destination airport: Select Approach Yes Understanding Vectors Finding Points on Land To Find Land Points: Find Land Points Marking a Waypoint To mark your present location: To mark a selected location as a waypoint: Creating a Flight Plan (Route) To create a route: To navigate a saved route: Routes Activate Route Following your Flight Plan Track Your Progress on the Map Page Terrain and Obstacle Changes View the HSI on the Panel Page Alerts AVIATION MODE PAGES Map Orientation Zooming In and Out of the Map Panning the Map Airspace Information Clearing Unwanted Details from the Map Measuring Distance Setting the Bug Indicator Setting Up the Map Page Changing the Page Layout and Data Fields Additional Map Data Obstacle Information Terrain Information Terrain and Obstacle Color Code Alerts Additional Terrain Page Options Setting Up the Terrain Page and Alerts Caution Elevation Look Ahead Time Alert Sensitivity Panel Page Setting Up the Panel Page Manually Setting a Course VNAV (Vertical Navigation) Using the VNAV Feature Setting up VNAV Active Route Page Options Position Data Page Options Viewing the Flight Log Deleting Flight Records Entering Your Aircraft Proﬁle Calculating the Weight & Balance To open the E6B tab of the Main Menu: E6B Indicated Altitude Total Air To calculate true airspeed and density altitude: Indicated Altitude To calculate winds aloft: To restore defaults on the E6B tab: Restore Default Automotive Mode Page Sequence To add the Compass or Highway Pages: Display Compass Page Page Navigating in Automotive Mode To go to a highlighted map item: To start new route using the Find Menu: To search for an item and route to it: NRST/FIND Cities Using the Find From Feature Recently Found Items Viewing the Information Page Find Menu Options Creating Routes To create a route using the Find Menu: To create a route graphically: Edit on Map Edit as Text To follow a saved route in Automotive Mode: Follow Roads Marking Your Present Location Creating Waypoints From the Map Creating a Waypoint by Entering Coordinates Track Your Progress with the Map Page Watch your Trip Data Current Route Page in Automotive Mode Starting and Stopping Navigation Entering Custom Avoids Creating a Detour Adding and Editing Stops (Via Points) AUTOMOTIVE MODE PAGES AND FEATURES Custom Avoids Using the Highway Page Highway Page Options Saving the Current Route Trip Computer Page Options Viewing All of Your Saved Routes Using the Route Options Manually Transitioning to the Next Waypoint Navigating a Saved Route Editing a Route To review individual route points: To add points to the route: To edit the route on the map: To set speed and fuel/plan your route: Editing and Managing Waypoints To access the Waypoint Review Page from the Map: To access the Waypoint Edit Page: Viewing the Waypoint on the Map Adding a Waypoint to a Route Averaging the Waypoint’s Location Projecting a Waypoint Organizing Waypoints into Categories Managing Points User Sub Tab Deleting Waypoints Proximity Points To turn proximity alarms on or off: Proximity Alarm OFF To add a proximity waypoint: To clear one or all proximity waypoints from the list: Setting Up and Saving Your Tracks To clear the track log: Clear To save a portion of the track log: Active To save the entire track log: Saved Sub Tab Navigating a Saved Track TracBack Tips BASIC OPERATION IN MARINE MODE Marine Mode Page Sequence Man OverBoard (MOB) MARINE MODE PAGES AND FEATURES Compass Page Options Using the Marine Timer DSC Page Understanding Distress Calls Understanding Position Reports Receiving DSC Calls DSC Call List DSC Log DSC Directory Navigating to a Position Report or Distress Call Setting up DSC MAIN MENU To restore defaults: 4.Highlight Restore Default GPS Tab Proximity Sub Tab Active Sub Tab Aircraft Tab Alarms Tab To access the Alarms tab on the Main Menu: To set an alarm: Airspace Alarms Sub Tab (Aviation Mode Only) Navigation (Nav) Alarms Sub Tab System Alarms Sub Tab Sonar Alarms Sub Tab (Marine Mode Only) Day View Sub Tab Week View Sub Tab Month View Sub Tab Calendar Options Sub Tab Sun & Moon Sub Tab Tide Sub Tab To view a tide chart for a different tide station: To view the tide chart for another date: Tide Use Current Date Move Cursor Hunt & Fish Sub Tab Message Tab To view the messages: Message To show or hide messages using the Log Filter: Log Filter Display Tab To view the Display tab: Main Menu Day Sound Tab To view the Sound tab: Sound Beeper Key and Alarm System Sub Tab VNAV Sub Tab Road Routing Sub Tab Guidance Sub Tab Timers Sub Tab Time Sub Tab Units Sub Tab Location Format Sub Tab Map Datum Sub Tab Selecting a Different Heading Reference Welcome Sub Tab Com 1 and Com 2 Sub Tabs Out None To have the unit automatically scan for a frequency: Tuning Scanning Receiving Check Wiring Advanced NMEA Output Setup SETTING UP AND USING SONAR Showing Sonar on the Map Page To show the Sonar Page on the Map Page: Map with Sonar To resize the Map Page sonar split screen: Size Split Using the Sonar Page Fish Symbols Dual Adjusting the Sonar Page Adjustment Options Split Zoom Btm (Bottom) Split Lock View/Span No Zoom View Resizing the Split Screen Using the Pointer on the Sonar Page Setting Up the Sonar Page Sonar Fish Symbols Water Calibrating the Water Speed Setting Up the Sonar Display Understanding the Sonar Display Transducer Coverage Whiteline Thermoclines Changing the Temperature Screen Reset the Temperature Graph Physical Speciﬁcations Power Performance Accuracy Optional Accessories Auto Navigation Kit GA 29F GA 26C Connecting the Power/Data Cable Connecting Your GPSMAP 296 to a Computer Information about USB Drivers Installing and Removing Data Cards Interfacing Removing the GPS Antenna Common GPS Terms What is Differential GPS (DGPS) Differential Field What is WAAS LORAN TD Feature Using the LORAN TD Format To set up Loran TD from the Main Menu: Location Format Loran TD What are Map Datums What is a Location Format What is a Maritime Mobile Service Identity (MMSI) How Are MMSI Assignments Obtained United States Non-FederalUser United States Federal User User Outside the United States User In Canada Database Updates Messages Accuracy Clock Approaching Target Altitude—within1,000 feet of ﬁnal VNAV target altitude Approaching No DGPS Position Route Memory Route Truncated Data Field Options Cross Dest Wpt Waypoint (Destination) Steer—see Course to Steer Trip Timer (Total) Ttl Avg Spd—see Trip Avg. Speed (Total) Timer Software License Agreement Product Registration Contact Garmin Limited Warranty FCC Compliance INDEX Symbols