Sonar Fish Finder with 5.6in 256 Color LCD Display 50/200 KHz Dual Frequency for Ice Lake Sea River Fishing Item Type: Sonar Fish Finder Material: ABS Display Type: 5.6in Color TFT LCD Display Effective Display Area: Approx. 84.7x113.3mm / 3.3x4.5in (W x H) Pixels: 480 x 640 pixels Display Modes: Single Frequency (HF/LF), Dual Frequency, Wave Zoom, A Scope Basic Range: Approx. 1-1000m/3.28-3280ft (m, ft can be selected in the menu) Range Phase: Up to approx.1000m/3280ft Pulse Length and PRR: 0.1-3 ms, maximum 3,000 pulses/min Data Recording: 1s, 15s, 30s, 1min Data interface: NMEA0183 GPS: Sensor required Power: 11-35 VDC, 0.8-0.4 A Production: This color video sounder determines the distance between its sensor and underwater objects such as fish, lake bottom or seabed and displays the results on a 5.6in color screen. It does this by exploiting the fact that ultrasonic waves propagating through water travel at a nearly constant velocity of 4,800 feet (1,500 meters) per second. When sound waves strike underwater objects such as fish or the ocean floor, some of the sound waves are reflected back to the source. Therefore, by calculating the time difference between the emission of the sound wave and the reception of the reflected sound wave, the depth of the object can be determined. In a sense, the sounder can be considered an extremely complex and fast timer, as it is able to resolve time differences of less than a thousandth of a second. The whole process starts with the display unit. The transmitter power is sent to the transducer as short pulses of electrical energy. The electrical signal generated by the transmitter is converted into an ultrasonic signal by a transducer and emitted into the water. Any reflected signal from an intervening subject (such as a school of fish) is picked up by the sensor and converted back into an electrical signal. It is then enlarged in the magnifier section and finally displayed on the screen. The picture displayed by the color video sounder consists of a series of vertical scan lines, transmitted one at a time, with each line representing a Snapshot of what happened on the bottom of the ship. This series of snapshots accumulates side-by-side across the screen and shows the resulting bottom profile and fish between the bottom and the surface. The historical number of objects passing through the bottom of the ship in a series of transmissions varies from less than a minute to several minutes, depending on how you adjust the units. The compact, lightweight yet robust unit is easy to install and operate for both fresh and salt water applications. Characteristic: 1. Enhanced digital filter provides comprehensive detection in shallow and deep water 2. The main bang (the directly below the transducer) is suppressed to less than 40 cm so that the fish position below the transducer can be easily observed 3. Provides two automatic modes: automatic gain and automatic range 4. Fast pulse transmission rate for excellent shallow water presentation 5. Dual frequency 50/200 kHz 6. 5.6in bright sunlight-viewable 256 color LCD with wide viewing angles 8. Easy desktop installation and flush installation 9. Sound and light alarm for water depth and fish Function: The Sounder consists of a main unit that displays information on the depth and formation of the seabed and a transducer mounted on the bottom of the ship's hull. This information is gained by using utrasonic waves sent from the transducer that are then reflected off the sea bottom and picked up again by the transducer. The maximum measurable sounding depth is 1000 meters, and the power is 1000W, with 5.6 inch high resolution (640 x 480 or 480 x640) color LCD digital display. The function is powerful, the precision of sounding is high, the operation is simple, the appearance is compact, and it can be widely used in fishing industry in the sea, rivers, and lakes.