How does the Sonar Works?
The word "sonar" is an abbreviation for "SOund, NAvigation, and Ranging". It was developed as a means of tracking enemy submarines during World War II. A sonar consists of a transmitter, transducer, receiver, and display.
In the simplest terms, an electrical impulse from a transmitter is converted into a sound wave by the transducer and sent into the water. When this wave strikes an object, it rebounds. This echo strikes the transducer of the fishfinder , which converts it back into an electric signal, which is amplified by the receiver and sent to the display. Since the speed of sound in water is constant (approximately 4800 feet per second), the time lapse between the transmitted signal and the received echo can be measured and the distance to the object determined. This process repeats itself many times per second.
The frequency used by typical sonar is between 50-200 kHz. Although this frequency is in the sound spectrum, it's inaudible to both humans and fish. (You don’t have to worry about the sonar unit spooking the fish - they can’t hear it.)
As mentioned earlier, the sonar unit sends and receives signals, then “prints?the echo on the display. Since this happens many times per second, a continuous line is drawn across the display, showing the bottom signal. In addition, echoes returned from any object in the water between the surface and bottom are also displayed. By knowing the speed of sound through water (4800 feet per second) and the time it takes for the echo to be received, the unit can show the depth of the water and any fish in the water.
What is CHIRP all about?
Benefits of CHIRP sounders:
Standard, non-CHIRP Fish Finders operate at one or two individual frequencies and are generally capable of detecting targets and displaying them only within those narrow frequency bands. CHIRP Fish Finders transmit pulses across a wide range of frequencies, allowing superior digital signal processing (DSP) to display fish and structure targets with unparalleled clarity, accuracy and resolution.
Typical Non-CHIRP Fish Finders operate with a maximum duty cycle of 1% - meaning they transmit a voltage to the transducer no more than 1% of the time. Consequently the transmit pulse can be high power but very short duration, limiting the total energy that is transmitted into the water column.
The CHIRP Fish Finders uses a precise sweep pattern across frequencies within a long-duration transmission. The equivalent sound energy transmitted into the water is 10 to 1,000 times greater than a conventional Fish Finder, resulting in more energy on target. The results are up to 5x greater resolution and depth capability than comparably powered, standard Fish Finders due to the advanced signal processing of the return echo.
When used with a compatible CHIRP transducer (sold separately), it displays crystal-clear sonar images to help find the next hidden fishing spot, ship wreckage or diving location. With our Spread-Spectrum technology, you can see target separation and resolution at extraordinary depths, and dial into specific frequencies to target certain species of sport fish. Bottom contours are more visible, and signal noise can be suppressed at greater depths to provide a more timely interpretation of what’s below for safer navigation and better fishing.
Summary of the fishfinders
||Garmin sidevu Fishfinders
||Garmin downvu & Sidevu
||Lowrance Elite Ti Touch
||Garmin downvu Fishfinder
|Raymarine eS CHIRP Fishfinder
||Lowrance HDS Gen3
||Lowrance HDS Gen2 Touch
||Lowrance elite Fishfinders
||Lowrance HOOK Fishfinders
|Forward Scan Sonar
||Raymarine Sonar Blackbox