The Humminbird 570 DI is a popular low-cost fishfinder. The “DI” stands for down-imaging sonar. We’ll explain more on that later. When you use it on your next fishing trip, you will be able to see a view of what is under the water below the boat. This is accomplished using sonar technology. The Humminbird fishfinder is made by a company called Johnson Outdoors which specializes in fishfinders, depth sounders, marine radios and GPS systems for fishermen.
The basic technology used in a fishfinder is sonar. A sound wave is propagated into the water and when it hits an object, there will be a wave that is reflected back. Knowing the time it takes between when the original wave started and when the reflected wave was detected, the distance of the object can be calculated. If the sonar does not hit any object on the way down, it will bounce off the bottom of the lake or river and tell you the depth. As the boat moves along, slices of depth “images” are taken and then stitched together electronically to present a view of the structure of things under the boat including fish.
The coverage area of the sonar beam is determined by its cone angle. The larger the cone angle, the larger an area under the water that it can scan. In shallow or medium depth bodies of water, you would want to have a larger cone. If you are fishing in deep water, a smaller cone will give you more depth penetration. The depth penetration depends on the output power of the sonar. The Humminbird fishfinder will display the water temperature, water depth, total distance travelled, and average speed.
The Humminbird 570 DI has a 5″ monochrome 640×320 display. It uses 455/800 kHz Down-Imaging sonar. The higher frequencies are better for imaging. The Down-Imaging sonar uses a razor thin beam that is scanned back and forth to create a composite image. It can cover a depth of up to 250 feet. In addition to the Down-Imaging sonar, there is a conventional down-beam sonar that operates at 200 or 455 kHz. The lower frequency is good for determining depth up to 600 feet. The depth determination can be affected by things like boat speed, wave action, hardness of the bottom of the body of water, water conditions and transducer installation.
For the down-beam sonar, the cone angles are 25 degrees for 200 kHz and 16 degrees for 455 kHz. The transducer on this model has a total output power of 2400 Watts peak-to-peak. It comes with a quick-disconnect mounting system so that you can easily mount it on your boat.
In the 500-series family, the difference between the 570 DI and the 550 or 560 models is that the latter models use only a single beam sonar operating at 200 kHz with a cone angle of 20 degrees.
You can purchase the Humminbird 570 DI at retail stores that specialize in angler equipment but you can also get good deals on it at Amazon.Latest News on Fishfinders
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