How does the fish finder transducer detect fish
How does the fish finder transducer detect fish?
The fish finder detects the fish school mainly by sensing the bubbles in the water through the ultrasonic wave sent by the probe and detecting the echo to judge the fish school.
Maw: Most fish have an organ called the swim bladder. The function of the swim bladder is that the fish can control the balance of water pressure and adjust the depth of plankton at different depths underwater. Since the swim bladder is filled with gas, the relative density of fish meat and bones changes according to the air concentration. Generally speaking, a fish with a large swim bladder is a big fish, and a small fish swim bladder is a small fish. the case of fish.
The most commonly used working frequencies of blue water type common fishfinders are generally designed to be 50kHz and 200kHz; the most commonly used operating frequencies of freshwater type common fishfinders are generally designed to be 77kHz and 200kHz.
For different frequencies, the propagation distance and signal clarity are different. In general, the higher the frequency, the shorter the wavelength, the clearer the signal, but the shorter the propagation distance; the lower the frequency, the longer the wavelength, the longer the propagation distance but the signal will be blurred.
If it is a large-scale search, you can choose a low frequency, and if you want to see the target clearly, choose a high frequency.
Under normal circumstances, the 200kHz detection fish echo is the clearest, but the usual sounding range does not exceed 600ft/200m, and the beam angle is usually designed to be within 20°, which is suitable for shallow waters and is mainly used to display fine target images.
The 50kHz detection fish echo can be seen relatively deep, and the beam angle is also designed to be relatively large, usually reaching more than 40°, which is mainly used to display the contour topography of the deep water bottom.
Due to the long wavelength, it is easy to overlook some small targets. The 77kHz detection fish can be seen relatively deep, but generally focus on the use of freshwater lakes, especially increase the beam angle to more than 30°. Different species of fish such as marine fish and freshwater fish have different echo responses to different frequencies, but generally have a relatively obvious response to the frequency of 200kHz, which is why 200kHz is the main working frequency of the fish finder.
50kHz looks deeper, but the resolution is relatively lower than 200kHz, and 200kHz has a shallower depth, but it is very clear.
In short, the fish finder uses ultrasonic waves to find fish, and then works according to different frequencies. Different powers can also choose high frequency or low frequency to work according to different needs.
