Why are there various interferences on the fish finder?
Why are there various interferences on the fish finder?
With the development of today's electronic technology, more and more electronic and electrical equipment are installed on ships, and the corresponding electromagnetic environment is also more and more complex, which greatly increases the occurrence of various interference problems. In order to suppress these interferences, we must first know the type of interference before we can take corresponding measures to reduce or eliminate them.
On the screen of the fish finder, the angle of noise presented by different interferences on the screen is also different. Spurious signals generated by parasitic interference sometimes look like real target echoes, and strong noise interference sometimes completely overwhelms the screen so that real echoes cannot be displayed normally.
There are five common types of interference in general fishfinders:
1. Acoustic turbulence interference: mainly caused by the wrong probe installation position. This interference generally only occurs during the navigation of the ship, and the main reason is that the uneven turbulence or the bubbles generated by the waves flowing on the surface of the probe interfere with the echo signal reception of the probe. This is most common on ships using sidemount or in-cabin probes.
2. Sonar crosstalk Co-channel interference: The most likely interference situation is mainly caused by other fishfinders using similar frequencies nearby, which is basically co-channel interference. It usually appears as a line revolving around the dial of the flasher or as a set of diagonal lines across the screen, caused by two or more fishfinder probe cone beams overlapping each other and transmitting and receiving from each unit The echo signals are confused.
3. Engine ignition interference: It is mainly caused by the introduction of the engine ignition noise into the power line. These power spikes travel through the power cord and into the fishfinder causing noise to be displayed on the screen or heard on the radio.
4. Pulse conduction interference: It is mainly caused by the electric propulsion whose speed is controlled by pulse width modulation (PWM). The noise interference will only appear in the process of using electric propulsion, and it changes with the change of the propulsion speed, and is conducted through the power line. Access the fish finder via the power connection. This interference often occurs in lure boats where electric propulsion is widely used.
5. Electromagnetic Interference: It is mainly the alternating electromagnetic field generated by the use of a powerful current charger, which is radiated into the air through the lower unit of the motor and the power line, penetrates the cable shielding layer and noise reduction circuit, and then absorbs it to connect the fish finder. in the cable.
Different types of disturbances sometimes appear discrete but very similar on the fishfinder screen. In summary, the most common interference is the co-frequency interference produced by other fishfinders and the electromagnetic interference produced by other electrical equipment.
How to adjust anti-interference？
Properly adjusting the sensitivity can reduce the disturbing effects of nearby noise sources.
For sonar crosstalk co-channel interference, the general solution is as follows:
• Adjust the working frequency of the fish finder so that it does not work on the same frequency as other fish finder.
• Try to stay away from the working position of other fishfinders that cause co-frequency interference, and also try to stay away from other fishfinders, generators, chargers and other equipment that may cause interference.
• Reduce interference with fishfinder noise suppression adjustment.
Precautions:
1. The slashes are not necessarily interference. Generally, the slashes with high left and right low are mostly corn bait, while low left and high right are generally interference.
2. Correcting installation problems that cause noise is always the best way to eliminate interference.
3. Using the fish finder while charging may also cause interference.
4. The more complex the electronic environment produces the more interference.
5. Saiyang fish finder has strong anti-interference ability. Improve the machine's anti-interference ability by carefully selecting different noise suppression levels, so that the noise is gradually eliminated but has the smallest impact on the target echo signal, so that the minimum anti-jamming setting that can achieve the required improvement level can eliminate the interference on the screen.
