Why Does My Fish Finder Have A Bunch Of Lines?

By Wade Johnson

Why My Fish Finder Have A Bunch Of LinesFish finders are valuable devices, and if you use them correctly, they can give you a lot of helpful information about the underwater environment.

But sometimes, you may get unwanted interference that might be in the form of a bunch of lines. These lines block the actual reading and increase the chances of missing vital information. With the unnecessary lines displayed on the screen, you can not efficiently read the screen, and this results in a loss of focus and accurate data.

If you have these lines on your fish finder, then there is no need to replace your fishfinder because we will discuss the causes of the lines on the fish finder screen and how you can get rid of them.

Why The Fish Finder Have A Bunch Of Lines

There can be various reasons for having the lines on the fish finder screen. These lines can be due to the improper setting of the fishfinder or because of the inappropriate environment. Some other reasons that may cause lines on Fishfinder are given below.

Interference From Other Sources

The most common reason you are getting the unwanted lines on the fish finder screen is that another sonar emits the signals in the area. This can be due to other fishing boats sweeping the region. You can easily avoid this by changing the frequency range of the sonar or reducing its sensitivity.

The Speed

If you are moving too slowly or not moving at all, the fish might appear as the straight lines on the fish finder. This is because the stationary fish finder is constantly getting the readings and plotting them on the screen.

The Depth

If you are in deep waters, then the cone section that the fishfinder is generating would be more comprehensive. This would cause the fish finder to cover a large area, and the chances of errors increase. Usually, when covering a large extent, the sound waves travel back from the layers of water, and you can get an unusual response on the screen in the form of a bunch of lines.

The Frequency

The frequency of the fish finder has a significant role in the generation of lines on the fish finder screen. High-frequency waves travel a short distance, but they are highly accurate. On the other hand, low-frequency waves are inaccurate, but they can cover a lot more space. Moreover, their cone angle is also vast, which means that they can sweep a large area. Due to this, the low-frequency waves may get double bounces and generate an unwanted response on the screen that can sometimes be in the form of many lines.


The fish finder’s sensitivity will also contribute to the line generation on the fish finder screen. Generally, the fish finder’s sensitivity is increased to have a more visible response to the underwater environment and to analyze the type of bottom, but this can have effects on the unwanted signals and the screen plots even the slightest feedback that is coming towards the sensor.

Low Depth

The unwanted lines on the screen can also be due to the shallow depth, and this can cause the waves to bounce up and down several times, recording more responses than there should be.

How To Solve Line Problem In Fish Finders

This problem can be easily solved by adopting simple techniques. If you are having the response from other fish finders in the area, try to change your position and if it is not possible, then try to change the frequency of the waves. Choosing the high frequency will reduce the coverage area and chances of collision and change the receiving sensitivity of the sensor. If you get the responses by the higher sensitivity, then change the sensitivity to low levels. Make sure that you choose the optimum levels not to miss the genuine readings.

If you are getting the lines due to the low depth, switch to high-frequency mode because they can not travel much distance, and the interference is minimal.

Final Thought

Displaying the unwanted and unpleasant lines can destroy your fishing experience if you encounter them too frequently. If this is caused by external problems such as the environment or interference, then it can be solved within easy steps. If the problem occurs due to the fish finder’s malfunction, it can require a professional technician’s proper inspection.


Wade Johnson
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