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fish finder basics

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So you broke down and went out and got a fish finder. Now what?

These great little units look so helpful when you are watching the fishing shows or when out on a charter fishing trip, but now that you have one, they look so complicated. Where do you get started?

In this article, I hope to share with you some of the fish finder basics that will help you land the trophy fish like the pros. After all, that is why you bought a fish finder right? So let’s get started.

Basic Fish Finder Components

Fish finders have four essential components. They are…

  • Transmitter
  • Transducer
  • Receiver
  • Display

The Fish Finder Transmitter

The transmitter converts the dc power from your battery into electronic pulses and then sends those electronic pulses to the transducer.

The Transducer

graphic of a fish finder sonar systemThe transducer receives the pulses from the transmitter and converts them into sonic signals that it sends and then gets the echo back from those sonic signals. It then sends those signals to the receiver which processes the signal into a video display. All quality transducers use cultured piezoelectric crystals to convert the audio signals to electronic signals.

There are two types of transducers. Primary sonar and CHIRP sonar.

Primary sonar was developed during World War 1 by a joint effort between the British and the Americans. Think of an old submarine war movie where they ping a high pitched sound and listen for an echo back. That is basic sonar technology. A further improvement in this technology happened in the 1950’s with side imaging sonar.

CHIRP sonar technology uses multiple frequencies when sweeping the bottom of the lake or ocean. It is a continuous signal which gives a higher definition of the bottom, objects, and of course, fish!

The Receiver

The returning echoes picked up by the transducer are then sent to the receiver. The signal is amplified and then analyzed to compare the time it took for the echo return, the strength of the echo, and the frequency range of the echo. All of this information is then sent to your display screen.

The Display Screen


The computer in the receiver sends its results to the display screen. It is displayed in a series of dots on the screen. These dots are called pixels. They are measured by the number of dots displayed horizontally and vertically. Today’s fish finders usually come with at least a display of 240 pixels, but many come with much more all the way up to what we would call HD.

Picture of a boat on a clear lake in an article on fish finder basicsBasic Fish Finder Operation

  1. Take Your Fish Finder Out For A Spin. One of the easiest ways to learn how to operate your fish finder is by doing a little experimentation. Take a spin out on a clear water lake where you can see the bottom at least ten feet away from you. Compare what you are seeing on the bottom of the lake with what you see on your fish finder. Notice the rocks and brush, and other objects below you and how they look on the screen.
  2. Don’t Get Hooked On The Automatic Fish ID Feature. This feature is tempting for the first time user but doesn’t get hooked on it. Many times this feature will give you false reads and you will end up fishing in a dry spot thinking you see fish. It also takes more power to use this feature so don’t drain your battery with something that is not very accurate. Learn how to tell fish from the rocks and brush using the standard display.
  3. Manually Adjust Your Gain Control. Most fish finders come with an automatic gain control however many times this setting is quite noisy and makes it hard to see the fish. Turn off the automatic gain control and manually adjust it. Turn it all the way down and then start to slightly raise it up until you see a false or second bottom. This appears typically around double the depth of the actual bottom. This is the best setting to keep the noise out and keep the fish clear.
  4. Use The Zoom Feature. If you are fishing for bottom-hugging fish like Walleye in a lake or Ling Cod in the ocean, then use the zoom feature to zoom in on the bottom to give you are a clearer picture of the bottom.
  5. Don’t Second Guess The Type Of Fish. Many people try to figure out what type of fish they are looking at. This is folly. You cannot tell if it is a large trout or kokanee. You cannot know if it is a Walleye or another bottom fish. So mark the fish and decide if you want to go for it.

Fish Finder Basics – Finding Fish With Modern Technology

Here is a great informative video you can watch to learn how to find fish with your new fish finder.

I hope that this article showing you the fish finder basics helped you. Please feel free to leave a comment below on what you think would be helpful tips for people to learn how to use a fish finder.

If you haven’t purchased a fish finder yet, you might be interested in our list of the leading fish finders of 2020 on the market today. Alternatively, you might want to read our buying guide or other informative articles on fish finders or our reviews of the latest fish finders.

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