What is Transducer for Fishfinder? [Where to Mount it?]

What is Transducer for Fishfinder

Fishfinders are extremely useful devices that can improve your fishing success a lot, especially when you are fishing in unfamiliar waters.

If you are buying one, you have to check their features and learn how to use and mount it properly, in order to get maximum efficiency.

So, what is transducer for fishfinder and where to mount fishfinder transducer? Transducer is a crucial part of the system, and it sends and receives the signals that are then interpreted and used to show you underwater structures and fish. Mount it close to the centerline of your boat, in the aft part, in a way that it is always under water.

Without a good transducer, you can’t get a realistic and accurate image on the screen. You can influence its accuracy by proper placement, so even if you own a good one, you have to know where to mount it.

If you are new to this, don’t worry, it may sound complicated at first, but it is actually very logical. Just keep in mind to always choose fishfinders from reputable manufacturers.

Here I will tell you more about how transducers work and explain its role when it comes to fishing.



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What is Transducer for Fishfinder?

I already explained it in simple words, but here is a bit more details about what is transducer for fishfinder.

Fishfinders consist of two unites. One is a screen with controls and that one is used for you to see an image and interpret it. But to be able to get this image, this unit is connected with a transducer.

Transducer is a device that sends ultrasonic waves which travel through the water and reflect when they hit an obstacle. Transducer also receives these reflected impulses, and that data is then processed and displayed as an image.

Its main part is the piezoceramic element. This part is used for conversion of electrical pulses into sound waves. The same part also converts the reflected waves back into electrical pulses.

A cable is used for connection, and the main elements are in a housing that contains sound absorbing material, in order to capture as much reflected soundwaves as possible.

How Does a Transducer for Fishfinder Work?

Now you know that transducers send and receive impulses and show the interpreted image on the screen, but here is a bit more info about how exactly it works.

Accuracy and details on the image depend on how sensitive and well made the transducer is. Depth, distances, and size of objects is calculated within the system by the time that elapsed between the moment when signals were sent and the moment in which the transducer caught their reflections.

The reason why these devices have to be precise and sensitive is the fact that the time is measured in microseconds. Sending pulses is easy, but transducers spend the majority of their energy and capability on receiving echo.

When pulses hit an obstacle, their reflections also depend on an obstacle surface/material. So, the sand will reflect it differently than the rocks. This is why good units can show you bottom features very well.

It can detect fish mostly because of their air (swim) bladders. The density of an air bladder is completely different than anything else underwater.

Fishfinders can show you single fish, shoals, and even inform you about the fish species. Some are so accurate that you can observe the efficiency of your bait.

What is Transducer for Fishfinder - Mount

Can a Fishfinder Work Without a Transducer?

Now you know what is transducer for fishfinder, but is there any chance that a fishfinder can work without it?

The answer is both YES and NO. Transducer, which is basically a sonar, is used in a previously described way, and you can`t get an image of fish and bottom contours without it.

But some fish finders come with GPS and chart plotter functions, which can be used without a transducer, for navigation purposes or similar. Just keep in mind that without it, you will not have a reading on how deep the water is.

You may have maps available to show you the depth, but it is not the same.

Cheaper units that have a sole purpose of showing you fish can’t be used without a transducer because those devices do not have GPS and charts available.

Majority of fishfinders on the market come with transducers, but you can also buy them separately. I will mention this in the last chapter.

Where to Mount Fishfinder Transducer?

Where to mount fishfinder transducer is an important question, because even the best unit won`t provide accurate readings if mounted improperly.

These devices have to be submerged at all times when in use, so you should choose a place on your boat that is constantly submerged. Most often, that place is along the boat centerline, closer to the aft part.

There are two main ways of mounting it, and those are through-hull and in-hull. The first one means that the transducer is flushed with the hull, and it does not “stick” out. It is ideal for smaller boats or sailboats. External through-hull means that the transducer is extended and not flushed with a boat. This is excellent for creating vertical pulses and removing the transducer away from any boat part that could interfere with the pulses.

In-hull means that the unit is inside the boat, on the bottom, sensing signals through the hull. This is used by anglers who do not want to drill their boats. It is also practical for service purposes as you do not have to take the boat out of the water. Besides, there is no risk that you will damage while transporting your boat on a trailer.

No matter which mounting way you choose, it has to be positioned on a place where the water is calm, never behind a propellr or area with a lot of bubbles or water turbulence.

Are Fish Finder Transducers Universal?

Are fish finder transducers universal or not is the last important question here. As already mentioned, transducers come with fishfinders, but you can also buy them separately.

Depending on a model, you may want to upgrade to a better one. Most manufacturers have transducers that are compatible with various models of fishfinders of the same brand. That info is always stated on the product and to be sure, check on their website.

But, when it comes to connecting them to a different fishfinder brand, things may not be that simple. Some are compatible, and some are not. If you are handy with electronics, you may even change the connector and use it, just make sure to check the power ratings.

There are dozens of brands and models on the markets so I will not make a “compatibility” list here, but you can find info for every model in less than a minute if you search the web.

Here you can find also the difference about ice fishing fish finder vs flasher ...


What is transducer for fishfinder is a common question among beginners, and hopefully you got the answers in the previous chapters. Transducer is the crucial part of the system, and accuracy of displayed images depends on it.

Knowing where to mount fishfinder transducer is important, because even the best unit can give bad images if the placement is wrong.

Before installation, check the manufacturers instructions and be careful not to damage it if mounted below the hull. And of course, enjoy your new fishing adventures!

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