What Is a Transducer on a Fish Finder

If you are a fishing enthusiast, a fish finder is a must-have tool for fruitful catches. They detect fish schools helping you maximize on spots that are rich in fish, saving you time and effort when fishing. This is thanks to a transducer, that is an integral part of every fish finder.

A transducer receives echo sounds from the water and converts them into numerical data or graphic images. These images are translated on a screen where anglers can monitor the underwater environment, essential for evaluating the position and distribution of fish.

Knowing what a transducer is, how it works and how to install it will save you time when fishing and using the device. This article covers everything you need to know about transducers.

What Is a Transducer?

A transducer is a device that converts one form of energy to another. The transducer acts as both the transmitter and the receiver in a fish finder. It scans the underwater environment by sending out pre-set frequencies. The frequencies bounce off various objects in the water and are picked up by the receiver on the transducer [1].

The data is then converted into images or digital figures and displayed on the screen that comes with the transducer. It shows vital information such as fish schools, rocks, water depth, and bottom contour

Understanding Frequencies

Frequency is the number of cycles or sound waves your transducer emits every second. The accuracy of a fish finder is dependent on the frequency that the transducer releases. Transducers can be tuned to different frequencies depending on what you want to scan. The majority of transducers emit frequencies ranging from 50 to 200 kHz.

Low frequencies of around 50 kHz are excellent for scanning water depth since they have higher penetrating capabilities. They also scan a wider area because the transducer transmits the frequency on a broad beam angle of roughly 35 degrees. However, the images lack clarity, and you will need to switch to a higher frequency for more precision.

On the other hand, a high-frequency transducer of around 200 kHz offers more definition. It scans an area on a narrow beam angle and can pick fine details in the water column. However, it is limited in its depth capabilities. As you go deeper into the water, the transducer begins to lose signal, and you must switch to a low frequency.

Advanced fish finders come with a dual-frequency transducer. It allows you to switch between high and low frequencies depending on where you are fishing. Some can automatically switch between the two frequencies, and others can simultaneously display a split-screen with both frequencies.

Transducer Power

The power a transducer sends out an echo sound or ping is expressed in watts. A transducer with a higher wattage increases the probability of obtaining a return echo in deep-sea or bad water conditions.

It also allows you to see underwater structures better and with incredible target separation. On the other hand, a transducer with low power will be slower and more efficient in shallow water.

Types of Transducers on Fish Finders

Transducers are classified according to their installation methods. We have transom mount, in-hull, trolling motors and thru-hull transducers. Let’s look at them in detail.

Transom Mount Transducers

These transducers are the easiest to install and maintain. They do not require you to drill anything on your boat. They come with a mounting bracket that you can easily adjust to change the beam angle or fold away for safe storage.

They are usually installed on the transom and can be mounted on any material, including wood, aluminium, fibreglass and steel. If your boat uses a single-engine, mount the transducer on the starboard side of the transom. But if it uses twin engines, install the transducer between the engines.

These transducers offer the best performance when travelling at low speeds. At higher speeds, they produce low-quality images due to interference from turbulence.

In-hull Transducers

These transducers are usually installed on the inside wall of the hull. They do not require any drilling to install. They only require to be glued with silicone or epoxy.

The advantage of this kind of installation is that it produces minimal drag; therefore, the device has a higher performance. Secondly, since the device is installed on the inside of the boat, there is no risk of damage from underwater structures. Thirdly, the device is easy to uninstall for maintenance. It can be installed and uninstalled even when the boat is on the water.

However, one major downside is that you can only install this transducer on fibreglass. The transducer is also not powerful because the hull absorbs some of the echo return.

Thru-hull transducers

These transducers are the most accurate since they receive sonar returns without much interference. They also give the best performance at high or low speed since they are not subjected to much turbulence.

However, installing a thru-hull transducer can be quite challenging. You must drill through the hull and place the transducer flush against the hull and parallel to the waterline. Placing the transducer incorrectly will result in inaccurate readings.

Trolling Motor

This transducer is installed permanently inside the trolling motor’s propeller. Installing it can be quite tricky because you must route the cables so that they do not interfere with the operation of the motor or get pulled [2].

The transducer has its pros and cons. One of the advantages is that you will receive sonar feedback without much inference. However, since the transducer hangs low in the water, it is likely to be damaged by underwater structures.

See our article on transducer mounting height to learn how to properly mount each type of transducer.

Testing the Transducer

After installing the transducer, the next thing is to test it and determine whether it works. The first step is to ensure that the boat is in the water and the transducer is submerged. Next, switch on the monitor to see if it will display sonar data. If it doesn’t, check your connection and try again.

If the device is working properly, the next step is to test how it works at different speeds. Start with a low speed and gradually increase the speed. If the device is correctly placed, it will display sonar data on the screen. If it doesn’t, adjust it and try again.

How to Maintain a Transducer

It is always advisable to take good care of your transducer to get the most out of it. You should clean it regularly with a soft cloth to remove dirt and residue. You should also paint it to protect it from the corrosive effects of salty water. Additionally, you can inspect the cables for kinks, cuts and corrosion and replace them if damaged.

There are also signs that you can look for if a transducer has gone bad.

The Bottom Line

Hopefully, this article answers the question of what a transducer is on a fish finder. You can use it as a guide when buying an appropriate fish finder. This guide can also be helpful for complete beginners that do not understand how fish finders work, giving you an upper hand at figuring out the functions of a transducer on a fish finder.

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