An echo sounder is a device for determining the depth of a reservoir, studying the structure and topography of the bottom, and searching for fish. The very first sounders were intended for military purposes - to detect enemy submarines. Later, echo sounders spread and were widely used for fishing and control of river and sea vessels. The echo sounder can be used for fishing in summer and winter, as well as fishing from a boat or from the shore. There are many models of echo sounders on the market, which differ in functions, characteristics and price.

In the article we will try to understand how the echo sounder works. We will discuss the technical characteristics and parameters, we will talk about the principles of choosing a sonar model.

Who needs an echo sounder?

One of the main tasks of an angler during fishing is to find the locations of fish. Experienced anglers use various methods for this:

• The location is indicated by those floating to the surface fish.
• Flocks of seagulls are circling in one area, indicating that there is a high concentration of fry in this area.
• The favorite parking places of predatory fish related to the bottom relief: pits, edges of banks and channels, areas with branches of trees and bushes on the bottom.

It can be useful for the fisherman to know in which depth horizon the fish is on the day of fishing: the fish can be standing on the bottom, in the middle layer of water or on the very surface.

A modern electronic device - echo sounder - helps to answer all these questions. The use of fish finders by fishermen has changed fishing dramatically. Detailed information about a body of water gives the angler a huge advantage.

The echo sounder allows:

• Determine the depth at the fishing spot with high accuracy
• To study the general topography of the bottom, to detect if there are no edges, depressions, ridges in the bottom
• Spot schools of fish that are food for predators

Some anglers mistakenly believe that using an echo sounder is the easiest way to catch fish. In fact, this is not the case, the echo sounder allows you to find promising fishing spots, but that fishing to be effective, the angler must be able to catch it.

What does an echo sounder consist of?

Different echo sounder models may differ in design, but all echo sounder designs have much in common. All echo sounders consist of the following elements:

• Transmitter
• Receiver sensor
• Processor
• Screen
• battery
• body

How the echo sounder works

All echo sounders have a similar principle of operation. The sonar transmitter generates an electrical pulse that is converted into an ultrasound signal. The beam of the ultrasound signal is directed downwards.

The ultrasonic signal passes freely through the water, reflects off the bottom and any other underwater objects, including fish, and returns to the echo sounder, where it is captured by its receiver.

Data from the receiver is sent to the processor, which processes it. The sonar processor analyzes the time it took for the signal to reach the obstacle and return. Since the speed of sound in water is constant, the processor calculates the distance to the object based on the signal transmission time in milliseconds.

The processor displays a graphic image in the form of contours of the bottom and conditional images of fish that have entered the zone of the sonar beam on the color or black and white screen of the echo sounder.

What are echo sounders?

All echo sounders currently on the market can be divided into three groups, depending on their intended use:

• Echo sounders for winter fishing
• Echo sounders for shore fishing
• Echo sounders for fishing from a boat

Echo sounders of all three groups have a common principle of operation, but each type has its own design features and differences.

Sonar for winter fishing

An echo sounder is needed for winter fishing no less than for summer fishing. In winter, it is more difficult to find fish than in summer, and there is much less time to do it.

Sonar allows you to find fish by making fewer holes in the ice. In order to use the echo sounder, it is not necessary to drill a full-fledged hole, it is enough to make a small depression, collect water there, the echo sounder sensor can work through ice.

An echo sounder intended for winter fishing must be: compact, reliable, resistant to water and cold in the most extreme conditions. Recently, many models have appeared that meet all these conditions and are sold at quite reasonable prices.

Ice fishing fish finders are lightweight, compact and fit easily into a small case. Winter echo sounders work with batteries or a battery. Such echo sounder can be used not only for winter fishing, but also in summer, fishing from a boat. The disadvantages of echo sounders for winter fishing are small screens, which are not very convenient to use.

Sonar for shore fishing

Sounders for fishing from the shore - this is a new type of device that appeared quite recently and is gradually gaining popularity among anglers. Such echo sounders are a small diameter ball inside which there is an echo sounder sensor and a wireless communication module (Bluetooth or Wi-Fi). The echo sounder is cast a certain distance with a rod and then pulled towards the shore with a steady reel. A special application is installed on the angler's smartphone or tablet device, which displays the information received from the echo sounder: the depth of the reservoir, the topography of the bottom and the fish. When choosing a wireless fish finder, it should be taken into account that a fish finder with a Wi-Fi module works at a greater distance than with a Bluetooth module. The wireless fish finder is a great helper for the shore angler.

Sonar for fishing from a boat

A boat echo sounder consists of a sensor and a head unit, which are connected to each other by a cable.

The sensor can be mounted on the bottom of the boat or on a special bracket on the side of the boat. The sonar head unit is fixed in the boat in such a place that it is convenient for the fisherman to observe its screen.

When the boat moves, the angler sees a picture of the bottom of the reservoir on the screen and selects a promising fishing spot.

Boat echo sounders are stationary devices and are not intended to be moved from one boat to another. The body of this type of fish finder is usually larger than other fish finder bodies, so they often have a larger screen and more features.

Technical characteristics of the echo sounder

Frequency

The pulses sent by the echo sounder can be of various frequencies - 60 Hz, 83 Hz, 200 Hz, etc. The signal sent by the echo sounder is a cone with a certain angle.

The higher the frequency of the sounder's signal, the narrower the beam. The higher frequency beam provides a more detailed image of the bottom of the tank and objects in the water column, but at the same time captures a smaller area. Low-frequency beams have a wider angle, so they capture a larger area, but at the same time provide less detail.

The lower the frequency of the signal, the deeper it can penetrate into the water depth. The most versatile will be an echo sounder with an operating frequency of 50 to 200 kHz.

An angler who plans to fish at shallower depths should choose a higher frequency sonar, but if he plans to fish at greater depths, he should choose a lower frequency sonar.

Number of rays

An important characteristic of the echo sounder is the number of rays directed to the bottom of the tank. Echo sounders can be one, two or more beams. The more beams the sonar has, the better, but devices with more beams are more expensive.

Different echo sounder beams have different frequencies and different angles, the result of their combined action is visible on the echo sounder screen. The narrow angle, high frequency beam is perfect for exploring the bottom structure in depth. The wide angle and lower frequency beam is good for detecting fish.

When choosing an echo sounder based on the number of beams, it is worth deciding what goals and tasks the device must perform.

• In winter, the simplest single beam 83 kHz echo sounder is enough for fishing.
• For fishing from a boat, a dual beam 83/200 kHz echo sounder would be better suited, such a device allows you to see the general picture of what is going on below the boat and closely inspect the structure of the bottom.
• 83/200/800 kHz three-beam echo sounder suitable for fishing in large and deep rivers and lakes
• Echo sounders with 5-6 beams are used for sea fishing, searching for large schools of fish

Sonar power

When choosing an echo sounder, you should pay attention to the power of the device. The higher the power of the sonar, the greater the depth it will be able to operate.

The power of the sonar affects the quality of the displayed image. A low power echo sounder may work well in shallow areas, but when working at great depths and holes, it will not be able to show them clearly enough, let alone detect if there are fish in them.

The power of the echo sounder is directly related to its sensitivity, a powerful echo sounder with poor sensitivity will not be able to produce a quality image. Sonar power is measured in watts.

As you know, the unit of power is watts, so pay attention to this parameter when buying. However, even with the purchase of a high-power echo sounder, it is not enough to make the image on the sonar screen clear and understandable. Power without sensitivity means nothing and these features are directly related.

• A 150-watt echo sounder transmitter power is sufficient for shallow fishing.
• 200-300 watt transmitter power echo sounders are used for fishing in medium depth.
• For fishing in the sea, at great depth, echo sounders with a transmitter power of 500 watts are used, with the possibility of increasing the transmitter power up to 2400 watts for a short time.

Sonar beam angle

The sonar beam can have a different angle, this parameter depends on the frequency. The higher the sonar frequency, the narrower the beam angle. The size of the sonar beam angle determines the area covered.

• 16-20 degrees - a radius that allows you to explore the bottom of the tank in detail
• 40-50 degrees - the beam of the echo sounder at this angle allows you to take into account not only the bottom of the tank, but also a large area of the water column
• 75-90 degrees - the sonar beam at this angle allows you to cover a large area of the water column

Currently, many echo sounders have multiple beams, each operating at its own frequency and angle.

Sonar screen

The quality of the sonar display has a direct impact on the content of the information and the quality factor of the information display. Echo sounders can be colored or black and white. Color echo sounder displays better represent the nuances of the bottom topography, but at the same time they are much more expensive. Image quality depends on the number of colors in color sounders and the amount of gray shades in black and white. The more of these parameters, the better. The sonar display with good brightness and image contrast allows you to get a high-quality image even in bright sunlight. It is good if the sonar screen has a non-reflective coating.

The sonar screen can range from 2 to 10 inches. The bigger the screen, the better you can see everything on it. If you're using a sonar with a small screen, you'll often have to zoom in and drag the image to understand what it's showing. The wider the angle of the sonar beam, the larger the screen required.

Sonar screens differ in resolution, which is the number of pixels on the screen that determines the clarity of the image. The more pixels on the screen, the more detailed the image. A school of fish looks like a blur on a low-resolution screen, but every nuance will be visible on a high-resolution screen. The simplest echo sounders have a screen with a resolution of 240×240 or 240×270 pixels. Mid-level echo sounders are equipped with a 320×320 or 320×480 pixel resolution screen.

Sonar body

The housing of the echo sounder must have high-quality protection against water entering the device. The reliability and durability of the device directly depends on the degree of moisture protection of the sonar housing.

There are two common options for body protection:

• IP x6 - allows splashes of water to enter surfaces. The echo sounder remains intact. Models with this degree of protection can be installed on the boat away from the side.
• IP x7 - the case protects the device even if it is briefly dropped into water up to 1 m deep. Such protection is especially relevant for portable echo sounders that can accidentally fall out of your hands and into the water.

Additional sonar functions

Modern echo sounders have many additional functions that can be very useful for anglers in certain conditions:

• GPS receiver - can be used to mark points and record the boat's route, by memorizing the fish points in the finder's memory, the angler can easily return there, this feature is especially useful for anglers who like to fish large areas of water.
• map – echo sounder with map function allows installation of electronic maps with bathymetry data. Echo sounders can also draw a bathymetric map themselves and store it in their memory.
• Temperature sensor – Knowing the water temperature at a certain depth allows the angler to predict fish activity.
• Determining the distance to the fish – function can be useful if you need to determine which layer of water the fish is in.

Chirp technology

The principle of operation of this technology lies in the packet transmission of pulses, which allows for a much better and more accurate selection of underwater objects. The image quality of such sounders is more detailed and less noisy.

Side scan technology

In such echo sounders, the rays are directed not only down under the boat, but also to its sides. Echo sounders with a side scan function have the ability to scan the underwater space, to the left and right of the boat, tens of meters. The most complete picture of the underwater situation is obtained by combining the information obtained from the side beams with the information from the bottom beam.

The difference between the classic and scanning echo sounder is that the beam projection of the classical echo sounder is a circle at the bottom, the diameter of which depends on the angle and depth of the beam, while the beam projection scanning echo sounder is a narrow strip.