How Do Fishing Sonars Work?

How Do Fishing Sonars Work?

26 September 2018

Fishing sonars are an advanced type of fish finder that locates fish in all directions under the water. Using sound navigation and ranging technology, known as SONAR for short, these are very important tools in today’s fishing industry. They’re used in everything from large-scale Atlantic commercial fishing to leisure activities. However, the process remains the same at all levels.

The fishing sonar uses sonar technology to locate the fish in the water, displaying its exact location on either an LCD or CRT type screen. Fishing sonar technology has been used since the 1990s, but has been updated since it first hit the commercial market to be more accurate and effective. Today, fish-finding technology also makes use of GPS technology, electronic compasses and radar. So fish-finding sonars are more reliable than ever.

How Sonar Fish Finders Work

A transmitter is placed on the boat or river bank and sends signals out into the water. These sonar signals are then bounced back off any objects in the water to the transmitter, with the reflected waves recorded and displayed on the screen.

Fish finders operate at high frequencies, between approximately 20 and 200 kHz. This helps define the targets in the water and even allows the device to distinguish between one or several fish in the water. The devices can sometimes be used at lower frequencies to penetrate deeper into the water, but these will produce signals that are less clear.

Of course, not every solid object in the water will be a fish, so in order to make sure no false signals are received, the waves reflected back from fish are different to those from stones, corals or other obstructions in the water. The sonar echoes differ in size and shape so that objects other than fish are displayed with different signals.

The fish sonar screen usually displays the presence of a fish with a clear signal. If you’re in a boat, the symbol may change as your location moves closer to the fish, often being represented by arches as the boat cruises over the top of the fish’s location.

As the fish moves through the sonar beam and enters the cone of signal, it shows up on the screen. The arch representing the fish begins to flatten out as it reaches the closest point to the transmitter. As it moves further away it begins to curve downwards, so you can tell which way the fish is moving.

Types of Sonar Fish Finder Available

There are many different kinds and brands of fishing sonars available on the market. Some of the most popular brands include Garmin, Furuno and Eagle. Deeper creates fishing sonars that use your phone or tablet as the screen and their Pro+ model includes a GPS.

A fish finder – particularly one with sonar – is a great way to make your fishing trips both more fun and successful. Once you can accurately locate the fish, then comes the exciting part of trying to catch them. So why not make your trips more focused with a fish finder from Harris Sportsmail.