Everything you need to know about marine radars

Today, we have GPS, chart plotters, card readers, all focused on fixed elements, but safety at sea beyond coastal areas involves many mobile or fixed risks. That's why we now have the assistance of one of the key devices in boat safety, marine radars.

In this article, we will provide a detailed explanation of what a marine radar is, how it works, its components, and more.

What is a Marine Radar?

A marine radar is a marine geolocation system that uses waves to detect and warn of obstacles or mobile elements and measure distances to them, such as boats, aircraft, vehicles, fish, reefs, buoys, and even weather formations.

How Does a Marine Radar Work?

Its operation involves emitting a high-intensity radio frequency or microwave frequency (depending on the radar technology) and detecting objects thanks to the return of the emitted frequency or wave. This is explained by the fact that the wave we emit collides with the object to be detected and bounces back, allowing us to determine the distance based on the time it takes for our wave to return.

Components of a Marine Radar

A marine radar typically consists of:

• A high-frequency radio transmitter responsible for generating and sending a frequency or wave.
• A receiver, a device capable of receiving the same frequency or wave sent previously.
• A monitor or screen on board that conveys the information collected by the other radar components, usually presenting it as a heat map.
• An antenna, the part of the radar that detects echoes, eliminates noise, and provides an image to the monitor.

Types of Marine Radar Antennas

There are two possible types of antennas on a boat:

• Radome Antenna (closed): These antennas are ideal for small motorized boats and sailboats. They offer excellent performance, even in adverse conditions. The radome is the antenna's protective covering. Being lightweight, compact, and of reduced size, they are the best option when energy efficiency is essential and rigging limits mounting space. Moreover, this type of antenna consumes less power than other options, making it advantageous for long-distance navigation.
• Open Antennas: These antennas are typically found on larger vessels like yachts. They feature an open scanner that provides optimal range and performance due to their larger size, more efficient antenna, and narrower pulse. They also offer improvements in distance and delay resolution and have a clearer separation of targets.

Where Is the Radar Antenna Installed?

The range of the radar is limited by the curvature of the Earth, so the height of the device above the sea surface and the height of the obstacle to be perceived determine the radar's detection range.

The higher the radar's location on a boat, the greater its maximum range. However, it will also increase the minimum range around the boat where targets won't be detected. This is an important consideration when maneuvering, such as entering a harbor in fog or darkness, as buoys, docked boats, and others won't be as easily detected at short distances. Therefore, the recommended installation height for the radar is above head height to avoid exposure to the electromagnetic energy emitted by the radar antenna, which could be harmful to health. The ideal location is the highest point on the boat, providing a 360-degree unobstructed view.

Additionally, the radar on the boat is usually installed in the front part of the mast. In the case of a closed antenna, its power supply comes from its connection to the monitor via a multi-conductor cable composed of positive and negative power cables. In contrast, radars with open antennas often contain a separate DC power supply cable for their antenna.

Leading Brands of Marine Radars

There are numerous brands of marine radars, but perhaps the most well-known ones include:

B&G

Furuno

Garmin

Humminbird

Icom

Lowrance

MarQuipt

Mer-Veille

Raymarine

Simrad

X10D

If you are looking for a marine radar for your boat, click here and enter Mercanautic.