Have you ever been out on the water and had no idea about what was around you? Was the rain so hard, the fog so thick or the night so dark that you didn’t see that piling on your starboard bow until you were right next to it?
Radar helps you avoid those hidden dangers, making your boating not only safer but also more pleasurable.
Radar can be effective for navigation in poor visibility, for collision avoidance and as a method of determining your location based on what is around you. It is good for watching weather and seeing the direction it is moving in without being at the mercy of a cellular signal.
It can be used to detect birds feeding on schooling fish as well as other boats gathered on a hot spot. Radar can help find competitors in a race and track their movements. It can also alert you to approaching vessels while at anchor, giving you warning before they get too close.
With technology available today radar is no longer restricted to larger vessels with deep-pocketed owners. Smaller full-featured radars are now available for vessels as small as 17 to 18 feet. Many manufacturers offer a wide array (pun intended) of radars to suit any boater’s needs. Common deciding factors for radar buyers are usually range, screen size and price. There should be more considerations, however, to assure the right fit for your specific boating needs.
Understanding the basic principles of how traditional and newer technology broadband radar works will help in getting the right system.
For decades, commercial radar changed little – until recently. All radar systems are composed of a screen (it can be a dedicated screen or a multifunction display sharing information with chartplotters, depthsounders, etc.), a processor and an antenna. The antenna can be a lighter weight dome in varying sizes from 12 to 36 inches or, for more powerful radars, a heavier open array in lengths from 24 inches up to more than 6 feet.
A traditional radar antenna transmits a signal created by a magnetron outward. When that signal is reflected by an object, the antenna receives the return signal. This information is sent to the processor and the distance and location of the return is identified and displayed on the screen.
Newer broadband radars do essentially the same thing but instead of sending just one signal they send a continuous transmission wave that increases in linear frequency. As a return comes back at a certain frequency a higher frequency is simultaneously being transmitted and received. The information received between these transmissions allows a highly detailed image to be deciphered and displayed. Unlike traditional radar the return energy of broadband radar is far greater, allowing for better target definition and separation.
This new broadband technology’s benefits over its traditional brethren include lower power draw and drastically reduced radiation (so low that your cell phone probably has a higher radiation rate than some broadband radar on the market). The lower transmission radiation means the antenna can be mounted in locations previously deemed inappropriate due to possible contact with passengers.
Another benefit is the ability of the radar unit to see as close as 1/32 of a mile, opening up the ability to view vessels, markers and obstructions very close to the vessel. This is something that traditional radars are not able to accomplish due to the “blind circle” in close proximity to the vessel caused by the transmission pattern of their signal.
The signal that is being transmitted by the antennas of a radar system can best be described as if it were a beam of light on a very dark night. A small radome antenna will transmit a signal with a broader horizontal beam width than a six-foot radar with a narrow horizontal beam width. Think of the broader beam as a floodlight that emits a wide wash of light out into the night. It will see individual markers that are close together at the same time, with the radar registering them as one return on the screen.
A larger antenna or one with a tighter horizontal beam (think tight spotlight beam) will see those markers one at a time and the return signal reflects two targets instead of just one. The tighter beam of larger open array antennas will be able to decipher birds and will give more accurate feedback at longer ranges.
As with anything to do with boating, everything is a trade-off or compromise.
Larger array antennas are the best performers at longer ranges, but they are heavier and more power hungry than smaller dome systems. They are a necessity if you have a sport-fish boat and are heading offshore in search of tell-tale birds, or wish to have the power and range to punch through heavy weather and see what is on the other side. They need to be mounted out of the way of human obstruction high on a structure that can handle their weight.
Smaller radars (especially the newer broadband dome systems) do not have the power or range of larger traditional systems, but they offer a viable option for the smaller vessel that is limited in mounting locations or where maximum range or power is not a critical factor. They offer a range of features that most boaters find useful yet do so within the limitations of range and power.
No matter which radar is chosen, having radar on board will allow a captain to gain more confidence not only in low visibility conditions, but also for vessel security and weather prediction and will allow for a less stressful time on the water. There are more offerings of radar systems than ever before, so find the one that will work best for your boating and see what you’ve been missing.