Skip to main content

Point of Contact

Radar has been around for more than 100 years and has progressed from being a scientific novelty to becoming the most versatile of marine electronics. You can use radar to find out where you are, to find your way into unfamiliar harbors, to dodge thunderstorms, or even to find fish by picking out flocks of feeding seabirds. By far its most important use it that for which it was first

Radar has been around for more than 100 years and has progressed from being a scientific novelty to becoming the most versatile of marine electronics. You can use radar to find out where you are, to find your way into unfamiliar harbors, to dodge thunderstorms, or even to find fish by picking out flocks of feeding seabirds. By far its most important use it that for which it was first intended—collision avoidance.

Radar works by transmitting short, intense pulses of radio energy, then listening for the faint echoes that come back. Using radar effectively is a multi-stage process that involves making the most of the tiny scraps of energy that are reflected from distant objects or poor reflectors, then removing the clutter that is produced by reflections from things we don’t want to see, such as waves and sometimes clouds. After that, you can start on the third stage—interpreting the useful information you have received.

THE RIGHT SETTINGS

Brightness, contrast and color: These elements help you see contacts more clearly, so they need to be set up properly. Set the brightness control high enough for the picture to be visible, but not so high that it is dazzling. If you still have a unit with a monochrome display, adjust the contrast so it gives the clearest picture possible. Most color displays offer a choice of color palettes, and which one you choose is up to you. Most people prefer to have a dark background at night.

Gain: The gain control adjusts the receiver’s amplification. If gain is set too high, the screen will be filled with a mass of speckles. This is the visual equivalent of the noise you hear when the squelch control is wrongly adjusted on a radio. If it is set too low, real echoes will be missed.

First, increase the gain control until the screen is full of speckles, then reduce it until the speckles have disappeared from all but the center of the screen. At short ranges, it often pays to turn the gain down a little further, because this produces a less “blobby” picture. When looking for weak or distant targets, turn it back up until the speckles start to reappear.

Tuning: Even though a radar listens for the echoes of its own transmissions, the receiver still needs to be tuned to the right frequency. Luckily, the “auto-tune” function on most modern radar sets is very good at doing this. If you want, or need to, tune your set by hand, set the gain first, then select a long or medium range and look for a weak contact on the screen. Next, adjust the tuning in small steps, either up or down, waiting about three seconds after each adjustment for the picture to be completely redrawn under the new setting. If the contact looks weaker, adjust the tuning back the other way. Keep going until the contact is as strong and bright as possible.

Clutter control: Some things produce echoes we don’t really want to see. Seawater, in particular, is such a good reflector that the center of a radar screen is often packed with big bright blobs generated by the radar energy being reflected from waves immediately around the boat. The sea-clutter control can remove these blobs, but it’s a crude tool that can also erase boats, buoys and even land.

To be sure it is working effectively, turn the sea-clutter control down to its minimum setting. That way you will know it’s doing no harm. Then, if sea clutter truly is a problem, you can turn the clutter control back up, as little as possible.


Finally, there is the interference-rejection control that erases visual clutter caused when your radar receives transmissions from another boat’s radar. This control can do nothing but good, so there’s no point in switching it off.

Rain-clutter controls can be equally dangerous. While they do remove smudgy contacts created by rain clouds, they also degrade echoes from genuine targets. The rule of thumb here is the same as for the sea-clutter control: turn it off when you don’t need it, and then use it as sparingly as you can.

Some radars have two rain-clutter controls, one usually affects only the area in the middle of the screen, while the other, often called “FTC,” affects the entire scanning area.

Related

00-LEAD-210918_11HR_AZIMUT48HRS_AMO_00411

11th Hour Racing Team's Green Mission

“I’ll admit, it’s still hard to watch the boat leave the dock sometimes,” says former Volvo Ocean Race sailor Mark Towill. Since meeting during a Transpac campaign over 15 years ago, he and his teammate Charlie Enright have sailed thousands of miles together aboard two Volvo ...read more

D61_JKELAGOPIAN-3

Boat Review: Dufour 61

Dufour, long one of France’s most well-respected builders, has been producing sailboats in La Rochelle since the dawn of fiberglass boatbuilding. Having recently merged with another La Rochelle-based builder, Fountaine Pajot, Dufour has now joined other European mass-production ...read more

m138123_14_00_210609_TORE02_SE_2152_2504-2048x

The Ocean Race to be “Climate Positive”

The 2023 Ocean Race intends to be one of the world’s first climate positive sporting events, offsetting more greenhouse gasses than are produced. The two-fold effort means cutting emissions by 75 percent and investing in ocean projects that sequester carbon and restore ocean ...read more

01-LEAD-Ancients-3-2048x

Cruising Lake Superior

Almost anywhere a sailor drops the hook someone else has been there before. We are hardly ever the first. That remote Maine harbor without a soul in sight: there’s a lobster trap. The south coast of Newfoundland: the crumbling remains of a fisherman’s cabin lie hidden among the ...read more

01-LEAD-Tablet-Holder-4

Fabricating a Tablet Holder

During the pandemic, I was stuck aboard Guiding Light, a Lagoon 410, in St. Lucia for over a month. During that time, as I worked on the boat, I started by doing a spring cleaning in my spares locker and finding some parts and material that I forgot I had. As soon as I saw them, ...read more

00-LEAD-AdobeStock_486335954

A Catamaran for a New Era

Anacortes, Washington, is an unassuming sea-salty town near the San Juan Islands of Puget Sound, and the Betts Boats yard is easy for a passerby to miss. But within Betts’ facilities, the dawn of an era in Pacific Northwest production boatbuilding could be breaking with the ...read more

X5_plus_slide-01

Boat Review: Xquisite X5 Plus

The Xquisite X5 Plus is a major update of the boat that SAIL awarded Best Large Multihull and Best Systems titles in 2017. The changes were not just cosmetic, but genuine improvements to an already fine boat, making it lighter, faster and less dependent on fuel. The builder’s ...read more

01-LEAD-AdobeStock_40632434

Cruising: Offshore Prep Talk

When I began preparing Minx, my 1987 Pearson 39-2, for extended Caribbean cruising, I had to balance my champagne wish list against my beer budget. Every buck spent on the boat before leaving would be one less frosty can of Carib down in the islands. On the other hand, I had to ...read more