When BR24 Broadband radar was introduced by Lowrance and Simrad a few years ago, it redefined clarity and sensitivity in close-range radar. Instead of radiating microwave pulses with a magnetron, Broadband sends out a continuous transmission wave. This wave increases in frequency as it moves away from the dome, hits a target, and is reflected back. The difference between frequency in the transmitted and returned waves is how the unit determines target distance. Since there’s no powerful magnetron pulse there’s no need for “bang suppression,” which eliminates masses of clutter in the first 100 feet or so of the boat—and also eliminates the ability to see anything this close, on all standard radar units.
Now, with Broadband, suddenly it was possible to pick up targets just a few feet off the bow or stern. That can be incredibly helpful in low visibility situations, and those targets could be as small as a single piling, a crab trap float, or even a bird. But Broadband had one weakness: its range was limited to 24 miles.
It only took a couple of seasons for Navico (the parent company of Lowrance and Simrad, among others) to tackle this challenge head-on, and as they developed the NSE and NSO systems they rolled out the Broadband 3G. Transmission power was doubled, and this delivered 30-percent more range and better long-distance target detection. At the same time, 3G still transmits a mere fraction of the energy of a cell phone, and fits into a compact 18” dome.
Yet 32 miles of range remains a bit on the wimpy side, for some large boat owners. Remember: the most important factor in radar range is actually the height of the antenna, because of the curvature of the Earth. If you have a 20- to 30-something center console, cruiser, or express, chances are your radar won’t live up to its full potential no matter how weak or powerful it may be. (Learn more about radar range here). But if you have a 50’ convertible and the radar is 25’ off the water at the top of a tuna tower, a 32 mile unit doesn’t quite cut it.
Now, behold 4G—Navico has introduced yet another version of Broadband barely a year after 3G hit the market, and this one can peek out an additional four nautical miles into the distance with a 36 NM range. The trick lies in reducing the amount of “noise” the radar registers via advanced digital signal processing, 4G can see farther than any Broadband created to date. And there’s one more nifty perk: this system allows you to look at multiple ranges on split-screens, at the same time.
The down side? If there is one, it must be cost. The Simrad 4G dome (which is still a little 18” tyke, just like the original Broadband) carries an average price of $1,900, about $200 more than 3G. Is it worth the extra bucks? If your radome is going to be mounted high enough to see beyond the original Broadband’s 24 miles and the 3G’s 32 miles, the answer is a resounding yes.