The average boat owner doesn't have the foggiest notion how to select a radar. Why should he? In truth, that's what guys like me are for. But you should be armed with a little knowledge so you can make the best choices for your needs. The differences among radars extend beyond range and price. Unfortunately, a unit's true usefulness is often hidden behind a lot of technobabble. What I will reveal here are which tech specs you need to pay attention to and how to understand them.
HOW FAR CAN IT SEE? Naturally, the farther your radar can see, the greater its value. Prices usually escalate with a radar's range. But what you may not realize is that range won't tell you everything you need to know. The same technical attributes that allow a radar to reach out at a greater distance are also the very characteristics that create a more detailed picture with greater resolution. You need to concern yourself with power output, antenna type and size, and horizontal beam width.
POWER TO THE PEOPLE. The more energy your radar throws out, the more energy will be reflected off the radar target to make its way back to the antenna. The more target energy received, the more defined the resulting picture will be. In other words, the more kilowatts (kW) a radar boasts, the better.
SIZE (AND SHAPE) MATTER. If you can, learn the internal antenna length. If you can't, the size of the enclosure is enough to serve as a guide for comparison. A radar's signal is in the microwave frequency band, so its electrical wavelength is short. What this means is that an antenna that's just a few inches longer than another will significantly outperform the shorter antenna. People gravitate to the open-array antenna. Why? Because you can see it spinning, so it looks like it's working. But these antennas take a considerable amount of effort to build, waterproof, and protect from the elements. Housing the antenna inside a fiberglass enclosure - a dome - significantly reduces its cost. So which is better? Provided that the length of each antenna is the same and the antenna element used is similar, there's no difference.
IT'S ELEMENTARY. Antenna elements are either metal waveguide (fabricated from a sort of square metal pipe) or printed circuit board (PCB, or microstrip constructed of plastic or fiberglass). Metal waveguide antennas are superior performers. PCB antenna elements are responsible for cutting the cost and overall antenna size. There's also a hybrid antenna element that's part waveguide and part PCB. Its performance exceeds that of more economically advantaged radar antennas with PCB elements.