From the outside, they all look like white sticks with different heights. When choosing an antenna, how can you tell which one is going to be the best fit for your boat? They generally look the same but there are so many differences between antenna types. You aren’t paying more for one just because it has a cooler name, there’s a lot to consider in finding the antenna that’s the best fit for your boat.
One of the first factors to decide on is dB. The belief that a higher dB is always the better option for your boat isn’t true, there’s more to consider. A higher dB is a more focused signal. Think about it like a focused flashlight, it’ll be brighter in the area that it shines but it won’t cover as much space above and below where it shines. Because of this you need to think about how much your boat rocks on rough seas. If it’s a lot, the receiving radio may experience a fading signal. For a powerboat under 24 feet or a sailboat, a 3 dB antenna is recommended. Usually a 6 dB antenna is recommended for boats over 24 feet and a 9 dB antenna is recommended for boats over 32 feet. Longer antennas generally have higher dB ratings but check the technical specifications of the antenna to be sure.
Additionally, height is always an important factor. The higher you can get your antenna mounted, the farther it’ll reach. When selecting your antenna, make sure to choose an antenna length that’ll combine with the mounting point on your boat to become as tall as possible. To estimate the line of sight different antennas will have on your boat, you can use Shakespeare’s line of sight calculator. This will allow you to input your own numbers and give you a communication range in nautical miles.
It is important to remember that the line of sight does not equal your transmission range. To maximize your range, make sure to drown out the noise from other radios and the environment by having an efficient transmission system. This means pay attention to the quality of the antenna elements, connectors and coax cable on the antenna you want. Better conducting elements help create better efficiency in your signal transmission so silver plated elements are more effective than brass elements. Additionally, thicker brass elements conduct better than thinner brass elements. As for coax cables, there is some loss with every length of coax that you use. Take a look at Shakespeare’s cable loss and efficiency chart to see the differences in coax cables and their effect on your antenna.
Hopefully these steps will ease your decision-making process. You can find all of this information and more illustrated on Shakespeare’s Antenna Selector Guide.