If you’re planning on owning and/or operating a boat out at sea, having the right marine antenna is of crucial importance. And, when looking for the range of an antenna, the length of it is an extremely important factor.
The length of a marine antenna is incredibly important because VHF radio waves travel in straight lines. In order to communicate effectively with another antenna, your antenna has to be in, “eye sight,” of that antenna. Because of the earth’s curvature, two antennas moving in opposite directions will eventually both fall behind the earth’s horizon and communication between the two antennas will become hampered.
When choosing what type of marine antenna you need, you’ll have to factor in the length and height of your boat as well. Sailboats have an advantage here because a shorter antenna can be mounted high atop the mast and still communicate effectively with other vessels or base stations that have antennas mounted high.
Luckily, many base stations will mount an antenna high atop a mountain almost like a lighthouse. This way, that antenna will be able to communicate, or “see,” shorter antennas, making communication between the two possible.
The Antenna Equation
To calculate the range of an antenna, you multiply the square root of the antenna’s height above water (in feet) by 1.42. The product will equal the antenna’s communication range in miles. If you mount a two foot antenna onto a boat that is six feet above water, you take the square root of 8 (which is 2.83) and multiply that by 1.42 to get a range of 4.02 miles. So, to know how you can still communicate with another antenna that is 70 miles away, you have to perform this equation for both antennas. For example, the weather antenna may be far away but be mounted very high in order to communicate with multiple vessels at the same time.
At GAM Electronics, we can work with you to custom design an antenna that will suit your unique needs. Our focus has always been on exceptional customer service, quality products, and unbeatable warranties. When you’re looking for the right marine antenna for your vessel, leave the math to us!
If you’re interested in marine antennas, contact us at: 207-583-4670