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Why is the Height of a VHF Radio Antenna Important?

why is the height of a vhf radio antenna important

Owning a boat may be a fantastic way to loosen up and relax in the sun when the weather gets warmer. As a boat owner, you should be aware of the proper equipment for the foundation of maritime safety. VHF radios are one of them; these radios are highly recommended for reliable on-the-water communications.

When you are trapped in a rut, a VHF radio can be your lifeline. Therefore, owning a good VHF radio system is essential, as well as the height of its antenna. Still, why is the height of a VHF radio antenna important? The answer is to enhance VHF radio performance to take radio listening and user experiences to the next level. So to learn more, read on!

What Exactly is a VHF Radio, and Why Should You Have One

The heart of your boat safety equipment is a VHF radio. VHF is an abbreviation for very high frequency, which relates to the wavelength of the signals transmitted by these radios. Because their longer radio waves can travel further than UHF (ultra-high frequency) transmission, they are mostly used outside.

VHF radios may be used by groundskeepers or security personnel roaming outside an arena to communicate with one another. VHF radio communication is also frequently used in aviation and sailing, as well as on golf courses.

A VHF radio is your greatest option to call for assistance in the event of a marine emergency. Although VHF radios are not required by federal boating rules, most insurers strongly urge boat owners to have one on board. Thus, learn how to use it and make sure it functions smoothly by putting it in a checklist before launching.

Furthermore, in non-emergency scenarios, marine VHF provides a handy and effective method of connecting with other boats. VHF communications help you stay connected with your fellow boat captains, whether you want to alert a neighboring boat about potentially dangerous circumstances, ask about local villages onshore, or receive information about a nearby harbor.

Understanding Your VHF Radio


Knowing the essential components of your VHF radio is crucial to operating your watercraft correctly and safely, whether you have a sailboat, pontoon, or fishing boat. You’ll be more confident using your radio if you understand it properly. Moreover, if it breaks down, you’ll be better equipped to solve it.

Your VHF radio gear might be immobile, integrated with a radio and a separate hand-held mic, or mobile, with the radio, microphone, and all other elements integrated into a small, portable device. A VHF communication system is made up of the following components in general:

  • A source of power. Stationary devices are wired to the boat’s electricity, whilst portable units are battery-powered.
  • The radio device, which includes a receiver and a transmitter, allows you to broadcast and receive VHF signals. The radio has an LCD display that displays the current volume and channel, and other information (for example, battery life of portable devices). It also contains controls for using the radio, such as choosing channels, adjusting the volume, switching between receiving and sending, and many more.
  • The VHF antenna is a device used to enhance the receiver’s potential to recognize transmissions. In the event that your primary VHF antenna is broken, it is best to carry a backup antenna on board.
  • The DSC controller is used to provide your boat with a distinctive digital identity known as an MMSI (maritime mobile service identity). The DSC controller is also in charge of handling distress signals.
  • An automated identification system (usually found in modern devices) uses a GPS device to send location coordinates, and other information such as destinations or MMSI.

What is a VHF Antenna? And Why is the Height of a VHF Radio Antenna Important


A VHF antenna serves as a radiator to transfer the energy produced by the radio’s transmitter in the right direction. VHF antennas must also be weather-protected (or constructed of corrosion-proof materials) and able to endure the significant pressures created by a sailboat hammering in rough seas.

Speaking about the height of the VHF radio antenna, it is clear that it plays a vital role in enhancing your VHF radio performance. This is since VHF radio frequencies move in a straight line and weaken at longer distances. The receiving antenna must be able to detect the signals of the transmitting antenna for effective communications.

The longer the distance between the two antennas, as well as the number of obstacles between them, the more difficult it is for the signal to get through. Because of these features, VHF communication is commonly referred to as “line of sight” or “LOS” communication.

Obstacles like trees, buildings, or natural landforms like cliffs and canyons, may hinder the antenna from transmitting data to the intended recipient, or they may be hard to hear or interpret. In particular settings, VHF transmissions can be reflected by objects like buildings or buildings, causing the receiving antenna to pick up different signals every time confusingly. This phenomenon is known as multi-path propagation, which can make the data transmission worthless and incomprehensible.

To address this problem, you should have the antenna mounted as high as possible. At this point, the height of the antenna directly impacts the range of transmission. The higher the VHF radio antenna, the less probable it is that objects can interfere with the radio frequencies. Depending on the boat’s designs, VHF antennas can be mounted on the cabin roof, a mast, or the helm.

On a normal 20-foot yacht with an 18-foot mast, putting the VHF antenna at the top of the mast adds around 5 miles to your transmission distance compared to mounting it on the cabin roof. Not only will the increased range help you, but the additional distance between the VHF antenna and other electrical devices onboard will minimize the frequency of interference with your VHF transmission.

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Last but not least, the height of the VHF antenna also affects the range calculation. As the longer antennas are, the further the range is. Well, speaking about the VHF range, we will show you a way to calculate the VHF radio range in the next section.

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VHF Radio Range Calculation

To calculate your VHF range, multiply the square root of antenna height (in feet) by 1.2246. The result is the distance your signal may travel (in nautical miles).

In addition to being affected by VHF antenna’s height, the transmitter’s power directly influences your VHF frequency range because the more power it supplies, the farther the transmission can travel. The maximum power of consumer radio equipment is 25 watts. Also, it is vital to make sure that your VHF antenna is precisely upright. Otherwise, the radio waves can’t reach a longer range.

Other Factors to Consider

Besides the height of the antenna, you should also consider these factors for a smooth operation:

  • Having a 3dB antenna mounted at the mast’s top. The dB rating of an antenna shows the marked increase in transmission power caused by its capacity to concentrate radiation. High dB antennas collect energy in a disk-shaped field straight-up to the shaft of the antennas. This increases the strength of your radio signal to nearby receiving stations.
  • The radio should be placed out of direct sunshine, far from the machine noise and engine vibrations that might make it difficult for hearing.
  • The radio should be installed at least 3 to 4 feet away from electromagnetic devices because these devices can cause atmospheric interference.
  • The radio must be within a reachable range, and the controls are visible.
  • Inspect your radio system regularly to check on weathering, corrosion, or any damages. Seek a professional installer or electrician when you’re in doubt.

Wrapping Things Up

So, with that, you have reached the end of this article. I hope you have picked up a lot of valuable information regarding the importance of a VHF radio antenna’s height. It is a tool helping you in enhancing VHF radio performance.

To get the greatest performance, remember to mount the VHF antenna in your boat’s highest position. Because the height of an antenna significantly affects the distance your signal can travel. Furthermore, there will be less interference when the antenna is placed higher.

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