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

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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.

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.

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