Why Is The Height Of A VHF Radio Antenna Important

Although the Federal Boating Regulations don’t include a VHF radio as essential equipment to keep while boating, this is a vital one in reality. If you are not overconfident with your safety out there in the ocean, it’s better to set said having a VHF radio set up on the mast or helm of your boat. Yes, it should be placed in a higher position of your boat.

The height of a VHF radio antenna is important because the way this radio frequency works is popularly known as the line-of-sight technique. This basically means the two antennas can communicate if both are visible to each other. Unless you are placing the antenna at a high position, the frequency will be blocked by different objects like trees, mountains, buildings, etc.


What Is a VHF Radio? 

VHF radio elaborates as Very High Frequency. The frequency ranges from 156 MHz to 162 MHz. As per the International Telecommunication Union, this frequency is termed as VHF Maritime Mobile Band.

Yes, the name gives it away – this radio uses a very high frequency to communicate. The wavelength that this radio emits is quite high and can supersede Ultra High Frequency, as well. That’s why VHF radios are basically used in open areas like golf fields, groundskeeping crews, guards patrolling a vast area, boats, etc. It is also widely used in the aviation area. Plus, you can use VHF radios for non-emergency applications, as well.

You can use the radio signals to warn other boaters about a potential threat around by sending an immediate signal to others. Then again, you can ask for navigation help from other mariners around. If you are not sure of an area, you can also ask for guidelines from the middle of the sea too.


Understanding The Basics of A VHF Radio

Using a gadget becomes much easier if you get to know about the ins and outs of that device. That’s why you need to have a clear idea of the basics of the VHF radio before you get to operate it on your boat. To ease it up, we are going to share some primary facts about a VHF radio. Here are the key parts of a VHF radio that you should be able to recognize and distinguish.


  • The Power Source: This is the primary source of power for the radio. It can be AC or DC powered, depending on the model you are using. If it’s AC powered, it will be connected to the boat’s power output.
  • The Radio Unit: This is the actual unit that you need to communicate with. It will have a transmitter and a receiver through which you can receive and send signals. In most cases, there should be an LCD screen to communicate through. The screen will also show you the channel selection option, volume adjustment system, etc.
  • The Antenna: The antenna is used to receive the signal from other devices. This is quite crucial because if it’s damaged, you won’t be able to communicate at all.
  • DCS Controller: This controller assigns a unique ID to your boat while operating the radio. This is known as Maritime Mobile Service Identity or MMSI in short. It can be sued if you need to go for distress calls.
  • AI System: The AI system is the automatic identification process that you can find on some of the most advanced models. It applies a GPS receiver that can send your location and MMSI information to nearby stations.


How High Should I Place the VHF Radio Antenna? 

So, now that you know how exactly a VHF radio operates, it’s time to make sure you understand the importance of the height of the antenna. As discussed earlier, the VHF radio works on a Line of Sight (LOS) mechanism; you mustn’t allow any hindrance between two signal receivers.

The watered-down idea is that both the antennas should ‘see’ each other in order to communicate well. Let’s say you are standing on the street and trying to look as far as you can to put things into context. You will definitely have a limited vision as your eyesight will be hampered by buildings, people, trees, and other natural or artificial obstacles. However, if you are standing on the peak of Burj Khalifa in Dubai, chances are that you will have a clear view of each and every house around the city!

The same applies to the VHF radiofrequency. The higher you mount the antenna, the more accurately it will transmit and receive signals. That’s why you should place the antenna to the highest position of your boat, like the top of the cabin, the mast, or the helm of your boat.

Apart from the position, the length of the antenna itself is also a vital factor. Longer antennas perform better than shorter ones. Plus, the more wattage power the radio has, the better it’s going to perform in case of transmission. Consumer VHF radios come with the highest 25w transmitting power. It’s up to your budget and planning how much powerful you want the radio to be.


As for calculating the range of the radio, you can easily find it out by using the following formula.


d = 1.2246 X h    


In this formula, ‘d’ represents the distance, and ‘h’ represents the height of the antenna in feet. So, if you multiply the square root of the height by 1.2246, you will get the distance the radio frequency is going to cover. So, it’s obvious that the higher the antenna, the better signal you will transmit and receive.


Additional Tips for Maintaining the VHF Radio 

  • Put the antenna in a perfectly vertical position. Leaning on its side can compromise its transmission accuracy.
  • Keep the radio away from direct sunlight and keep aside from the engine of the boat. Make sure it’s not being affected by any kind of vibration.
  • Keep the device at least 5 feet away from any electromagnetic device you are using. It will overlap with the frequency of the radio, distorting transmission.
  • According to the US Coastguards, any LED light on the boat can overlap with the automatic identification system and digital selective control. So, it’s better to keep the radio away from any LED light on the boat.
  • Check for any corrosion or damage on the antenna on a regular basis. If there’s any damage, try to fix it by an expert or replace it with a new one.


Final Words 

So, it should be obvious to you how important it is to put the VHF radio antenna at a high position. If you don’t find a way to keep it upright and high enough over the boat, you can always use an extension. Extensions will make it easier for you to place the antenna to a higher level.

Above all, try to put the radio in a suitable, dry, and easy-to-reach position so that you can use it immediately when you need it. Then again, try to read the complete manual of the device before installing it and starting to use it. It will definitely make things easier and more convenient.


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