VHF Marine Radio Antenna: All you need to Know

If you're a boater, you know that a VHF marine radio is a vital piece of equipment. But what you may not know is that the antenna is just as important as the radio itself. 

A VHF marine radio antenna is used to transmit and receive VHF marine radio signals enabling communication with other boats, as well as with the shore and other emergency services. 

In this blog post, we'll discuss everything you need to know about VHF marine radio antennas, including choosing the right VHF antenna for your needs, installation and maintenance.

VHF MARINE RADIO ANTENNA

What is A VHF Marine Radio Antenna, and why is it Important?

A VHF marine radio antenna is a vital piece of equipment for any boat that uses VHF radio communications. The antenna helps to transmit and receive radio signals over long distances, allowing boaters to stay in touch with each other and with shore-based radio stations.

VHF antennas are essential for safety at sea, as they allow for the exchange of information about weather, navigational hazards, and emergency situations.

How Many Antennas for VHF Marine Radio?

It's generally accepted to have an individual antenna for transmitting and receiving VHF marine radio signals.  

There is one exception to this rule, however. If you are using a VHF marine radio with an Automatic Identification System (AIS) that receives and transmits, you need two antennas - one for broadcasting and one for receiving. 

This is because VHF AIS radio waves travel in a straight line and can only be received by an antenna that is directly in line with the transmitting antenna. 

If your marine radios are equipped with receive only AIS, you can use one VHF antenna for both functions. 

Please note: You can also get a VHF antenna that is also your AM/FM antenna. These antennas will work for both VHF and AM/FM, but they won't work as well as a dedicated antenna. So, to ensure optimal signal transmission, each system should have its dedicated antenna.

What Should You Look For When Choosing A VHF Marine Radio Antenna?

There are many factors to consider when choosing the right VHF marine radio antenna for your needs. In this section, we'll explore some of the most important factors to keep in mind when making your selection.

Performance

Performance is important because you want your antenna to be able to transmit and receive signals clearly.

For a better VHF antenna experience, you need to choose the ones with quick-connect adapters. These make it easy to connect and disconnect to your marine VHF radio. 

Durability 

Your VHF antenna should be able to stand up to the elements such as strong waves and winds. 

VHF antennas made from stainless steel or heavy-duty fiberglass are typically more durable than those made from plastic.

Price 

There is a wide range of VHF Marine Radio Antennas on the market, ranging in price from $30 to more than $300. 

When selecting a VHF Marine Radio Antenna, it's essential to consider both the price and the value for money.

The most expensive VHF Marine Radio Antennas may not necessarily be the best value for money. Instead, it's essential to consider the features and performance of the antenna in order to find the best value for money. 

Range

When selecting a VHF marine radio antenna, one of the most important factors to consider is range. How far will the antenna be able to transmit?  

Generally speaking, VHF radio waves have a range of 10 miles to 25+ miles. 

However, a number of factors can affect this, including the type of antenna you are using, the power of the radio, the height of the antenna, and the terrain between you and the antenna.

In general, the higher the antenna is, the further the radio waves will be able to travel. This is why most VHF antennas are mounted on the boat's highest point.

VHF RADIO ANTENNA

How do I increase my VHF range?

There are a few things you can do to increase the range of your marine VHF antenna:

  • First, ensure the antenna is mounted as high as possible on the vessel. This will give it a clear line of sight to the horizon, maximally extending its range. 
  • Second, check the antenna's connections and make sure they are tight and corrosion-free. 
  • Third, extend it to its full length if you have an extendable antenna. 
  • Finally, ensure that the antenna is not obstructed by other objects on the vessel. 

By following these simple tips, you can maximize the range of your marine VHF antenna and stay safe on the water.

Height and Gain

Why is the height or length of a VHF radio antenna important?

The height or length of a VHF radio antenna is vital because it determines how well the antenna will be able to receive and transmit radio signals. 

The taller the antenna, the better it will be able to receive and transmit radio signals. This is because the taller the antenna, the more it will be able to "catch" radio waves. 

The antenna height of a boat should generally be less than half its length.

What is VHF antenna Gain, and why is it important?

Gain is a measure of how well an antenna can focus a radio signal in a particular direction. The higher the gain, the better the antenna will be at concentrating the signal in a specific direction.

There are two main reasons why gain is so important:

First, it can help to increase the range of your radio. If the signal is focused in a specific direction, it can travel further than if it were dispersed in all directions. 

Second, gain can help to reduce interference from other nearby radios. If the signal is focused in a specific direction, it's less likely to be interrupted by other radios transmitting on the same frequency.

Here is a table describing the recommended Height and Gain for various boat sizes:

Boat size

VHF Antenna Height

VHF Antenna Gain

Below 24 feet

3-4 feet

3dB

24-32 feet

7-8 feet

6dB

Above 32 feet

12-18 feet

8dB

 

Why does the size of a VHF radio antenna matter?

It is also vital to select an antenna that is the appropriate size for the vessel on which it will be installed. A small antenna may not be able to communicate effectively over long distances, while a large antenna may be too cumbersome to install on a small boat.

Warranty

When choosing a marine VHF antenna, it's essential to consider the warranty. Most antennas come with 3-5 year warranties, so you will want to select an antenna that will be covered in case of any problems. 

Additionally, you may want to choose an antenna with a longer warranty if you plan on using it in a saltwater environment, as saltwater can be tough on electronics.

Location and environment of use

It's crucial to select an antenna that will work well in the specific environment in which it will be used. 

For example, an antenna that works well in a calm harbor may not work well in a harsh offshore environment.

VHF Antenna Installation

Antennas are responsible for sending and receiving signals, and they need to be placed in just the right spot on a vessel in order for them to work properly.

How do you mount a VHF antenna on a boat?

VHF antennas are designed to be mounted on a boat in various ways. The most popular method is to mount the antenna on the backstay, but it can also be mounted on the mast, boom, or deck.

To mount the antenna on the backstay, you will need to attach a bracket to the backstay using U-bolts. The bracket should be positioned so that the antenna is in the center of the backstay. Once the bracket is in place, you can then attach the antenna to the bracket using the supplied hardware. 

To mount the antenna on the mast, you will need to attach a bracket to the mast using U-bolts. The bracket should be positioned so that the antenna is at least 18 inches (45 cm) below the top of the mast. 

Where do you mount a VHF antenna on a boat?

If you want to get the best signal possible, you'll need to place your antenna high up on the ship. The higher the better, as it will give you a clear line of sight to the horizon. 

Here are a few tips to help you get the most out of your VHF antenna:

  • Place the antenna as high as possible. The higher the antenna, the better the signal.
  • Avoid placing the antenna near metal objects. Metal objects can reflect and distort the signal.
  • Make sure the antenna is pointing in the right direction. To get the best signal, the antenna should be pointing towards the radio station you want to listen to.
  • Mount away from other VHF antennas. If the antenna is too close to another antenna, it can cause interference. This can reduce the quality of the signal and make it more difficult to communicate.

Additional factors to consider when installing a marine VHF antenna

Line of sight

Line of sight refers to the path a signal takes from the antenna to its destination. If there are any obstacles in the way, the signal will be weakened, and the connection will be lost.

Cable quality and connections integrity

When installing a marine VHF antenna, it's essential to consider the quality of the cable and the integrity of the connections. 

The cables must be able to withstand the elements, and the connections must be secure to maintain a strong signal.

It's also important to note that the cable's length will affect the signal's quality. The shorter the cable, the better the signal will be.

Therefore, it's crucial to choose a location for the antenna that is close to the VHF radio.

Lifespan and Maintenance

Lifespan

A marine VHF antenna lifespan is hard to establish as it depends on how well you take care of the equipment. But, the average lifespan of a marine VHF antenna, taking into account all the different types and brands, is about five years

With proper care and using a high-quality VHF marine antenna, you can expect a lifespan of up to 20 years

Maintenance 

To ensure that the antenna is in good working condition, it's essential to perform regular maintenance. 

This includes checking for physical damage, such as cracks or corrosion, and ensuring that the connections are secure.

It's also important to check the performance of the antenna. This can be done by testing the signal strength and range. If the antenna is not performing up to standard, it may need to be repaired or replaced.

Another crucial maintenance practice for VHF antennas is cleaning. It’s best practice to clean the antennas every time you wash your boat. Use water and soap for this and not harsh detergents that may damage the fiberglass material. 

By performing regular maintenance on your marine VHF antenna, you can be sure that it will be ready to use when you need it.

MARINE RADIO ANTENNA

 

FAQs

Why do some boats have 2 VHF antennas?

Some boats have two VHF antennas because they are equipped with both an Automatic Identification System (AIS) and a marine radio. 

The AIS tracks the movement of boats and other objects in the water, while the marine radio is used for communications between boats. 

The two VHF antennas allow the boat to have both systems operational simultaneously.

While it's not required by law to have two VHF antennas on a boat, it is recommended. 

Having two VHF antennas also provides a backup in case one fails.

How can I improve my marine VHF reception?

To improve your marine VHF reception, do the following:

  • Make sure your antenna is properly installed and positioned. 
  • Use a quality marine VHF antenna. 
  • Use a marine VHF antenna booster if needed. 
  • Reduce interference by turning off any electronic devices that may be causing it. 
  • Make sure you're tuned to the right channel. 

Conclusion

Today's boats and ships are equipped with state-of-the-art navigation and communication systems, one of the most important being VHF marine radio antennas.

VHF marine radio antennas are vital for anyone who spends time on the water. They are an essential part of staying safe and keeping in communication with others.  

Once you have the right antenna, you'll be amazed at how much better your marine radio performs. From longer range to clearer reception, the right antenna can make all the difference.

Chapters

1) Marine Handheld Radios