We’ve explored and compared some of the best high-quality marine radios on the market today, now let’s proceed to evaluate another important part of VHF installation: the antenna.
No matter how good your fixed mount vhf marine radio is, it can’t perform well with a wrong antenna. Think of VHF antennas as your car’s wheels. They’re essential features that keep your car moving. VHF antennas are key equipment used for your VHF marine radio. They are the radio’s contact point to the world inland. Without proper antennas, you can’t make or receive transmissions.
One of the most common questions we hear is why the height of the VHF antenna is important? The simplest answer is that VHF radios work off line of sight, so a taller antenna will "increase your line of sight meaning you will be able to transmit and receive broadcasts from further distances. With that being said it is not practical to have a 30ft. antenna so you will need to decide what length is appropriate for where you will be using your radio and under what conditions.
There are different types of antenna designs. Some of the commonly used ones today are the Log Periodic Antennas, VHF Arrays, Conical Arrays and Multi-Element Yagis. VHF antenna’s are designed to receive signals between 30 MHz and 300 MHz. Unlike UHF signals (Ultra-High Frequency Signals), VHF doesn’t degrade easily and can be used for longer range broadcasting. VHF antenna’s main purpose is to provide a radiator and radiate energy in the right direction. Essentially, your VHF radio wouldn’t work if it’s not connected to a suitable antenna.
Is your boat is using the right VHF antenna? In this article, we’re going to find out which antenna best fits your vessel for a smooth and safe boating trip.
Things to Consider Before Choosing a VHF Marine Antenna
Many consumers don’t know what to look for or consider when it comes to purchasing a VHF antenna for their vessels. Choosing an antenna based on price or looks rarely results in a good buy. A good VHF antenna will always have a fair price for its size and gain. In order to understand how VHF marine antennas are priced, you need to have some basic knowledge of how they work.
There are different types of Marine VHF antennas today. Depending on the distance you will need to transmit, the size of your boat, and your ship’s transport needs - you’ll need to choose the right kind of antenna in order for your radio to perform well. Below are some of the things you should know before buying!
What is antenna gain and dB rating?
The first factor that plays a role in an antenna’s effectiveness is the antenna gain (also known as dB rating in VHF marine antennas). All antennas have gain and it is seen in the increase in power from the antenna. In a nutshell, gain refers to the horizontal focus or degree of polarity of the signal.
The gain is usually measured by multiplying the radio’s output by 4 or 8 for 6db and 9db antennas respectively while a 3db antenna gain is equal to 2 times the radio’s output power. So, a typical VHF marine fixed radio with a 25-watt output if applied with a 3dB gain will result in 50 watts.
Basically, a high dB rating antenna will help improve your signal so you can better receive the stations around you - which means the higher the focus, the more concentrated the energy transmission. Large boats sailing through stormy weathers should invest in a high-gain antenna in order to maximize range. Medium-sized boats will work fine with a medium-gain antenna with a good range.
Length is another factor to consider when it comes to choosing an antenna. Antennas can range from a few inches to over 20 feet. Depending on the size of your vessel, you can have a shorter one for portability or a longer one for better communication. Again VHF radio works on the line of sight principle.
There are two kinds of antenna length. (1) the antenna’s physical length and (2) the antenna’s electrical length. Physical length refers to the length of the “non-conducting” whip while the electrical length is the “operating” length of the antenna based on its electrical structure.
You need to determine how much range you’ll need. Consider this: a 3-foot antenna mounted at eye level can get you around 5 miles of range. For the sole reason that VHF devices are line of sight, the power of the signal significantly relies on the length of the antenna (length matters!), so the taller the antenna, the better signal and reach!
For the majority of powerboats (24 to 32 ft) a good choice would be 8ft antenna with 6dB gain rating. 3ft-5ft VHF antenna and 3 dB rating is recommended for vessels under 24ft.
Why is the height of a vhf radio antenna important?
Look for the highest point of the boat to mount your marine antenna, because VHF signals are limited to line of sight, the higher the marine antenna mounted - the further it will be able to transmit and receiver signal.
There are three techniques in mounting:1) mast mounting 2) surface mounting 3) rail mounting. Of all three, rail mounting is most used since its offered in a wide variety of sizes, unlike mast and surface mounting which only encompass a certain range of vertical and horizontal surfaces.
The antenna’s internal and external components also affect the quality of its reception and transmission (including its price). Most high-quality VHF antennas are made of fiberglass or stainless steel. But there are actually four main elemental cores used: 1) copper wire 2) brass tubing 3) copper and brass tubing and 4) silver-plated brass tubing.
VHF Antenna Installation Tips
Lots of VHF antennas today are already pre-tuned for use which means you don’t need a technician to install them. However, you need to have some basic knowledge in order to keep the antennas working properly for a long time.
- Mount the antenna as high as possible. Remember the number one rule: the higher the antenna, the better the range.
- Ensure that the fiberglass is not vertically close to any metal object as it can change the antenna’s radiation pattern.
- Rout the coax cable properly so it doesn’t become deformed or pinched. Keep it as far as possible from other electronics and cables. Keep it to at least 3 feet measured from the cable to the antenna.
- Always ensure a good connection to the radio. Always check the antenna cable for signs of damage or breakdown from sun exposure. The connectors should always be soldered to the end of the coaxial cable and securely screwed into the radio’s antenna port.
- Do no use ‘antenna combiners’ which allow the same antenna to be used on both AM and FM broadcast receiver.
- Cut the coax and support the antenna properly.
- Keep the antenna tuner close to the antenna.
- Don’t forget to use amplifiers when needed.
- Use quality coaxial cable sand connectors if you want to have consistent signal strength.
- Don’t let cleaning solvents, paints, adhesives, or other chemicals come close to the antenna. This can destroy the antenna’s finish. If you’re going to clean the antenna, use a mild dishwashing liquid.
Best Marine VHF Antennas on the Market
Get the most out of your boat’s VHF radio by selecting the best marine antenna. Carefully weighing your options before purchasing an antenna will always save you from buyer’s remorse. So before you decide to buy one make sure to compare the features and options of each product. Check out our three best VHF Marine antennas:
Shakespeare 5104 Classic VHF Antenna
A 4ft 3 dB antenna complete with high-quality features for excellent performance. It is made of brass and copper elements with a smooth polyurethane finish (a great material that reduces sun damage when used on a regular basis). Shakespeare 5104 also includes a 15ft RG-58 cable which can be cut to size depending on your preference. The device has a PL-259 connector with suggested mounts (style 418 or 518).
Shakespeare 5101 Centennial 8’ VHF Marine Antenna
An 8ft low-cost VHF antenna that will fit your budget, Shakespeare’s 5101 can cover all kinds of marine band frequencies. It’s made of brass and copper with chrome brass ferrule and a standard 1in-14 thread. It also comes with a 15ft RG58 coaxial cable and a PL-259 connector.
Shakespeare 5215 Classic AIS Squatty Body® Antenna
Shakespeare 5215 is a lightweight, stainless steel VHF antenna built with extra bandwidth to respond to all popular AIS transceivers. Also known as the SQUATTY BODY antenna, this product boasts of a 36” stainless whip! A popular consumer favorite, Shakespeare 5215 is lightweight, and comes with a stainless, sealed tin-plated copper wire coil. It’s designed for masthead mounting and for AIS transceivers.
Low-quality antennas can misdirect your signal OR worse shorten your potential range! Don’t make this mistake! Buy a great quality antenna for your VHF device. We highly recommend the products listed above. Buying a marine antenna doesn’t have to be overwhelming. We hope this article has helped answer your questions when it comes to choosing the best VHF antenna for your boating needs.
Stil havent found the right antenat for you and your boating needs? Read our other reviews below!
Most of the antennas that you buy now will usually come with a coaxial cable and a connector. However, you will need to purchase a mount separate to secure the antenna to the boat.
Here are the best selling VHF antenna mounts on the markets today:
If you have bought or used this radio accessories please feel free to leave a comment with your experience below to help others who may have questions.