How Marine VHF Radios Work?

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Before we get into how a marine VHF radio works, it’s crucial to fully understand what it is. A VHF radio is used by sailors as safety equipment and is placed on every powerboat. This is why people need to know how to use one, as it can quite literally save the lives of everyone on board that powerboat.

You can use the marine VHF radio to access lines of communication with other vehicles in the sea, maritime operators, and even lock and drawbridges. Now let’s get into how marine VHF radios work for communication.

Marine VHF radios work by operating on MHz that fall anywhere between 156 to 172. This can be considered a small fragment of the MHz used in high-frequency radios that work with radio waves between 30 to 300 MHz. Think of it as an FM radio, which is something that we are all quite familiar with any time we sit in our cars for a commute.

The way we change stations slightly to get that ideal reception is how you could think of how a marine VHF radio works. However, Marine VHF radios are known to work on the basis of a concept called line-of-sight. What this means is that Marine VHF radios are able to both transmit as well receive transmissions, which is possible due to the antenna.

Power Output of The Marine VHF Radio

The power output is an important part to understand when looking at the workings of the Marine VHF radio. This is because the power output of the Marine VHF radio has the ability to increase the range. However, the real aspect that affects the range difference between a 5-watt handheld and a 25-watt fixed Marine VHF radio is the antenna.

So, if you are able to mount the antenna at a taller height, the Marine VHF radio is given the ability to see farther away. With a taller antenna, you can increase the range of line-of-sight communication. Combine that with an increase in power output, and the Marine VHF radio will be able to punch through all of that static.

Specifics of The Antenna

With a Marine VHF radio, an 8-foot antenna can be mounted, which allows the antenna to be 12 feet above sea level. Simultaneously, the horizon for the marine VHF radio will broaden by a whole 4.5 miles. Of course, you can go a lot further than just an 8-foot antenna.

To explain this further, let us take the example of communication between boats in open water. So, if your buddy at sea has a marine VHF radio with an 18-foot antenna mounted above sea level and you have got a 12-foot antenna mounted on your marine VHF radio above sea level, then you have the ability to communicate with each other a whole 6.7 miles away from each other.

For some boat-to-coast communication, if the Coast Guard has a 100-foot-tall antenna mounted, then you can open a line of communication using your marine VHF radio from an entire 13.3 miles. Due to the atmospheric refractions within the open sea, the distances in actuality are, in fact, a little farther away.

However, the good thing is that the distances mentioned above are ones that you can definitely count on. So, for anyone who is cruising the open sea, making emergency positions indicating radio beacons, personal locator beacons, and even satellite phones are a great deal.

Guide on How to Use Marine VHF Radios

So how do Marine VHF radios work? It’s best to go through a guide on how to make one function to truly understand. First, start by turning the VHF radio on. Start turning the knob to adjust the squelch, and don’t stop until the static stops. There are several channels that the VHF radio lets you tune into.

For a primary communication channel, tune into channel 9. For distress calls and emergencies, tune into channel 16. For communications between boats, tune into channel 13. For working channels, you can tune into channels 78A, 72, 71, 69, and 68. It is important to check if the VHF radio is working properly by tuning into an open working channel. Then change the setting to 1-watt power and start keying in the microphone.

When opening communications with another vehicle in a non-emergency situation, you must remember that the purpose is to have operational conversations. So, communicating on the weather is a-okay but having conversations on sports isn’t.

You should also be sure to use the word “over” at the end of every single transmission; this communicates that you have completed your message. The last thing to remember is that when mounting your antenna, be sure to mount it in a vertical position as it works better.

Related: How to Test a VHF Marine Radio

Final Words

And there you have it – a guide on how marine VHF radios work. We hope that it is helpful for you and that you can feel safe when out on the water.

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