What is a VHF marine radio?
When you’re out boating it’s likely you’ll need to communicate with others around you (for instance to relay information or to raise an alarm), and the way you do this onboard is via your marine VHF radio. This is one of the most important pieces of safety equipment you will carry on board and it is strongly advised to make sure you have a working one before heading out on the water.
Marine VHF radio is a global system of two way radio transmission on boats and other water vessels. It uses FM channels in the very high frequency (VHF) radio band in in the frequency range between 156 and 174 MHz. This frequency has been designated by the International Telecommunication Union as the official VHF maritime mobile band. Transmitter power is limited to 25 watts, giving VHF radio a max range of about 62 miles (100 kilometres).
In some countries additional channels are used for local marine radio. Whether your boat is in the Caribbean maps, Adriatic, Baltic, North Sea charts or the Mediterranean, knowing how to use your VHF radio is crucial.
Different vhf radio channels
The VHF radio band is divided up into different channels, many of which have a specific designated purpose. Channel 16 is perhaps the most well known (and important!) as it’s the international distress, safety and calling channel. All boats equipped with VHF radios are required to maintain a listening watch so messages of distress are likely to be heard. Because most boats are listening, Channel 16 is also used to initially hail other parties. Once contact has been established the conversation is switched to a “working channel” to free 16 up again. The US Navigation Centre of Excellence provides a full list of international VHF marine radio channels and frequencies while this Wikipedia provides has a great overview of the different regional and country breakdowns for each VHF channel and frequency.
When you broadcast on a VHF channel every other vessel listening on that channel (within your radio’s range) will hear your message. Under normal circumstances you’ll be calling just one other party (a friends boat, or a marina) so no-one else will be interested in what you have to say. Therefore always keep communication short and to the point to avoid clogging up the channel and irritating other people!
How to use a VHF radio on a boat?
The importance of etiquette
- Transmit with identification: calls should start with saying the name of the boat you’re calling and the name of your own boat, three times.
- When you’re finished say “over”; not “over and out” (however many times you’ve heard it in a movie!). “Out” means you’re done and not expecting any further communication.
- Use the NATO phonetic alphabet when speaking letters
- Read radio numbers single digits for clarity (six, eight, not sixty eight).
- Speed: Talk a little slower than you would in a normal conversation.
- Volume: There’s no need to shout, talk at the same level as you would on the phone.
Different types of VHF communication
Non emergency ship-to-ship or ship-to-shore communication
These are routine calls to other boats and to shore stations. Conversations could be about reserving a berth for the night, arranging fuel or finding out when your friends boat is expected in the anchorage.
Safety Call - Securite
VHF radios can also be used to relay important safety information or to alert other vessels of something unusual in the area (floating debris or an unlit buoy are pretty common). Usually Securite calls originate from the coastguard but there maybe a time when you need to do one yourself.
Emergency Communication (Mayday, Pan-Pan)
There are two types of emergency call. A Mayday is used when there’s imminent threat to life or vessel. For example when someone has gone overboard, is unconscious or seriously ill. For the boat this could mean it is sinking or on fire. A Pan-Pan
VHF Radio FAQs
Are marine vhf radios required on boats?
VHF radios are not required on recreational boats which are under 65.5 feet in length. However, it is strongly advised to carry one as it is the easiest means of communication between you and other boats, including the coast guard or emergency services.
How to install a vhf radio in a boat?
This video gives a great overview of how to install a VHF
Do I need a vhf marine radio licence?
Most countries require you to have a license to operate a VHF radio. One of the main reasons is to help keep on-air conversations following specific protocols, which helps shape the communication and keep everything understandable. In some countries, like the U.S., laws allow recreational users to use VHF radios without requiring a license. Despite the lack of licensing in some countries, all users must adhere to the established communication protocols.
How to test a vhf marine radio?
In order to check if your VHF radio is working properly you should use an open channel (not channel 16) to test performance. Repeat the words "radio check" followed by your boat name and location three times and wait for someone to respond confirming that they have heard you.
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What is the range of a vhf marine radio?
There are a few factors which affect how far a marine vhf radio will transmit. A handheld VHR normally transmits a power of six watts while a fixed radio will do around 25 watts. However, VHF range is impacted more by antenna height and antenna gain than transit power. So you can significantly increase your range by connecting an external antenna and/or by mounting it to the highest possible point on the boat.
VHF radio is used mainly for short range communication, generally 5-10 miles (8-16km). For longer range communication a satellite telephone or an MF/HF marine radiotelephone is more suitable.
What is a good vhf marine radio?
First of all the answer depends on whether you want a handheld or mounted radio. Generally speaking Icom IC, Standard Horizon and Raymarine all make high quality VHF radios and you won't go wrong with any of them.
Why is the height of a vhf radio antenna important?
As mentioned above VHF range is impacted more by antenna height and antenna gain than transit power. So the height of your radio antenna has a major impact on your range of communication. For this reason it is recommended to mount your antenna it to the highest possible point on the boat.
VHF marine radio protocol cheat sheet
We find this simple cheat sheet amazing to have onboard created by Sail Magazine
A (great!) online tutorial
The US Coast Guard and the Boat U.S. Foundation have put together a great (half hour) online tutorial called “Can You Hear Me?” which summarises the use of VHF and DSC radios. You can find it here. Good to know: the download only works for PC’s.
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