The importance of having VHF radios on board

Alan Winstanely.

As a Coastguard Skipper, I am amazed at the number of recreational boaties who do not carry a marine VHF radio for their own safety.

VHF radios are cheap to buy these days, have a long lifespan, and are easy and quick to use.

The beauty of using a VHF radio is that it is a “one to many” communication system. This means that if you broadcast on Channel 16, the call up and emergency channel, other VHF radios turned on in your area will hear you. If you need assistance quickly, then other boats in your area are your best option. Telephone calls can only be made to one contact at a time and typically this help needs to come from shore.

VHF radios are also made for the harsh marine environment. Most are fully waterproof, and are made to withstand salty conditions well protected against oxidation and seizures. The equipment is more dependable and is more likely to work when you need to use it in a hurry. Prices for radios are reducing over time. You can now purchase basic fixed radios for under $200. And handheld radios start from a similar cost.

Fixed VHF radios versus Handheld radios

The reach of a two-way radio is largely dependent on the output power of the radio. This is measured in watts. As an example, a typical fixed mount radio outputs at 25 watts and is good for a range of in excess of 50 km unobstructed. Handheld radios typically transmit at 5 to 6 watts and are therefore good for a range of 12 to 18 km.  This is only a rough measure as other aspects affect the effective range of a VHF radio. The antenna type, design and length will have an effect on range.

As with all wireless devices, radio waves can be interrupted by hills. I call this shadowing, much like a shadow from the sun.  If your radio is situated behind a hill or other obstruction, then the radio waves will be interrupted and communications may not be clear.  Moving further away from the obstruction will typically bring you out of the shadow and communications will come back. A longer antenna will help with this to a small extent.

Another advantage of a fixed mount VHF radio is that they are powered by your vessels electrical system and therefore is generally less likely to be interrupted. A handheld radio runs on rechargeable batteries and you will need to ensure they are regularly charged for effective operation. One could also argue that a handheld VHF radio on board provides a good backup for your fixed mounted unit. If your electrical system goes down, then your handheld VHF radio will operate stand-alone.

Fixed VHF Radios are easy to install. They just need a 12V power source and an antenna installed.

Handheld VHF radios have the advantage that the radio goes with you if you get thrown out or fall off your vessel .  It is recommended that you have a backup handheld radio that you have tethered to your person or keep in a grab bag. A grab bag is a waterproof carry bag easily accessible if need to abandon ship in a hurry. Typical items you would keep in a grab bag apart from a handheld VHF radio would include a knife, flares, a personal location beacon, a torch and anything that could aid your survival and assist with your rescue.  

Why do some boats have such tall antennas?

The length of your VHF antenna is not as important as the height at which your antenna is mounted on your vessel. Yachts have a distinct advantage here as they are able to mount their antenna on the top of their mast.  The height helps minimise shadowing and allows you to see over the horizon, thereby improving your range.

With modern antenna designs, manufacturers are able to attain better performances from antennas of shorter lengths. In days gone by, better performing antennas were generally longer in length. Other factors that can affect the performance of your antenna is the condition of the cable linking the antenna to your radio and the condition of your cable connectors.

Why cost of VHF Marine Radios varies

The low cost VHF Marine Radios, whether they are fixed or handheld, provide you with basic functionality. This means, that they will provide basic communications well, but will not likely to have additional features. The performance of the radio will be quite adequate and help keep you safe while on the water.

Additional features and functions that more expensive radios may have may include…

Level of waterproofness – This is obviously important when dealing with a handheld radio but is less important for a fixed radio if mounted inside a cabin where it is kept dry.

Capacity to Float – This relates to handheld radios which are more likely to be used over and in the water. A Floatable handheld radio will cost more but enables the radio to be retrievable if dropped over the side.

GPS Receiver – GPS receivers maybe found in fixed or handheld radios these days which enables you to display your current position. This function allows you to relay your position to rescue authorities without having to rely on another electrical piece of kit such as a Chartplotter.

Remote Controls – Some models of VHF Radios offer additional controls on the microphones to provide better ease of changing channel and/or volume. In addition, some radios have the main brain of the radio in a black box that can be hidden behind a dash, or under a seat out of harm’s way, and the only visible sign of the radio is a remote speaker microphone.

Digital Selective Calling – More and more radio models on the New Zealand market have Digital Selective Calling, often known as DSC. This is simply the ability for a radio to transmit an emergency signal to all other radios in its locality as well as transmitting its coordinates. This system is widely used in the USA, however to-date, New Zealand operators have primarily used voice on channel 16 in emergencies. Please note that the DSC transmissions from VHF Radios in New Zealand are not currently monitored by emergency services.

Quality of Build – As you would expect, paying more for a piece of electronic equipment for your vessel should mean a better build quality and level of performance. In my experience, this is generally the case. You can expect a better voice sound quality and better background noise filtration with higher end radios.  This is usually backed up by a lengthier warranty period also and one would assume a longer life expectancy.

Having mentioned the reasons why you could expect to pay more for your VHF Marine Radio, you are definitely better to have a low end radio fitted to your vessel than have none at all!

Wishing you all safe boating!


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