Are You Using Your VHF Radio Correctly?

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VHF radios differ in detail, but all have broadly the same functions and controls as this unit

VHF radios differ in detail, but all have broadly the same functions and controls as this unit



VHF Guide

If you’re one of those sailors who reckons everything should be done by the book, then you’re doomed to go through your boating life constantly enraged by two things—the incorrect use of navigation lights and inane prattle on VHF Channel 16.


Just as there’s no excuse for sailing blithely through the night lit up like a Christmas tree, so that no one has a clue what you are or what you’re doing, nor is there one for misusing the international distress frequency, or being ignorant of VHF protocol in general. Both are safety features that should be treated with respect, yet there are widespread misconceptions among sailors not only about the correct way to use a VHF radio, but how to make the best of its potentially life-saving features. Prime among these is Digital Selective Calling.

Push-button distress calling

Yes, you too can learn how to connect a GPS to a VHF radio

Yes, you too can learn how to connect a GPS to a VHF radio

Digital Selective Calling—DSC—is one of those features that, despite having been standard on every fixed-mount VHF for more than a decade, is little understood and little used by recreational sailors. One reason is perhaps that it requires two devices to be wired together—a process that requires some head-scratching if the two are from different manufacturers. Another might be that DSC requires you to obtain a Marine Mobile Service Identity (MMSI) number that must be programmed into the radio.

Basically, DSC sends out a distress signal at the push of a button, and if you’ve hooked your radio up to your plotter or GPS and done the paperwork to acquire an MMSI number, it’ll also broadcast your boat’s name, position and other information rescuers might find useful. And it keeps broadcasting that signal until someone responds or you switch it off.

The MMSI is like a phone number in that if you know your friends’ numbers you make their VHF radios ring loudly and then switch to a preferred audio channel when they respond. You’ll also be able to direct-call ships seen on AIS. This may not be important to you, but the safety aspect of DSC should be. The ability to push a button and then have the distress signal sent automatically while you attend to whatever emergency prompted the button-push could, literally, be a life-saver.

The information you give when registering for a MMSI number is kept in a database accessible to the Coast Guard for SAR operations. If you have an AIS transponder on board, you will already have an MMSI number, and it’s easy to key that into your DSC-capable VHF.

A handheld VHF is a useful backup

A handheld VHF is a useful backup

As for the necessary radio-GPS connection, that’s an entirely different kettle of fish. Unless you’ve sensibly bought one of the latest-model VHF sets with integral GPS from Standard Horizon, Raymarine or Icom, in which case all you have to do is connect power cables and antennas, you’ll likely have to do battle with NMEA 0183. This is the 30-year-old marine electronics wiring protocol that has driven many DIY boat owners to the brink of insanity. The rationale behind it was simple enough—basically, you connect one device’s output and input wires to the corresponding ones on the second device—but each manufacturer came up with its own color codes. You can guess the rest.


Still, by reading the instructions in each instrument’s manual, a persistent DIYer will soon work out which wire should be connected to which, even on different makes. Take heart from the fact that I managed it twice, and I know zip about wiring marine electronics.

Buying your radio and plotter from the same maker will simplify your task considerably. Anorther shortcut, if your boat has an NMEA 2000 (N2K) data network with GPS on it, is a VHF with an N2K port; these are available from Garmin, Simrad, Lowrance, B&G, Raymarine and Icom.

As for the MMSI number, you can get one from Boat US ( unless you intend to sail beyond U.S. waters, in which case you should use an MMSI issued with an FCC Ship Station license.

The Coast Guard urges in the “strongest terms possible” that you take the time to connect your radio and your GPS. Who are we to argue?

Breaker, Breaker …

Most countries require boaters to pass a test before they can use a VHF radio, but not the United States, which accounts for the widespread ignorance of proper VHF protocol on our waters. The point of radio jargon is to avoid ambiguity and to ensure that communications are clearly understood. This is why it is important to learn the procedure words or “prowords” and use them correctly. If you start channeling your inner Burt Reynolds and throwing around CB radio terms­ like 10-4, Negatory, Breaker, Come Back, Do You Copy and so on you’ll reveal yourself to be something of a dork. You’ll also introduce another element of confusion into an already fraught situation should you be involved in an emergency where rescuers have to make sense of such gibberish.

The latest generation VHFs, such as this Raymarine Ray70, combine full DSC, GPS and AIS functions

The latest generation VHFs, such as this Raymarine Ray70, combine full DSC, GPS and AIS functions

The jargon is just one aspect of VHF protocol and etiquette. Let’s run through some others.

VHF radio is first and foremost an operational service intended for commercial inter-ship and ship-to-shore communications. It is not a social networking facility for recreational boaters or sailors.

Remember that when you are using a VHF channel, you are broadcasting to everyone within your antenna’s line of sight. Also, remember that no one else can use that channel while you have your mic keyed. Keep conversations as brief as possible and don’t use profanity.

VHF radios have two settings—low and high power. Use low power as your default setting. It's shorter range means that other boats a few miles away can use the same channel.

Don’t use Channel 16 for anything but the briefest of calls. There is nothing more infuriating (and potentially dangerous) than having 16 tied up by airheads arranging to meet for cocktails. Use your cell phone to organize social gatherings.

Some USCG districts prefer recreational boaters initiate calls to each other on Channel 9, but it’s optional. Whether hailing other vessels on 9 or 16, quickly arrange to switch to one of the working channels (see “Using Your VHF Guide).

Don’t let children play with the radio. You might think it’s cute to have little Johnny chatting away to the world at large about the fish he caught, but no one else will. Your VHF is a tool. Teach your kids to use it responsibly.

It’s bad form to interrupt a conversation in progress. Unless, of course, said conversation is on Channel 16 between two boats trying to arrange a cocktail rendezvous. In that case, interrupt away.

Never call the Coast Guard and ask for a radio check. It’s illegal. If you want a radio check, go to Channel 9, or use Sea Tow’s automated radio check service, which uses one of Channels 24, 26, 27 or 28, depending on your location.


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