A VHF Primer, Part 3 Safe Boating Resource Center

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A VHF Primer - Part 3

VHF (Very High Frequency) Marine Radios, like other electronics, are becoming more feature laden, smaller and, best of all, cheaper. I saw one VHF advertised recently for just $99.00. While the radio was nearly featureless, it did have a digital display and all the U.S. channels. At the other end of the spectrum there are VHF radios selling for 700 to 800 dollars. In between, there's a plethora of models with varying features. Let's take a look at some of the features you might expect on a new radio:

DSC (Digital Selective Calling) - All passenger ships and ships greater than 300 tons will be required to have a DSC equipped radio by February 1, 1999. All manufacturers of VHF and HF marine radios will be required to have DSC capability on all radios accepted by June 17, 1999. This requirement is part of the Safety of Life at Sea Treaty (SOLAS). One of the primary benefits of DSC technology is automated distress calling. With a radio so equipped, a simple push of a button will alert other ships and the Coast Guard; automatically transmitting your position, your vessel ID and the time of the call. Other DSC equipped radios will automatically receive your distress call and display your vessel ID and position. As with a cellular phone, the unique vessel ID is the key to many of DSC's benefits. DSC will additionally permit one vessel to contact another vessel directly - without a contact broadcast, just like using a telephone. And speaking of telephones, a DSC equipped radio can call a land based telephone without the intervention of a marine operator. The downside is that, in the future, DSC equipped vessels will not be required to monitor channel 16. Therefore, that big commercial ship passing nearby may not be able to hear your oral MAYDAY call.

Integration Capabilities - Obviously, for a DSC equipped radio to transmit a position, it has to have position data fed into it from a GPS. The day is rapidly approaching when all of your electronics will feed into a PC that will assimilate the data and provide you will a complete display. Your radar, depth sounder, GPS, radio and gyrocompass will provide a screen-full of data showing your position, course and speed on a chart; the position, course and speed of any nearby vessels; any buoys in the area; land masses; the position of any vessels in distress and any inclement weather in the area. A split screen will show you all your internal systems data - temperatures in each of your cylinders, fuel consumption, fuel levels, water levels, oil levels, etc. Virtually any piece of data you would like displayed can be. Alarms can be preset to notify you of water in the bilge, a too-high temperature (or too low), a falling pressure, an open door or valve, a vessel too close, a weather alert - you name it. The key, of course, is integration capability to a recognized standard. If you venture offshore, make sure that whatever radio you buy can be upgraded to DSC capability in the future.

GASFET Technology - A "GASFET" is a super sensitive transistor that processes weak signals faster and with less distortion than conventional transistors. The use of this technology allows the radio to pick up weak signals more clearly.

Weather Alert - Some of the new radios will automatically alert you when NOAA (National Oceanographic and Atmospheric Agency) broadcasts an warning of emergency weather conditions.

Scrambling options - If you and another vessel both have compatible scrambling capability, you can hold completely private conversations.

Scanning options - A radio I saw recently had five different scanning programs built in. One could be set for the frequencies usually used by fishermen, another for commercial traffic, one for Coast Guard frequencies, etc. A simple push of a button would change the scanning programs. Most radios have one or two customizable scanning functions to permit the operator to monitor several channels at the same time.

U.S., Canadian and International Frequencies - If you ever plan to travel more than a few miles offshore shore, insist on a radio with at least the international channels as well as the U.S. channels.

High/low - Virtually all radios offer a high/low or DX/Low button. Most console mounted radios transmit 25 watts of power on high and 1 watt on low (hand helds are usually 5 and 1.) Be kind to the boating community. When you are exchanging recipes or sea stories with the boat anchored next to you, please switch your radio to LOW.

Hailing Option - some radios can be used as a hailer when coupled to an external hailing speaker. A few of the newer radios allow this hailing speaker to function as a parabolic microphone to receive distant fog signals or to more clearly hear the dockmaster yelling at you to slow down.

Weather proofing - Boaters (and I'm right at the top of the list) take complex electronic and mechanical equipment, place it in one of the most toxic, corrosive environments on earth and then complain about the required maintenance and the failure rate. It's actually a miracle that the stuff lasts as long as it does. Most radios today are "water resistant" and some reference MIL specs and J.I.S. standards. Check out the standards for any radio that you are considering.

This is the conclusion of the three-part VHF primer. Your comments and suggestions are welcome.

This article was written by Sea Tow Captain Les Hall