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VHF The following is about important advances in VHF (marine) radio communications you ought to know about and it's one of the courses we teach - see courses.

VHF, the mode of radio communication that is used by recreational boaters across the nation is undergoing a fundamental change in the way it is used. Boaters have long been frustrated with having to compete for access to Channel 16 for calling, emergencies and making contacts and that's starting to change.
Digital Selective Service, referred to as DSC is a feature well underway around the globe, that reduces the crowding on Channel 16 and makes contact simpler, at the same time more effective in emergency situations, through linkages with on-board GPS, radar and LORAN receivers.
This means that new designs of VHF radios are now on the market that offer the DSC features and are attractive as initial or replacement units to buyers. This raises questions for boaters, in terms of what are the advantages of having one, how do they work and what is required to use them, and each of these questions lead to answers that warrant knowing about.
First, in order to operate any marine radio, a Radio Operator's (Maritime) Certificate is required, by law and prescribed training is the best means to acquire this. Should a person wish to operate a DSC equipped radio, then an Operator's Certificate that includes DSC qualification or a DSC endorsement to his or her original Certificate is required.
Pleasure craft are not required to be equipped with a DSC-capable radio but one may be chosen to be used aboard. During 2005, the Canadian side of the Great Lakes is expected to have DSC in operation. The American side should follow by 2007.
Each vessel that is equipped with a DSC-capable radio is assigned a Maritime Mobile Service Identity (MMSI) number and before the radio is used with the DSC function, the MMSI number must be programmed into the radio. The MMSI number is obtainable free from Industry Canada.
VHF-DSC radios function on a line-of-site basis, i.e. short distances. They use satellite technology but only for determining position and this must be done through interface with a GPS receiver, unless one is built into the radio. Currently, Industry Canada requires as a minimum for compulsorily fitted radios on vessels, that they are built to the Class 'D' standard the agency has adopted. The U.S. FCC has approved less expensive and less capable VHF-DSC radios built to the newer 'SC-101' standard and these may be used by voluntarily fitted radios on recreational vessels in Canada. But, because the cost of Class 'D' radios has dropped significantly, boaters can now choose a model based on comparative features rather than cost.
Channel 70 is automatically monitored by VHF-DSC radios and is designated exclusively for DSC digital use, i.e. not for voice use. Distress, Urgency, Safety and routine contact initiated with another DCS equipped station is digitally made on Channel 70; the channel to be used for subsequent voice conversation is automatically displayed to the answering stations. All other channels may be used by DSC equipped radios in the conventional non-DSC manner. Improved reliability and ease of operation, plus less congestion on Channel 16 will result from employing the DSC function.
To sum up, VHF-DSC capability enables vessels to efficiently issue and receive all types of alerts and to establish contacts with other vessels and coast guard stations directly and automatically, without having to use the conventional voice-distress channels.

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