Marine Electronics Reviews
Digital Selective Calling, What You Need To Know

Digital Selective Calling or DSC is an attempt to enhance communications between operators using marine radios. As recreational boaters our main concern is with the marine VHF radio aboard our boats.

Another important point for most boaters is the fact that the USCG in a long planned upgrade of its shore and sea based radio equipment will include Digital Selective Calling capability.

Once the USCG finishes their communications upgrade, now called Rescue 21 with a planned completion date sometime in 2011, they anticipate having VHF radio coverage out to 20 miles offshore over 98% of the U.S. coastline. This coverage also includes Hawaii, the Great Lakes, San Juan PR, and Guam.

They will also have full DSC capabilities at over 270 shore stations and aboard nearly 700 Coast Guard vessels.

Currently 11 regions are fully operational and providing coverage over approximately 13,000 miles of coastline. They still have a way to go as the US has about 90,000 miles of coastline.

When it is complete, it will be an impressive communication and search and rescue system.

DSC Today

Does Digital Selective Calling benefit boaters today? Yes, in a number of ways.

First and foremost, as a distress-calling device your DSC equipped VHF radio may not be heard by the Coast Guard just yet but the signal will likely be picked up by other recreational or commercial vessels in your area who are also equipped with DSC radios.

Another benefit available today is the individual ship call. You can use this feature to make a discrete call to a friend (as long as his vessel is also DSC equipped and you know his MMSI number) and advise him electronically to talk to you on another frequency.

With more sophisticated DSC capabilities even your position can be reported to another vessel electronically. So what is the upside of this? You and a fishing or cruising partner could exchange the location of each others boats without actually talking on your marine VHF radio.

Other messages that can be sent via DSC include an all-ships call. This one will send a message to any vessel in your VHF coverage area. Message priority can also be attached indicating whether your message is routine, safety, or emergency related.

Geographical calls cover only a specific area while group calls go out to only a specified group of vessels. You likely won’t use all of these DSC features but some you’ll use everyday once you become familiar with them.

When You Buy a Marine VHF

A couple of things to remember when you purchase a fixed mount VHF radio. Right now most any VHF you find for recreational use will be either a Class D or RTCM SC101.

Basically what these classifications mean is this. Class D radios have two receivers so they can listen on channel 70 at all times for DSC traffic.

Recreational marine VHF radios without this class rating will only have one receiver sharing DSC reception with voice reception.

The bottom line on this is if you can afford it buy a marine VHF that is DSC Class D.