So, I ask you, if there were too many false distress calls on VHF channel-16 twenty years ago, why is it almost all VHF radios today come equipped with a DSC emergency distress button? Isn't this just opening up a whole new can of worms? In fact, if you go to the USCG Navigation Center web page you will find the following statement:
The International Telecommunications Union Sector for Radiocommunications has indicated that excessive test calls on MF/HF DSC distress and safety frequencies are overloading the system to the point where interference to distress and safety calls has become a cause for concern.. To minimize possible interference, live testing on DSC distress and safety frequencies with coast stations should be limited to once a week as recommended by the International Maritime Organization.
I'm at a loss to understand the logic of giving up a problematic MAYDAY system only to replace it with a similarly problematic system twenty years later. Just how problematic is DSC? Here's more from the Coast Guard Web Page:
The single largest operational problem of the U.S. Coast Guard concerning DSC had been responding to the large number of MF/HF DSC distress relays being sent by ships. ITU regulations require each relay to be individually acknowledged. The Coast Guard treats each distress alert relay as if it were a separate distress. Worse, certain radios insert the identity of a ship sending a relay, rather than a ship sending a distress, into the menu of a relay message, and ship operators are transmitting this relay falsely identifying the ship in distress to Coast Guard rescue coordination centers. The USCG requested that vessels not relay any DSC distress message which has already been acknowledged. If you do relay a distress message, make sure the identity of the vessel in distress is correct, and send the relay to a USCG radio station using an identity such as 003669999, rather than sending it to all ships.The biggest problem listed above (important enough to mention twice) is the lack of follow-up communications. If I'm not mistaken, the lack of comms with the MAYDAY vessel was one of the two reason for getting rid of the old EPIRBs. The second reason, which obviously contributed to the first, was the anonymousness of the Class C EPIRB.
Since this problem was identified, radio operators have cooperated to reduce the number of relays transmitted. Consequently, this is far less of a problem now.
If we were to identify the single largest operational problem of the U.S. Coast Guard concerning DSC today, it would likely be the lack of follow-up voice communications after transmission of a DSC call.
Continuing DSC problems include:
- the lack of follow-up voice comms after transmission of a DSC call, particularly a distress call
- Unnecessary and frequent alarms
- Distress alerts without accurate location information
- Distress alerts with unregistered MMSI identification
- Limited use of DSC for routine communications
- Inconsistent and illogical software menu defaults
- Alarms disrupting ongoing radiocommunications
Regarding the latter point: In order to make a DSC-equipped radio identifiable it must be programmed with a Maritime Mobile Service Identity (MMSI) number. How do you get a DSC MMSI? Commercial users, or those who travel outside the U.S. or Canada, must apply for a ship station license, or an amendment to a ship station license, to obtain an MMSI. Non-commercial users (e.g. recreational boaters) who stay in U.S. waters can obtain a U.S. MMSI through BOAT US and SeaTow. Canadian vessels should contact Industry Canada.
But if you call a retail store and ask someone there, they'll likely be at a loss as to where to send you. I know, because I just called three retailers and nobody knew where to get an MMSI, even though, collectively, they have over a hundred DSC-equipped radios on their shelves.
How many DSC-equipped radios do you think will be sold? Answer: Millions. Of those radios, how many will represent unidentifiable and untraceable potential MAYDAYs?