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A Distress DSC call is called an Alert. Urgency, Safety and Routine are called Announcements. Class A VHFs, used on commercial ships, have the ability to send distress, distress relay, all ships urgency, all ships safety, individual, group, geographic area and telephone alerts/announcements on DSC channel 70 (Digital channel reserved for DSC ...
DSC distress alerts, which consist of a preformatted distress message, are used to initiate emergency communications with ships and rescue coordination centers. DSC was intended to eliminate the need for persons on a ship's bridge or on shore to continuously guard radio receivers on voice radio channels, including VHF channel 16 (156.8 MHz) and ...
Alert or notification of an emergency in progress; Position or location (or localization or pinpointing) of the party in distress. For example, a single aerial flare alerts observers to the existence of a vessel in distress somewhere in the general direction of the flare sighting on the horizon but extinguishes within one minute or less. A hand ...
Fishermen rely on mayday calls for emergency help at sea —know how to make one when needed.
For much of the 20th century, 500 kHz was the primary international distress frequency. Its use has been phased out in favor of the Global Maritime Distress Safety System. Use of some distress frequencies is permitted for calling other stations to establish contact, whereupon the stations move to another frequency.
The DSC safety alert should not be acknowledged by voice, but merely listened to and noted. The proper etiquette for sending a safety alert is as follows: first, the DSC safety alert must be sent on Channel 16 VHF or at 2182 kHz instead of using a working channel or frequency. Second, the targeted group must be selected, if necessary.
2182 kHz is analogous to channel 16 on the marine VHF band, but unlike VHF which is limited to ranges of about 20 to 50 nautical miles (40 to 90 km) depending on antenna height, [3] communications on 2182 kHz and nearby frequencies have a reliable range of around 50 to 100 nautical miles (90 to 190 km) during the day and 150 to 300 nautical miles (280 to 560 km) or sometimes more at night.
Alert colors vary by state with the exception of the Amber alerts. An Amber Alert is for a child under 18 who is missing or endangered. It was named after Amber Hagerman, 9, who was kidnapped and ...