458:
receiver is installed on the bridge, or the place from where the ship is navigated, and checks each incoming message to see if it has been received during an earlier transmission, or if it is of a category of no interest to the ship's master. The frequency of transmission of these messages is 518 kHz in
English, while 490 kHz is sometime used to broadcast in a local language. The messages are coded with a header code identified by the using single letters of the alphabet to represent broadcasting stations, type of messages, and followed by two figures indicating the serial number of the message. For example:
542:
has an end of life scheduled for 1 December 2020. No definite alternatives are currently defined. The
Inmarsat C provides ship/shore, shore/ship and ship/ship store-and-forward data and email messaging, the capability for sending preformatted distress messages to a rescue coordination center, and the Inmarsat C SafetyNET service. The Inmarsat C SafetyNET service is a satellite-based worldwide maritime safety information broadcast service of high seas weather warnings,
181:
357:, which was the world's busiest radiotelephony station, provided HF long-range services. In 1974, it had 154 radio operators who handled over 20 million words per year. Such large radiotelephony stations employed large numbers of people and were expensive to operate. By the end of the 1980s, satellite services had started to take an increasingly large share of the market for ship-to-shore communications.
77:
36:
597:(DSC). Worldwide broadcasts of maritime safety information can also be made on HF narrow-band direct printing channels. All ships trading in Sea area A4 must carry HF DSC and NBDP equipment which can also operate from the ships reserve energy supply (typically a 24v battery supply). This HF provision is necessary as the Inmarsat coverage does not extend to the polar regions.
368:, which called for development of a global search and rescue plan. This group also passed a resolution calling for development by IMO of a Global Maritime Distress and Safety System (GMDSS) to provide the communication support needed to implement the search and rescue plan. This new system, which the world's maritime nations are implementing, is based upon a combination of
661:, which will be DSC-compatible. Countries having a GMDSS A1 Area should be able to identify and track AIS-equipped vessels in its waters without any additional radio equipment. A DSC-equipped radio cannot be interrogated and tracked unless that option was included by the manufacturer, and unless the user configures it to allow tracking.
440:) enabled beacons. 406 MHz EPIRBs transmit an ID which is linked to a database of information about the vessel. Typically a vessel has a unique ID: MMSI. The serviceability of these items is checked monthly and annually and they have limited battery shelf life, between two and five years using mostly lithium-type batteries.
326:(ITU)—which now is a United Nations agency—followed suit for ships of all nations. Morse encoded distress calling has saved thousands of lives since its inception almost a century ago, but its use requires skilled radio operators spending many hours listening to the radio distress frequency. Its daytime range on the
816:(GROL), which requires passing commercial written exam elements 1 and 3 (and thus supersedes the MROP). Upon the further passing of optional written exam element 8 the ship radar endorsement will be added to both the GROL and Maintainer licenses. This allows the holder to adjust, maintain, and repair shipboard
720:, this area lies between about latitude 76 Degrees North and South, but excludes A1 and/or A2 designated areas. Inmarsat guarantees their system will work between 70 South and 70 North though it will often work to 76 degrees South or North. For vessel fitted with Iridium A3 also includes the polar regions
705:
number and type of radio safety equipment ships have to carry depends upon the GMDSS areas in which they travel. GMDSS sea areas are classified into the following four areas: A1, A2, A3 and A4. In 2024 the definitions of A3 and A4 were updated to account for the global coverage now provided by
Iridium.
691:
During Coast Guard inspections, the batteries must be able to go from 100% discharge to fully charged in no longer than 10 hours in order to pass certification. The charger too must be obtainable at all times during vessel operation and should be inspected to make sure it functions properly. When the
652:
IMO and ITU both require that the DSC-equipped MF/HF and VHF radios be externally connected to a satellite navigation receiver (GPS). That connection will ensure accurate location information is sent to a rescue coordination center if a distress alert is transmitted. The FCC requires that all new VHF
872:
Which
Certificate of Competence a seafarer requires will depend on two factors. Firstly officers on board SOLAS vessels (GMDSS compulsory fit vessels) require the ROC or GOC. Operators onboard non SOLAS vessels (which includes leisure craft) may take the shorter Short Range Certificate or Long Range
742:
Presently, until an A1 or A2 Sea Area is established, GMDSS-mandated ships operating off the U.S. coast must fit to Sea Areas A3 (or A4) regardless of where they operate. U.S. ships whose voyage allows them to always remain within VHF channel 16 coverage of U.S. Coast Guard stations may apply to the
704:
GMDSS sea areas serve two purposes: to describe areas where GMDSS services are available, and to define what radio equipment GMDSS ships must carry (carriage requirements). Prior to the GMDSS, the number and type of radio safety equipment ships had to carry depended upon its tonnage. With GMDSS, the
541:
and high-speed data services, including a distress priority telephone and telex service to and from rescue coordination centers. Fleet 77 fully supports the Global
Maritime Distress and Safety System (GMDSS) and includes advanced features such as emergency call prioritisation. Unfortunately Fleet 77
823:
Until March 25, 2008 GMDSS operator and maintainer licenses expired after five years but could be renewed upon payment of a fee. On that date all new certificates were issued valid for the lifetimes of their holders. For those still valid but previously issued with expiration dates, the FCC states:
709:
Sea Area A1—An area within the radiotelephone coverage of at least one VHF coast station in which continuous digital selective calling (Ch.70/156.525 MHz) alerting and radiotelephony services are available. Such an area could extend typically 30 to 40 nautical miles (56 to 74 km) from the
687:
The batteries are required to have a capacity to power the equipment for 1 hour on ships with an emergency generator or built prior to
February 1995, and 6 hours on ships not fitted with an emergency generator or built after February 1995 in order to comply with SOLAS. The batteries must be charged
733:
In addition to equipment listed, all GMDSS-regulated ships must carry a satellite EPIRB, a NAVTEX receiver (if they travel in any areas served by NAVTEX), an
Inmarsat-C SafetyNET receiver (if they travel in any areas not served by NAVTEX), a DSC-equipped VHF radiotelephone, two (if between 300 and
572:
SOLAS now requires that
Inmarsat C equipment have an integral satellite navigation receiver, or be externally connected to a satellite navigation receiver. That connection will ensure accurate location information to be sent to a rescue coordination center if a distress alert is ever transmitted.
431:
ships, commercial fishing vessels, and all passenger ships, are designed to transmit to alert rescue coordination centers via the satellite system from anywhere in the world. The original COSPAS/SARSAT system used polar orbiting satellites, but in recent years the system has been expanded to also
635:
as part of the GMDSS system. DSC is primarily intended to initiate ship-to-ship, ship-to-shore and shore-to-ship radiotelephone and MF/HF radiotelex calls. DSC calls can also be made to individual stations, groups of stations, or "all stations" in one's radio range. Each DSC-equipped ship, shore
457:
is an international, automated system for instantly distributing maritime safety information (MSI) which includes navigational warnings, weather forecasts and weather warnings, search and rescue notices and similar information to ships. A small, low-cost and self-contained "smart" printing radio
648:
now used for distress, safety and calling. A listening watch aboard GMDSS-equipped ships on 2182 kHz ended on
February 1, 1999. In May 2002, IMO decided to postpone cessation of a VHF listening watch aboard ships. That watchkeeping requirement had been scheduled to end on February 1, 2005.
643:
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
616:
display. The detection range between these devices and ships, dependent upon the height of the ship's radar mast and the height of the Search and Rescue
Locating device, is normally about 15 km (8 nautical miles). Once detected by radar, the Search and Rescue Locating device will produce a
557:
Inmarsat C equipment is relatively small and lightweight, and costs much less than a F77 station. A F77 ship earth station requires a relatively large gyro-stabilized unidirectional antennas; the antenna size of the Inmarsat C is much smaller and is omnidirectional. Inmarsat C being a low power
576:
Also, the new LRIT long-range tracking systems are upgraded via GMDSS Inmarsat C, which are also compliant, along with inbuilt SSAS, or ship security alert system. SSAS provides a means to covertly transmit a security alert distress message to local authorities in the event of a mutiny, pirate
808:
examinations, these are given by private, FCC-approved groups. These are generally not the same agencies who administer the ham tests. Written test elements 1 and 7 are required for the Operator license, and elements 1 and 7R for the Restricted Operator. (Passing element 1 also automatically
390:) Convention, requiring ships subject to it to fit GMDSS equipment. Such ships were required to carry NAVTEX and satellite EPIRBs by August 1, 1993, and had to fit all other GMDSS equipment by February 1, 1999. US ships were allowed to fit GMDSS in lieu of Morse telegraphy equipment by the
310:
and first used in 1844, for distress and safety telecommunications. The need for ship and coast radio stations to have and use radiotelegraph equipment, and to listen to a common radio frequency for Morse encoded distress calls, was recognized in the aftermath of the sinking of the liner
611:
The GMDSS installation on ships include one (two on vessels over 500 GT) search-and-rescue locating device called Search and Rescue Radar Transponders (SART) which are used to locate survival craft or distressed vessels by creating a series of twelve dots on a rescuing ship's 3 cm
758:
National maritime authorities may issue various classes of licenses. The General Operator’s Certificate is required on SOLAS vessels operating also outside GMDSS Sea Area A1, while a Restricted Operator’s Certificate is needed on SOLAS vessels operated solely within GMDSS Sea Area A1,
695:
Storage batteries provided as a reserve source of energy must be installed in accordance with applicable electrical codes and good engineering practice. They must be protected from adverse weather and physical damage. They must be readily accessible for maintenance and replacement.
558:
system allows for its operation from the vessels emergency 24volt battery supply under emergency conditions. This coupled to the omni directional antenna arrangements allow for a guaranteed response to a distress alert between 76 degrees North and 76 degrees South (Sea area A3).
827:
Any GMDSS Radio Operator's License, Restricted GMDSS Radio Operator's License, GMDSS Radio Maintainer's License, GMDSS Radio Operator/Maintainer License, or Marine Radio Operator Permit that was active, i.e., had not expired, as of March 25, 2008, does not have to be renewed.
656:
VHF digital selective calling also has other capabilities beyond those required for the GMDSS. The US Coast Guard uses this system to track vessels in Prince William Sound, Alaska, Vessel Traffic Service. IMO and the USCG also plan to require ships carry a Universal Shipborne
372:
and terrestrial radio services, and has changed international distress communications from being primarily ship-to-ship based to ship-to-shore (Rescue Coordination Center) based. It spelled the end of Morse code communications for all but a few users, such as
876:
The second deciding factor is the intended operating area of the vessel. Craft operating exclusively in Sea Area A1 can use the SRC or ROC certificates, where as vessels venturing further offshore into Sea Areas A2, A3 and/or A4 require the LRC or GOC.
688:
by an automatic charger, which is also required to be powered from the main and emergency generators. Changeover from AC to battery supply must be automatic, and effected in such a way that any data held by the equipment is not corrupted ("no break").
743:
Federal Communications Commission for an individual waiver to fit to Sea Area A1 requirements. Similarly, those who remain within 2182 kHz coverage of U.S. Coast Guard stations may apply for a waiver to fit to Sea Area A2 requirements.
364:(IMO), a United Nations agency specializing in safety of shipping and preventing ships from polluting the seas, began looking at ways of improving maritime distress and safety communications. In 1979, a group of experts drafted the
525:(IMSO) are important elements of the GMDSS. The types of Inmarsat ship earth station terminals recognized by the GMDSS are: Inmarsat C and F77. Inmarsat F77, an updated version of the now redundant Inmarsat A and B, provide
514:. The certification of Iridium in 2020 ended a monopoly on the provision of the satellite-based portion of maritime distress services that had previously been held by Inmarsat since the system became operational in 1999.
1035:
664:
GMDSS telecommunications equipment should not be reserved for emergency use only. The International Maritime Organization encourages mariners to use GMDSS equipment for routine as well as safety telecommunications.
385:
call, and, for the first time, requires ships to receive broadcasts of maritime safety information which could prevent a disaster from happening in the first place. In 1988, IMO amended the Safety of Life at Sea
262:
GMDSS consists of several systems which are intended to perform the following functions: alerting (including position determination of the ship in distress) ships in the vicinity and ashore authorities,
831:
Since an older certificate does show an expiration date, for crewmembers sailing internationally it may be worth paying the fee (as of 2010 it was $ 60) to avoid any confusion with local authorities.
692:
reserve source of energy consists of batteries, the battery capacity must be checked at intervals not exceeding 12 months. If not completed within past 12 months, this must be done during inspection.
723:
Sea Area A4—An area outside Sea Areas A1, A2 and A3 is called Sea Area A4. For ships fitted with Inmarst as their RMSS this is essentially the polar regions, north and south of about 76 degrees of
898:
GMDSS Publications: The United Kingdom Hydrographic Office publishes a GMDSS Admiralty List of Radio Signals (Global Maritime Distress and Safety System (GMDSS) Volume 5, NP285, 2023 edition is
800:
To obtain any of these licenses a person must be a U.S. citizen or otherwise eligible for work in the country, be able to communicate in English, and take written examinations approved by the
94:
49:
387:
365:
256:
1043:
255:
procedures, types of equipment, and communication protocols used for safety and rescue operations of the distressed ships, boats, and aircraft. It is supplemental to the
411:
562:
195:. The reason given is: this article refers to potentially outdated system(s) as being current, suggests possible future events for dates that have already occurred.
55:
891:
1375:
423:-based search and rescue system, established by Canada, France, the United States, and Russia. These four countries jointly helped develop the 406 MHz
522:
424:
141:
716:
Sea Area A3—An area, excluding sea areas A1 and A2, within the coverage of an RMSS (Recognised Mobile Satellite System). For ships fitted with Inmarsat
113:
1380:
813:
120:
903:
323:
337:
Not all ship-to-shore radio communications were short-range. Some radio stations provided long-range radiotelephony services, such as radio
127:
1218:
937:
361:
241:
109:
812:
For the Maintainer license, written exam element 9 must be passed. However, to obtain this certificate an applicant must also hold a
1268:
801:
713:
Sea area A2—An area within a coverage of at least one coast station continuous listening on MF (2187.5 kHz) other than Area A1
219:
160:
63:
427:(EPIRB), an element of the GMDSS designed to operate with Cospas-Sarsat system. These automatic-activating EPIRBs, now required on
436:
receivers to transmit highly accurate positions (within about 20 metres) of the distress position. EPIRB manufacturers offer AIS (
1370:
869:
Each certificate is issued on the successful completion of a course and exam and each Certificate is recognised internationally.
637:
1329:
734:
less than 500 GRT) or three VHF handhelds (if 500 GRT or more), and two 9 GHz search and rescue radar transponders (SART).
377:. The GMDSS provides for automatic distress alerting and locating in cases where a radio operator does not have time to send an
1390:
886:
658:
503:
437:
268:
554:, and other similar information not provided by NAVTEX. SafetyNET works similarly to NAVTEX in areas outside NAVTEX coverage.
1261:
1094:
391:
98:
1316:
1303:
1290:
1277:
606:
319:
190:
930:
134:
569:
reports can now be sent to both the USCG AMVER Center, and NOAA, using an Inmarsat C ship earth station, at no charge.
240:) is a worldwide system for automated emergency signal communication for ships at sea developed by the United Nations'
530:
1182:
322:
soon enacted legislation, requiring U.S. ships to use Morse code radiotelegraph equipment for distress calls. The
87:
1400:
835:
626:
594:
433:
279:
278:
Recreational vessels do not need to comply with GMDSS radio carriage requirements, but will increasingly use the
1395:
551:
382:
1385:
850:
773:
766:
717:
432:
include 4 geostationary satellites and 50 medium orbiting navigation satellites. Newest designs incorporate
783:
A GMDSS Radio Maintainer's License allows a person to maintain, install, and repair GMDSS equipment at sea.
776:
but limited VHF DSC radio operation. Some countries do not consider this adequate for GMDSS qualification.
856:
762:
499:
374:
959:
511:
653:
and MF/HF maritime radiotelephones type accepted after June 1999 have at least a basic DSC capability.
727:, excluding any A1, A2 and A3 areas. For ships that carry Iridium as their RMSS, there is no Area A4.
495:
267:
coordination, locating (homing), maritime safety information broadcasts, general communications, and
1207:
765:
may be issued, and is required on non-SOLAS vessels operating outside GMDSS Sea Area A1, while a
632:
299:
275:. The system also provides redundant means of distress alerting, and emergency sources of power.
271:. Specific radio carriage requirements depend upon the ship's area of operation, rather than its
838:
requires additional classroom training and practical experience beyond just holding a license.
17:
899:
264:
846:
In the United Kingdom and Europe four different GMDSS certificates of Competence are issued:
772:
Finally there is a restricted radiotelephone operator's certificate, which is similar to the
995:
428:
354:
327:
283:
245:
786:
A GMDSS Radio Operator's License is necessary for a person to use required GMDSS equipment.
1333:
1320:
1307:
1294:
1281:
1265:
986:
789:
The holder of both certificates can be issued one GMDSS Radio Operator/Maintainer License.
547:
507:
252:
1355:
796:
is available for VHF operations only within 20 nautical miles (37 km) of the coast.
197:
Please help update this article to reflect recent events or newly available information.
999:
586:
346:
1364:
1326:
805:
590:
534:
526:
416:
287:
1065:
1014:"The story of Portishead Radio: Long range maritime radio communications: 1920–1995"
746:
As of August 2013, the U.S. Coast Guard provides a Sea Area A1 service through its
486:
As of January 2020, there are two certified providers of GMDSS satellite services:
307:
1258:
809:
qualifies the applicant for the Marine Radiotelephone Operator Permit, the MROP.)
1313:
1300:
1140:
334:) is limited, and the amount of traffic Morse signals can carry is also limited.
1287:
1274:
342:
312:
76:
834:
Finally, to actually serve as a GMDSS operator on most commercial vessels the
303:
1233:
1161:
1119:
747:
510:(LEO) that can cover higher latitudes and operate with lower communications
420:
369:
286:. Offshore vessels may elect to equip themselves further. Vessels under 300
1186:
1013:
769:
is issued for non-SOLAS vessels operating only inside GMDSS Sea Area A1.
724:
645:
518:
487:
338:
673:
GMDSS equipment is required to be powered from three sources of supply:
543:
491:
331:
272:
1036:"International Convention for the Safety of Life at Sea (SOLAS), 1974"
631:
The IMO also introduced digital selective calling (DSC) on MF, HF and
1095:"Iridium marks major milestone with maritime safety, breaks monopoly"
960:"UNTC - International Convention on maritime search and rescue, 1979"
454:
449:
779:
In the United States four different GMDSS certificates are issued:
550:
warnings, ice reports and warnings generated by the USCG-conducted
259:(ICMSaR) adopted in 1979 and provides basis for the communication.
817:
613:
566:
538:
593:(narrow-band direct printing) equipment, with calls initiated by
1248:
577:
attack, or other hostile action towards the vessel or its crew.
1314:
FCC – Commercial Operator Licenses: Examination Question Pools
1253:
1079:
378:
350:
174:
70:
29:
353:) enabling worldwide communications with ships. For example,
1340:
302:
at the end of the 19th century, ships at sea have relied on
1208:
Commercial Radio Operator License Program: Term of Licenses
1244:
AMERC Association of Marine Electronic and Radio Colleges
1243:
1238:
984:
Johnson, B (1994). "English in maritime radiotelephony".
27:
Worldwide emergency communication system for ships at sea
931:"Shipping Emergencies – Search and Rescue and the GMDSS"
644:
channels, including VHF channel 16 (156.8 MHz) and
617:
visual and aural indication to the persons in distress.
738:
GMDSS radio equipment required for U.S. coastal voyages
680:
ship's emergency alternator/generator (if fitted); and
257:
International Convention on Maritime Search and Rescue
1254:
Search And Rescue Satellite Aided Tracking (SARSAT)
101:. Unsourced material may be challenged and removed.
406:Emergency position-indicating radio beacon (EPIRB)
565:(NOAA), combined meteorological observations and
412:Emergency position-indicating radiobeacon station
193:may be compromised due to out-of-date information
1259:FCC – Commercial Operator Licenses: Examinations
636:station and group is assigned a unique 9-digit
563:National Oceanic and Atmospheric Administration
402:The main types of equipment used in GMDSS are:
8:
1341:"CCIR 493-4 HF Selcall Information Resource"
290:(GT) are not subject to GMDSS requirements.
110:"Global Maritime Distress and Safety System"
1275:FCC – GMDSS Radio Maintainer's License (DM)
523:International Mobile Satellite Organization
64:Learn how and when to remove these messages
1183:"FCC – Commercial Radio Operator Licenses"
1066:"What Are AIS EPIRBs? – Casual Navigation"
425:Emergency Position-Indicating Radio Beacon
234:Global Maritime Distress and Safety System
1288:FCC – GMDSS Radio Operator's License (DO)
1141:"GMDSS AREAS AND SEARCH AND RESCUE AREAS"
220:Learn how and when to remove this message
161:Learn how and when to remove this message
915:
814:General radiotelephone operator license
561:Under a cooperative agreement with the
466:is the ID of the transmitting station,
892:Long-Range Identification and Tracking
842:Licensing of operators (UK and Europe)
862:Restricted Operator Certificate (ROC)
677:ship's normal alternators/generators;
324:International Telecommunication Union
7:
1162:"RESCUE 21 DISTRESS SYSTEM COVERAGE"
1120:"RESCUE 21 DISTRESS SYSTEM COVERAGE"
1093:Gebhardt, Chris (January 23, 2020).
925:
923:
921:
919:
601:Search and rescue transponder (SART)
99:adding citations to reliable sources
1376:International Maritime Organization
938:International Maritime Organization
478:is the consecutive message number.
362:International Maritime Organization
318:in the North Atlantic in 1912. The
242:International Maritime Organization
1000:10.1111/j.1467-971X.1994.tb00285.x
865:General Operator Certificate (GOC)
517:Satellite systems operated by the
25:
1269:Federal Communications Commission
1080:"US Coastguard Navigation Center"
802:Federal Communications Commission
683:a dedicated radio battery supply.
45:This article has multiple issues.
1381:International telecommunications
1219:GMDSS Training and Certification
638:Maritime Mobile Service Identity
179:
75:
34:
1327:GMDSS Ship Inspection Checklist
887:Automatic Identification System
659:automatic identification system
470:indicates the message category
438:Automatic Identification System
269:bridge-to-bridge communications
86:needs additional citations for
53:or discuss these issues on the
18:Maritime Distress Safety System
1249:COSPAS-SARSAT system home page
392:Telecommunications Act of 1996
1:
607:Search and rescue transponder
1301:FCC – Ship Radar Endorsement
1239:A Brief Explanation on GMDSS
754:Licensing of operators (USA)
1306:September 24, 2008, at the
1293:September 19, 2008, at the
585:A GMDSS system may include
1417:
1356:Indian GOC Renewal Process
624:
604:
504:66-satellite constellation
447:
409:
1332:October 11, 2010, at the
1319:October 19, 2008, at the
1280:October 20, 2008, at the
1264:October 19, 2008, at the
836:United States Coast Guard
669:Power supply requirements
627:Digital selective calling
621:Digital selective calling
595:digital selective calling
521:company, overseen by the
280:Digital Selective Calling
794:GMDSS Restricted License
589:(HF) radiotelephone and
552:International Ice Patrol
490:, with several of their
1371:Emergency communication
851:Short Range Certificate
774:Short Range Certificate
767:Short Range Certificate
718:geostationary satellite
546:navigational warnings,
375:amateur radio operators
360:For these reasons, the
1391:Maritime communication
857:Long Range Certificate
763:Long Range Certificate
500:Iridium Communications
1234:US Coast Guard: GMDSS
873:Certificate Courses.
244:(IMO) as part of the
1046:on February 12, 2017
496:geosynchronous orbit
472:navigational warning
419:is an international
330:(MF) distress band (
95:improve this article
1189:on October 19, 2008
1099:NasaSpaceflight.com
633:VHF maritime radios
398:Components of GMDSS
300:invention of radio
904:978-0-7077-4746-0
349:bands (3–30
284:Marine VHF radios
265:search and rescue
230:
229:
222:
212:
211:
171:
170:
163:
145:
68:
16:(Redirected from
1408:
1401:Rescue equipment
1352:
1350:
1348:
1221:
1216:
1210:
1205:
1199:
1198:
1196:
1194:
1185:. Archived from
1179:
1173:
1172:
1170:
1168:
1158:
1152:
1151:
1149:
1147:
1137:
1131:
1130:
1128:
1126:
1116:
1110:
1109:
1107:
1105:
1090:
1084:
1083:
1076:
1070:
1069:
1062:
1056:
1055:
1053:
1051:
1042:. Archived from
1032:
1026:
1025:
1023:
1021:
1010:
1004:
1003:
981:
975:
974:
972:
970:
956:
950:
949:
947:
945:
935:
927:
355:Portishead Radio
328:medium frequency
246:SOLAS Convention
225:
218:
207:
204:
198:
191:factual accuracy
183:
182:
175:
166:
159:
155:
152:
146:
144:
103:
79:
71:
60:
38:
37:
30:
21:
1416:
1415:
1411:
1410:
1409:
1407:
1406:
1405:
1396:Maritime safety
1361:
1360:
1346:
1344:
1339:
1334:Wayback Machine
1321:Wayback Machine
1308:Wayback Machine
1295:Wayback Machine
1282:Wayback Machine
1266:Wayback Machine
1230:
1225:
1224:
1217:
1213:
1206:
1202:
1192:
1190:
1181:
1180:
1176:
1166:
1164:
1160:
1159:
1155:
1145:
1143:
1139:
1138:
1134:
1124:
1122:
1118:
1117:
1113:
1103:
1101:
1092:
1091:
1087:
1078:
1077:
1073:
1064:
1063:
1059:
1049:
1047:
1034:
1033:
1029:
1019:
1017:
1016:. April 6, 2001
1012:
1011:
1007:
987:World Englishes
983:
982:
978:
968:
966:
964:treaties.un.org
958:
957:
953:
943:
941:
933:
929:
928:
917:
912:
883:
844:
756:
740:
702:
700:GMDSS sea areas
671:
629:
623:
609:
603:
583:
548:radionavigation
508:low Earth orbit
484:
452:
446:
414:
408:
400:
296:
251:It is a set of
226:
215:
214:
213:
208:
202:
199:
196:
188:This article's
184:
180:
167:
156:
150:
147:
104:
102:
92:
80:
39:
35:
28:
23:
22:
15:
12:
11:
5:
1414:
1412:
1404:
1403:
1398:
1393:
1388:
1386:Law of the sea
1383:
1378:
1373:
1363:
1362:
1359:
1358:
1353:
1343:. HFLINK. 2010
1337:
1324:
1311:
1298:
1285:
1272:
1256:
1251:
1246:
1241:
1236:
1229:
1228:External links
1226:
1223:
1222:
1211:
1200:
1174:
1153:
1132:
1111:
1085:
1071:
1057:
1027:
1005:
976:
951:
914:
913:
911:
908:
896:
895:
889:
882:
879:
867:
866:
863:
860:
854:
843:
840:
798:
797:
790:
787:
784:
755:
752:
739:
736:
729:
728:
721:
714:
711:
710:Coast Station.
701:
698:
685:
684:
681:
678:
670:
667:
625:Main article:
622:
619:
605:Main article:
602:
599:
587:high-frequency
582:
581:High frequency
579:
494:in equatorial
483:
480:
448:Main article:
445:
442:
410:Main article:
407:
404:
399:
396:
345:calls, on the
306:, invented by
295:
292:
228:
227:
210:
209:
187:
185:
178:
169:
168:
83:
81:
74:
69:
43:
42:
40:
33:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
1413:
1402:
1399:
1397:
1394:
1392:
1389:
1387:
1384:
1382:
1379:
1377:
1374:
1372:
1369:
1368:
1366:
1357:
1354:
1342:
1338:
1335:
1331:
1328:
1325:
1322:
1318:
1315:
1312:
1309:
1305:
1302:
1299:
1296:
1292:
1289:
1286:
1283:
1279:
1276:
1273:
1270:
1267:
1263:
1260:
1257:
1255:
1252:
1250:
1247:
1245:
1242:
1240:
1237:
1235:
1232:
1231:
1227:
1220:
1215:
1212:
1209:
1204:
1201:
1188:
1184:
1178:
1175:
1163:
1157:
1154:
1142:
1136:
1133:
1121:
1115:
1112:
1100:
1096:
1089:
1086:
1081:
1075:
1072:
1067:
1061:
1058:
1045:
1041:
1037:
1031:
1028:
1015:
1009:
1006:
1001:
997:
993:
989:
988:
980:
977:
965:
961:
955:
952:
939:
932:
926:
924:
922:
920:
916:
909:
907:
905:
901:
893:
890:
888:
885:
884:
880:
878:
874:
870:
864:
861:
858:
855:
852:
849:
848:
847:
841:
839:
837:
832:
829:
825:
821:
819:
815:
810:
807:
806:amateur radio
803:
795:
792:Finally, the
791:
788:
785:
782:
781:
780:
777:
775:
770:
768:
764:
760:
753:
751:
749:
744:
737:
735:
731:
726:
722:
719:
715:
712:
708:
707:
706:
699:
697:
693:
689:
682:
679:
676:
675:
674:
668:
666:
662:
660:
654:
650:
647:
641:
639:
634:
628:
620:
618:
615:
608:
600:
598:
596:
592:
588:
580:
578:
574:
570:
568:
564:
559:
555:
553:
549:
545:
540:
536:
535:shore-to-ship
532:
528:
527:ship-to-shore
524:
520:
515:
513:
509:
505:
502:, with their
501:
497:
493:
489:
481:
479:
477:
473:
469:
465:
461:
456:
451:
443:
441:
439:
435:
430:
426:
422:
418:
417:Cospas-Sarsat
413:
405:
403:
397:
395:
393:
389:
384:
380:
376:
371:
367:
363:
358:
356:
352:
348:
344:
340:
335:
333:
329:
325:
321:
320:U.S. Congress
317:
316:
309:
305:
301:
293:
291:
289:
288:gross tonnage
285:
281:
276:
274:
270:
266:
260:
258:
254:
249:
247:
243:
239:
235:
224:
221:
206:
203:February 2021
194:
192:
186:
177:
176:
173:
165:
162:
154:
151:February 2017
143:
140:
136:
133:
129:
126:
122:
119:
115:
112: –
111:
107:
106:Find sources:
100:
96:
90:
89:
84:This article
82:
78:
73:
72:
67:
65:
58:
57:
52:
51:
46:
41:
32:
31:
19:
1345:. Retrieved
1214:
1203:
1191:. Retrieved
1187:the original
1177:
1165:. Retrieved
1156:
1144:. Retrieved
1135:
1123:. Retrieved
1114:
1102:. Retrieved
1098:
1088:
1074:
1060:
1048:. Retrieved
1044:the original
1039:
1030:
1018:. Retrieved
1008:
994:(1): 83–91.
991:
985:
979:
969:November 12,
967:. Retrieved
963:
954:
942:. Retrieved
940:. March 1999
897:
875:
871:
868:
845:
833:
830:
826:
822:
811:
799:
793:
778:
771:
761:
757:
745:
741:
732:
730:
703:
694:
690:
686:
672:
663:
655:
651:
642:
630:
610:
584:
575:
571:
560:
556:
531:ship-to-ship
516:
485:
475:
471:
467:
463:
459:
453:
415:
401:
359:
336:
314:
308:Samuel Morse
297:
277:
261:
250:
237:
233:
231:
216:
200:
189:
172:
157:
148:
138:
131:
124:
117:
105:
93:Please help
88:verification
85:
61:
54:
48:
47:Please help
44:
1347:January 10,
1193:January 10,
1104:January 24,
1050:February 2,
1040:www.imo.org
820:equipment.
804:. Like the
537:telephone,
1365:Categories
1020:January 9,
944:January 6,
910:References
591:radiotelex
341:and radio
304:Morse code
298:Since the
121:newspapers
50:improve it
906:). (DMT)
748:Rescue 21
482:Satellite
421:satellite
370:satellite
339:telegrams
56:talk page
1330:Archived
1317:Archived
1304:Archived
1291:Archived
1278:Archived
1262:Archived
881:See also
750:system.
725:latitude
646:2182 kHz
519:Inmarsat
492:commsats
488:Inmarsat
544:NAVAREA
512:latency
332:500 kHz
315:Titanic
294:History
273:tonnage
135:scholar
1167:May 7,
1146:May 7,
1125:May 7,
902:
894:(LRIT)
498:, and
474:, and
462:where
455:Navtex
450:NAVTEX
444:NAVTEX
383:MAYDAY
366:ICMSaR
282:(DSC)
253:safety
137:
130:
123:
116:
108:
1271:(FCC)
934:(PDF)
859:(LRC)
853:(SRC)
818:radar
614:radar
567:AMVER
539:telex
429:SOLAS
388:SOLAS
343:telex
238:GMDSS
142:JSTOR
128:books
1349:2010
1195:2008
1169:2014
1148:2014
1127:2014
1106:2020
1052:2019
1022:2008
971:2021
946:2022
900:ISBN
533:and
460:FA56
313:RMS
232:The
114:news
1336:FCC
1323:FCC
1310:FCC
1297:FCC
1284:FCC
996:doi
506:in
434:GPS
381:or
379:SOS
351:MHz
97:by
1367::
1097:.
1038:.
992:13
990:.
962:.
936:.
918:^
640:.
529:,
476:56
394:.
347:HF
248:.
59:.
1351:.
1197:.
1171:.
1150:.
1129:.
1108:.
1082:.
1068:.
1054:.
1024:.
1002:.
998::
973:.
948:.
468:A
464:F
386:(
236:(
223:)
217:(
205:)
201:(
164:)
158:(
153:)
149:(
139:·
132:·
125:·
118:·
91:.
66:)
62:(
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
