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Maritime mobile

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Maritime mobile
Identifier/MM, or "maritime mobile" on voice
Approval neededThe ship's master (47 CFR §97.11)
Equipment ruleSeparate from the ship's own radio equipment; must not be a hazard
US-registered vesselUS license valid anywhere it sails, under §97.5
Where you are
International watersThe flag country's rules (FCC rules on a US-registered vessel), within the band limits of the ITU region
Territorial watersThe coastal country's rules; territorial seas extend up to 12 nautical miles
Foreign-flag vesselAuthorization from the flag country
Best-known netMaritime Mobile Service Network, 14.300 MHz
On the air
DXCC creditGenerally none for contacts with ships at sea

Maritime mobile operation is amateur radio from a ship or boat on the water, whether a sailboat crossing an ocean, a fishing trip on a lake or a passenger on a cruise. Maritime mobile stations add /MM to their call signs and are a familiar sound on HF, where a station hundreds of miles from land can still check into a net every evening. For long-distance sailors, amateur radio has long served as a link home and a source of weather information and help.

The basic rules

Under section 97.11 of the FCC rules, three conditions apply to an amateur station aboard any ship or aircraft:

  • its installation and operation must be approved by the master of the ship (or the pilot in command of an aircraft);[1]
  • it must be separate from and independent of the vessel's other radio equipment, although it may share an antenna with a voluntary ship radio installation, and it must not interfere with other equipment on board;[1]
  • it must not be a hazard to the safety of life or property.[1]

Which country's rules apply depends on the vessel's flag and on where it is. Section 97.5 allows a station to be operated under a US license aboard any vessel documented or registered in the United States.[2] In international waters, the high seas outside any country's territorial sea, a US licensee aboard a US vessel operates under the FCC rules, but must stay within the frequency limits of the ITU region the vessel is in.[3] The world is divided into three regions with different allocations, and the 40-meter band in Region 1, for example, ends at 7.200 MHz. Inside a country's territorial waters, which may extend up to 12 nautical miles from its coast, that country's communications rules apply, as they would on land;[3][4] see Operating abroad.

Foreign-flag ships

A ship is subject to the laws of the country whose flag it flies, so operating aboard a foreign-registered vessel needs authorization from that country, usually through CEPT, a reciprocal agreement or a permit, in addition to the master's approval.[3] Many cruise ships are registered abroad. Cruise lines also set their own policies; passengers generally need the company's written permission to bring a transmitter aboard, and the crew may limit when and where it is used.[3] Ask well before sailing.

Identifying and making contacts

Indicators such as /MM are optional under FCC rules but customary, because they tell other stations where the signal is coming from.[5] On voice, the call is followed by "maritime mobile" and, as the ARRL suggests, the ITU region, for example "W4ABC maritime mobile, Region 2"; on CW and digital modes, W4ABC/MM.[3]

A few practical points:

  • Awards. Contacts with stations aboard ships generally don't count for DXCC and most other awards based on location.[3]
  • Third-party traffic. Messages and phone patches for non-hams aboard may be exchanged with stations in other countries only if those countries have a third-party traffic agreement with the US.[3]
  • Email and weather. Many sailors use Winlink for email and weather files by radio, within the Part 97 limits on commercial use.

Maritime nets

The best-known maritime net in the US is the Maritime Mobile Service Network (MMSN), which meets daily on 14.300 MHz from noon until 10 p.m. Eastern Time (starting at 1 p.m. on Saturdays).[6][7] It began on January 3, 1968, to handle messages for military personnel serving overseas during the Vietnam War, and has used 14.300 MHz as its only frequency since before 2000.[6] Any ham may check in. The net handles traffic and phone patches for vessels at sea and deployed service members, relays emergency traffic with help from relay stations covering the Atlantic, Caribbean, Mediterranean and eastern Pacific, and repeats high-seas and tropical weather warnings from the National Weather Service and the National Hurricane Center.[6]

The same frequency is home to the Pacific Seafarer's Net, which meets daily at 0300 UTC and collects position reports from vessels crossing the Pacific.[8][9] It has helped coordinate rescues; in 2016 it relayed a distress call from a sinking sailboat south of Alaska to the US Coast Guard.[8] Because 14.300 MHz is used for traffic of this kind, stations on the 20-meter band should keep it clear while the nets are in session.

If you hear a weak /MM station calling on 14.300 MHz, stay quiet and let net control handle it. A maritime station may have only a few minutes of propagation, and it may be reporting a real emergency.

See also

References

  1. ↑ 1.0 1.1 1.2 47 CFR 97.11, eCFR.
  2. ↑ 47 CFR 97.5, eCFR.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Maritime Mobile Operation in International Waters, ARRL.
  4. ↑ United Nations Convention on the Law of the Sea, Part II, United Nations.
  5. ↑ 47 CFR 97.119, eCFR.
  6. ↑ 6.0 6.1 6.2 About Us, Maritime Mobile Service Network.
  7. ↑ Schedule, Maritime Mobile Service Network.
  8. ↑ 8.0 8.1 Pacific Seafarer's Net Assists in Maritime Rescue of Sailors on Sinking Sailboat, ARRL News, October 2016.
  9. ↑ Pacific: List of Radio Nets, Noonsite, February 2024.
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