The Maritime Mobile Service Network (MMSN) is dedicated to serving the amateur radio operator at sea, on either a personal
vessel or commercial vessel.
Our net control stations have all of the common emergency numbers at their fingertips and are very capable emergency traffic
handlers. We have a small staff of on-call doctors who can assist you with a medical problem ranging from a hang-nail
to a serious problem. We also have vets on-call who are willing to assist you if your onboard pet becomes ill.
Please read the sections below to learn more.
The MMSN offers our ShipTrak Position Display System
system was written with your family and friends in mind. It is intended as a means for them to follow your progress
across the water. This is a free service!
will display all of your position reports that have been entered into either the Yotreps database or the
Winlink 2000 database. When a callsign is entered, both databases are searched, the position reports for that callsign
are gathered, sorted by date and time and then displayed on a map with dots representing the positions. ShipTrak
displays the position reports in text form, below the map, and the map can be printed as a permanent record.
If you do not have Winlink 2000 or Yotreps onboard your vessel, the net control stations of the MMSN will be pleased take
it from you over the air and enter the information into the database for you. They will also ask you for some weather
information for the National Weather Service (see the next section below)
The MMSN is participating in the MAROB (Marine Observation) program of the National Weather Service (NWS). This is
a voluntary program whereby maritime mobile stations at sea are invited to assist in the collection of real-time weather
information for the NWS.
The MMSN sends the weather information to the NWS via the internet and this information goes into their computers and assists
the forecasters in making a more accurate forecast. The benefits come full cycle back to you, the sailor, in the form
of a more accurate forecast for the area that you are in.
We encourage all maritime mobile stations to participate in this very worthwhile program. Read more about the MAROB
The MMSN can assist you with the current high seas forecast and marine weather information from either the National Weather
Service or, if you are a way out there, the weather service whose area you are in. Our network covers all of the Atlantic
Ocean, the Caribbean, Gulf of Mexico and the Eastern Pacific. Under ideal radio conditions, we can also cover parts
of the Mediterranean Sea, the Indian Ocean and the central Pacific.
Our controllers will also keep you advised of tropical storm developments and hurricane information issued by the National
Hurricane Center. The bulletins are read hourly on the net frequency during times of active storms.
Of course, as it has always been, we offer phone patches to any maritime mobile station where third-party traffic is permitted. Several
of our net control stations have toll-free service to the US, Canada and Puerto Rico. Those without the toll-free service
would make the call collect.
In keeping with the times, we also offer to send an email to someone if you do not have shipboard email. We can also
get you the ball scores, hockey results and just about any other information you may want.
As mentioned above, we also have some active and retired medical practitioners who have volunteered to assist with onboard
medical problems. They are all hams and can either be patched to the vessel from their home or office or they can get
on the air and talk directly with the vessel. Should you need some medical advise, please check in and ask to speak
with a doctor.
Feel free to check into the net anytime, if even just to say hello. Again, the MMSN is here to serve the ham-at-sea.