ESD GmbH - Funk & Datensysteme

HF (Radio) E-Mail Radio Networks

1. HF E-Mail Network "Global Link Network (GLN)"

The GLN is a world-wide network of coast radio stations with radio mail servers within the HF bands, which
are exchanging the e-mail traffic between vessels, mobile and fixed units on one hand, and land-line based
e-mail subscribers on the other hand.

The direction of the traffic is insignificant; e-mails can be sent from a radio subscriber into the land-line
network or vice versa or within mobile subscribers. Also an e-mail exchange among mobile subscribers of
different mobile networks is possible.

The coast radio stations are distributed globally on all continents and are transmitting on several different
frequencies at the same time, in order to ascertain a world-wide coverage and availability at any given time
and at any given place.

The central main server is located in Switzerland because of its block-free neutrality!

GLN Coast Stations

The GLN is directed to the following user groups and demand bearers: 

- Professional- and Pleasure Shipping
- Security Organizations (Police, Security)
- Military Facilities
- Embassies and other Diplomatic Departments
- Humanitary Organzations, Development Aid, NGOs
- Civil Defense
- Industrial Users at Overseas Branches with unreliable telecommunication infrastructure

A Ship Station License with call sign, issued by the telecommunication authority of the flag state is needed
(on board of vessels) or another valid license for installation and operation of radio apparatus issued by
the prevailing reponsible telecommunication authority for the place of installation.

For the performance of the radio traffic within the Maritime Mobile Service (MMS) additionally a valid
maritime radio operators certificate accordingly to the prevailing type of vessel, is required (LRC/GOC).

Further information on that topic may be obtained from

- the Bundesnetzagentur (BNetzA)/Federal Network Agency (German Telecommunication Regulator),
- the Bundesamt für Seeschifffahrt und Hydrographie (BSH)/Federal Maritime and Hydrographic Agency and
- the Associations of the Small and Sport Shipping (Yachting Clubs)

The Registration can be done via the leading and network operating coast radio station Kiel Radio/DAO

Tel.: +49 (0) 431/2377856


More information regarding the GLN you may find here (System Documentation) or at Kiel Radio under



2. HF E-Mail Network Sailmail

The HF (Radio) e-mail network Sailmail is directed to small non-commercial vessels below 300 RT only, because Sailmail is a US-based non-profit organization.

It is basing on the Maritime Mobile Service (MMS), whereas in some parts frequencies are being used, which are outside of the regular ITU-Channels (Marine-Bands). Therefore it might be neccessary, to re-program the HF radio, to be enabled, that those frequencies are unblocked. Also Sailmail makes use of a world-wide network of coast stations, which can be connected by the users.

The main distinction to the GLN is, that there is no automatic establishment of a connection via MF/HF! The user has to select the coast stations and their frequencies manually via the client software, whereas the radio will be remote controlled by the computer. In such a way the operator has to try to establish a link on several coast stations and frequencies, until he is getting a connection.



The subscribers will be charged with an annual fee, which has to be paid in advance, in order to register the vessel. The user will get an e-mail account in the frame "callsign" Included are services like e-mail exchange, weather-services, position report, by a limited weekly airtime on MF/HF. Unaffected are connections done via Telnet (WiFi, LL-Internet or Sat connections).

As described under 1., the subscriber needs to hold a Ship Station License and Maritime Radio Operators Certificate, in order to operate legally via that system.

The registration may be done by us or directly at the network operator.

Further information may be obtained from here:



 3. HF E-Mail Network Winlink-2000 (WL2K)

The Winlink-2000 (WL2K) is also a HF e-mail network, which is basing on the Amateur Radio Service (ARS).
It is also using the waveforms Pactor II, III and IV on HF, and X.25 on VHF/UHF bands. The slower waveform
Pac-I is not supported anymore, in order to reduce airtime.

Legitimate subscribers are only amateur radio stations, which might be operated on board vessels as well,
but whereas the operator must hold a valid amateur radio operators certificate and an amateur stations
license respectively.

The maritime mobile radio operators certficate or the ship station license are NOT sufficiant for this.

Nevertheless, the marine radios might be used for amateur radio applications also, under the above mentioned
conditions - but NOT vice versa- amateur radio apparatus in the Maritime Mobile Service (MMS) are not permitted.
WL2K is a global network of so called Radio Mail Servers (RMS) in the HF, VHF and UHF bands, which provides
a world-wide coverage and availability, but no fully automatic operation.
Aside the exchange of e-mails in all directions of traffic (ship to shore, shore to ship, ship to ship or other
mobile subscribers) further services are offered, such as weather reports, navigational information, position-
reports and position requenst.

Permitted is traffic, restricted on

- private and non-commercial messages of personal need
- messages regarding the navigation of the vessel or another vehicle
- technical or scientific messages
- distress, urgent and safety messages
- messages of humanitary nature

WL2K is therefore directed only to the following user groups and demand bearers: 

- Sport and Small Shipping
- Campers
- Off Roaders
- Civil Defense and Relief Organzations
- Humanitary Organzations, Development Aid and other NGOs
- Universities and Scientific Institutions
- Research Stations
- Expeditions
- other non-commercial demand bearers