FINAL REPORT - Stakeholders - Ofcom

The frequencies used for distress and safety communications in the GMDSS are (for
details see Appendix 15 to the Radio Regulations):
• 156.3 MHz for communication between ship and aircraft stations engaged in coordinated
search and rescue operations;
• 156.525 for distress and safety calls using DSC, also used by DSC VHF EPIRBs
although none have been manufactured to date;
• 156.650 MHz for ship-to-ship communications relating to the safety of navigation;
• 156.800 MHz for distress and safety communications by radiotelephony.
The frequencies used for non-GMDSS distress and safety communications are (for
details see Appendix 13 to the Radio Regulations):
• the same frequencies as above for GMDSS with the exception of 156.525 MHz,
since distress alerting is by radiotelephony on 156.800 MHz and not by DSC.
The United Kingdom does not operate coast stations for public correspondence purposes.
6.8.2 Technology Description
• radiotelephony, class of emission F3E or G3E;
• narrow-band direct printing, class of emission F2B or G2B;
• digital selective calling (DSC), class of emission F2B or G2B;
• automatic identification (AIS, see Section 6.10)
The channel spacing is 25 kHz. However with the prior agreement of affected
administrations and administrations having an urgent need to reduce local congestion
may apply 12.5 kHz channel interleaving on a non-interference basis to 25 kHz channels,
provided that certain conditions are met, inter alia that Recommendation ITU-R M.1084 is
observed. For further details see Section 6.8.5.
Technical characteristics of equipment can be found in Recommendation ITU-R M. 489
(VHF radiotelephone equipment, incorporated by reference in the Radio Regulations), in
Recommendation ITU-R M. 493 (DSC) and in Recommendation ITU-R M. 693 (DSC VHF
EPIRB). Due to the international character of the service, agreed operational procedures
have to be observed. In addition to those contained in Chapters VII and IX of the Radio
Regulations, relevant requirements can be found in Recommendation ITU-R M. 541
(DSC, incorporated by reference in the Radio Regulations) and in Recommendation ITU-
R M. 1171 (radiotelephony).
6.8.3 Operational Requirements
VHF maritime services are extremely important international services which are used for
distress and safety, calling and communications, ship movement and navigation, port
operations, inter-ship communications and public correspondence applications. VHF
maritime services are also a fundamental part of the GMDSS. Maritime VHF
communications serve a variety of short-range communication needs up to a range of
abut 50 km, in particular in coastal waters and in port areas. VHF voice and data ship-toshore,
shore-to-ship and ship-to ship communications are a continuing requirement.
However, due to the availability of alternative systems, e.g. GSM and satellite systems,
public correspondence is, at least in Europe, rapidly decreasing. For this reason, the
United Kingdom has closed down all coast stations offering a commercial service (public
correspondence).
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