Guidance

MIN 662 (M+F) Amendment 1 Ofcom requirement for protecting the general public from radio emissions

Published 8 June 2022

This guidance was withdrawn on

MIN 662 has expired.

1. Introduction/background

1.1 Ofcom have varied UK radio transmitter licenses to protect the general public from harmful radio emissions. As a result, all UK ship station license holders must be able to show evidence of their compliance with the protection criteria.

1.2 MCA has contributed to Ofcom consultations on this matter but is not responsible for enforcement, MCA is not able to offer advice on compliance with the protection criteria.

2. Ofcom guidance

2.1 Ofcom has published guidance in a general and a technical form and targeted guidance (https://www.ofcom.org.uk/__data/assets/pdf_file/0026/220796/emf-licence-condition-what-you-need-to-know-ship-radio.pdf) for vessels (Ship Station Licence Holders).

2.2 The targeted guidance indicates that Ofcom require compliance evidence for specific GMDSS radiocommunications installations and for radar installations. But the guidance also identifies many product types for which no evidence is needed.

3. GMDSS installations – power and transmission time

3.1 Radio emissions for emergencies are exempt from compliance and any instructions provided to operators should make it clear that the restrictions on transmission time or power, under the new licence conditions, do not apply in emergencies.

3.2 All DSC transmissions except distress are brief, less than 1 second. A voice radio check transmitting time can be less than 10 seconds. This is compatible with minimising the burden on any responder and to keep channels clear for essential traffic.

3.3 When using VHF and MF/HF radios it is good practice to use the minimum power necessary for a call except in an emergency because more operators can use the same channel or frequency without congestion.

3.4 For GMDSS satellite terminals, messages using message codes have brief transmitting times, less than 1 second. For data or speech, the transmitting time is related to the amount data transmitted or the period of speech, but not the same. The operator cannot control power on GMDSS satellite terminals.

4 VHF radio: portable vs fixed installations

4.1 The range for marine VHF communications is largely determined by aerial heights because the radiocommunications deteriorates rapidly as aerials sink below the horizon to each other.

4.2 When trying to contact the Coastguard (CG), for example sending a distress alert, the distance from shore is less important than whether the CG radio site aerial is above the horizon for your aerial.

4.3 On smaller craft, the aerial of a portable VHF may only be 1.5m above sea level when the user is seated compared to 4m or much more for a fixed installation.

4.4 The published GMDSS Sea Area A1 is based on an aerial on the vessel that is 4m above sea level. Any aerial below 4m, whether part of a fixed VHF radio installation or a portable VHF operated below this height may not reach the CG in all parts of the published A1.

4.5 In high power mode and under the same conditions, a fixed VHF installation is more likely to get through than a portable VHF radio because it transmits more power.

5. GMDSS radio transmitters and safety

5.1 GMDSS radio communications was developed to enhance safety. GMDSS Sea Areas A1 – A4 are defined around VHF, MF, Inmarsat satellite coverage and HF communications respectively, but the use and benefits of such equipment is not restricted to the specified Sea Areas. For example, in many areas of Sea Area A1, MF or GMDSS Satellite terminal can provide a back-up means for distress alerting with two-way communications to shore if the shoreside VHF has failed.

6. Modifications to re-site aerials

6.1 Modification of a vessel by relocating aerials, particularly a radar antenna, or introducing new mounting structures can harm vessel stability, create structural problems and create new opportunities for interference to radio reception.

6.2 MCA Safety Bulletin No.8 contains information on interference from onboard equipment and cable runs.

More information

UK Technical Services Navigation
Maritime and Coastguard Agency
Bay 2/25
Spring Place
105 Commercial Road
Southampton
SO15 1EG

Telephone: +44 (0)203 817 2000

Email: Navigation.Safety@mcga.gov.uk

Website: www.gov.uk/mca

General enquiries: infoline@mcga.gov.uk