Radio Regulations

Source: the Radio Regulations published by the International Telecommunication Union (ITU).

All IBR Recommendations

As incorporated in RR-2016

This is not the text in force. It is the version of this Recommendation that RR-2016 gave treaty-binding force, kept so that the incorporated set can be read as it stood at each conference.

See the edition in force (RR-2024)
M

Recommendation ITU-R M.1084-5

Mandatory (1994-1995-1997-1998-2001-2012)

Interim solutions for improved efficiency in the use of the band 156-174 MHz by stations in the maritime mobile service

View official text at ITU

Version history

Version evolution

The number in each cell (e.g. −9) is the Recommendation's revision number — the “-9” in ITU-R M.585-9, not a negative value. So −8 → −9 means the binding reference moved from the 8th to the 9th revision.

RR-2008 -4
RR-2012 -4
RR-2016 -5
RR-2020 -5
RR-2024 -5

Incorporated into the RR by

RR provisions, footnotes and Resolutions that incorporate this Recommendation

Appendix

Appendix 18

Bands and services are derived from the footnotes of the Radio Regulations as they stand, so they are shown only on the edition in force.

Scope

This Recommendation provides ways to improve efficiency in the used of the band 156-174 MHz by stations in the maritime mobile service; specifically describes technical characteristics when using channels spaced by 12.5 kHz, migration to narrow-band channels, an example method for implementing interleaved narrow-band channels at 12.5 kHz offset spacing and assignment of channels numbers to interleaved channels and simplex operation of duplex channels.

Recommends

  1. that administrations having an urgent need to resolve congestion, should implement single frequency operation of two frequency channels as an interim expedient measure;
  2. that, for administrations having an urgent need to resolve congestion, changing to 12.5 kHz analogue frequency modulation (FM) as an interim expedient may be used to improve spectrum utilization but should consider the impact on current operations, especially where it involved international shipping using 25 kHz channel spacing;
  3. that administrations, when employing 12.5 kHz analogue FM channels as an interim measure, should take appropriate means to avoid interference to the distress and safety channels and channels affecting the safety of international shipping;
  4. that the interim arrangements referred to in recommends 2 and 3 should not prejudice the implementation of the longer term solution resulting from the ongoing studies which may result in the use of advanced technologies and channelling of bandwidth other than 12.5 kHz;
  5. that the interim arrangements referred to in recommends 2 and 3 shall not prejudice the implementation of a single international system for distress and safety communications by the international community in the longer term;
  6. that administrations intending to resolve current congestion problems through the use of narrow-band channels should consider Annex 2 as a guide to migration from 25 kHz channels to narrower bands;

+5 more in the full text

Source: ITU Radio Regulations, editions of 2008, 2012, 2016, 2020 and 2024. The English, French and Spanish texts are each taken from the official edition in that language, not translated from one another. Sources and citation.