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Statutory Documents - IMO Publications and Documents - Resolutions - Assembly - IMO Resolution A.808(19) Performance Standards for Ship Earth Stations Capable of Two-Way Communications (Adopted on 23 November 1995) - Annex - Performance Standards for Ship Earth Stations Capable of Two-Way Communications

Annex - Performance Standards for Ship Earth Stations Capable of Two-Way Communications

  1 Introduction

 The ship earth station installation capable of telephony and direct printing should comply with the general requirements set out in Resolution A.694(17) and with the following minimum requirements.

  2 Technical Requirements

 The equipment should be type approved by Inmarsat and should comply with the environmental conditions specified in its technical requirements for Inmarsat ship earth stations capable of two-way communications.

  3 Operation

  3.1 No control external to the equipment should be available for alteration of the ship station identity.

  3.2 It should be possible to initiate and make distress calls by telephony or direct printing from the position at which the ship is normally navigated and from any other position designated for distress alerting. In addition, where a room is provided for radiocommunications, means to initiate distress calls should also be fitted in that room.

  3.3 Where no other means of receiving distress, urgency and safety broadcasts or an addressed distress alert relay are provided and existing levels of aural signals produced by the telephone or teletype are considered to be inadequate, the ship earth station equipment should be configured to actuate an aural/visual alarm of appropriate level.

  3.4 It should be possible to interrupt or initiate distress calls at any time.

  3.5 A distress call should be activated only by means of a dedicated distress button. This button should not be any key of an ITU-T digital input panel or an ISO keyboard provided on the equipment.

  3.6 The dedicated distress button should:

  3.7 The distress call initiation should require at least two independent actions.

  3.8 Paragraphs 3.5, 3.6 and 3.7 do not apply to Inmarsat-A ship earth stations.

  4 Radio Frequency Hazards

 In order to permit warning of potential radiation hazards to be displayed in appropriate places, a label should be attached to the radome indicating the distance at which radiation levels of 100 W/m2, 25 W/m2 and 10 W/m2 exist.

  5 Power Supply

  5.1 The ship earth station should normally be powered from the ship's main source of electrical energy. In addition, it should be possible to operate the ship earth station and all equipment necessary for its normal functioning, including the antenna tracking system, from an alternative source of energy.

  5.2 Changing from one source of supply to another or any interruption up to 60 s of the supply of electrical energy should not render the equipment inoperative or require the equipment to be re-initialized.

  6 Antenna Siting

  6.1 It is desirable that the antenna be sited in such a position that no obstacles likely significantly to degrade the performance of the equipment appear in any azimuth down to an angle of elevation of -5.

  6.2 The siting of the antenna needs careful consideration, taking into account the adverse effect of high levels of vibration which might be introduced by the use of a tall mast and the need to minimize shadow sectors. Objects, especially those within 10 m of the radome which cause a shadow sector of greater than 6, are likely significantly to degrade the performance of the equipment.

  6.3 The above-deck equipment should be separated, as far as is practicable, from the antennae of other communication and navigation equipment.


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