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.
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.
3.1 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:
3.8 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.
5.1 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.
6.1 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.