1.1 The Inmarsat-C ship earth station installation
capable of transmitting and receiving direct-printing communications
should comply with the general requirements set out in Resolution A.694(17) and with the following minimum
performance requirements.
1.2 The performance of any enhanced group call
facility provided by the ship earth station should be in accordance
with the performance standards for enhanced group call equipment set
out in resolution A.664(16).
The ship earth station should be type-approved by Inmarsat
and should comply with the environmental conditions specified in its
technical requirements for Inmarsat-C ship earth stations.
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 from the position from which the ship is normally navigated
and from at least one other position designated for distress alerting.
3.3 A distress alert 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.
3.4 The dedicated distress button should:
3.6 The equipment should indicate the status of
the distress alert transmission.
3.8 Facilities should be provided to automatically
update the ship's position and the time at which the position was
determined from a suitable electronic position-fixing aid which may
be an integral part of the equipment. For equipment which does not
have an integral electronic position-fixing aid, such facilities should
include a suitable interface conforming to the appropriate international
standard.footnote
3.9 Provisions should also be made for manual
entry of position information and of the time at which the position
was determined.
3.10 An alarm should be activated when no position
data is received from the electronic position-fixing aid or, in the
case of manual input, the position information is over 4 hours old.
Any position information not updated for more than 24 hours should
be clearly identified.
4
Radio Frequency Hazards
In order to permit a warning of potential radiation hazards
to be displayed in appropriate locations, a label should be attached
to the radome indicating the distances external to the radome at which
radiation levels of 100 W/m2, 25 W/m2 and 10
W/m2 exist. However, the distances which are within a radome
need not be indicated.
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, where provided, from an alternative source of energy.
5.2 Changing from one source of supply to another
or any interruption of up to 60 s duration of the supply of electrical
energy should not require the equipment to be manually re-initialized
and should not result in loss of received messages stored in the memory.
6.1 Where an omnidirectional antenna is used it
should, if practicable, be sited in such a position that no obstacle
likely to degrade significantly the performance of the equipment appears
in the fore and aft directions down to -5° and in the port and
starboard directions down to -15°. For omnidirectional antennas,
objects, especially those within 1 m of the antenna, which cause a
shadow sector of greater than 2°, are likely to degrade significantly
the performance of the equipment.
6.2 Where a stabilized directive antenna is used
it should, if practicable, be sited in such a position that no obstacle
likely to degrade significantly the performance of the equipment appears
in any azimuth down to -5°. For directive antennas with a gain
of approximately 20 dB, objects, especially those within 10 m of the
antenna, which cause a shadow sector of greater than 6°, are likely
to degrade significantly the performance of the equipment.