Ingangsdatum: 23-11-1996
Geldig tot en met: 31-12-1999
1 INTRODUCTION1.1 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).
2
TECHNICAL REQUIREMENTSThe 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 OPERATION3.1 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:
.1 be
clearly identified; and
.2 be protected against inadvertent
operation.
3.5 The distress alert
initiation should require at least two independent actions.
3.6 The equipment should indicate the status of the distress
alert transmission.
3.7 It should be
possible to interrupt and initiate distress messages at any time.
3.8 Provision should be made for:
.1 automatic and manual entry of the position information; and
.2 automatic and manual entry of the time at which the position
was determined.
4 RADIO FREQUENCY HAZARDSIn 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/m
2, 25 W/m
2 and 10 W/m
2 exist. However, the
distances which are within a radome need not be indicated.
5 POWER SUPPLY5.1 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 ANTENNA SITING6.1 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.