Radiocommunications

GMDSS radiocommunication functions

Only qualified radio personnel should operate equipment for GMDSS purposes. GMDSS equipped ships are required to be able to do the following wherever they operate:

• transmit ship-to-shore distress alerts by two independent means;

• receive shore-to-ship alerts (usually relayed by RCCs);

• transmit and receive:

• ship-to-ship alerts

• SAR co-ordinating communications

• on-scene communications

• locating signals

• maritime safety information

• routine or general communications to and from shore

• bridge-to-bridge communications.

GMDSS equipment

Ships operating GMDSS are equipped according to carriage requirements that relate to trading areas i.e. Areas A1, A2, A3 and A4 as stipulated in SOLAS. All ships operating GMDSS can be expected to have at least the folowing equipment:

• VHP radiotelephone (Channels 6,13 and 16):

• Channel 6 may be used ship-to-ship for SAR operations

• Channel 13 is used for safety of navigation ship-to-ship

• Channel 16 is used for distress and urgency traffic, and may be used by
aircraft for safety purposes;

• VHP DSC (Channel 70) transmitter and watch receiver:

• Digital selective calling (DSC) is used for calling and replying, and for
transmitting, acknowledging and relaying distress alerts. It allows a
specific station to be contacted and made aware that the calling station
wishes to communicate with it, and to indicate how to reply, or which
station to listen to for subsequent distress traffic. Calls can also be
addressed to 'all ships' or 'all stations';

• Search and rescue transponder (SART) used for providing homing signals
from survival craft for detection by 9 GHz radar;

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• NAVTEX receiver used for receiving maritime safety information which is
automatically printed by the receiver. Enhanced group call (EGC) facilities will
also be required for ships operating outside NAVTEX range for the receipt of
SafetyNET broadcasts;

• Emergency position indicating radio beacon (EPIRB) used in SAR for alerting
and for providing homing signals for use by aircraft.

Ships sailing beyond range of a VHP DSC coast station must also have an MF DSC transmitter and watch receiver. If sailing beyond MF DSC range, they must have a ship earth station or an HF DSC transmitter and watch receiver including a radio telex system. Ships operating in polar regions will not have Inmarsat satellite coverage.

Date: 2016-04-22; view: 768