What is Global Maritime Distress and Safety System or GMDSS and its details?

On MF :-

1. Switch off transmitter immediately if the false alert is detected during transmission.
2. Switch on equipment and set to 2182 kHz.
3. Make broadcast to “All stations”, giving the ship’s Name, call sign, MMSI No and cancel the false distress alert.

ON HF :-

We will use same procedure as for MF band, but the alert will be cancelled on all the frequency bands on which the alert was transmitted. The transmitter should therefore be tuned consecutively to the radio telephone distress frequency in the 4, 6, 8, 12 and 16 MHz bands.

Note:-

• Avoid sending false alerts, the DSC distress alert will be received at greater distances than the cancellation by the wider transmission.
• If the sea area of receiving vessel is not mentioned then assume, vessel (it is in the same area as the alerting vessel).
• Never (Under Any circumstances), attempt to use the DSC equipments to relay a relayed distress alert. Such action can initiate a chain of misleading relays and responses to several RCCs.

What is Urgency and Safety communications:

Urgency alert:-

Alert is to be transmitted on the DSC distress frequencies. Urgency message normally to be transmitted on RT (Distress), 2182 kHz or NBDP frequency. Moreover, in case of a long message, a medical call, or in areas of heavy traffic when the message in being repeated, then it is send on a working frequency after an announcement using the urgency signal on an appropriate distress frequency.