Radio communication（）for many years and helps to save tens of thousands of lives.

Ship-to-ship distress alerting should be conducted by（）.

By using（）system a ship can send a distress message and know with certainty it will be received.

The quality of EGC messages is（）affected by the position of the ship, the time of reception and climatic conditions.

Before GMDSS, if the radio officer on board is serious ill,（）.

If the beacon is mounted at a wrong place, it may（）by sea water, chemicals, exhaust and vibrations.

As each MSI message will have a unique identity, the printing of messages already received correctly is（）.

（）by an ice-breaker, it is important to maintain a continuous listening watch on the appropriate VHF channel and to maintain a proper look-out for sound and visual signals.

Every lifeboat which is fitted with a fixed two-way（）radiotelephone apparatus with an antenna which is separately mounted shall be provided with arrangements for sitting and securing the antenna effectively in its operating position.

Distress traffic is the communication（）between the station in distress and the ships, aircraft, coast radio stations, coast earth stations and rescue centers participating in the rescue work.