Audio guard
The listening watch is the activity of a member of the ship's crew who is commissioned to listen in on marine radio traffic ( radio calls ; on large ships, this is the responsibility of the radio operator, which is now only available on passenger ships ).
Its purpose is to ensure that the ship's command learns about distress, urgency and safety information and that contact can be made with a ship. The listening watch therefore serves to ensure safety at sea and to ensure communication skills.
Car alarm receivers were soon available. The alarm was triggered on the telegraph frequency by 12 lines of 4 seconds each at an interval of 1 second, sent in A2A mode with 1300 Hz. The radio alarm signal is also 1 minute long and consists of two alternating sinusoidal tones of 2200 Hz and 1300 Hz, with each tone 250 ms long. The car alarm alerted the bridge and the radio officer to the receipt of an emergency signal.
VHF channel 16, the international emergency , urgency , safety and voice call channel , must be listened to when not communicating on another channel. In addition, permanent automatic watch on DSC channel 70 is required for GMDSS- equipped ships at sea .
In spite of Digital Selective Calling, all shipping in German territorial waters is legally obliged to be on guard duty. In the area of traffic control centers, there is a special obligation to listen to the respective working channel of the traffic control center.
In addition to the listening watch on radio frequencies, there is constant monitoring of the DSC channels by means of a watch receiver. At very high frequency channel is monitored 70 and SSB frequency 2187.5 kHz. On shortwave there are bands of DSC emergency frequencies that can be cyclically monitored by marine shortwave devices.
Some of the information can be elementary:
- Distress reports
- Hazard alerts
- Weather warnings
- Calls ( arrangements , e.g. navigation - "Princess - we'll pass you to port!" - or switching)
The listening watch therefore serves to ensure safety at sea and to ensure communication skills.
Individual evidence
- ^ The Navigation Center of Excellence: RADIO WATCHKEEPING REGULATIONS. Retrieved October 27, 2019 .
