GMDSS普通操作员 第06讲：Passage 31 第06讲：Passage 31.ppt

航运系航海教研室 航运系航海教研室 航运系航海教研室 航运系航海教研室 航运系航海教研室 航运系航海教研室 航运系航海教研室 航运系航海教研室 航运系航海教研室 航运系航海教研室 Passage 31 DSC controllers have a facility that allows the unit to be routinely tested without its associated transmitter being activated. The unit should be tested at least once per day, without radiating signals from the transmitter to establish that the DSC facility functions correctly. When within range of coast stations fitted with DSC equipment the ship should test for the correct operation of the DSC facilities by making a test call at least once per week. If the ship has been out of range a DSC equipped coast station for more than a week, a test call must be made at the first opportunity that the ship is within range of such a coast station. Passage 31 MF/HF equipment is tested by selecting the Safety Category (in some equipment this might occur automatically) and transmitting a special ‘‘Test” format, on one of the DSC Distress and Safety frequencies, to a GMDSS coast station. It is necessary to firstly ascertain that the coast station keeps watch on the relevant frequency-not all GMDSS stations scan all 6 MF7HF frequencies. Also the frequency should be checked to ensure that the call is not initiated if other signals are in progress. A minute or so after receiving the call, the coast station will automatically send a DSC acknowledgement call back to the vessel, thereby indicating that the test was successful. Passage 31 The only test which should be carried out on VHF DSC equipment is the daily internal test, without transmitting live signals. Live test calls on VHF Ch 70 should not be made. Regular use of DSC VHF Ch 70 0n a routine basis to make contact with another vessel or a coast station will confirm the VHF DSC equipment is operating correctly. Testing on the exclusive DSC distress and safety calling frequency 2,187.5 kHz should be avoided as far as possible by using other methods. Passage 31 1. What is the best title of the passage? A. Weekly Tests.