选C
21.When activated in a distress situation,SART should provide survivors______,when it is interrogated by a radar A.20 blips
B.special rad imagine C.visual and audible indication D.straight line 选C
22.What is the meaning of a Subscriber’s Number? A.The selective calling number assigned to the vessel B.The number assibned to a subacriber’s telephone,TELEX,etc C.The number assigned to the vessel by the U.S.Coast Guard D.The station’s call sign 选B
23.Every ship shall carry personnel qualified for______to the satisfaction of the Administration
A.distress and safety radiocommunication purposes B.life-saving purpose C.GMDSS requirements D.emergency position 选C
24.The abbreviation WWNWS means______ A.World Wide Network Warning Station B.World Wide Navigational Warning Service C.World Wide Number Watch Station D.World Wide Network Watch Service 选B
25.Radio telephones stations should be in the upper part of the ship and
be located away from noise that could______the quality communictions A.degrade B.decrese C.ensure D.warrant 选C
26.EGC SafetyNet transmits______types of messages for mariners A.four B.six C.five D.three 选A
27.A Navtex station in each NAVAREA is usually allowed of to
have______for transmission A.10 minutes every 4 hours B.half an hour every other hour C.irregular period of time D.5 minutes every two hours 选A
28.Tradition radio system has so many principle problems which______ A.can be tackled by traditional and terrestrial techniques B.can be solved by satellite communications
C.can be tackled by some other techniques except satellites D.can hardly solved by any other techniques 选B
29.______is the orbit of a geosynchronous satellite whose ci? and direct orbit lies in the plane of the Earth’s equator,and it is approximately
35,700 kilometers above the equator A.Polar Orbiting B.GPS Satellite Orbit C.Geostationary Satellite Orbit D.The North and South Poles 选C
30.DSC distress relays can be transmitted by either______or______ A.a coast station/a ship station B.an EPIRB/a SART C、ARQ/FEC
D.a back-up satellite/a land SAR unit 选A
31.______will from the basis for distress alerting and safety calling A.GMDSS