单项选择题
A.VHF channels 16 and 13 B.Appropriate DSC distress and safety frequencies C.INMARSAT TDM message channel D.VHF channel 70 and channel 8
General radio communications in the global system are t...
单项选择题General radio communications in the global system are those between（）concerning the management and operation of the ships and may have impact on their safety.
A.SAR party and the ship in distress B.SAR authorities and the ship in distress and survival craft C.A ship station and any coast station D.Ship stations and shore-based communication network
why do some stations keep silence?（）A.Because they are ...
单项选择题why do some stations keep silence?（）
A.Because they are not engaged in the distress traffic B.they will affect the transmission of the distress traffic C.The powers of these stations are very weak D.They are not in charge of search and rescue
What channel is general communication used?（）A.any appr...
单项选择题What channel is general communication used?（）
A.any appropriate channel except public communication B.any appropriate channel except for public communications C.any appropriate channel besides public communication D.any appropriate channel beside public communication
