[单选题]Operating method in which transmission is possible simultaneously in both directions of a communication channel is called ______
[单选题]The master or the person responsible for the ship is the _____with regard to the operation of the radio station.
[单选题]In each NAVTEX message there is a technical code (B1B2B3B4) which character is the subject indicator character?
[单选题]Every ship, while at sea ,shall maintain continuous watch on____,if the ship , in accordance with the requirements of regulation 7.3.4, is fitted with VHF radio installation.
[单选题]Every ship ( _) on or after 3 February 3995 shall comply with all the applicable requirements of chapter four
[单选题]International NAVTEX Service means the co-ordinated broadcast and automatic reception on ___ KHz of maritime safety information by narrow – band direct – printing telegraphy.
[单选题]When calling a VHF coast station operating on more than one channel, a ship station calling on a working channel should include the number of ________