单选题 ______________is a satellite system promulgating Maritime Safety Information

单选题 A Navtex station in each NAVAREA is usually allowed to have_________for transmission.

单选题 If a ship is fitted with a VHF radio installation， while at sea， shall______________,

单选题 Operator at sea received a distress alert on the frequency of 156.525Mhz， he should keep listening watch on ____________,

单选题 The followings are all characteristics of portable VHF radiotelephone sets， except____

单选题 In addition to the identification and position of the ship in distress， the distress alert may also contain informationRegarding the____________， the type of assistance， the course and speed of the ship and the time at which the informationWas recorded

单选题 Via shipboard satellite-based systems，__________is available

单选题 ____________means safety communications between ships from the position from which the ships are normallyNavigated.