Tổng quan hệ thống GMDSS phục vụ TKCN. Năm 1979,Tổ chức Hàng Hải quốc tế (International Maritime Organization IMO) đã tổ chức hội nghị về vấn đề tìm kiếm và cứu nạn trên biển. ... Hệ thống mới được tự động hóa và sử dụng sóng vô tuyến trái đất và vệ tinh cho báo động cấp cứu và các thông tin theo sa
Trang 1Cau hoi One of the guidelines when choosing an High Frequency (HF) band for a specific
range, is
A the greater the distance, the lower the required band
B use a lower band by day
C to have the antenna as high as possible
D use a higher band by day
Cau hoi Line-of-sight propagation would mainly involve
C Navtex communications
D SART, EPIRB, Inmarsat communications
Cau hoi Ground wave propagation is an important feature of communications on
Cau hoi The main path of propagation for an 8 MHz radio frequency is
B direct wave (line of sight)
Cau hoi The propagation path used by HF signals, from the SSB radio, to achieve long-range
communications, is
A direct wave (line of sight)
Cau hoi The main propagation path for an MF radio frequency is
D direct wave (line of sight)
Cau hoi The propagation path for signals from a VHF radio, under normal atmospheric
conditions, would be
D direct wave (line of sight)
Cau hoi Communications through the Inmarsat system are by
Trang 2A combination of ground wave and sky wave
Cau hoi The communications most affected by antenna height are
Cau hoi Sky wave propagation is an important feature of H24 communication on
Cau hoi When choosing an HF band for a specific communication, one of the guidelines is
A that ducting can increase the range
B to use a higher frequency band by day
C that the range of 2 MHz transmission is greater by day
D the greater the distance required, use a lower frequency band
Cau hoi The propagation path taken by a radio signal on VHF Ch.16 is
D direct wave (line of sight)
Cau hoi The propagation path used by Inmarsat equipment is
D direct wave (line of sight)
Cau hoi The propagation path for MF NAVTEX signals during daylight is
D direct wave (line of sight)
Cau hoi The propagation path used by satellite EPIRB equipment is
A direct wave (line of sight)
Trang 3Dap an A