单项选择题
A.the weather is always terrible
B.the condition there is complicated
C.the signals are too strong
D.their SES may receive the signals from unwanted satellite
单项选择题 If EGC receiver shares a same antenna with Inmarsat SES, it means that it can receive MSI（）.
单项选择题 The receiving stations can use the B2 character to（）different, classes of messages.
单项选择题 Navtex transmitter identification character（）is used to identify the broadcasts which are to be accepted by the receiver and those are to be rejected.