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單項選擇題

Loran-C is which type of system（）.

A.Reflected electron
B.Electrical radiation
C.Quarterpoint electrical navigation
D.Hyperbolic radio navigation

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單項選擇題

In using Loran-C，skywave reception gives greater range but is（）.

A.only accurate during daylight hours
B.much less accurate
C.only accurate at twilight
D.more accurate than using ground waves

單項選擇題

If the radio signal ground wave extends out for less distance than the minimum skywave distance，there is an area in which no signal is received．This is called the（）.

A.Skip zone
B.Blackout zone
C.Diffraction zone
D.Shadow zone

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