FCC Exam Question: 29C4
Which of the following is characteristic of an Inmarsat-C antenna?
Explanation: Inmarsat satellites transmit signals that are Right-Hand Circularly (RHC) polarized. This type of polarization is used in satellite communications to mitigate the effects of Faraday rotation in the ionosphere and multipath fading, ensuring more reliable signal reception regardless of the receiving antenna's orientation or movement. Inmarsat-C terminals are designed for applications where precise antenna pointing may be difficult or where the platform is in motion (e.g., on ships or vehicles). Therefore, they typically use an antenna with an omni-directional or very broad-beam radiation pattern. This wide coverage simplifies installation and maintains connectivity without requiring constant re-pointing, making the system practical for mobile and semi-fixed use. Option A is incorrect because a cardioid pattern is not characteristic. Options B and C are incorrect because Inmarsat uses circular polarization, not vertical or horizontal.
28C2
45F5
44F4
20B6
24C4
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Includes Elements 1, 3, 6, 7R, 8, and 9.