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Subelement K: K – Aircraft— Topic 73: Equipment Functions

Question 3-73K5

Element 3 (GROL)

What type of antenna is used in an aircraft’s Very High Frequency Omnidirectional Range (VOR) and Localizer (LOC) installations?

Explanation
Aircraft VOR (Very High Frequency Omnidirectional Range) and Localizer systems receive signals from ground stations. VOR ground stations specifically transmit **horizontally polarized** signals. For the aircraft's receiver to pick up these signals effectively and accurately process navigation data, its antenna must also be horizontally polarized. This ensures maximum signal transfer and minimizes signal loss due to polarization mismatch. Additionally, as an aircraft may be approaching or flying around a VOR station from any direction, the antenna requires an **omnidirectional reception pattern**. This allows the antenna to consistently receive signals regardless of the aircraft's heading relative to the ground station, providing continuous and reliable navigation information. Other options are incorrect as vertical polarization would lead to substantial signal loss, and VOR/LOC systems are designed for reception, not transmission.

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