FCC Exam Question: 3-69K5
The amplitude modulated variable phase signal and the frequency modulated reference phase signal of a Very-high-frequency Omnidirectional Range (VOR) station used for aircraft navigation are synchronized so that both signals are in phase with each other at ____________ of the VOR station.
Explanation: A Very-high-frequency Omnidirectional Range (VOR) station determines an aircraft's bearing by comparing the phase of two 30 Hz signals: a reference phase signal (omnidirectional, FM subcarrier) and a variable phase signal (rotating, AM). These two signals are intentionally synchronized to be in phase with each other precisely along the **0-degree (or 360-degree) radial** emanating from the VOR station. Crucially, VOR navigation systems operate using **magnetic bearings**, not true bearings. Therefore, the synchronization point is at 0 degrees North (or 360 degrees North) relative to magnetic north. * **Option B** correctly identifies "360 degrees North" and specifies "magnetic bearing position," aligning with how VOR radials are defined and synchronized. * **Option A, C, and D** are incorrect because they either refer to 180 degrees South (the opposite radial), use "true bearing" instead of "magnetic bearing," or both. VORs are fundamentally oriented to magnetic north.
3-95P5
3-47F6
3-46F3
3-34E5
3-83M6
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Includes Elements 1, 3, 6, 7R, 8, and 9.