FCC Exam Question: 30E3

Which of the following statements concerning COSPAS-SARSAT is false?

A. 406 MHz EPIRBs are units that are used as alerting devices.
B. Doppler frequency measurements provide more precise locations than GPIRB signals.
C. The Doppler frequency measurement concept is used to determine the EPIRB's location.
D. Satellites in a low-earth polar orbit detect EPIRB beacons on 406 MHz and relay the information to a Local
Correct Answer: B

Explanation: Statement B is false because GPIRB (GPS-enabled EPIRB) signals provide significantly *more* precise location data than Doppler frequency measurements. A GPIRB integrates a GPS receiver, allowing it to transmit its exact GPS coordinates (typically accurate to within meters) directly to the COSPAS-SARSAT system. In contrast, the Doppler frequency measurement method relies on detecting frequency shifts as a satellite passes over the beacon. While effective for initial localization, this method provides a less precise location (typically within a few kilometers) compared to direct GPS data. Statements A, C, and D are all true: A) 406 MHz EPIRBs are indeed used as alerting devices in distress situations. C) The Doppler frequency measurement concept is a fundamental method used by COSPAS-SARSAT satellites to determine the location of EPIRBs that do not transmit GPS data. D) Low-Earth Orbit (LEO) satellites with polar orbits detect 406 MHz EPIRB beacons and relay this information to ground stations called Local User Terminals (LUTs).

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Includes Elements 1, 3, 6, 7R, 8, and 9.