Which of the following methods is used to locate sources of noise interference or jamming?
The correct answer is C: Radio direction finding. Radio direction finding (RDF) is used to locate sources of noise interference or jamming. RDF uses directional antennas and signal strength measurements from multiple locations to triangulate the source of interfering signals. For amateur radio operators, RDF (also called foxhunting) is used to find sources of RF interference, locate illegal jammers, and participate in direction-finding activities. Understanding RDF helps when dealing with interference problems and participating in foxhunting events.
Exam Tip
Locate interference = Radio direction finding. Think 'R'DF = 'R'adiate 'D'irection 'F'inding. Uses directional antennas and triangulation to locate signal sources. Echolocation is biological, Doppler radar measures velocity, phase locking synchronizes oscillators - none locate interference.
Memory Aid
"Locate interference = Radio direction finding. Think 'R'DF = 'R'adiate 'D'irection 'F'inding. Uses directional antennas and triangulation to find signal sources. Standard technique for interference location."
Real-World Application
A neighbor reports interference on 2 meters. You use a directional antenna and portable receiver to take bearings from several locations. By triangulating these bearings, you locate the source - a faulty LED light dimmer in a nearby house. Radio direction finding is the standard technique for locating interference sources.
Key Concepts
Why Other Options Are Wrong
Option A (Echolocation): Incorrect. Echolocation is used by animals (like bats) to navigate using sound echoes, not for radio direction finding. It's a biological, not electronic, technique.
Option B (Doppler radar): Incorrect. Doppler radar measures velocity using frequency shift, not direction. It's used for weather and speed measurement, not for locating interference sources.
Option D (Phase locking): Incorrect. Phase locking is a technique for synchronizing oscillators, not for direction finding. It's used in PLL circuits, not for locating signals.
题目解析
The correct answer is C: Radio direction finding. Radio direction finding (RDF) is used to locate sources of noise interference or jamming. RDF uses directional antennas and signal strength measurements from multiple locations to triangulate the source of interfering signals. For amateur radio operators, RDF (also called foxhunting) is used to find sources of RF interference, locate illegal jammers, and participate in direction-finding activities. Understanding RDF helps when dealing with interference problems and participating in foxhunting events.
考试技巧
Locate interference = Radio direction finding. Think 'R'DF = 'R'adiate 'D'irection 'F'inding. Uses directional antennas and triangulation to locate signal sources. Echolocation is biological, Doppler radar measures velocity, phase locking synchronizes oscillators - none locate interference.
记忆口诀
Locate interference = Radio direction finding. Think 'R'DF = 'R'adiate 'D'irection 'F'inding. Uses directional antennas and triangulation to find signal sources. Standard technique for interference location.
实际应用示例
A neighbor reports interference on 2 meters. You use a directional antenna and portable receiver to take bearings from several locations. By triangulating these bearings, you locate the source - a faulty LED light dimmer in a nearby house. Radio direction finding is the standard technique for locating interference sources.
错误选项分析
Option A (Echolocation): Incorrect. Echolocation is used by animals (like bats) to navigate using sound echoes, not for radio direction finding. It's a biological, not electronic, technique. Option B (Doppler radar): Incorrect. Doppler radar measures velocity using frequency shift, not direction. It's used for weather and speed measurement, not for locating interference sources. Option D (Phase locking): Incorrect. Phase locking is a technique for synchronizing oscillators, not for direction finding. It's used in PLL circuits, not for locating signals.
知识点
Radio direction finding, RDF, Interference location, Foxhunting
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.