What is a characteristic of skywave signals arriving at your location by both short-path and long-path propagation?
The correct answer is D: A slightly delayed echo might be heard. A characteristic of skywave signals arriving at your location by both short-path and long-path propagation is that a slightly delayed echo might be heard. The long-path signal takes longer to arrive (traveling the longer route), creating an echo effect. For amateur radio operators, this is a distinctive characteristic of long-path propagation. Understanding this helps identify long-path signals.
Exam Tip
Short-path + long-path = slightly delayed echo might be heard. Think 'L'ong-'P'ath = 'L'onger 'P'ath = 'L'ate 'P'ulse (echo). Long-path signal takes longer to arrive, creating echo effect. Not periodic fading, not 3 dB increase, not cancellation - just echo.
Memory Aid
"Short-path + long-path = slightly delayed echo might be heard. Think 'L'ong-'P'ath = 'L'ate 'P'ulse. Long-path signal takes longer to arrive, creating echo effect. Characteristic of signals arriving by both paths."
Real-World Application
You receive a signal from Japan via both short-path (direct) and long-path (around the other side of Earth). The long-path signal arrives slightly later, creating an echo effect - you hear the signal twice, with a slight delay. This is characteristic of signals arriving by both paths simultaneously.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Periodic fading every 10 seconds isn't characteristic of short/long-path - that's more typical of other propagation effects. Echo is the key characteristic.
Option B: Incorrect. Signal strength isn't increased by 3 dB - the signals may combine, but 3 dB is too specific and not guaranteed.
Option C: Incorrect. Signal cancellation causing severe attenuation isn't typical - signals usually combine or create echo, not cancel completely.
题目解析
The correct answer is D: A slightly delayed echo might be heard. A characteristic of skywave signals arriving at your location by both short-path and long-path propagation is that a slightly delayed echo might be heard. The long-path signal takes longer to arrive (traveling the longer route), creating an echo effect. For amateur radio operators, this is a distinctive characteristic of long-path propagation. Understanding this helps identify long-path signals.
考试技巧
Short-path + long-path = slightly delayed echo might be heard. Think 'L'ong-'P'ath = 'L'onger 'P'ath = 'L'ate 'P'ulse (echo). Long-path signal takes longer to arrive, creating echo effect. Not periodic fading, not 3 dB increase, not cancellation - just echo.
记忆口诀
Short-path + long-path = slightly delayed echo might be heard. Think 'L'ong-'P'ath = 'L'ate 'P'ulse. Long-path signal takes longer to arrive, creating echo effect. Characteristic of signals arriving by both paths.
实际应用示例
You receive a signal from Japan via both short-path (direct) and long-path (around the other side of Earth). The long-path signal arrives slightly later, creating an echo effect - you hear the signal twice, with a slight delay. This is characteristic of signals arriving by both paths simultaneously.
错误选项分析
Option A: Incorrect. Periodic fading every 10 seconds isn't characteristic of short/long-path - that's more typical of other propagation effects. Echo is the key characteristic. Option B: Incorrect. Signal strength isn't increased by 3 dB - the signals may combine, but 3 dB is too specific and not guaranteed. Option C: Incorrect. Signal cancellation causing severe attenuation isn't typical - signals usually combine or create echo, not cancel completely.
知识点
Short-path, Long-path, Echo effect, Skywave propagation
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.