Which of the following paths is most likely to support long-distance propagation on 160 meters?
The correct answer is D: A path entirely in darkness. Which of the following paths is most likely to support long-distance propagation on 160 meters is a path entirely in darkness. 160 meters works best when the entire path is in darkness (no sun). For amateur radio operators, this is important for 160-meter operation. Understanding this helps when operating on 160 meters.
Exam Tip
160m long-distance propagation = path entirely in darkness. Think '1'60m = 'D'arkness needed. 160 meters works best when the entire path is in darkness. Not sunlight, not high latitudes, not north-south - just darkness.
Memory Aid
"160m long-distance propagation = path entirely in darkness. Think '1'60m = 'D'arkness. 160 meters works best when the entire path is in darkness. Important for 160-meter operation."
Real-World Application
Long-distance propagation on 160 meters: A path entirely in darkness is most likely to support it. 160 meters is absorbed by the D layer during daylight, so darkness is essential. When the entire path is in darkness, absorption is minimal and signals can propagate long distances. This is the path - entirely in darkness.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Path entirely in sunlight doesn't work well - 160 meters needs darkness. Sunlight path is wrong.
Option B: Incorrect. Paths at high latitudes isn't the key factor - darkness is the key factor. High latitudes isn't the answer.
Option C: Incorrect. Direct north-south path isn't the key factor - darkness is the key factor. North-south path isn't the answer.
题目解析
The correct answer is D: A path entirely in darkness. Which of the following paths is most likely to support long-distance propagation on 160 meters is a path entirely in darkness. 160 meters works best when the entire path is in darkness (no sun). For amateur radio operators, this is important for 160-meter operation. Understanding this helps when operating on 160 meters.
考试技巧
160m long-distance propagation = path entirely in darkness. Think '1'60m = 'D'arkness needed. 160 meters works best when the entire path is in darkness. Not sunlight, not high latitudes, not north-south - just darkness.
记忆口诀
160m long-distance propagation = path entirely in darkness. Think '1'60m = 'D'arkness. 160 meters works best when the entire path is in darkness. Important for 160-meter operation.
实际应用示例
Long-distance propagation on 160 meters: A path entirely in darkness is most likely to support it. 160 meters is absorbed by the D layer during daylight, so darkness is essential. When the entire path is in darkness, absorption is minimal and signals can propagate long distances. This is the path - entirely in darkness.
错误选项分析
Option A: Incorrect. Path entirely in sunlight doesn't work well - 160 meters needs darkness. Sunlight path is wrong. Option B: Incorrect. Paths at high latitudes isn't the key factor - darkness is the key factor. High latitudes isn't the answer. Option C: Incorrect. Direct north-south path isn't the key factor - darkness is the key factor. North-south path isn't the answer.
知识点
Long-distance propagation, 160 meters, Path entirely in darkness, 160-meter propagation
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.