Which of the following is indicated by a sudden rise in radio background noise across a large portion of the HF spectrum?
The correct answer is B: A coronal mass ejection impact or a solar flare has occurred. Which of the following is indicated by a sudden rise in radio background noise across a large portion of the HF spectrum is a coronal mass ejection impact or a solar flare has occurred. Sudden noise increases indicate solar events. For amateur radio operators, this is important for understanding propagation disruptions. Understanding this helps when experiencing noise increases.
Exam Tip
Sudden HF noise rise = coronal mass ejection impact or solar flare occurred. Think 'S'udden 'N'oise = 'S'olar 'N'oise. Sudden noise increases across HF spectrum indicate solar events. Not temperature inversion, not TEP, not long-path - just solar events.
Memory Aid
"Sudden HF noise rise = coronal mass ejection impact or solar flare occurred. Think 'S'udden 'N'oise = 'S'olar event. Sudden noise increases across HF spectrum indicate solar events. Important for understanding propagation disruptions."
Real-World Application
A sudden rise in radio background noise across a large portion of the HF spectrum: It indicates that a coronal mass ejection impact or a solar flare has occurred. These solar events create ionization that increases noise levels. This is the indication - solar events cause sudden noise increases.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Temperature inversion doesn't cause sudden HF noise rise - solar events do. Temperature inversion isn't the cause.
Option C: Incorrect. Transequatorial propagation on 6 meters isn't indicated - solar events are indicated. TEP on 6m isn't the indication.
Option D: Incorrect. Long-path propagation on higher HF bands isn't indicated - solar events are indicated. Long-path isn't the indication.
题目解析
The correct answer is B: A coronal mass ejection impact or a solar flare has occurred. Which of the following is indicated by a sudden rise in radio background noise across a large portion of the HF spectrum is a coronal mass ejection impact or a solar flare has occurred. Sudden noise increases indicate solar events. For amateur radio operators, this is important for understanding propagation disruptions. Understanding this helps when experiencing noise increases.
考试技巧
Sudden HF noise rise = coronal mass ejection impact or solar flare occurred. Think 'S'udden 'N'oise = 'S'olar 'N'oise. Sudden noise increases across HF spectrum indicate solar events. Not temperature inversion, not TEP, not long-path - just solar events.
记忆口诀
Sudden HF noise rise = coronal mass ejection impact or solar flare occurred. Think 'S'udden 'N'oise = 'S'olar event. Sudden noise increases across HF spectrum indicate solar events. Important for understanding propagation disruptions.
实际应用示例
A sudden rise in radio background noise across a large portion of the HF spectrum: It indicates that a coronal mass ejection impact or a solar flare has occurred. These solar events create ionization that increases noise levels. This is the indication - solar events cause sudden noise increases.
错误选项分析
Option A: Incorrect. Temperature inversion doesn't cause sudden HF noise rise - solar events do. Temperature inversion isn't the cause. Option C: Incorrect. Transequatorial propagation on 6 meters isn't indicated - solar events are indicated. TEP on 6m isn't the indication. Option D: Incorrect. Long-path propagation on higher HF bands isn't indicated - solar events are indicated. Long-path isn't the indication.
知识点
Sudden rise in radio background noise, Large portion of HF spectrum, Coronal mass ejection, Solar flare
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.