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E3C12
Which of the following is indicated by a sudden rise in radio background noise across a large portion of the HF spectrum?
Pick an answer to check it.
Answer: B. A coronal mass ejection impact or a solar flare has occurred
A sudden jump in background noise across much of HF suggests a coronal mass ejection impact or solar flare has disturbed the ionosphere. Temperature inversions affect VHF, not HF noise.
Tip: Sudden HF noise = solar event.