Radio Amateur Quiz Canadian License

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Question B-007-002-009

What is the main reason the 160, 80 and 40 metre amateur bands tend to be useful only for short-distance communications during daylight hours?

Correct Answer

Because of D-region absorption

Explanation

During the day, the D layer becomes heavily ionized and strongly absorbs signals on the lower HF bands (160m, 80m, 40m), preventing them from reaching the higher E or F layers for reflection.

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