Question
Which of the following types of propagation is most commonly associated with occasional strong signals on the 10, 6, and 2 meter bands from beyond the radio horizon?
Answer Options
- A) Backscatter
- B) Sporadic E
- C) D region absorption
- D) Gray-line propagation
Correct Answer: B
Explanation
Sporadic E (or Es) is a temporary, unpredictable type of propagation caused by patches of unusually dense ionization that form in the E layer of the ionosphere. These dense patches can reflect VHF signals, allowing them to travel far beyond the normal line-of-sight horizon.
Sporadic E is most common in the late spring and early summer and often allows for surprisingly strong, long-distance communication (up to 1,500 miles or more) on the 10-meter, 6-meter, and occasionally the 2-meter bands. It is a major source of unexpected VHF DX.
This topic was automatically created to facilitate community discussion about this exam question. Feel free to share study tips, memory tricks, or additional explanations!