*Question E3B09:
At what time of year is sporadic-E propagation most likely to occur?*  

*Correct Answer is  A: Around the solstices, especially the summer solstice*  

### AI Response: (may contain errors)  

Sporadic-E propagation is a phenomenon where radio waves are reflected off dense patches of ionization in the E layer of the ionosphere. This type of propagation is unpredictable but tends to occur more frequently during certain times of the year.

1. **Correct Answer: Around the solstices, especially the summer solstice (Choice A)**  
   - Sporadic-E propagation is most common around the summer solstice. This is due to increased ionization in the E layer of the ionosphere during this time, which is influenced by factors such as solar activity and atmospheric conditions. The summer solstice, occurring around June 21st in the Northern Hemisphere, provides the optimal conditions for sporadic-E events.

2. **Why the Other Choices are Incorrect:**
   - **Choice B: Around the solstices, especially the winter solstice**  
     - While sporadic-E can occur around the winter solstice, it is less frequent compared to the summer solstice. The ionospheric conditions are not as favorable during the winter months.
   - **Choice C: Around the equinoxes, especially the spring equinox**  
     - The equinoxes do not typically coincide with peak sporadic-E activity. The ionospheric conditions during the equinoxes are more stable and less conducive to sporadic-E.
   - **Choice D: Around the equinoxes, especially the fall equinox**  
     - Similar to the spring equinox, the fall equinox does not align with the peak times for sporadic-E propagation. The atmospheric and solar conditions are not as favorable as during the summer solstice.

In summary, sporadic-E propagation is most likely to occur around the summer solstice due to the optimal ionospheric conditions present at that time. This makes Choice A the correct answer.