*Question G3A07:
At what point in the solar cycle does the 20-meter band usually support worldwide propagation during daylight hours?*  

*Correct Answer is  D: At any point*  

### AI Response: (may contain errors)  

The correct answer to the question is **D: At any point**. Here's the explanation:

1. **Why the correct answer is correct:**
   - The 20-meter band (14 MHz to 14.350 MHz) can support worldwide propagation during daylight hours at any point in the solar cycle. While the maximum solar activity enhances propagation conditions, the band can still provide good communication opportunities even during the solar minimum. This is due to the ionospheric conditions that can vary based on factors like time of day, season, and solar activity, but the band is generally usable throughout the solar cycle.

2. **Why the other choices are incorrect:**
   - **A: At the summer solstice**: While propagation may be good during the summer solstice due to longer daylight hours, it is not limited to this time. The band can support worldwide propagation at other times as well.
   - **B: Only at the maximum point**: This is incorrect because, although maximum solar activity improves propagation, the 20-meter band can still be effective during periods of lower solar activity.
   - **C: Only at the minimum point**: This is also incorrect. While the band may have reduced propagation during solar minimum, it is still capable of supporting worldwide communication, just not as reliably as during solar maximum.

3. **Useful rules of thumb:**
   - The 20-meter band is generally open for worldwide communication during daylight hours, especially when the sun is above the horizon.
   - Propagation can be influenced by factors such as sunspots, solar flares, and the time of year, but the band remains usable throughout the solar cycle.

In summary, the 20-meter band is versatile and can support worldwide propagation at any point in the solar cycle, making option D the correct choice.