*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 20-meter band is known for its reliable propagation characteristics, making it a popular choice for worldwide communication. Here's why the correct answer is "At any point":

1. **Correct Answer: At any point (D)**
   - The 20-meter band (14 MHz) is less affected by the solar cycle compared to higher frequency bands. It can support worldwide propagation during daylight hours throughout the entire solar cycle, whether at solar minimum or maximum. This is due to its ability to reflect off the ionosphere effectively, even when solar activity is low.

2. **Why Other Choices Are Incorrect:**
   - **A: At the summer solstice**
     - The summer solstice does not specifically enhance 20-meter propagation. While seasonal changes can affect propagation, the 20-meter band remains reliable year-round.
   - **B: Only at the maximum point**
     - While solar maximum enhances propagation on higher frequency bands (like 10 meters), the 20-meter band is not limited to these conditions and remains effective even at solar minimum.
   - **C: Only at the minimum point**
     - This is incorrect because the 20-meter band is not restricted to solar minimum conditions. It supports worldwide propagation at any point in the solar cycle.

3. **Useful Rules of Thumb:**
   - The 20-meter band is often open for long-distance communication during daylight hours, regardless of the solar cycle phase.
   - Higher frequency bands (above 20 meters) are more dependent on solar activity, while lower frequency bands (like 20 meters) are more stable.

Understanding these characteristics helps operators choose the right band for reliable communication under varying solar conditions.