*Question E3C09:
What type of data is reported by amateur radio propagation reporting networks?*  

*Correct Answer is  D: Digital-mode and CW signals*  

### AI Response: (may contain errors)  

The correct answer to the question about what type of data is reported by amateur radio propagation reporting networks is:

**D: Digital-mode and CW signals**

### Explanation:

1. **Why the correct answer is correct:**
   - Amateur radio propagation reporting networks primarily focus on the conditions affecting radio wave propagation. They collect and report data on the performance of various modes of communication, including digital modes (like FT8, PSK31) and Continuous Wave (CW) signals. This information helps operators understand how well these modes are performing under current propagation conditions.

2. **Why the other choices are incorrect:**
   - **A: Solar flux**  
     While solar flux is an important factor in propagation, it is a measurement of solar radiation and not a direct report from propagation networks. It influences propagation but is not the type of data these networks report.
   
   - **B: Electric field intensity**  
     Electric field intensity is a measure of the strength of the electric field at a given point, which can be relevant in some contexts, but it is not typically the focus of amateur radio propagation reporting networks.
   
   - **C: Magnetic declination**  
     Magnetic declination refers to the angle between magnetic north and true north. This is related to navigation and compass use, not to radio propagation reporting.

### Useful Information:
- Propagation reporting networks often utilize tools like the Reverse Beacon Network (RBN) to gather data on signal reports from various locations, which helps in assessing the effectiveness of different modes under varying conditions.
- Understanding propagation conditions can significantly enhance communication effectiveness, especially during contests or emergency communications. 

By focusing on digital modes and CW signals, these networks provide valuable insights into how well these modes are performing in real-time, which is crucial for amateur radio operators.