*Question E3A09:
Which of the following frequency ranges is most suited for meteor-scatter communications?*  

*Correct Answer is  C: 28 MHz - 148 MHz*  

### AI Response: (may contain errors)  

Meteor-scatter communications rely on the reflection of radio waves off ionized trails left by meteors entering the Earth's atmosphere. The frequency range that is most effective for this type of communication is typically in the VHF (Very High Frequency) range.

### Correct Answer: 28 MHz - 148 MHz
- **Reason**: This frequency range falls within the VHF spectrum, which is ideal for meteor-scatter communications. Frequencies in this range can effectively utilize the ionization caused by meteors, allowing for reliable communication over distances that can exceed 1,000 kilometers under the right conditions.

### Why the Other Choices are Incorrect:
- **A: 1.8 MHz - 1.9 MHz**  
  - This range is in the HF (High Frequency) band. While HF can support some forms of propagation, it is not effective for meteor scatter due to the lower frequency and longer wavelengths, which do not interact well with the short-lived ionized trails.

- **B: 10 MHz - 14 MHz**  
  - Similar to choice A, this range is also in the HF band. While it can support various propagation modes, it is not optimal for meteor scatter, as the ionization effects are less pronounced at these frequencies.

- **D: 220 MHz - 450 MHz**  
  - This range is in the UHF (Ultra High Frequency) band. While UHF can be used for some forms of scatter communication, it is generally less effective for meteor scatter compared to the VHF range. The higher frequencies may not reflect as well off the meteor trails.

### Summary
- **Best Range for Meteor-Scatter**: 28 MHz - 148 MHz (VHF)
- **Ineffective Ranges**: 1.8 MHz - 1.9 MHz (HF), 10 MHz - 14 MHz (HF), 220 MHz - 450 MHz (UHF)

Understanding the propagation characteristics of different frequency bands is crucial for effective communication methods, especially in specialized techniques like meteor scatter.