*Question E3B07:
What effect does lowering a signal’s transmitted elevation angle have on ionospheric HF skip propagation?*  

*Correct Answer is  C: The distance covered by each hop increases*  

### AI Response: (may contain errors)  

Lowering a signal’s transmitted elevation angle affects ionospheric HF skip propagation in the following way:

### Correct Answer: C: The distance covered by each hop increases

1. **Why the correct answer is correct:**
   - When you lower the elevation angle of a transmitted signal, it enters the ionosphere at a shallower angle. This causes the signal to travel a longer distance before it returns to Earth, effectively increasing the distance covered by each hop. This is because the signal path is more horizontal, allowing it to skip further.

2. **Why the other choices are incorrect:**
   - **A: Faraday rotation becomes stronger**  
     Faraday rotation is the rotation of the plane of polarization of a radio wave as it passes through the ionosphere. It is more influenced by the Earth's magnetic field and the frequency of the signal rather than the elevation angle.
   
   - **B: The MUF decreases**  
     The Maximum Usable Frequency (MUF) is the highest frequency at which a radio wave can be transmitted between two points via ionospheric reflection. The MUF is more dependent on ionospheric conditions and the time of day, not directly on the elevation angle.
   
   - **D: The critical frequency increases**  
     The critical frequency is the highest frequency that can be reflected directly back to Earth by the ionosphere when transmitted vertically. It is determined by the electron density of the ionosphere and is not affected by the elevation angle of the transmitted signal.

### Useful Rule of Thumb:
- **Lower Elevation Angle = Longer Skip Distance**  
  Lowering the elevation angle increases the skip distance because the signal travels a longer path through the ionosphere before returning to Earth. This is a key concept in understanding how to optimize long-distance HF communication.