*Question E3B08:
How does the maximum range of ground-wave propagation change when the signal frequency is increased?*  

*Correct Answer is  C: It decreases*  

### AI Response: (may contain errors)  

The correct answer to the question about how the maximum range of ground-wave propagation changes when the signal frequency is increased is:

**C: It decreases.**

### Explanation:

1. **Why the correct answer is correct:**
   - Ground-wave propagation is primarily affected by the frequency of the signal. As the frequency increases, the wavelength decreases, which leads to higher attenuation of the signal as it travels along the ground. This means that higher frequencies do not propagate as far as lower frequencies when using ground-wave propagation. 

2. **Why the other choices are incorrect:**
   - **A: It stays the same** - This is incorrect because the range of ground-wave propagation is not constant; it varies with frequency.
   - **B: It increases** - This is incorrect because higher frequencies experience more loss and therefore have a shorter range.
   - **D: It peaks at roughly 8 MHz** - While there is a point where ground-wave propagation is more effective, it does not mean that the range increases indefinitely up to that frequency. Instead, ground-wave propagation generally decreases as frequency increases beyond certain points.

### Useful Concepts:
- Ground-wave propagation is effective at lower frequencies (typically below 2 MHz) and diminishes as frequency increases.
- A rule of thumb is that ground-wave propagation is most effective for frequencies below 2 MHz, where the signal can follow the curvature of the Earth more effectively.

In summary, as frequency increases, the maximum range of ground-wave propagation decreases due to increased signal attenuation.