Frequencies in the `UHF` range normally propagate by means of:

Options

A. ground waves
B. sky wave
C. surface waves
D. space waves

Explanation

To solve the question regarding how frequencies in the UHF (Ultra High Frequency) range propagate, we will analyze the different types of wave propagation and determine which is applicable to UHF.

### Step-by-Step Solution:

1. **Understanding UHF**:
- UHF stands for Ultra High Frequency, which typically ranges from 300 MHz to 3 GHz.

2. **Types of Wave Propagation**:
- There are three main types of wave propagation:
- Ground wave propagation
- Sky wave propagation
- Space wave propagation

3. **Analyzing Ground Wave Propagation**:
- Ground wave propagation occurs when radio waves travel along the surface of the Earth.
- This method is effective for lower frequencies but is not suitable for UHF frequencies due to their higher frequency and shorter wavelength.
- **Conclusion**: UHF cannot propagate via ground wave propagation.

4. **Analyzing Sky Wave Propagation**:
- Sky wave propagation involves radio waves being reflected off the ionosphere back to the Earth.
- This method is effective for medium and high frequencies but is not suitable for UHF frequencies, as UHF waves do not reflect well off the ionosphere.
- **Conclusion**: UHF cannot propagate via sky wave propagation.

5. **Analyzing Space Wave Propagation**:
- Space wave propagation, also known as line-of-sight propagation, occurs when radio waves travel directly from the transmitter to the receiver without reflecting off the ground or the ionosphere.
- This method is suitable for UHF frequencies, as the shorter wavelengths can travel directly over the horizon.
- **Conclusion**: UHF frequencies propagate via space wave propagation.

6. **Final Answer**:
- Frequencies in the UHF range normally propagate by means of **space wave propagation**.