Which of the following frequencies will be suitable for beyond the horizon communication using sky waves?

Options

A. 10KHz
B. 10MHz
C. 1GHz
D. 1000GHz

Explanation

To determine which frequencies are suitable for beyond the horizon communication using sky waves, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Wave Propagation**:
- **Ground Wave Propagation**: This type of wave propagation is effective for lower frequencies, typically ranging from 530 kHz to 1710 kHz. Ground waves travel along the surface of the Earth and are limited to line-of-sight communication.
- **Sky Wave Propagation**: This type of propagation is used for higher frequencies that can reflect off the ionosphere. The frequency range for sky wave propagation is generally from 3 MHz to 30 MHz.
- **Space Wave Propagation**: Frequencies above 30 MHz, such as 1 GHz and 1000 GHz, are considered space wave propagation, which is used for satellite and microwave communications.

2. **Identify the Frequency Ranges**:
- For the purpose of beyond the horizon communication using sky waves, we need to focus on the frequency range of 3 MHz to 30 MHz.

3. **Analyze the Given Options**:
- If the question provides specific frequency options, we need to check which of these fall within the 3 MHz to 30 MHz range.
- Frequencies below 3 MHz will not be suitable for sky wave propagation, and frequencies above 30 MHz will fall into the space wave category.

4. **Select the Suitable Frequency**:
- After analyzing the options, the frequency that lies within the range of 3 MHz to 30 MHz will be the suitable choice for beyond the horizon communication using sky waves.

5. **Conclusion**:
- Based on the analysis, the correct answer will be the frequency option that falls within the specified range for sky wave propagation.