A ground receiver in line-of-sight communication cannot receive direct waves due to

Options

A. its low frequency
B. curvature of earth
C. its high intensity
D. smaller antenna

Explanation

To solve the question regarding why a ground receiver in line-of-sight communication cannot receive direct waves, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Line-of-Sight Communication**:
- Line-of-sight communication involves transmitting signals directly from a transmitter to a receiver without any obstacles in between. The signals travel in straight lines.

2. **Identify the Components**:
- In this scenario, we have a transmitter antenna and a receiver antenna. The transmitter sends out signals that are supposed to be received by the receiver.

3. **Consider the Earth's Curvature**:
- The Earth is not flat; it is curved. This curvature can obstruct the direct path of the signal waves from the transmitter to the receiver.

4. **Analyze the Height of the Antennas**:
- If the transmitter antenna is at a certain height (h), the direct signal path will be affected by how high the receiver antenna is positioned relative to the curvature of the Earth.

5. **Determine the Point of Obstruction**:
- As the signal travels, there will be a point where the curvature of the Earth causes the signal to dip below the line of sight to the ground receiver. This means that if the receiver is too close to the ground, it may not be able to receive the signal because the signal will not reach it.

6. **Conclude the Reason**:
- Therefore, the reason a ground receiver in line-of-sight communication cannot receive direct waves is due to the curvature of the Earth.

### Final Answer:
The ground receiver cannot receive direct waves due to the curvature of the Earth.

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