Long range propagation is not possible by space wave propagation because

Options

A. height of troposhere is quite small
B. height of troposhere is large
C. troposphere absorbs transmitted wave
D. None of these

Answer

To solve the question "Long range propagation is not possible by space wave propagation because", we will analyze the options provided and understand the concept of space wave propagation.

### Step-by-Step Solution:

1. **Understanding Space Wave Propagation**:
- Space wave propagation refers to the transmission of radio waves in the frequency range of 30 MHz to 3000 MHz. It includes both direct waves and ground-reflected waves.

2. **Analyzing the Options**:
- **Option A**: Height of troposphere is quite small.
- **Option B**: Height of troposphere is large.
- **Option C**: Troposphere absorbs transmitted wave.
- **Option D**: None of these.

3. **Evaluating Option A**:
- The troposphere is the lowest layer of Earth's atmosphere, which extends from the Earth's surface up to about 8-15 kilometers. This height is relatively small compared to the distances required for long-range communication.

4. **Evaluating Option B**:
- This option is incorrect because the height of the troposphere is not large; it is actually small compared to the distances needed for effective long-range communication.

5. **Evaluating Option C**:
- While the troposphere can absorb some radio waves, this is not the primary reason for the limitations of space wave propagation for long-range communication.

6. **Conclusion**:
- The main reason long-range propagation is not possible by space wave propagation is due to the small height of the troposphere. This limits the ability of waves to reflect back to the ground for long distances. Therefore, the correct answer is **Option A**: "Height of troposphere is quite small."

### Final Answer:
Long range propagation is not possible by space wave propagation because the height of the troposphere is quite small.

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