The frequency band used in the downlink of s atellite communication is

Options

A. 9.5 to 2.5 GHz
B. 8 96 to 0901 MHz
C. 3.7 to 4.2 GHz
D. 840 to 935 MHz

Explanation

### Step-by-Step Solution:

1. **Understanding Satellite Communication**:
Satellite communication involves the transmission of signals to and from satellites orbiting the Earth. It requires specific frequency bands for effective communication.

2. **Frequency Ranges for Different Signals**:
- Audio signals typically range from 20 Hz to 20 kHz.
- Video signals range from approximately 4.2 MHz to 6 MHz.
- Satellite communication, however, operates on much higher frequencies.

3. **High Frequency Requirement**:
Satellite communication utilizes ultra high frequencies (UHF) because these frequencies can travel long distances without significant loss of signal quality.

4. **Frequency Band for Satellite Communication**:
The frequency band used for satellite communication is generally in the gigahertz (GHz) range. This is necessary for effective transmission over the vast distances involved.

5. **Specific Downlink Frequency Band**:
For the downlink of satellite communication, the frequency band is specifically identified as ranging from 3.7 GHz to 4.2 GHz. This range is crucial for various types of satellite communication systems, including different signal types like X, KU, and DTH broadcasting.

6. **Conclusion**:
Therefore, the frequency band used in the downlink of satellite communication is **3.7 to 4.2 GHz**.

### Final Answer:
The frequency band used in the downlink of satellite communication is **3.7 to 4.2 GHz**.

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