A ground receiver station is receiving a signal at 100MHz transmitted from a ground transmitter at a height of 300m located at a distance of 1000km. It is coming via

Options

A. Ground wave
B. Space wave
C. Sky wave
D. Satellite communication

Answer

To determine the suitable propagation mode for the given communication scenario, we can follow these steps:

### Step 1: Identify the Frequency of the Signal
The frequency of the signal being transmitted is given as 100 MHz.

### Step 2: Determine the Propagation Modes
Based on the frequency, we can categorize the propagation modes:
- **Ground Wave**: Suitable for frequencies less than 2 MHz.
- **Sky Wave**: Suitable for frequencies between 2 MHz and 20 MHz.
- **Space Wave**: Suitable for frequencies greater than 30 MHz.
- **Satellite Communication**: Also suitable for frequencies greater than 30 MHz.

Since the frequency of the signal is 100 MHz, it falls into the category of Space Wave and Satellite Communication.

### Step 3: Calculate the Maximum Range for Space Wave Communication
The maximum range for space wave communication can be calculated using the formula:
\[ R = \sqrt{2 \cdot h \cdot R_e} \]
Where:
- \( R \) = maximum range
- \( h \) = height of the transmitting antenna (300 m)
- \( R_e \) = radius of the Earth (approximately \( 6.4 \times 10^6 \) m)

Substituting the values:
\[ R = \sqrt{2 \cdot 300 \, \text{m} \cdot 6.4 \times 10^6 \, \text{m}} \]

### Step 4: Perform the Calculation
1. Calculate \( 2 \cdot 300 \):
\[ 2 \cdot 300 = 600 \]

2. Now multiply by the radius of the Earth:
\[ 600 \cdot 6.4 \times 10^6 = 3.84 \times 10^9 \]

3. Take the square root:
\[ R = \sqrt{3.84 \times 10^9} \approx 62000 \, \text{m} \]

4. Convert to kilometers:
\[ R \approx 62 \, \text{km} \]

### Step 5: Compare the Calculated Range with the Given Distance
The distance between the transmitting and receiving stations is given as 1000 km. Since the maximum range for space wave communication (62 km) is much less than the distance (1000 km), space wave communication is not suitable.

### Step 6: Conclusion
Since the distance exceeds the maximum range for space wave communication, the suitable propagation mode for this communication is **Satellite Communication**.

### Final Answer
The correct answer is **Satellite Communication**.

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