Topic: Satellite Communication
A satellite transmits signals at a frequency of 6 GHz to a user 40000 km away. The free space path loss incurred by the signal is nearly:
- A. 100 dB
- B. 150 dB
- C. 200 dB
- D. 300 dB
Answer: C. 200 dB
Explanation: Free Space Path Loss (FSPL) in dB is calculated as $FSPL = 20 \log_{10}(d) + 20 \log_{10}(f) + 32.44$ where $d$ is in km and $f$ is in MHz. Substituting $d = 40000$ km and $f = 6000$ MHz, $FSPL = 20\log_{10}(40000) + 20\log_{10}(6000) + 32.44 = 92.04 + 75.56 + 32.44 \approx 200$ dB.