Answer:
Step-by-step explanation:
To compute the attenuation due to diffraction at 900 MHz using the Deygout method, we need to calculate the diffraction loss for each screen and then sum them up.
The Deygout method provides the following formula to calculate the diffraction loss:
Ld = 17.3 + 40log10(d) + 20log10(h) - 9log10(D)
Where:
Ld is the diffraction loss in decibels (dB)
d is the distance between the TX (transmitter) and the screen in meters
h is the height of the screen in meters
D is the distance between the TX and the RX (receiver) in meters
Let's calculate the diffraction loss for each screen:
For the first screen (30 m from TX, 30 m high):
Ld1 = 17.3 + 40log10(30) + 20log10(30) - 9log10(100)
≈ 17.3 + 40(1.477) + 20(1.477) - 9(2)
≈ 17.3 + 59.08 + 29.54 - 18
≈ 87.92 dB
For the second screen (50 m from TX, 40 m high):
Ld2 = 17.3 + 40log10(50) + 20log10(40) - 9log10(100)
≈ 17.3 + 40(1.699) + 20(1.602) - 9(2)
≈ 17.3 + 67.96 + 32.04 - 18
≈ 99.3 dB
For the third screen (80 m from TX, 25 m high):
Ld3 = 17.3 + 40log10(80) + 20log10(25) - 9log10(100)
≈ 17.3 + 40(1.903) + 20(1.397) - 9(2)
≈ 17.3 + 76.12 + 27.94 - 18
≈ 103.36 dB
Finally, we sum up the diffraction losses:
Total diffraction loss = Ld1 + Ld2 + Ld3
= 87.92 + 99.3 + 103.36
≈ 290.58 dB