Refers to scenarios where signal is absorbed by rain, snow, ice
• Absorption becomes significant factor above 11GHz
• Signal quality degrades
• Represented by “dB/km” parameter which is related the rain
density which represented “mm/hr”
• Rain drops falls as flattened droplet
V better than H (more immune to rain fading)
Climatic
Terrain
Atmospheric (refraction)
Multipath/ducting
Multipath transmission is the main cause of fading in LOW frequencies
Multipath occurs when there is more then one beam reaching the receiver with different amplitude or phase
Humidity/Gas
Dispersion
Electromagnetic signal propagating in a physical medium is degraded
because the various wave components (i.e., frequencies, wavelengths)
have different propagation velocities within the physical medium:
• Low frequencies have longer wavelength and refract less
• High frequencies have shorter wavelength and refract more
