The path loss is the sum of the attenuation of the path if there were no obstacles in the way (Free Space Path Loss), the attenuation caused by obstacles (Excess Path Loss) and a margin to allow for possible fading of the radio signal (Fade Margin). The following calculation needs to be performed to judge whether a particular link can be installed:
Lfree_space + Lexcess + Lfade + Lseasonal < Lcapability
Where:
Lfree_space is Free Space Path Loss (dB)
Lexcess is Excess Path Loss (dB)
Lfade is Fade Margin Required (dB)
Lseasonal is Seasonal Fading (dB)
Lcapability is Equipment Capability