What losses are included in the “XPL” (excess path)

All path loss that is not Free Space loss (diffraction, fresnel zone, reflections, clutter):

  • Percentage of Location variability margin (propagation parameters dialog)
  • Percentage of Time variability margin (propagation parameters dialog)
  • Margin (in dB) (propagation parameters dialog)
  • Atmospheric Absorption (>20GHz) (propagation parameters dialog)
  • Reflection Loss

Reflection loss can cause a large amount of variability between study locations. This is because a small change in receiver location can cause the phase relationship between the ground reflection ray and direct ray to go through a 180 degree shift (signals adding versus signals subtracting). Turning off “use ground reflections” in the Propagation Model parameters will produce a less variable XPL for small changes in TX – RX positions.