rf-models-and-sampling.md

RF Models and Coverage Sampling

Propagation models

• FSPL: free-space path loss only. Fast and optimistic. No terrain blocking.
• TwoRay: direct plus ground reflection. Useful on flatter/open terrain. No terrain profile blocking.
• ITM (default): terrain-aware approximation in LinkSim. Uses loaded terrain elevation for diffraction/excess-loss estimation.

Coverage map sampling modes

• BestSite: each sample point takes strongest predicted site signal.
• Polar: radial sampling around selected From site.
• Cartesian: regular grid across analysis bounds.
• Route: samples along a path corridor.

Pass/Fail interpretation

• Pass/Fail compares predicted calibrated RX dBm to RX target dBm.
• PASS means RX >= target.
• LOS obstruction checks (blocked/clear) use the same terrain LOS evaluator across map overlays, path profile hover states, and selected-link analysis.
• Curvature in LOS checks uses effective Earth radius (k-factor) derived from atmospheric bending N-units in propagation environment settings.
• Map colors in Pass/Fail mode:
  • green: clear path and meets target
  • yellow: blocked path but still meets target
  • orange: clear path but below target
  • red: blocked path and below target
• Terrain influences this result when ITM is selected and terrain tiles are loaded.