Radio Path Profile: Mountain Relay Fresnel Clearance

Real radio-link engineers plan mountain relays with exactly this view: a 2D vertical cross-section of the terrain — a "path profile" — rather than a full 3D scene, because what determines link quality is the shape of the ground directly under the straight line between two antennas, not the surrounding landscape. This simulation renders that profile for a mountain-rescue drone relay chain and replaces a simple line-of-sight yes/no test with the physics real links actually obey: the Fresnel-Kirchhoff knife-edge diffraction approximation, which lets radio waves bend partway around a ridge instead of cutting off the instant it touches the direct line. Watch the shaded Fresnel-zone ellipse around each hop pinch against the terrain as you add relays, change the radio frequency, raise transmit power or make the mountains more rugged, and compare a terrain-following relay placement against a naive straight-line chain that dips into valleys and clips far more ridgelines.