A clear line of sight can still have a clearance problemThe midpoint first Fresnel radius is √(λD/4). Its use in installation planning still requires a terrain profile, clearance criterion and actual site survey.A clear line of sight can still have a clearance problemFirst Fresnel zone geometry; terrain, foliage and fading are not simulated.Midpoint radiusr = √(λD / 4)A visible optical path does not describe the whole radio clearance volume.³Ô¹Ïtv engineering illustration · conceptual, not to scale · no measured product data