What effect does increased air density have on radar beams according to refraction concepts?

• A. It shifts the beam downward toward the surface.
• B. It eliminates refraction effects.
• C. It bends the beam so it can see over the horizon.
• D. It blocks RF energy completely.

Answer: (C)

Radar beams bend as they travel through the atmosphere because the air’s refractive index changes with density, temperature, and humidity. Higher density near the surface raises the refractive index there, so as the beam moves upward it encounters a gradient that makes it curve toward the Earth rather than go straight. This downward curvature lets the beam follow the curvature of the ground and reach farther than the geometric line of sight, effectively letting you see over the horizon. So increased air density causes the beam to bend downward enough to extend the horizon, which is why this option is the best description. It does not stop refraction or block RF energy.