What is the primary property that allows sky waves to enhance communication range?

The primary property that enhances communication range through sky waves is the ability of long wavelengths to reflect off the ionosphere and bounce back to the Earth's surface. This phenomenon allows signals to travel beyond the horizon, covering greater distances than ground waves alone would permit. The ionosphere can refract or reflect these waves, which enables them to hit various points on the Earth's surface and reach areas that would otherwise be out of range for direct transmission.

In contrast, shorter wavelengths tend to pass through the atmosphere and do not effectively reflect off the ionosphere, which limits their ability to enhance communication over long distances. Additionally, direct transmission without reflection does not tap into the benefits provided by the ionosphere, and limited distance communication does not leverage the advantages of sky wave propagation. This understanding emphasizes the importance of wavelength characteristics in facilitating long-range communication.