What is the effect of chordal-hop propagation?

In typical multi-hop propagation, a radio signal bounces repeatedly between the ionosphere and the Earth's surface. Every time the signal strikes the Earth to bounce back up, a significant amount of RF energy is absorbed by the ground or water, weakening the signal. Chordal-hop propagation happens when a signal travels along the ionosphere, refracting between different density layers of the ionosphere itself without touching the Earth in between hops. The path essentially forms a 'chord' drawn across the curve of the Earth and the ionosphere. Because the signal completely avoids multiple lossy reflections from the Earth's surface, it reaches its final destination with much less attenuation. This results in surprisingly strong signals over very long distances.