English: Radio signals are split into two components (the ordinary component in red and the extraordinary component in green) when they penetrate into the ionosphere. This example shows two signals transmitted at different elevation angles from the transmitter at the left. The receiver is denoted by the triangle at the base of the grid on the right approximately 16,000 km away. Ionospheric reflection, tilted refraction and ordinary ray ducting between layers is visible in this image. en:http://en.wikipedia.org/wiki/Image:Signal_splitting_and_traced-rays.gif Click here to display a movie showing the three-dimensionality of the example.