1. Ground Wave propagation is a method of radio frequency propagation which uses the area between the surface of the earth and the ionosphere for transmission of signals. The ground wave can propagate a considerable distance over the surface of earth particularly in the low frequency and medium frequency portion of the radio spectrum. Ground wave radio propagation is used to provide relatively local radio communications coverage.

2. The radio waves having high frequencies are basically called as space waves. These waves have the ability to propagate through atmosphere, from transmitter antenna to receiver antenna. These waves can travel directly or can travel after reflecting from earths surface to the troposphere surface of earth. So, it is also called as Tropospherical Propagation.

3. In radio communication, skywave refers to the propagation of those radiowaves that are reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere. Since it is not limited by the curvature of the Earth, skywave propagation can be used to communicate beyond the horizon, at intercontinental distances. It is mostly used in the short wave frequency bands.