FM broadcasting
VHF Radio waves do not travel far beyond the visual horizon, so reception distances for FM stations are usually limited to 30–40 miles (50–65 km) They can also be blocked by hills or buildings.
Longwave
Because of their long wavelength, radio waves in this frequency range can diffract over obstacles like mountain ranges and travel beyond the horizon, following the contour of the Earth. This mode of propagation, called "ground wave", is the main mode in the longwave band. The attenuation of signal strength with distance by absorption in the ground is lower than at higher frequencies, and falls with frequency. Low frequency ground waves can be received up to from the transmitting antenna. Very low frequency waves below 30 kHz can be used to communicate at transcontinental distances, and can penetrate saltwater to depths of hundreds of feet, and is used by the military to communicate with submerged submarines.