Terrestrial waves are a type of wave produced by the interaction of electromagnetic waves with the earth's surface as they propagate. It is an electromagnetic wave that travels along the Earth's surface and can play an important role in communication over long distances. Terrestrial waves are waves formed by the reflection, scattering, and refraction of electromagnetic waves with the earth's surface during transmission.
The frequency range of terrestrial waves depends on the specific communication or transmission system. In general, terrestrial waves can include a wide range of frequencies, from very low to ultra-high frequencies. The specific frequency used depends on factors such as the requirements of the communication system, the transmission distance, the available spectrum and technical limitations.
In radio communications, terrestrial waves are often used for long-range communications, especially in the shortwave and mediumwave bands. Electromagnetic waves in these bands are able to interact with the Earth's surface and be reflected or scattered by the Earth, allowing the signal to cover longer distances. However, with the development of technology, high-frequency signals can also be transmitted over long distances by different propagation modes, such as ionospheric reflection or satellite relay, so terrestrial waves are not the dominant mode of transmission in all cases.