Kortvåglängd

Kortvåglängd, often referred to as shortwave, is a range of electromagnetic radiation wavelengths. Specifically, it typically refers to radio waves with wavelengths ranging from about 10 to 100 meters, corresponding to frequencies between 3 and 30 megahertz. This portion of the radio spectrum is known for its ability to travel long distances. Unlike shorter radio waves that tend to travel in straight lines and are easily blocked by obstructions, shortwave radio waves can bounce off the Earth's ionosphere, allowing them to be reflected back to Earth over vast geographical areas. This characteristic makes shortwave broadcasting particularly useful for international communication and reaching remote locations.

The propagation of shortwave signals is influenced by various factors, including the time of day, season, and solar activity, which affect the state of the ionosphere. During the day, the D layer of the ionosphere absorbs shortwave signals, making long-distance propagation more difficult. At night, the D layer dissipates, allowing signals to reach higher layers of the ionosphere and reflect more effectively. This phenomenon is why shortwave listening can be a dynamic experience, with different stations and frequencies becoming audible at different times. Shortwave broadcasting has historically played a significant role in international news dissemination, cultural exchange, and amateur radio communications.