The activities that take place on the sun have a major impact upon high-frequency (HF) radio broadcasts. Some types of radio propagation affected by the sun's activity include short-wave, AM and ham-radio operations.
Propagating, informing and entertaining
Function
The sun is the source of radiation that affects the state of the earth's ionosphere, which either serves as a reflector of certain types of radio waves (facilitating long-distance communication on Earth) or allows signals above 30 Megahertz (MHz) to pass into space (enabling ground-to-space communication).
Solar Flares
Solar flares emit large amounts of energy and protons, which make their way to the earth. These may have either beneficial or adverse effects upon radio broadcasts depending upon the circumstances.
Coronal mass ejections
Bubbles of gas threaded with magnetic lines that are cast out from the sun are called coronal mass ejections (CME). These may cause short-lived benefits to ionospheric radio broadcasts but can suddenly create blackout conditions.
The Sun's Corona
At times, dark areas appear on the sun's corona (a type of "atmosphere" surrounding the sun) that are associated with open magnetic field lines. These coronal holes create high-speed solar winds that affect ionospheric radio conditions.
Identification
International radio broadcasters, such as Radio Netherlands Worldwide, suggest that radio operators listen to Geophysical Alert Broadcasts, which outline the solar-terrestrial conditions at any given time. (See Reference 3.)
Tags: radio broadcasts, ionospheric radio, mass ejections, types radio