Shortwave bands are frequency allocations for use within the
shortwave radio spectrum (the upper
MF band and all of the
HF band). They are the primary medium for applications such as maritime communications, international broadcasting and worldwide
amateur radio activity because they take advantage of
ionospheric skip propagation to send data around the world. The bands are conventionally stated in
wavelength, measured in metres.
Propagation behavior on the shortwave bands depends on the time of day, the season and the level of
solar activity.