Why do we use high frequency signals?

High-frequency (HF) radio is in the 100- to 10-metre wavelength band, extending from 3 megahertz to 30 megahertz . Much of the HF band is allocated to mobile and fixed voice communication services requiring transmission bandwidths of less than 12 kilohertz.

Originally Answered: Why do we use high frequency waves as carrier waves? HF (2 – 30 MHz) is used for long distance communications because the atmosphere acts to bend these rays and bounce them back towards earth, so that they can travel all over the world, using very modest power to do so.

Like the LF band, the Medium Frequency (MF) band is also mostly used for AM radio broadcasting. The High Frequency (HF) band is most useful in shortwave radio applications, as well as aviation air-to-ground communications .