high frequency (HF)
Radio frequency (RF) generally refers to all frequencies used for terrestrial transmission of signals.
Coastal radio, maritime radio and amateur radio, CB radio but also cable distribution networks and many other radio technologies use high frequency for signal transmission. This is the case with the classic broadcasting transmission oflong wave, medium wave and short wave as well as analog terrestrial television.
In terms of frequency, the RF range is the frequency range from 30 kHz to 30 MHz, with wavelengths from 10 km to 10 m, the decameter waves. This frequency range has the band number 7 at the International Telecommunication Union( ITU), which is mathematically related to the frequency band. Frequencies above 30 MHz are referred to as Very High Frequency( VHF) and even higher ones above 300 MHz as Ultra High Frequency( UHF).