frequency bands

Because the complete radio spectrum is so broad it is considered to be divided up into bands, ranging from extremely low frequency (longest wavelengths) to extremely high frequency (shortest wavelengths).


General radio band designations
abbreviation meaning wavelength frequency
ELF extremely low frequency 10,000-100 km 30 Hz-3 kHz
VLF very low frequency 100-10 km 3-30 kHz
LF low frequency 10-1 km 30-300 kHz
MF medium frequency 1 km-100 m 300 kHz-3 MHz
HF high frequency 100-10 m 3-30 MHz
VHF very high frequency 10-1 m 30-300 MHz
UHF ultra high frequency 1 m-10 cm 300 MHz-3 GHz
SHF super high frequency 10-1 cm 3-30 GHz
EHF extremely high frequency 1 cm-1 mm 30-300 GHz


Only a small part of this spectrum, from about one gigahertz (GHz) to a few tens of GHz, is used for practical radio communications. International agreements control the usage and allocation of frequencies within this important region. Communications bands are designated by letters that appear to have been chosen at random-S, C, X, and so on. Indeed, this is exactly how they were chosen. The band letters originate from World War II when reference to which frequency bands were being used needed to be kept secret. Most commercial communications use the C (the first to be used), Ku, K, and Ka bands. The shorter wavelength bands, such as Ka are used in conjunction with small (including handheld) receivers on the ground but suffer severe attenuation from rain. The X-band is used heavily for military applications.


Some IEEE radio band designations
band frequency wavelength
L 1-2 GHz 30-15 cm
S 2-4 GHz 15-7.5 cm
C 4-8 GHz 7.5-3.75 cm
X 8-12 GHz 3.75-2.5 cm
Ku 12-18 GHz 2.5-1.67 cm
K 18-27 GHz 1.67-1.11 cm
Ka 27-40 GHz 1.11-0.75 cm