Radiowave Frequency Ranges | ||
---|---|---|
Abbr. | Name | Frequencies |
ELF | Extremely Low Frequencies | 30 - 300 Hz |
VF | Voice Frequencies | 0.3 - 3 kHz |
VLF | Very Low Frequencies | 3 - 30 kHz |
LF | Low Frequencies | 30 - 300 kHz |
MF | Medium Frequencies | 0.3 - 3 MHz |
HF | High Frequencies | 3 - 30 MHz |
VHF | Very High Frequencies | 30 - 300 MHz |
UHF | Ultra High Frequencies | 0.3 - 3 GHz |
SHF | Super High Frequencies | 3 - 30 GHz |
EHF | Extremely High Freqiencies | 30 - 300 GHz |
The International Telecommunication Union (ITU) has defined the radiowave frequency ranges as shown in the table. Note that most of the plasma waves occurring in the magnetosphere are "ultra-low-frequency" (ULF) range geomagnetic pulsations occurring below 5 Hz, i.e., outside of this classification. Their high frequency limit corresponds to magnetospheric ion gyrofrequencies (which are low because of small B and high m).
On the other hand, wave types relating to electrons, or those created at the ionospheric altitudes, can reach frequencies covered by the table (ELF - VLF). Instruments like incoherent radars work typically at VHF and UHF frequencies.
See also: