Electromagnetic Spectrum

Discussion

introduction

A good, general sequence to remember is radio waves, microwaves, infrared, light, ultraviolet, x‑rays, gamma rays

table-spectrum.shtml

micropulsations

radio waves

name ITU number frequency wavelength
extremely low frequency (ELF)* 1 (~1001 Hz) 3 30 Hz 100,000 10,000 km
super low frequency (SLF)* 2 (~1002 Hz) 30 300 Hz 10,000 1000 km
ultra low frequency (ULF)* 3 (~1003 Hz) 300 3000 Hz 1000 100 km
very low frequency (VLF) 4 (~1004 Hz) 3 30 kHz 100 10 km
low frequency (LF)** 5 (~1005 Hz) 30 300 kHz 10 1 km
medium frequency (MF)** 6 (~1006 Hz) 300 3000 kHz 1000 100 m
high frequency (HF)** 7 (~1007 Hz) 3 30 MHz 100 10 m
very high frequency (VHF) 8 (~1008 Hz) 30 300 MHz 10 1 m
ultra high frequency (UHF) 9 (~1009 Hz) 300 3000 MHz 1000 100 mm
super high frequency (SHF) 10 (~1010 Hz) 3 30 GHz 100 10 mm
extremely high frequency (EHF) 11 (~1011 Hz) 30 300 GHz 10 1 mm
tremendously high frequency (THF)*** 12 (~1012 Hz) 0.3 3 THz 1 0.1 mm
Radio Frequency Bands
Source: ITU
* The ITU actually assigns the designation ELF to everything below VLF. Thus ELF on the table above is ELF1, SLF is ELF2, and ULF is ELF3.
** The middle bands are sometimes identified by their relative wavelengths. Thus low frequency (LF) is also called long wave (LW), medium frequency (MF) is also called medium wave (MW), and high frequency (HF) is also called short wave (SW).
*** This designation is not official, but I like it. The "t" in tremendous matches the "t" in terahertz (the geometric center of the band), matches the "t" in twelve (1 THz = 1012 Hz), matches the "t" in trillion (1012 is also known as a trillion).