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Radio waves



         


RF can also denote rheumatoid factor

Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna. Such frequencies account for the following parts of the spectrum:

Band name Abbr ITU band Frequencies Wavelength
Below 3 Hz > 100,000 km
Extremely low frequency
ELF
1
3-30 Hz 100,000 km – 10,000 km
Super low frequency
SLF
1
30–300 Hz 10,000 km – 1000 km
Ultra low frequency
ULF
2
300–3000 Hz 1000 km – 100 km
Very low frequency
VLF
3
3–30 kHz 100 km – 10 km
Low frequency
LF
4
30–300 kHz 10 km – 1 km
Medium frequency
MF
5
300–3000 kHz 1 km – 100 m
High frequency
HF
6
3–30 MHz 100 m – 10 m
Very high frequency
VHF
7
30–300 MHz 10 m – 1 m
Ultra high frequency
UHF
8
300–3000 MHz 1 m – 100 mm
Super high frequency
SHF
9
3–30 GHz 100 mm – 10 mm
Extremely high frequency
EHF
10
30–300 GHz 10 mm – 1 mm
Above 300 GHz < 1 mm

Note: above 300 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that the atmosphere is effectively opaque to higher frequencies of electromagnetic radiation, until the atmosphere becomes transparent again in the so-called infrared and optical window frequency ranges.

The ELF, SLF, ULF, and VLF bands overlap the AF (audio frequency) spectrum, which is approximately 20–20,000 Hz. However, sounds move at the speed of sound, rather than the speed of light.

Electrical connectors designed to work at radio frequencies are known as RF connectors. RF is also the name of a standard audio/video connector, also called BNC (BayoNet Connector).

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Named Frequency Bands

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Microwave (IEEE US)

L band 1 to 2GHz
S band 2 to 4GHz
C band 4 to 8GHz
X band 8 to 12GHz
Ku band 12 to 18GHz
K band 18 to 26GHz
Ka band 26 to 40GHz
V band 40 to 75GHz
W band 75 to 110GHz
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See also


Radio spectrum
ELF | SLF | ULF | VLF | LF/LW | MF/MW | HF/SW | VHF | UHF | SHF | EHF
3 Hz | 30 Hz | 300 Hz | 3 kHz | 30 kHz | 300 kHz | 3 MHz | 30 MHz | 300 MHz | 3 GHz | 30 GHz | 300 GHz



Electromagnetic Spectrum

Radio waves | Microwave | Infrared | Visible light | Ultraviolet | X-ray | Gamma ray


Visible: Red | Orange | Yellow | Green | Blue | Indigo | Violet


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