Radio frequency

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 shown in the table below.

Radio frequency spectrum

Band name	Abbr	ITU band	Frequency Wavelength	Example uses
			< 3 Hz > 100,000 km
Extremely low frequency	ELF	1	3–30 Hz 100,000 km – 10,000 km	Communication with submarines
Super low frequency	SLF	2	30–300 Hz 10,000 km – 1000 km	Communication with submarines
Ultra low frequency	ULF	3	300–3000 Hz 1000 km – 100 km	Communication within mines
Very low frequency	VLF	4	3–30 kHz 100 km – 10 km	Submarine communication, avalanche beacons, wireless heart rate monitors
Low frequency	LF	5	30–300 kHz 10 km – 1 km	Navigation, time signals, AM longwave broadcasting
Medium frequency	MF	6	300–3000 kHz 1 km – 100 m	AM (Medium-wave) broadcasts
High frequency	HF	7	3–30 MHz 100 m – 10 m	Shortwave broadcasts and amateur radio
Very high frequency	VHF	8	30–300 MHz 10 m – 1 m	FM and television broadcasts
Ultra high frequency	UHF	9	300–3000 MHz 1 m – 100 mm	television broadcasts, mobile phones, wireless LAN, ground-to-air and air-to-air communications
Super high frequency	SHF	10	3–30 GHz 100 mm – 10 mm	microwave devices, mobile phones (W-CDMA), wireless LAN, most modern Radars
Extremely high frequency	EHF	11	30–300 GHz 10 mm – 1 mm	Radio astronomy, high-speed microwave radio relay
			Above 300 GHz < 1 mm	Night vision

Notes

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 are transmitted by atmospheric compression and expansion, and not by electromagnetic energy.
The SHF and EHF bands are often considered to be not part of the radio spectrum and form their own microwave spectrum.

Named frequency bands

General

Broadcast Frequencies:

AM Radio = 535kHz - 1605kHz (MF)
TV Band I (Channels 2 - 6) = 54MHz - 88MHz (VHF)
FM Radio Band II = 88MHz - 108MHz (VHF)
TV Band III (Channels 7 - 13) = 174MHz - 216MHz (VHF)
TV Bands IV & V (Channels 14 - 69) = 512MHz - 806MHz (UHF)

For more information see the NTIA frequency allocation chart: http://www.ntia.doc.gov/osmhome/allochrt.html

Amateur radio frequencies

The range of allowed frequencies vary between countries. These are just some of the more common bands. In the article about amateur radio is another list.

Band	Frequency range
160 m	1.815 to 1.89 MHz
80 m	3.5 to 3.8 MHz
40 m	7 to 7.1 MHz
30 m	10.1 to 10.15 MHz
20 m	14 to 14.35 MHz
15 m	21 to 21.45 MHz
12 m	24.89 to 24.99 MHz
10 m	28.0 to 29.7 MHz
6 m	50.08 to 51 MHz
2 m	144 to 148 MHz
70 cm	430 to 440 MHz
23 cm	1240 to 1300 MHz

IEEE US

Band	Frequency range	Origin of name
I band	to 0.2GHz
G band	0.2 to 0.25 GHz
P band	0.25 to 0.5 GHz	Previous, since early British Radar used this band but later switched to higher frequencies
L band	0.5 to 1.5 GHz	Long wave
S band	2 to 4 GHz	Short wave
C band	4 to 8 GHz	Compromise between S and X
X band	8 to 12 GHz	Used in WW II for fire control, X for cross (as in crosshair)
K_u band	12 to 18 GHz	Kurz-under
K band	18 to 26 GHz	German Kurz (short)
K_a band	26 to 40 GHz	Kurz-above
V band	40 to 75 GHz	Very high frequency
W band	75 to 111 GHz	W follows V in the alphabet

EU, NATO

Band	Frequency range
A band	to 0.25 GHz test
B band	0.25 to 0.5 GHz
C band	0.5 to 1.0 GHz
D band	1 to 2 GHz
E band	2 to 3 GHz
F band	3 to 4 GHz
G band	4 to 6 GHz
H band	6 to 8 GHz
I band	8 to 10 GHz
J band	10 to 20 GHz
K band	20 to 40 GHz
L band	40 to 60 GHz
M band	60 to 100 GHz

References

ITU-R Recommendation V.431: Nomenclature of the frequency and wavelength bands used in telecommunications. International Telecommunication Union, Geneva.

ANSI/IEEE Standard 521-2002: Letter designations for radar-frequency bands.

External links

Tomislav Stimac, "Definition of frequency bands (VLF, ELF... etc.)". IK1QFK Home Page (vlf.it).
Radio, light, and sound waves, conversion between wavelength and frequency

Radio spectrum | Wireless communications

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