Radio Frequency

#REDIRECT Radio frequency

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 (electronics). Such frequencies account for the following parts of the spectrum shown in the table below. ''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 are transmitted by atmospheric compression and expansion, and not by electromagnetic energy. 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 Neill-Concelman). {| |- bgcolor="#CCCCCC" ! Band name ! Abbreviation ! International Telecommunication Union band ! Frequency
Wavelength ! Example uses |- | |align="center"| |align="center"| |align="center" style="white-space: nowrap;"| < 3 Hertz
> 100,000 km |align="center"| |- | Extremely low frequency |align="center"| ELF |align="center"| 1 |align="center" style="white-space: nowrap;"| 3–30 Hertz
100,000 km – 10,000 km |align="center"| |- | Super low frequency |align="center"| SLF |align="center"| 2 |align="center" style="white-space: nowrap;"| 30–300 Hertz
10,000 km – 1000 km |align="center"| |- | Ultra low frequency |align="center"| ULF |align="center"| 3 |align="center" style="white-space: nowrap;"| 300–3000 Hertz
1000 km – 100 km |align="center"| |- | Very low frequency |align="center"| VLF |align="center"| 4 |align="center" style="white-space: nowrap;"| 3–30 Kilohertz
100 km – 10 km |align="center"| Military communication |- | Low frequency |align="center"| LF |align="center"| 5 |align="center" style="white-space: nowrap;"| 30–300 Kilohertz
10 km – 1 km |align="center"| Navigation, time signals, AM longwave broadcasting |- | Medium frequency |align="center"| MF |align="center"| 6 |align="center" style="white-space: nowrap;"| 300–3000 Kilohertz
1 km – 100 m |align="center"| AM radio broadcasts |- | High frequency |align="center"| HF |align="center"| 7 |align="center" style="white-space: nowrap;"| 3–30 Megahertz
100 m – 10 m |align="center"| Shortwave broadcasts and amateur radio |- | Very high frequency |align="center"| VHF |align="center"| 8 |align="center" style="white-space: nowrap;"| 30–300 Megahertz
10 m – 1 m |align="center"| FM radio and television broadcasts |- | Ultra high frequency |align="center"| UHF |align="center"| 9 |align="center" style="white-space: nowrap;"| 300–3000 Megahertz
1 m – 100 mm |align="center"| television broadcasts |- | Super high frequency |align="center"| SHF |align="center"| 10 |align="center" style="white-space: nowrap;"| 3–30 Gigahertz
100 mm – 10 mm |align="center"| microwave devices, mobile phones, wireless LAN |- | Extremely high frequency |align="center"| EHF |align="center"| 11 |align="center" style="white-space: nowrap;"| 30–300 Gigahertz
10 mm – 1 mm |align="center"| |- | |align="center"| |align="center"| |align="center" style="white-space: nowrap;"| Above 300 Gigahertz
< 1 mm |align="center"| |} == Named frequency bands == *Band III - 174–245 MHz *ISM band......specific frequencies vary === Microwave (IEEE US) === {| |- bgcolor="#CCCCCC" ! Band !! Frequency range |- | L band || 1 to 2 GHz |- | S band || 2 to 4 GHz |- | C band || 4 to 8 GHz |- | X band || 8 to 12 GHz |- | Ku band || 12 to 18 GHz |- | K band || 18 to 26 GHz |- | Ka band || 26 to 40 GHz |- | V band || 40 to 75 GHz |- | W band || 75 to 111 GHz |} == See also == * Radio propagation == External links == *[http://www.sengpielaudio.com/calculator-wavelength.htm Radio and light waves conversion: frequency to wavelength and vice versa] Radio spectrum Wireless communications

Radio frequency

== ELF == Isn't there a ELF, Extreme Low Frequeny ? Yes, but there doesn't seem to be agreement on the extent of it, so I finally settled for "below 3 kHz." -Palmpilot900 : Try Extremely low frequency (User:SEWilco 08:34, 27 May 2005 (UTC)) == This page is lacking in many areas IMHO. == First off BNC is (British Nut Connector or it varies) (and this is most often Video, or in it rg58 form yes RF) The most common connector is a F connector on a RG6 cable vis-a-vis house hold cable or outdoor antenna connection. Not a BNC. Also need to mention RF radiation. (IE are you getting zapped) RF Engineering. And the H and vertical elements and magnetic. (above from anonymous) == More charts == Maybe https://ewhdbks.mugu.navy.mil/freqspec.htm would be of use. (User:SEWilco 08:34, 27 May 2005 (UTC))

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