n. (Abbr. RF)
- The frequency of the waves transmitted by a specific radio station.
- A frequency in the range within which radio waves may be transmitted, from about 3 kilohertz to about 300,000 megahertz.
radio frequency
| Dictionary: radio frequency |
n. (Abbr. RF)
| 5min Related Video: radio frequency |
| Columbia Encyclopedia: radio frequency |
radio frequency, range of electromagnetic waves with a frequency or wavelength suitable for utilization in radio communication. Some of these waves serve as carriers of the lower-frequency audio waves; others are modulated by video or digital information. Short waves have relatively high frequencies; long waves have relatively low frequencies. Radio waves are identified by their frequencies, expressed in kilohertz (kHz), i.e., thousands of cycles per second, in megahertz (MHz), i.e., millions of cycles per second, or in gigahertz, i.e., billions of cycles per seconds. Signals in the amplitude modulation (AM) broadcast band have frequencies ranging from 540 to 1,800 kHz. Frequency modulation (FM) broadcast frequencies range from 88 MHz to 108 MHz. A range, or band, of radio frequencies is regularly assigned to a broadcasting station or service by the nation in which it operates. In the United States, the Federal Communications Commission is responsible for that task. Countries cooperate on on a worldwide basis through the International Telecommunication Union, which holds periodic conferences. See also the table entitled Radio Frequencies for the classification of radio frequencies.
| Medical Dictionary: ra·di·o frequency |
| WordNet: radio frequency |
Note: click on a word meaning below to see its connections and related words.
The noun has one meaning:
Meaning #1:
an electromagnetic wave frequency between audio and infrared
| Wikipedia: Radio frequency |
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This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (May 2009) |
Radio frequency (RF) is a frequency or rate of oscillation within the range of about 3 Hz to 300 GHz. This range corresponds to frequency of alternating current electrical signals used to produce and detect radio waves. Since most of this range is beyond the vibration rate that most mechanical systems can respond to, RF usually refers to oscillations in electrical circuits.
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Special properties of RF electrical signals
Electrical currents that oscillate at RF have special properties not shared by direct current signals. One such property is the ease with which they can ionize air to create a conductive path through air. This property is exploited by 'high frequency' units used in electric arc welding, although strictly speaking these machines do not typically employ frequencies within the HF band. Another special property is an electromagnetic force that drives the RF current to the surface of conductors, known as the skin effect. Another property is the ability to appear to flow through paths that contain insulating material, like the dielectric insulator of a capacitor. The degree of effect of these properties depends on the frequency of the signals.
Frequencies
| Name | Symbol | Frequency | Wavelength | Applications |
|---|---|---|---|---|
| Extremely low frequency | ELF | 3–30 Hz | 10–100 Mm | Directly audible when converted to sound (above ~20 Hz), communication with submarines |
| Super low frequency | SLF | 30–300 Hz | 1–10 Mm | Directly audible when converted to sound, AC power grids (50–60 Hz) |
| Ultra low frequency | ULF | 300–3000 Hz | 100–1000 km | Directly audible when converted to sound, communication within mines |
| Very low frequency | VLF | 3–30 kHz | 10–100 km | Directly audible when converted to sound (below ~20 kHz; or ultrasound otherwise) |
| Low frequency | LF | 30–300 kHz | 1–10 km | AM broadcasting, navigational beacons, lowFER, amateur radio |
| Medium frequency | MF | 300–3000 kHz | 100–1000 m | Navigational beacons, AM broadcasting, amateur radio, maritime and aviation communication |
| High frequency | HF | 3–30 MHz | 10–100 m | Shortwave, amateur radio, citizens' band radio, skywave propagation |
| Very high frequency | VHF | 30–300 MHz | 1–10 m | FM broadcasting, amateur radio, broadcast television, aviation, GPR, MRI |
| Ultra high frequency | UHF | 300–3000 MHz | 10–100 cm | Broadcast television, amateur radio, mobile telephones, cordless telephones, wireless networking, remote keyless entry for automobiles, microwave ovens, GPR |
| Super high frequency | SHF | 3–30 GHz | 1–10 cm | Wireless networking, satellite links, amateur radio, microwave links, satellite television, door openers |
| Extremely high frequency | EHF | 30–300 GHz | 1–10 mm | Microwave data links, radio astronomy, amateur radio, remote sensing, advanced weapons systems, advanced security scanning |
See also
- Frequency allocation
- Frequency bandwidth
- Radio waves
- Plastic Sealing/Welding Technologies
- RF connector
- Spectrum management
- Ultrasound
- RF Switch Matrix – A custom configuration of high frequency switches used in automated test for testing high frequency components and electronic devices
External links
- Definition of frequency bands (VLF, ELF … etc.) IK1QFK Home Page (vlf.it)
- Radio, light, and sound waves, conversion between wavelength and frequency
- RF and Telecommunication eBooks
- RF Terms Glossary
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/ Read more |
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| Medical Dictionary. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Read more |
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| WordNet. WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Radio frequency". Read more |
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