Information about Radio Frequency
Radio frequency, or RF, is a frequency or rate of oscillation within the range of about 3 Hz and 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 it can ionize air to create a conductive path through air. This property is exploited by 'high frequency' units used in electric arc welding. 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 depend on the frequency of the signals.See also
| Radio spectrum | ||||||||||
| ELF | SLF | ULF | VLF | LF | MF | HF | 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 |
| 30 Hz | 300 Hz | 3 kHz | 30 kHz | 300 kHz | 3 MHz | 30 MHz | 300 MHz | 3 GHz | 30 GHz | 300 GHz |
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 eBooks - Some free RF related eBooks
- RF and Telecommunication eBooks
Radio is the wireless transmission of signals, by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space.
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FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. A sequel, titled Amplitude was released in 2003.
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- ''For other uses, see oscillator (disambiguation)
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alternating current (AC) is an electrical current whose magnitude and direction vary cyclically, as opposed to direct current, whose direction remains constant. The usual waveform of an AC power circuit is a sine wave, as this results in the most efficient transmission of
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Radio waves are electromagnetic waves occurring on the radio frequency portion of the electromagnetic spectrum. A common use is to transport information through the atmosphere or outer space without wires.
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Direct current (DC or "continuous current") is the constant flow of electric charge. This is typically in a conductor such as a wire, but can also be through semiconductors, insulators, or even through a vacuum as in electron or ion beams.
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Arc welding uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes.
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The skin effect is the tendency of an alternating electric current (AC) to distribute itself within a conductor so that the current density near the surface of the conductor is greater than that at its core. That is, the electric current tends to flow at the "skin" of the conductor.
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Radio frequency, or RF, is a frequency or rate of oscillation within the range of about 3 Hz and 300 GHz. This range corresponds to frequency of alternating current electrical signals used to produce and detect radio waves.
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Extremely low frequency (ELF) is the band of radio frequencies from 3 to 30 Hz. ELF was used by the US Navy and Soviet/Russian Navy to communicate with submerged submarines.
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Super Low Frequency (SLF) is the frequency range between 30 hertz and 300 hertz. This frequency range includes the frequencies of AC power grids (50 hertz and 60 hertz).
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The Ultra Low Frequency (ULF) is the frequency range between 300 hertz and 3 kilohertz. Many types of waves in the ULF frequency band can be observed in the magnetosphere and on the ground.
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Very low frequency or VLF refers to radio frequencies (RF) in the range of 3 kHz to 30 kHz. Since there is not much bandwidth in this band of the radio spectrum, only the very simplest signals are used, such as for radio navigation.
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Low Frequency or LF refers to Radio Frequencies (RF) in the range of 30 kHz–300 kHz. In Europe, and parts of Northern Africa and of Asia, part of the LF spectrum is used for AM broadcast service.
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Medium frequency (MF) refers to radio frequencies (RF) in the range of 300 kHz to 3000 kHz. Part of this band is the medium wave (MW) AM broadcast band.
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High frequency (HF) radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters. Shortwave (2.310 - 25.820 MHz) overlaps and is slightly lower than HF.
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Very high frequency (VHF) is the radio frequency range from 30 MHz to 300 MHz. It is also known as the meter band or meter wave as the wavelengths range from ten to one meters.
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Cycles per second: 300 MHz to 3 GHz
Wavelength: 1 m to 100 mm Ultra high frequency (UHF) designates a range (band) of electromagnetic waves whose frequency is between 300 MHz and 3 GHz, which is 300 MHz to 3,000 MHz.
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Wavelength: 1 m to 100 mm Ultra high frequency (UHF) designates a range (band) of electromagnetic waves whose frequency is between 300 MHz and 3 GHz, which is 300 MHz to 3,000 MHz.
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Super high frequency (or SHF) refers to radio frequencies (RF) in the range of 3 GHz and 30 GHz. Also known as the centimeter band or centimeter wave as the wavelengths range from ten to one centimeters.
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Extremely high frequency is the highest radio frequency band. EHF runs the range of frequencies from 30 to 300 gigahertz, above which electromagnetic radiation is considered to be low (or far) infrared light, also referred to as Terahertz radiation.
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