Radio Frequency

RF is basically a short form for the term radio frequency. This refers to the section of the electromagnetic spectrum in which electromagnetic waves can be generated by an alternating current which is fed to an antenna. The radio frequency spectrum ranges from extremely low frequency (3-30 Hz) to extremely high frequency (30-300 GHz).

Examples of usage on this radio frequency range include: Communication with submarines at super low frequency (30-300 Hz); wireless heart rate monitors at very low frequency (3-30 kHz); AM long wave radio broadcasting at low wave frequency (30-300 kHz); AM medium wave broadcasts at medium frequency (300-3000 kHz); shortwave and amateur radio broadcasts at high frequency (3-30 MHz); television and FM radio broadcasts at very high frequency (30-300 MHz); mobile phones and wireless LAN at ultra high frequency (300-3000 MHz); microwave devices and most radar systems at super high frequency (3-30 GHz) and radio astronomy and high speed microwave relay at extremely high frequency (30-300 GHz).

At any frequency above 300 GHz, the absorption of electromagnetic radiation by the Earth's atmosphere is so high 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 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 usually considered not to belong to the radio spectrum and form their own microwave spectrum.

Although radio frequency electromagnetic fields are commonly used throughout the world it isn’t exactly clear what effect exposure to it has on humans and the environment. In the U.S.A., the Federal Communications Commission (FCC) authorizes or licenses most telecommunications facilities, services and devices that are used by the public, industry and other organizations. The FCC has adopted and used recognized safety guidelines for evaluating RF exposure since 1985. The FCC is required by the National Environmental Policy Act of 1969 to evaluate the effect RF emissions from all FCC-regulated transmitters on the quality of the human environment. However there is currently no federally-mandated radio frequency exposure standard.

There are many types of electrical devices that are associated with the world of radio frequency. These include RF amplifiers, RF attenuators, RF filters, RF receivers, RF terminations, RF transmitters, RF switches, RF transistors, RF modules, RF frequency converters, RF adapters, RF repeaters, RF couplers and RF generators.

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