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:

\n{| border="1" cellpadding="3" cellspacing="0"\n! Band name || Abbr || ITU band || Frequencies || Wavelength\n|-\n| || || || Below 3 Hz || > 100000 km \n|-\n| Extremely low frequency || ELF || 1 || 3-30 Hz || 100000 km – 10000 km
(100 Mm - 10 Mm)\n|-\n| Super low frequency || SLF || 2 || 30–300 Hz || 10000 km – 1000 km\n|-\n| Ultra low frequency || ULF || 3 || 300–3000 Hz || 1000 km – 100 km\n|-\n| Very low frequency || VLF || 4 || 3–30 kHz || 100 km – 10 km\n|-\n| Low frequency || LF || 5 || 30–300 kHz || 10 km – 1 km\n|-\n| Medium frequency || MF || 6 || 300–3000 kHz || 1 km – 100 m\n|-\n| High frequency || HF || 7 || 3–30 MHz || 100 m – 10 m\n|-\n| Very high frequency || VHF || 8 || 30–300 MHz || 10 m – 1 m\n|-\n| Ultra high frequency || UHF || 9 || 300–3000 MHz || 1 m – 100 mm\n|-\n| Super high frequency || SHF || 10 || 3–30 GHz || 100 mm – 10 mm\n|-\n| Extremely high frequency || EHF || 11 || 30–300 GHz || 10 mm – 1 mm\n|-\n| || || || Above 300 GHz || < 1 mm\n|}\n

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 move at the speed of sound, rather than the speed of light. 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 Connector).

Named Frequency Bands

\n*Band III - 174–245 MHz\n*ISM band......specific frequencies vary

Microwave (IEEE US)

\n

\n{|\n| L band || 1 to 2GHz\n|-\n| S band || 2 to 4GHz\n|-\n| C band || 4 to 8GHz\n|-\n| X band || 8 to 12GHz\n|-\n| K_u band || 12 to 18GHz\n|-\n| K band || 18 to 26GHz\n|-\n| K_a band || 26 to 40GHz\n|-\n| V band || 40 to 75GHz\n|-\n| W band || 75 to 110GHz\n|}\n

See also

\n* Radio propagation

External Link

• Radio and light waves conversion: frequency to wavelength and back