While watching TV or Listening to FM Radio, what we do? We switch between channels/stations which in fact is tuning the frequencies of electromagnetic spectrum which are measured in Hertz (Hz). By the way who regulates this? What frequency is used for what purpose? Is there any standards? Know more now…
Radio spectrum refers to the part of the electromagnetic spectrum corresponding to radio frequencies – that is, frequencies lower than around 300 GHz. Electromagnetic waves in this frequency range, called radio waves, are used for radio communication and various other applications.
So, your TV or Radio Stations produce the radio waves which you receive and enjoy.
Who can generate the Radio waves? Who controls it?
The generation of radio waves is strictly regulated by the government in most countries, coordinated by an international standards body called the International Telecommunications Union (ITU). Different parts of the radio spectrum are allocated for different radio transmission technologies and applications. In some cases, parts of the radio spectrum is sold or licensed to operators of private radio transmission services (for example, cellular telephone operators or broadcast television stations). Ranges of allocated frequencies are often referred to by their provisioned use (for example, cellular spectrum or television spectrum)
ITU is a specialized agency of the United Nations (UN) that is responsible for issues that concern information and communication technologies. The ITU coordinates the shared global use of the radio spectrum, promotes international cooperation in assigning satellite orbits, works to improve telecommunication infrastructure in the developing world, and assists in the development and coordination of worldwide technical standards. The ITU is active in areas including broadband Internet, latest-generation wireless technologies, aeronautical and maritime navigation, radio astronomy, satellite-based meteorology, convergence in fixed-mobile phone, Internet access, data, voice, TV broadcasting, and next-generation networks.
ITU, based in Geneva, Switzerland, is a member of the United Nations Development Group. Its membership includes 193 Member States and around 700 Sector Members and Associates.
Okay, what are the frequencies or wave lengths used by our Televisions? What about our mobile phones?
Well, the ITU regulates it along with governments of various countries and allocates the frequencies as bands, for various purposes. The list below will explain the typical allocation.
A band is a small section of the spectrum of radio communication frequencies, in which channels are usually used or set aside for the same purpose. Above 300 GHz, the absorption of electromagnetic radiation by Earth’s atmosphere is so great that the atmosphere is effectively opaque, until it becomes transparent again in the near-infrared and optical window frequency ranges.
To prevent interference and allow for efficient use of the radio spectrum, similar services are allocated in bands. For example, broadcasting, mobile radio, or navigation devices, will be allocated in non-overlapping ranges of frequencies. Each of these bands has a basic bandplan which dictates how it is to be used and shared, to avoid interference and to set protocol for the compatibility of transmitters and receivers.
| Band name | Abbreviation | ITU band | Frequency and wavelength in air |
Example uses |
|---|---|---|---|---|
| Tremendously low frequency | TLF | < 3 Hz > 100,000 km |
Natural and artificial electromagnetic noise | |
| Extremely low frequency | ELF | 3–30 Hz 100,000 km – 10,000 km |
Communication with submarines | |
| Super low frequency | SLF | 30–300 Hz 10,000 km – 1000 km |
Communication with submarines | |
| Ultra low frequency | ULF | 300–3000 Hz 1000 km – 100 km |
Submarine communication, Communication within mines | |
| Very low frequency | VLF | 4 | 3–30 kHz 100 km – 10 km |
Navigation, time signals, submarine communication, wireless heart rate monitors, geophysics |
| Low frequency | LF | 5 | 30–300 kHz 10 km – 1 km |
Navigation, time signals, AM longwavebroadcasting (Europe and parts of Asia),RFID, amateur radio |
| Medium frequency | MF | 6 | 300–3000 kHz 1 km – 100 m |
AM (medium-wave) broadcasts, amateur radio, avalanche beacons |
| High frequency | HF | 7 | 3–30 MHz 100 m – 10 m |
Shortwave broadcasts, citizens’ band radio, amateur radio and over-the-horizon aviation communications, RFID, Over-the-horizon radar, Automatic link establishment (ALE) /Near Vertical Incidence Skywave (NVIS) radio communications, Marine and mobile radio telephony |
| Very high frequency | VHF | 8 | 30–300 MHz 10 m – 1 m |
FM, television broadcasts and line-of-sight ground-to-aircraft and aircraft-to-aircraft communications. Land Mobile and Maritime Mobile communications, amateur radio,weather radio |
| Ultra high frequency | UHF | 9 | 300–3000 MHz 1 m – 100 mm |
Television broadcasts, Microwave oven,Microwave devices/communications, radio astronomy, mobile phones, wireless LAN,Bluetooth, ZigBee, GPS and two-way radios such as Land Mobile, FRS and GMRSradios, amateur radio |
| Super high frequency | SHF | 10 | 3–30 GHz 100 mm – 10 mm |
Radio astronomy, microwave devices/communications, wireless LAN, most modern radars, communications satellites, satellite television broadcasting,DBS, amateur radio |
| Extremely high frequency | EHF | 11 | 30–300 GHz 10 mm – 1 mm |
Radio astronomy, high-frequencymicrowave radio relay, microwave remote sensing, amateur radio, directed-energy weapon, millimeter wave scanner |
| Terahertz orTremendously high frequency | THz or THF | 12 | 300–3,000 GHz 1 mm – 100 μm |
Terahertz imaging – a potential replacement for X-rays in some medical applications, ultrafast molecular dynamics,condensed-matter physics, terahertz time-domain spectroscopy, terahertz computing/communications, sub-mm remote sensing, amateur radio |
Courtesy : Wikipedia and ITU
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