Curiosity : Something behind TV and Radio

Watching TVWhile 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)

Flag of ITU.svgITU 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.

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
Navigationtime signals, submarine communication, wireless heart rate monitorsgeophysics
Low frequency LF 5 30–300 kHz
10 km – 1 km
Navigation, time signals, AM longwavebroadcasting (Europe and parts of Asia),RFIDamateur 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, RFIDOver-the-horizon radarAutomatic 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
FMtelevision 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 astronomymobile phoneswireless LAN,BluetoothZigBeeGPS 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 radarscommunications 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 weaponmillimeter 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 physicsterahertz time-domain spectroscopy, terahertz computing/communications, sub-mm remote sensing, amateur radio

Courtesy : Wikipedia and ITU

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Eco-Preservation : Bioluminescence

Glowing Bioluminescent Plankton
Bioluminescence is the production and emission of light by a living organism. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms and terrestrial invertebrates. Some symbiotic organisms carried within larger organisms produce light.
Glowing Bioluminescent Plankton

Before the development of the safety lamp for use in coal mines, dried fish skins were used in Britain and Europe as a weak source of light

Glowing Bioluminescent Plankton

Bioluminescence is a form of luminescence, or “cold light” emission by living organisms; less than 20% of the light generates thermal radiation. It should not be confused with iridescencestructural colorationphosphorescence.

By etymology, bioluminescence is a hybrid word, originating from the Greek bios for “living” and the Latin lumen “light”.

Bioluminescence is a form of chemiluminescence where light energy is released by a chemical reactionFirefliesanglerfish, and other creatures produce the chemicals luciferin (a pigment) and luciferase (an enzyme). The luciferin reacts with oxygen to create light. The luciferase acts as a catalyst to speed up the reaction, which is sometimes mediated by cofactors such as calcium ions or ATP. The chemical reaction can occur either inside or outside the cell. In bacteria, the expression of genes related to bioluminescence is controlled by an operon called the Lux operon.
Glowing Bioluminescent Plankton 

Bioluminescence occurs widely among some groups of animals, especially in the open sea; in some fungi and bacteria; and in various terrestrial invertebrates including insects. Many, perhaps most deep-sea animals produce light. Most marine light-emission is in the blue and green light spectrum, the wavelengths that pass furthest through seawater. However, some loose-jawed fish emit red and infrared light, and the genusTomopteris emits yellow light. Sometimes thousands of square miles of the ocean shine with the light of bioluminescent bacteria in the “Milky seas effect“.

Non-marine bioluminescence is less widely distributed. The two best-known forms of land bioluminescence are fireflies and glow worms. Other insects, insect larvaeannelidsarachnids and even species of fungi have been noted to possess bioluminescent abilities. Some forms of bioluminescence are brighter (or exist only) at night, following a circadian rhythm.

Glowing Bioluminescent Plankton 

Bioluminescent organisms are a target for many areas of research. Luciferase systems are widely used in the field of genetic engineering as reporter genes. Luciferase systems have also been harnessed for biomedical research usingbioluminescence imagingVibrio symbiosis with numerous marine invertebrates and fish, namely the Hawaiian Bobtail Squid (Euprymna scolopes), are key experimental models for bioluminescence.

The structures of photophores, the light producing organs in bioluminescent organisms, are being investigated byindustrial designers. Engineered bioluminescence could perhaps one day be used to reduce the need for street lighting, or for decorative purposes.

The gene that makes firefly‘s tails glow has been added to mustard plants. The plants glow faintly for an hour when touched, but a sensitive camera is needed to see the glow

File:Glowing tobacco plant.jpg

Glowing Bioluminescent Plankton
Glowing Bioluminescent Plankton
Glowing Bioluminescent Plankton
Glowing Bioluminescent Plankton
Glowing Bioluminescent Plankton
Glowing Bioluminescent Plankton
Glowing Bioluminescent Plankton
Glowing Bioluminescent Plankton
Glowing Bioluminescent Plankton

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Courtesy and Source : Wikipedia, Avaxnews, Aquaviews