RADIO transmission or reception of
electromagnetic radiation in the radio frequency range. The term is
commonly applied also to the equipment used, especially to the radio
receiver.

Uses of Radio Waves

The prime purpose of radio is to convey information from one
place to another through the intervening media (i.e., air, space,
nonconducting materials) without wires. Besides being used for
transmitting sound and television signals, radio is used for the
transmission of data in coded form. In the form of radar it is used also
for sending out signals and picking up their reflections from objects
in their path. Long-range radio signals enable astronauts to communicate
with the earth from the moon and carry information from space probes as
they travel to distant planets (see space exploration ). For navigation
of ships and aircraft the radio range , radio compass (or direction
finder), and radio time signals are widely used. Radio signals sent from
global positioning satellites can also be used by special receivers for
a precise indication of position (see navigation satellite ). Digital
radio , both satellite and terrestrial, provides improved audio clarity
and volume. Various remote-control devices, including rocket and
artificial satellite operations systems and automatic valves in
pipelines, are activated by radio signals. The development of the
transistor and other microelectronic devices (see microelectronics ) led
to the development of portable transmitters and receivers. Cellular and
cordless telephones are actually radio transceivers. Many telephone
calls routinely are relayed by radio rather than by wires; some are sent
via radio to relay satellites. Some celestial bodies and interstellar
gases emit relatively strong radio waves that are observed with radio
telescopes composed of very sensitive receivers and large directional
antennas (see radio astronomy ).

Transmission and Reception of Radio Waves

For the propagation and interception of radio waves, a
transmitter and receiver are employed. A radio wave acts as a carrier of
information-bearing signals; the information may be encoded directly on
the wave by periodically interrupting its transmission (as in
dot-and-dash telegraphy) or impressed on it by a process called
modulation . The actual information in a modulated signal is contained
in its sidebands , or frequencies added to the carrier wave, rather than
in the carrier wave itself. The two most common types of modulation
used in radio are amplitude modulation (AM) and frequency modulation
(FM). Frequency modulation minimizes noise and provides greater fidelity
than amplitude modulation, which is the older method of broadcasting .
Both AM and FM are analog transmission systems, that is, they process
sounds into continuously varying patterns of electrical signals which
resemble sound waves. Digital radio uses a transmission system in which
the signals propagate as discrete voltage pulses, that is, as patterns
of numbers; before transmission, an analog audio signal is converted
into a digital signal, which may be transmitted in the AM or FM
frequency range. A digital radio broadcast offers compact-disc-quality
reception and reproduction on the FM band and FM-quality reception and
reproduction on the AM band.

In its most common form, radio is used for the transmission
of sounds (voice and music) and pictures (television). The sounds and
images are converted into electrical signals by a microphone (sounds) or
video camera (images), amplified, and used to modulate a carrier wave
that has been generated by an oscillator circuit in a transmitter. The
modulated carrier is also amplified, then applied to an antenna that
converts the electrical signals to electromagnetic waves for radiation
into space. Such waves radiate at the speed of light and are transmitted
not only by line of sight but also by deflection from the ionosphere .

Receiving antennas intercept part of this radiation, change
it back to the form of electrical signals, and feed it to a receiver.
The most efficient and most common circuit for radio-frequency selection
and amplification used in radio receivers is the superheterodyne. In
that system, incoming signals are mixed with a signal from a local
oscillator to produce intermediate frequencies (IF) that are equal to
the arithmetical sum and difference of the incoming and local
frequencies. One of those frequencies is applied to an amplifier.
Because the IF amplifier operates at a single frequency, namely the
intermediate frequency, it can be built for optimum selectivity and
gain. The tuning control on a radio receiver adjusts the local
oscillator frequency. If the incoming signals are above the threshold of
sensitivity of the receiver and if the receiver is tuned to the
frequency of the signal, it will amplify the signal and feed it to
circuits that demodulate it, i.e., separate the signal wave itself from
the carrier wave.

There are certain differences between AM and FM receivers. In
an AM transmission the carrier wave is constant in frequency and varies
in amplitude (strength) according to the sounds present at the
microphone; in FM the carrier is constant in amplitude and varies in
frequency. Because the noise that affects radio signals is partly, but
not completely, manifested in amplitude variations, wideband FM
receivers are inherently less sensitive to noise. In an FM receiver, the
limiter and discriminator stages are circuits that respond solely to
changes in frequency. The other stages of the FM receiver are similar to
those of the AM receiver but require more care in design and assembly
to make full use of FM's advantages. FM is also used in television sound
systems. In both radio and television receivers, once the basic signals
have been separated from the carrier wave they are fed to a loudspeaker
or a display device (usually a cathode-ray tube), where they are
converted into sound and visual images, respectively.

Development of Radio Technology

Radio is based on the studies of James Clerk Maxwell, who
developed the mathematical theory of electromagnetic waves, and Heinrich
Hertz, who devised an apparatus for generating and detecting them.
Guglielmo Marconi, recognizing the possibility of using these waves for a
wireless communication system, gave a demonstration (1895) of the
wireless telegraph, using Hertz's spark coil as a transmitter and
Edouard Branly's coherer (a radio detector in which the conductance
between two conductors is improved by the passage of a high-frequency
current) as the first radio receiver. The effective operating distance
of this system increased as the equipment was improved, and in 1901,
Marconi succeeded in sending the letter S across the Atlantic Ocean
using Morse code . In 1904, Sir John A. Fleming developed the first
vacuum electron tube , which was able to detect radio waves
electronically. Two years later, Lee de Forest invented the audion, a
type of triode, or three-element tube, which not only detected radio
waves but also amplified them.

Radio telephony—the transmission of music and speech—also
began in 1906 with the work of Reginald Fessiden and Ernst F. W.
Alexanderson, but it was not until Edwin H. Armstrong patented (1913)
the circuit for the regenerative receiver that long-range radio
reception became practicable. The major developments in radio initially
were for ship-to-shore communications. Following the establishment
(1920) of station KDKA at Pittsburgh, Pa., the first commercial
broadcasting station in the United States, technical improvements in the
industry increased, as did radio's popularity. In 1926 the first
broadcasting network was formed, ushering in the golden age of radio.
Generally credited with creating the first modern broadband FM system,
Armstrong built and operated the first FM radio station, KE2XCC, in 1938
at Alpine, N.J. The least expensive form of entertainment during the
Great Depression, the radio receiver became a standard household
fixture, particularly in the United States. Subsequent research gave
rise to countless technical improvements and to such applications as
radio facsimile , radar, and television. The latter changed radio
programming drastically, and the 1940s and 50s witnessed the migration
of the most popular comedy and drama shows from radio to television.
Radio programming became mostly music and news and, to a lesser extent,
talk shows. The turn of the century saw a potential rebirth for radio as
mobile digital radio entered the market with a satellite-based
subscription service in Europe (1998) and in the United States (2000).
Two years later, a land-based digital radio subscription service was
inaugurated in the United States.

Radios that combine transmitters and receivers are now widely
used for communications. Police and military forces and various
businesses commonly use such radios to maintain contact with dispersed
individuals or groups. Citizens band (CB) radios, two-way radios
operating at frequencies near 27 megahertz, most typically used in
vehicles for communication while traveling, became popular in the 1970s.
Cellular telephones , despite the name, are another popular form of
radio used for communication.

Russian is the most geographically widespread language of Eurasia
and the most widely spoken of the Slavic languages. Russian belongs to
the family of Indo-European languages and is one of three (or, according
to some authorities, four) living members of the East Slavic languages,
the others being Belarusian and Ukrainian (and possibly Rusyn, often
considered a dialect of Ukrainian).

Written examples of Old East Slavonic are attested from the
10th century onwards, and while Russian preserves much of East Slavonic
grammar and a Common Slavonic word base, modern Russian exhibits a large
stock of borrowed international vocabulary for politics, science, and
technology. Due to the status of the Soviet Union as a superpower,
Russian had great political importance in the 20th century, and is still
one of the official languages of the United Nations.

Russian has palatal secondary articulation of consonants, the
so-called soft and hard sounds. This distinction is found in almost all
consonant phonemes and is one of the most distinguishing features of
the language. Another important aspect is the reduction, or drawling, of
unstressed vowels, not entirely unlike a similar process present in
most forms of English. Stress in Russian is generally quite
unpredictable and can be placed on almost any syllable, one of the most
difficult aspects for foreign language learners.

Classification

Russian is a Slavic language in the Indo-European family. From
the point of view of the spoken language, its closest relatives are
Ukrainian and Belarusian, the other two national languages in the East
Slavic group. Some academics also consider Rusyn an East Slavic
language; others consider Rusyn just a dialect of Ukrainian.

The basic vocabulary, principles of word formation, and, to
some extent, inflections and literary style of Russian have been also
influenced by Church Slavonic, a developed and partly adopted form of
the South Slavic Old Church Slavonic language used by the Russian
Orthodox Church. Upon annexion of the Novgorod by Muscovy in 1478,
Old-Novgorod dialect although vanished during 15–16 century, played a
significant role in formation of the modern Russian language. The
literary Russian has also a noticeable similarity with the modern
Bulgarian language sharing about 60% vocabulary in fiction literature
and up to 80% of the words used in journalistic genre while having
notable differences in grammar.

However, the East Slavic forms have tended to remain in the
various dialects that are experiencing a rapid decline. In some cases,
both the East Slavic and the Church Slavonic forms are in use, with
slightly different meanings. For details, see Russian phonology and
History of the Russian language.

Russian phonology and syntax (especially in northern
dialects) have also been influenced to some extent by the numerous
Finnic languages of the Finno-Ugric subfamily: Merya, Moksha, Muromian,
the language of the Meshchera, Veps etc. These languages, some of them
now extinct, used to be spoken right in the center and in the north of
what is now the European part of Russia. They came in contact with
Eastern Slavic as far back as the early Middle Ages and eventually
served as substratum for the modern Russian language. The Russian
dialects spoken north, north-east and north-west of Moscow have a
considerable number of words of Finno-Ugric origin.[1][2] The vocabulary
and literary style of Russian have also been greatly influenced by
Greek, Latin, French, German, and English. Modern Russian also has a
considerable number of words adopted from Bulgarian, Tatar and some
other Turkic languages.

According to the Defense Language Institute in Monterey,
California, Russian is classified as a level III language in terms of
learning difficulty for native English speakers,[3] requiring
approximately 780 hours of immersion instruction to achieve intermediate
fluency. It is also regarded by the United States Intelligence
Community as a "hard target" language, due to both its difficulty to
master for English speakers as well as due to its critical role in
American foreign policy.

Geographic distribution

Russian is primarily spoken in Russia and, to a lesser extent,
the other countries that were once constituent republics of the USSR.
Until 1917, it was the sole official language of the Russian Empire.
During the Soviet period, the policy toward the languages of the various
other ethnic groups fluctuated in practice. Though each of the
constituent republics had its own official language, the unifying role
and superior status was reserved for Russian. Following the break-up of
1991, several of the newly independent states have encouraged their
native languages, which has partly reversed the privileged status of
Russian, though its role as the language of post-Soviet national
intercourse throughout the region has continued.

In Latvia, notably, its official recognition and legality in
the classroom have been a topic of considerable debate in a country
where more than one-third of the population is Russian-speaking,
consisting mostly of post-World War II immigrants from Russia and other
parts of the former USSR (Belarus, Ukraine). Similarly, in Estonia, the
Soviet-era immigrants and their Russian-speaking descendants constitute
about one quarter of the country's current population.

A much smaller Russian-speaking minority in Lithuania has
largely been assimilated during the decade of independence and currently
represent less than 1/10 of the country's overall population.
Nevertheless, around 80% of the population of the Baltic states are able
to hold a conversation in Russian and almost all have at least some
familiarity with the most basic spoken and written phrases. The Russian
occupation of Finland in 1809–1918, however, has left few Russian
speakers to Finland. There are 33,400 Russian speakers in Finland,
amounting to 0.6% of the population. 5000 (0.1%) of them are late 19th
century and 20th century immigrants, and the rest are recent immigrants,
who have arrived in the 90's and later.

In the twentieth century, Russian was widely taught in the
schools of the members of the old Warsaw Pact and in other countries
that used to be satellites of the USSR. In particular, these countries
include Poland, Bulgaria, the Czech Republic, Slovakia, Hungary,
Romania, and Albania. However, younger generations are usually not
fluent in it, because Russian is no longer mandatory in the school
system. It was, and to a lesser extent still is, widely taught in Asian
countries such as Laos, Vietnam, and Mongolia due to Soviet influence.
Russian is still used as a lingua franca in Afghanistan by a few tribes.
It was also taught as the mandatory foreign language requisite in the
People's Republic of China before the Sino-Soviet Split.

Russian is also spoken in Israel by at least 750,000 ethnic
Jewish immigrants from the former Soviet Union (1999 census). The
Israeli press and websites regularly publish material in Russian.

Sizable Russian-speaking communities also exist in North
America, especially in large urban centers of the U.S. and Canada such
as New York City, Philadelphia, Boston, Los Angeles, San Francisco,
Seattle, Toronto, Baltimore, Miami, Chicago, and the Cleveland suburb of
Richmond Heights. In the former two Russian-speaking groups total over
half a million. In a number of locations they issue their own
newspapers, and live in their self-sufficient neighborhoods (especially
the generation of immigrants who started arriving in the early sixties).
It is important to note, however, that only about a quarter of them are
ethnic Russians. Before the dissolution of the Soviet Union, the
overwhelming majority of Russophones in North America were
Russian-speaking Jews. Afterwards the influx from the countries of the
former Soviet Union changed the statistics somewhat. According to the
United States 2000 Census, Russian is the primary language spoken in the
homes of over 700,000 individuals living in the United States.

Significant Russian-speaking groups also exist in Western
Europe. These have been fed by several waves of immigrants since the
beginning of the twentieth century, each with its own flavor of
language. Germany, the United Kingdom, Spain, France, Italy, Belgium,
Greece, Brazil and Turkey have significant Russian-speaking communities
totaling 3 million people.

Two thirds of them are actually Russian-speaking descendants
of Germans, Greeks, Jews, Armenians, or Ukrainians who either
repatriated after the USSR collapsed or are just looking for temporary
employment.

Earlier, the descendants of the Russian emigres tended to
lose the tongue of their ancestors by the third generation. Now, because
the border is more open, Russian is likely to survive longer,
especially because many of the emigrants visit their homelands at least
once a year and also have access to Russian websites and TV channels.

Official status

Russian is the official language of Russia, and an official
language of Belarus, Kazakhstan, Kyrgyzstan and the unrecognized
Transnistria, South Ossetia and Abkhazia. It is one of the six official
languages of the United Nations. Education in Russian is still a popular
choice for many of the both native and RSL (Russian as a second
language) speakers in Russia and many of the former Soviet republics.

97% of the public school students of Russia, 75% in Belarus,
41% in Kazakhstan, 53% in Ukraine, 23% in Kyrgyzstan, 21% in Moldova, 7%
in Azerbaijan, 5% in Georgia and 2% in Armenia and Tajikistan receive
their education only or mostly in Russian, although the corresponding
percentage of ethnic Russians is 78% in Russia, 10% in Belarus, 26% in
Kazakhstan, 54% in Ukraine, 9% in Kyrgyzstan, 6% in Moldova, 2% in
Azerbaijan, 1.5% in Georgia and less than 1% in both Armenia and
Tajikistan.

Russian-language schooling is also available in Latvia,
Estonia and Lithuania, despite the government attempts to reduce the
number of subjects taught in Russian.

Russian has co-official status alongside Romanian in seven
Romanian communes in Tulcea and Constanta counties. In these localities,
Russian-speaking Lipovans, who are a recognized ethnic minority, make
up more than 20% of the population. Thus, according to Romania's
minority rights law, education, signage and access to public
administration and the justice system are provided in Russian, alongside
Romanian.

This is what mr. Macky, school councellorfrom South park says. And people do believe, people think they do not need more knowledge, as this may be dangerous..

But have you ever though of the Scientia potentia est (Knowledge is power) pronoun? This relates to anything people may know about, because it is necessary to know even your fiercest enemies to overcome them!

Drugs are bad. But what are drugs? Is this anything that can change the consciousness, make person drunk, or is it something that brings to abuse? Do you know the answers? I think I do.

Drugs are the substances which summon the special state of the consciousness and physiology, but far not every kind of them brings to an abuse. The only abusive kind of drugs is Opiates - the substances that are extracted from Poppy plant. They are very harmful, they kill human starting from its personality and up to physical death... but that is all.

Also there are several kinds of substances, which less harmful than allowed alcohol, and unlike it do not bring to an abuse. They are Psychedelics, Cannabioids, Dissociatives and stimulators. These  are not abusive, but still harmful. However harmful doesn't mean killing at once, or making you kill, rob or steal things. They are less harful than alcoholoc bewerages, even being more active with your body and soul.

People should differ the substances and only after this we all will be set freу from social drug abuse.

Thus, I ask you not to believe propagada and get information yourself!

As questions if you have, will give you knwledge I have!