Radio

Radio is originally a form of wireless telecommunication in which a radio channel messages spread in the form of radio waves . The signal was received by a radio device.Nowadays, each channel through which unfinished transmittance is broadcast as radio, regardless of the technique.

Contents

 * 1 Operation of the radio
 * 2 Technical history
 * 2.1 Dispute about the invention
 * 2.2 AM and FM
 * 2.3 analog to digital
 * 2.4 The electromagnetic spectrum
 * 3 Use Development

Operation of the radio
An important part of a radio transmitter is the oscillator . This generates the radio frequency signal as a carrier wave serves, and after modulation by an antenna can be radiated. To sound to transmit the sound by means of a microphone is first converted into an electrical signal, which is modulated the generated oscillator signal (changed) becomes. The most common types of modulation are amplitude modulation (AM) and frequency modulation (FM). FM broadcasts provide higher sound quality than AM broadcasts. On the reception side, the transmitted signal captured by the receiving antenna, and transmitted to the receiver. In the beginning, this crystal radios, which sound using a headset made ​​audible. After the invention of the electron tube (in short "tube", and in the vernacular "lamp" referred to) were receivers equipped therewith, so that these were of better quality, in particular by application of the principle of the superheterodyne . Also could by strengthening the sound through a speaker are displayed.

Technical History
In 1895 wanted Nikola Tesla first give a demonstration to send electrical signals over long distances. Unfortunately, summed up his workspace fire and he could not carry out the experiment. In the same year succeeded Guglielmo Marconi (1874-1937) or for the first few kilometers to a radio link with a homemade transmitter and receiver which was based on an oscillator of Tesla's designs. Around the same time did Alexander Stepanovich Popov same. Both built on the work of Heinrich Hertz, who in 1887 discovered how electromagnetic radio waves could be generated and returned.

Dispute over the invention
In Italy Marconi's work was not appreciated and that is why he went to England . He managed to bridge larger distances and he could send a message across the Atlantic in 1901. However, there can not be one of those mentioned above is the inventor of the radio. This requires both a transmitter and a receiver needed and are each contain several components that each have gone through their own development. The antenna, an important part, however, is an invention of Marconi. Otis Pond, an engineer who worked for Tesla once said, "It seems that Marconi has the idea of ​​you." Tesla replied, "Marconi is a good man. Let him go. He used 17 patents from me." When Marconi Nobel Prize was given in 1909, Tesla was furious. However it was only until 1943 -a few months after the death of Tesla Tesla finally got the patent on the invention of the radio, with the number 645.576.

In a few years were bridged longer distances led by Marconi: In the beginning was used radio only as a means to Morse signals to broadcast. By the invention of the electron tube in 1906 became possible to transmit the actual sounds. Messages could now be recorded directly and no longer have to be translated into Morse code. After the development of the transistor in 1947, it became possible to build much smaller receivers, which also require less energy to operate.
 * In 1899 the first radio link over the English Channel between England and France.
 * 1901 The first transatlantic radio link between Britain and Newfoundland.
 * In 1919 the first Dutch radio program. Initiator and presenter was broadcasting pioneer ir. Hanso Schotanus à Steringa Idzerda who organized the broadcast from his home in The Hague.

AM and FM
The first common way to realize sound transmission was by the amplitude of the carrier wave to let vary, is proportional to the amplitude of the sound signal to be transferred. This form is called modulation amplitude modulation, abbreviated AM.

Edwin Armstrong discovered another way to modulate the carrier wave: by not the amplitude, but to vary the frequency of the carrier wave with the amplitude of the signal, creating frequency modulation (FM). FM is much less susceptible to interference than AM and FM broadcasts deliver HiFi sound for videos

From analog to digital
The digital radio is at present developing into full-fledged successor to the original.

Via the Internet, it is possible for Internet radio listening. It is not made use of radio waves, but the Internet connections between computers, sending digital data to each other. These connections between computers on the Internet, however, can (partially) are wireless, and therefore possible to use radio waves.

The electromagnetic spectrum
Radio waves are still applied in the band from VLF (Very Low Frequency) to EHF (radio spectrum) (Extreme High Frequency). Standard Radio Traffic is overwhelmingly in the band 30 kHz (world broadcasters) t / m 300 GHz (satellite connections).

The other abbreviations are, from top to bottom:
 * Gamma
 * High X-ray ( X-ray )
 * Super X-ray
 * Extreme Ultra Violet ( UV )
 * Normal Ultra Violet
 * Visible light
 * Normal Infra-red ( IR )
 * Medium Infra-red
 * Far Infra-red
 * Extreme High Frequency
 * Super High Frequency Ultra High Frequency
 * Very High Frequency
 * High Frequency ( shortwave )
 * Medium Frequency ( MW )
 * Low Frequency ( long wave )
 * Very Low Frequency
 * VF
 * Extreme Low Frequency

Use Development
The first radio communications were intended for wireless telegraphy between coast stations (in Netherlands Scheveningen Radio ) and ships at sea. For this, it was Morse used. Later telephony for short connections with fishing boats went into operation.

The development of the aviation came around the First World War, the radio traffic between aircraft and ground stations in use.

In Belgium in 1914 the first radio broadcast. When listening to the entire royal family via a radio receiver to an aria from "Tosca". Albert and his wife Elisabeth were among the first radio enthusiasts.

In 1919 the first broadcast station in the world was in the air in The Hague . It was the station with the call letters of PCGG Hanso Schotanus à Steringa Idzerda .

In 1933 became the first European car offered with a car radio as an option.

Around 1935 were in England held the first test broadcasts with image, the birth of the television .

During the Second World War for military purposes became more applications have been developed and put into use radio signals, such as radar , radio navigation , beacon transmitters and time channels .

Nowadays, a lot of listening to the radio at work, in the car, at the store .... In factories and on ships is often used a central radio system in which the receiver and the distribution amplifier is installed in a space where the loudspeaker signal is distributed through distribution amplifiers across the entire company. The sections are arranged on the ceiling loudspeakers and radio's volume to a department can be adjusted by means of a volume control on the wall. The loudspeaker signal is about 100 V to suffer less from the loss resistance of long lines. In the loudspeakers is then a matching transformer in order to adapt the 100 V signal to the loudspeaker. Through the installation can also be summoned and communications are transmitted.