Science & Technology: RADIO TECHNOLOGY: HISTORY AND ITS DEVELOPMENT (English Version)

RADIO TECHNOLOGY: HISTORY AND ITS DEVELOPMENT

Radio is a technology used for sending signals by modulation and electromagnetic waves. These waves propagate through the air and can also propagate through empty space because these waves do not need a transport medium such as air molecules. The radio inventor should owe two other inventions, namely: telephone and telegraph. Radio, telephone and telegraph technology has a very close relationship because everything starts from the discovery of radio waves.

HISTORY OF RADIO TECHNOLOGY

In 1834, Samuel Morse invented Telegraph technology. And in 1876, Alexander Graham Bell invented telephone technology. But these two technologies still use cables. In the 1860s, the basis of the theory of electromagnetic waves was first explained by Scottish physicist James Maxwell, regarding the theory of electromagnetic fields in his paper at the Royalty Society.

In 1878, David E. Hugher became the first person to send and receive radio waves when he discovered that his induction balance caused interference with his telephone. He demonstrated his findings to the Royal Society in 1880, but only said that this was only induction.

In 1886, Heinrich Rudolf Hertz became the first person to prove Maxwell's theory to be correct by exhibiting projections of the variation of the swift currents of electricity into space in the form of radio waves. It was only in 1909 that radio technology was discovered, an electrical engineer from Italy, Guglielmo Marconi, developed a wireless telegraphic system known as "radio". For this discovery, he was awarded the Nobel prize with his colleague Karl Braun.

Gugliemo Marconi was born in 1874 in Bologna, Italy. He is the second son of the couple Giuseppe Marconi with Annie Jameson. He completed his education at the University of Bologna. When he was 20 years old, Marconi learned a lot of experiments conducted by Heinrich Hertz about electromagnetic waves that move through the air at the speed of sound. Marconi then thought of the idea that these waves could be used to send signals remotely without using cables that provided a lot of possibilities for communication to be unreachable by telegrams, for example: with this technology, information could be sent to ships in the middle of the sea.

In 1896, Guglielmo Marconi patented his findings regarding the wireless telegraph using two circuits. The tool he discovered was the beginning of the use of technology to create radio. Initially the signal that can be sent by the wireless network is less than 10 miles. But in 1897, Guglielmo Marconi re-published new findings that could send wireless signals at a distance farther than before, which was 12 miles.

In mid-1894, Marconi realized that an electric current could jump across the air from wire to wire. Over eight weeks, he conducted research by buying batteries, wires, tubes and oscillators. With a battery power transmitter, it makes a signal that can jump across space into the receiver wire so that the compass magnetic needle slowly changes direction, but no one is impressed by the success of this first test. He tried to find out what caused the movement of the compass needle which only moved slowly. For one month, he studied the knowledge of electric current. It turns out that the electric current received by the receiver is too weak to do anything more.

One day he got the idea that a large glass glass filled with iron metal could receive a signal better than a flat wire. With an iron-filled tube in the receiver, Marconi can make the receiver stronger in detecting electrical signals from the transmitter. Marconi tried to make the doorbell as the receiver on the third floor. Meanwhile, the transmitter is on the first floor. The experiment was successful, except that his father thought it was just a joke.

In the next experiment, Marconi replaced iron contents with nickel and silver. He called it a "signal condenser" incandescent. Then it flattens the metal plate horizontally below the condenser signal to reflect the additional signal strength into the condenser and prevents the signal from coming out of the condenser. He tried sending a signal to the top of a hill near his house which had a distance of about 200 meters. And finally, Marconi's father began to be impressed by the discovery of his son.

Marconi successfully demonstrated his discovery in England and obtained his first patent for this invention. Then Marconi started to establish his first company in 1898. A year later, in 1899, Guglielmo Marconi succeeded in making wireless communication between France and England through the English Channel using the tesla oscillator. His company has been able to send information wirelessly across the English Channel. And in 1901, he managed to send radio news across the Atlantic Ocean from England to Newfoundland.

Then in 1904, John Ambrose Fleming managed to find an audio tube that could be used as a wireless signal receiver for radio technology that was previously developed by Guglielmo Marconi. In 1906, 1906, Reginald Fessenden used synchronous rotary-spark transmitter for his first radio broadcast program in Brant Rock, Massachusetts, USA. Dr. Lee de Forest developed audio tube technology consisting of three elements, called triode audion. The discovery of Lee de Forest allows sound wave signals to be transmitted through wireless communication systems. Although the signal captured by the device is still very weak.

The significance of this discovery was dramatically described in 1909 when the ship S.S. Republic was damaged by collisions and sank to the sea floor. Radio news is very helpful in saving ship passengers. In the same year Marconi won the Nobel prize for his discovery, namely: a wireless telegraphic system commonly known as "radio".

Around 1912, Edwin Howard Armstrong invented a device called a radio amplifier, a device for radio wave amplifiers. This tool works by capturing electromagnetic signals from radio transmissions and sending back signals from audio tubes. With this radio wave amplifier, the signal produced will increase by 20,000 times per second. This tool can also allow the sound to be issued louder, so that it can be heard directly without the need for earphones. The discovery of this tool then becomes very important in radio communication systems because it is far better and more efficient than the findings of previous tools.

The first radio broadcast containing news programs began airing by the 8MK station in Detroit, Michigan, USA, on August 31, 1920. The first college radio station called 2ADD which later changed its name to WRUC began broadcasting on October 14, 1920 at Union College, Schenectady, New York, USA. The first regular entertainment radio broadcast aired in 1922 at Marconi Research Center, Writtle, near Chelmsford, England.

Edwin Howard Armstrong then found a frequency modulation system (FM) that produced clearer sound, and was not disturbed by bad weather in 1933. However, his discovery was not supported by many people, because when the new tool was created there was economic turbulence in the world, so cannot be mass produced. Armstrong later founded the first FM radio station at his own expense in 1940. His struggle to develop the FM system was so heavy that he was finally depressed and decided to end his life.

In the late 1960s, US long-distance telephone networks began using digital radio signals for several connections. The first radio communications satellite, TELSTAR, was launched in 1963. In the 1970s, the US Navy developed a radio satellite navigation experiment, and launched a GPS constellation in 1987. In the early 1990s, amateur radio experimenters began using PCs ( personal computer) equipped with an audio card to process radio signals. In the late 1990s, digital radio signal transmission began to be used on radio broadcasts. In 1994, the US Army and DARPA succeeded in making a radio software development project.

Armstrong's FM is a system that can be accepted by the community. Nearly 2,000 FM radio stations are spread throughout the United States. Frequency modulation is a tool that supports the emergence of microwaves. Until finally FM was recognized as a superior system that was very influential in all fields of communication.

RADIO WAVE

Radio waves are a form of electromagnetic radiation, and are formed when electrically charged objects from oscillator waves (carrier waves) are modulated with audio waves (frequency superimposed) at frequencies contained in radio wave frequencies (RF; "radio frequency")) on a spectrum electromagnetic, and electromagnetic radiation moves by electric or magnetic oscillations.

Other electromagnetic waves that have frequencies above radio waves include gamma rays, X-rays, infrared, ultraviolet and visible light. When radio waves are sent through a cable then emitted by an antenna, the oscillations of the electric and magnetic fields are expressed in the form of alternating current and voltage inside the cable. From the emission of radio waves can then be changed by the receiving radio (radio plane) into an audio signal or other that carries broadcast and information.

Radio waves travel at frequencies of 100,000 Hz to 100,000,000,000 Hz, while audio waves propagate at frequencies of 20 Hz to 20,000 Hz. On radio broadcasts, audio waves are not transmitted directly but are superimposed on radio waves that will propagate through space. There are two methods of transmitting audio waves, namely through amplitude modulation (AM) and frequency modulation (FM).

Although the word 'radio' is used for matters relating to sound wave receivers, the wave transmission is used as the basis of waves on television, radio, radar, and mobile phones in general.

SATELLITE RADIO

A satellite radio or radio subscription is a digital radio that receives signals broadcast by communication satellites, which cover a wider geographical area than ordinary radio signals.

Satellite radio works in a place where there is a line of sight between antennas and satellites, provided that there are no major obstacles, such as tunnels or buildings. These radio listeners can follow a single channel without seeing the range of locations.

Because this technology requires access to commercial satellites for signal distribution, satellite radio services are a commercial business, which offers a channel package as part of their services - requires a subscription from the end user to access the channel.

Currently, the main satellite radio providers are WorldSpace (Intl.), XM Radio & sirius (U.S.). Because the signal is copyrighted and incompatible with each other, it requires special equipment for decoding and playback. They offer news, weather, sports and music channels.

HISTORY OF SATELLITE RADIO

Now, radio broadcast technology is undergoing a revolution with the advent of satellite-based radio broadcasts (satellite radio broadcast). Its history began in 1992 in the United States (US). At that time, the FCC (Federal Communications Commission) which is a telecommunications regulatory agency in the US allocated a spectrum in the "S" frequency band (around 2.3 GHz) for satellite-based national (US) broadcasts using digital audio (digital audio radio service / DARS). Only four companies have volunteered to get broadcast permits. In 1997, the FCC gave permission to: CD Radio (which was renamed Sirius Satellite Radio) and American Mobile Radio (which changed its name to XM Satellite Radio). Each pays more than 80 million US dollars to use a band or available frequency band. As it turned out, only XM Radio could continue its business and start broadcasting nationally on September 25, 2001. While Sirius had not been able to follow up, XM Radio offered various programs and high-quality audio reception for fans of home audio and car audio. From the broadcast center (broadcast center) in Washington DC that has 82 digital studios, XM Radio emits 101 channels containing programs: music, news, interviews or talk shows, sports, comedy, and children's events. The 101 channels were emitted together to the satellite. Customers can receive directly from satellites or through existing repeater stations.

ADVANTAGE OF SATELLITE RADIO

By using satellites, the area coverage produced by this system is clearly wider than what conventional radio stations have achieved. In the US, the area coverage is restricted to all regions of the country. That way, listeners who are traveling from one city to another in the US no longer need to move channels to different radio stations. Just tune it to XM Radio once, after that it doesn't need to be changed again.

Basically, the radio signal emitted will always experience attenuation. The farther the distance traveled, the weaker the signal will reduce the quality of the audio received. The use of high-power satellites (XM Radio using a 500 kilowatt satellite) with a direct beam to Earth will produce radio signals that are acceptable to the receiving aircraft. To be able to receive broadcasts from satellites, the receiving antenna and satellite must be in line of sight conditions (straight, straight without obstruction). This condition will not be achieved if the recipient is located in a valley or city full of high rise buildings. To overcome this, a repeater station is installed which functions as a satellite intermediary with the receiver. This method will reduce blankspot areas.

CHARACTERISTICS OF RADIO MEDIA IN PODCAST

Unlike television, radio listeners do not need to judge something that appears on the screen. Because radio has a personal character, which makes listeners feel close. What was conveyed by the announcer entered the minds of listeners so that they were immediately accepted. Therefore a good announcer in broadcasting must speak to one person or individual, not to many people.

The closeness of listeners with this radio station is of more value than radio media that only relies on votes. The only limitation to sound does not mean that the radio becomes excluded from other media. Only by sound, the listener becomes able to imagine only refers to sound. According to Stanley Alten in his book Audio in Media, sound has a visual component that creates images in the minds of listeners or the theater of mind.

PODCASTING BENEFITS

There are many benefits of podcasting that you can receive if you use it as a marketing and communication tool:

Increase your site's visibility Your target audience will be able to find your site more easily when you list your podcast in the available podcast directory. Visibility for your site will increase greatly. Similarly, search engines will be able to find your podcast easier too.
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Providing ease of use Your podcast can be easily played on a portable MP3 player. People will be able to listen to your podcast anywhere and anytime. Podcasting makes listening to your messages so easy, without fuss.