Radio station

A radio station is a set of equipment necessary to carry on communication via radio waves. Generally, it is a receiver and/or transmitter, an antenna, and some smaller additional equipment necessary to operate them. Radio stations play a vital role in communication technology as they are heavily relied on to transfer data and information across the world.

More broadly, the definition of a radio station includes the aforementioned equipment and a building in which it is installed. Such a station may include several "radio stations" defined above (i.e. several sets of receivers and/or transmitters installed in one building but functioning independently, and several antennas installed on a field next to the building). This definition of a radio station is more often referred to as a transmitter site, transmitter station, transmission facility or transmitting station. An example of this definition is Bethany Relay Station of the Voice of America which had seven broadcast transmitters and could broadcast up to seven independent programs (even produced by different broadcasters) simultaneously, as well as several communications transmitters and receivers.

Radio broadcasting

Radio broadcasting is a unidirectional wireless transmission over radio waves intended to reach a wide audience. Stations can be linked in radio networks to broadcast a common radio format, either in broadcast syndication or simulcast or both. Audio broadcasting also can be done via cable radio, local wire television networks, satellite radio, and internet radio via streaming media on the Internet. The signal types can be either analog audio or digital audio.

In 2009, there were 3,494 radio broadcasting stations in the United States.

History

The earliest radio stations were simply radiotelegraphy systems and did not carry audio. For audio broadcasts to be possible electronic detection and amplification devices had to be incorporated.

The thermionic valve was invented in 1904 by the English physicist John Ambrose Fleming. He developed a device he called an "oscillation valve" (because it passes current in only one direction). The heated filament, or cathode, was capable of thermionic emission of electrons that would flow to the plate (or anode) when it was at a higher voltage. Electrons, however, could not pass in the reverse direction because the plate was not heated and thus not capable of thermionic emission of electrons. Later known as the Fleming valve, it could be used as a rectifier of alternating current and as a radio wave detector. This greatly improved the crystal set which rectified the radio signal using an early solid-state diode based on a crystal and a so-called cat's whisker. However, what was still required was an amplifier.

Radio

Radio is the use of radio waves is to carry information, such as sound, by systematically modulating some property of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.

Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation). Radio systems also need an antenna to convert electric currents into radio waves, and vice versa. An antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual stations to be selected. The electromagnetic wave is intercepted by a tuned receiving antenna. A radio receiver receives its input from an antenna and converts it into a form usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc. Radio frequencies occupy the range from a 3 kHz to 300 GHz, although commercially important uses of radio use only a small part of this spectrum.

Names of the United States

This is a list of names of the United States of America in languages of the world.

List of names

See also

Matt Jordan

Matt Jordan (born October 13, 1975 in Aurora, Colorado) is a former soccer goalkeeper. He is currently the Technical Director and General Manager for the Houston Dynamo of Major League Soccer.

Career

Matt Jordan spent four years as the Montreal Impact's Technical Director after being appointed to the position, following a 13-year professional playing career. Jordan was named the Houston Dynamo's Technical Director/General Manager on November 4, 2014. Source

Playing career

As a player, Jordan, a product of Clemson University where he was a two-time First team All-American and Finalist for NCAA player of the year, was drafted 10th overall by the Dallas Burn in the first round of the 1998 MLS College Draft. He went on to play 117 games in eight seasons in Major League Soccer, compiling a record of 53-46-17 and 30 shutouts with Dallas, Columbus and Colorado.

Dallas Burn

With Dallas, Jordan was selected to the 1999 MLS All-Star Game and was a Finalist for MLS Goalkeeper of the Year, after finishing that season with a goal-against average of 1.08 and setting a new league record for shutouts with 11. He helped the team reach the playoffs in each of his five seasons with the club and was voted the club’s defender of the year and humanitarian of the year during that time.