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.

Napa

Napa may refer to:

Places:

People:

Other uses:

NAPA may stand for:

Los Angeles

Los Angeles (ⁱ/lɒs ˈændʒəlᵻs/ loss AN-jə-ləs or loss AN-jə-liss) (Spanish for "The Angels"), officially the City of Los Angeles and often known by its initials L.A., is the second-largest city in the United States after New York City, the most populous city in the state of California, and the county seat of Los Angeles County.

Situated in Southern California, Los Angeles is known for its mediterranean climate, ethnic diversity, sprawling metropolis, and as a major center of the American entertainment industry. Los Angeles lies in a large coastal basin surrounded on three sides by mountains reaching up to and over 10,000 feet (3,000 m).

Historically home to the Chumash and Tongva, Los Angeles was claimed by Juan Rodríguez Cabrillo for Spain in 1542 along with the rest of what would become Alta California. The city was officially founded on September 4, 1781, by Spanish governor Felipe de Neve. It became a part of Mexico in 1821 following the Mexican War of Independence. In 1848, at the end of the Mexican–American War, Los Angeles and the rest of California were purchased as part of the Treaty of Guadalupe Hidalgo, thereby becoming part of the United States. Los Angeles was incorporated as a municipality on April 4, 1850, five months before California achieved statehood. The city experienced rapid growth with the discovery of oil.

Napa County, California

Napa County is a county located north of San Pablo Bay in the northern portion of the U.S. state of California. As of the 2010 census, the population was 136,484. The county seat is the City of Napa. Napa County was one of the original counties of California, created in 1850 at the time of statehood. Parts of the county's territory were given to Lake County in 1861.

Napa County comprises the Napa, CA Metropolitan Statistical Area, which is also included in the San Jose-San Francisco-Oakland, CA Combined Statistical Area. It is one of four North Bay counties.

Napa County, once the producer of many different crops, is known today for its regional wine industry, rising to the first rank of wine regions with France by local wineries Stag's Leap Wine Cellars and Chateau Montelena winning the "Judgment of Paris" in 1976.

History

Prehistory–18th century

In prehistoric times, the valley was inhabited by the Patwin Native Americans, with possible habitation by Wappo tribes in the northwestern foothills. Most villages are thought to have been constructed near the floodplains of watercourses that drain the valley. Their food consisted of wild roots, acorns, small animals, earthworms, grasshoppers, and bread made from crushed California buckeye kernels. In winter they would construct huts made of tree branches. In summer they camped near rivers and streams. In winter months, they were half clad in wild animal skins and at other times they wore no clothing. The maximum prehistoric population is thought not to have exceeded 5000 persons.

Radio advertisement

Commercial radio stations make most of their revenue selling "airtime" to advertisers. Of total media expenditures, radio accounts for 6.9%. Radio advertisements or "spots" are available when a business or service provides valuable consideration, usually cash, in exchange for the station airing their spot or mentioning them on air. The United States Federal Communications Commission (FCC), established under the Communications Act of 1934, regulates commercial broadcasting, and the laws regarding radio advertisements remain relatively unchanged from the original Radio Act of 1927, enacted to deal with increasing problems of signal interference as more and more stations sprung up around the country.

History

The first radio broadcasts aired in the early 1900s. However, it wasn't until 1919 that radio stations began to broadcast continuously, similar to the modern practice. In the United States, on November 2, 1920, KDKA Pittsburgh became the first radio station to receive a commercial license from the government. KDKA engineer Frank Conrad may have been the first to broadcast a radio advertisement on his own experimental station in 1919 when he thanked a Pittsburgh music store on the air for supplying him with phonograph records, although that was for trade, not cash.