AM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for medium wave (also known as "AM band") transmissions, but also on the longwave and shortwave radio bands.
132-569: WNBF (1290 AM ) is a commercial radio station in Binghamton, New York . It airs a news/talk format and is owned by Townsquare Media . The studios and offices are on Court Street in Binghamton. By day, WNBF is powered at 9,300 watts using a non-directional antenna . But at night, to protect other stations on AM 1290 , it reduces power to 5,000 watts and switches to a three- tower array directional antenna . The transmitter
264-405: A council-manager government, with the council members elected at-large. In 1967, the city changed its government to elect four of the seven city council members from single-member districts or wards, rather than at-large. This enabled a broader representation of voters. As with many major urban areas, the city core began losing population to the suburbs in the 1960s (the peak population of 208,982
396-472: A "chain". The Radio Corporation of America (RCA), General Electric , and Westinghouse organized a competing network around its own flagship station, RCA's WJZ (now WABC) in New York City, but were hampered by AT&T's refusal to lease connecting lines or allow them to sell airtime. In 1926 AT&T sold its radio operations to RCA, which used them to form the nucleus of the new NBC network. By
528-846: A 10 shilling receiver license fee. Both highbrow and mass-appeal programmes were carried by the National and Regional networks. The period from the early 1920s through the 1940s is often called the "Golden Age of Radio". During this period AM radio was the main source of home entertainment, until it was replaced by television. For the first time entertainment was provided from outside the home, replacing traditional forms of entertainment such as oral storytelling and music from family members. New forms were created, including radio plays , mystery serials, soap operas , quiz shows , variety hours , situation comedies and children's shows . Radio news, including remote reporting, allowed listeners to be vicariously present at notable events. Radio greatly eased
660-516: A 5-foot-thick (1.5 m) coal bed. By 1876, this mine employed 150 men and shipped 20 carloads of coal per day. By 1885, numerous mine shafts were within the city limits, and mining began to spread into the surrounding countryside. By 1893, 23 mines were in the region. By 1908, Des Moines' coal resources were largely exhausted. In 1912, Des Moines still had eight locals of the United Mine Workers union, representing 1,410 miners. This
792-570: A central station to all parts of the United States", he was unable to overcome the inherent distance limitations of this technology. The earliest public radiotelegraph broadcasts were provided as government services, beginning with daily time signals inaugurated on January 1, 1905, by a number of U.S. Navy stations. In Europe, signals transmitted from a station located on the Eiffel Tower were received throughout much of Europe. In both
924-610: A concerted attempt to specify performance of AM receivers through the 1993 AMAX standard, a joint effort of the EIA and the NAB, with FCC backing... The FCC rapidly followed up on this with codification of the CQUAM AM stereo standard, also in 1993. At this point, the stage appeared to be set for rejuvenation of the AM band. Nevertheless, with the legacy of confusion and disappointment in the rollout of
1056-635: A consortium, the British Broadcasting Company (BBC), established on 18 October 1922, which was given a monopoly on broadcasting. This enterprise was supported by a tax on radio sets sales, plus an annual license fee on receivers, collected by the Post Office. Initially the eight stations were allowed regional autonomy. In 1927, the original broadcasting organization was replaced by a government chartered British Broadcasting Corporation . an independent nonprofit supported solely by
1188-564: A continuous-wave (CW) transmitter. Fessenden began his research on audio transmissions while doing developmental work for the United States Weather Service on Cobb Island, Maryland. Because he did not yet have a continuous-wave transmitter, initially he worked with an experimental "high-frequency spark" transmitter, taking advantage of the fact that the higher the spark rate, the closer a spark-gap transmission comes to producing continuous waves. He later reported that, in
1320-428: A female householder with no husband present, 5.3% had a male householder with no wife present, and 41.6% were non-families. 32.5% of all households were made up of individuals, and 9.4% had someone living alone who was 65 years of age or older. The average household size was 2.43 and the average family size was 3.11. The median age in the city was 33.5 years. 24.8% of residents were under the age of 18; 10.9% were between
1452-580: A few " telephone newspaper " systems, most of which were established in Europe, beginning with the Paris Théâtrophone . With this in mind, most early radiotelephone development envisioned that the device would be more profitably developed as a "wireless telephone" for personal communication, or for providing links where regular telephone lines could not be run, rather than for the uncertain finances of broadcasting. The person generally credited as
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#17327808821551584-463: A few hundred ( Hz ), to increase its rotational speed and so generate currents of tens-of-thousands Hz, thus producing a steady continuous-wave transmission when connected to an aerial. The next step, adopted from standard wire-telephone practice, was to insert a simple carbon microphone into the transmission line, to modulate the carrier wave signal to produce AM audio transmissions. However, it would take many years of expensive development before even
1716-516: A home audio device prior to the introduction of the high-fidelity , long-playing record in the late 1940s. Listening habits changed in the 1960s due to the introduction of the revolutionary transistor radio (Regency TR-1, the first transistor radio released December 1954), which was made possible by the invention of the transistor in 1948. (The transistor was invented at Bell labs and released in June 1948.) Their compact size — small enough to fit in
1848-474: A listening site at Plymouth, Massachusetts. An American Telephone Journal account of the December 21 alternator-transmitter demonstration included the statement that "It is admirably adapted to the transmission of news, music, etc. as, owing to the fact that no wires are needed, simultaneous transmission to many subscribers can be effected as easily as to a few", echoing the words of a handout distributed to
1980-487: A majority of early broadcasting stations operated on mediumwave frequencies, whose limited range generally restricted them to local audiences. One method for overcoming this limitation, as well as a method for sharing program costs, was to create radio networks , linking stations together with telephone lines to provide a nationwide audience. In the U.S., the American Telephone and Telegraph Company (AT&T)
2112-506: A national scale. The introduction of nationwide talk shows, most prominently Rush Limbaugh 's beginning in 1988, was sometimes credited with "saving" AM radio. However, these stations tended to attract older listeners who were of lesser interest to advertisers, and AM radio's audience share continued to erode. In 1961, the FCC adopted a single standard for FM stereo transmissions, which was widely credited with enhancing FM's popularity. Developing
2244-575: A peak in the warmer months. Winters are slightly colder than Chicago , but still warmer than Minneapolis , with summer temperatures being very similar between the Upper Midwest metropolitan areas. The city has the largest African American population in Iowa. The 2020 United States census counted 214,133 people, 87,958 households, and 48,599 families in Des Moines. The population density
2376-399: A policy allowing AM stations to simulcast over FM translator stations. Translators had previously been available only to FM broadcasters, in order to increase coverage in fringe areas. Their assignment for use by AM stations was intended to approximate the station's daytime coverage, which in cases where the stations reduced power at night, often resulted in expanded nighttime coverage. Although
2508-410: A project to provide local employment and improve infrastructure. The ornamental fountains that stood along the riverbank were buried in the 1950s when the city began a postindustrial decline that lasted until the late 1980s. The city has since rebounded, transforming from a blue-collar industrial city to a white-collar professional city. In 1907, the city adopted a city commission government known as
2640-486: A prototype alternator-transmitter would be ready, and a few years beyond that for high-power versions to become available. Fessenden worked with General Electric 's (GE) Ernst F. W. Alexanderson , who in August 1906 delivered an improved model which operated at a transmitting frequency of approximately 50 kHz, although at low power. The alternator-transmitter achieved the goal of transmitting quality audio signals, but
2772-423: A result, AM radio tends to do best in areas where FM frequencies are in short supply, or in thinly populated or mountainous areas where FM coverage is poor. Great care must be taken to avoid mutual interference between stations operating on the same frequency. In general, an AM transmission needs to be about 20 times stronger than an interfering signal to avoid a reduction in quality, in contrast to FM signals, where
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#17327808821552904-651: A sequential roster of available call signs. The station was moved to 1450 kHz on June 15, 1927. On November 11, 1928, it was reassigned to 1500 kHz as a low-powered "local" station, as part of a major reallocation implemented by the Federal Radio Commission 's General Order 40 . Later that month the studios moved to the Arlington Hotel in Binghamton. In 1940, the Federal Communications Commission awarded
3036-452: A shirt pocket — and lower power requirements, compared to vacuum tubes, meant that for the first time radio receivers were readily portable. The transistor radio became the most widely used communication device in history, with billions manufactured by the 1970s. Radio became a ubiquitous "companion medium" which people could take with them anywhere they went. The demarcation between what is considered "experimental" and "organized" broadcasting
3168-427: A short-range "wireless telephone" demonstration, that included simultaneously broadcasting speech and music to seven locations throughout Murray, Kentucky. However, this was transmitted using induction rather than radio signals, and although Stubblefield predicted that his system would be perfected so that "it will be possible to communicate with hundreds of homes at the same time", and "a single message can be sent from
3300-461: A widespread audience — dates back to the founding period of radio development, even though the earliest radio transmissions, originally known as "Hertzian radiation" and "wireless telegraphy", used spark-gap transmitters that could only transmit the dots-and-dashes of Morse code . In October 1898 a London publication, The Electrician , noted that "there are rare cases where, as Dr. [Oliver] Lodge once expressed it, it might be advantageous to 'shout'
3432-527: Is a member of ICLEI Local Governments for Sustainability USA . Through ICLEI, Des Moines has implemented "The Tomorrow Plan", a regional plan focused on developing central Iowa in a sustainable fashion, centrally-planned growth, and resource consumption to manage the local population. According to the United States Census Bureau , the city has an area of 90.65 square miles (234.78 km ), of which 88.93 square miles (230.33 km )
3564-536: Is at the juncture of the Des Moines and Raccoon Rivers. It is mostly a level prairie with a few swells or hills around it. We have a court house of "brick" and one church, a plain, framed building belonging to the Methodists. There are two taverns here, one of which has a most important little bell that rings together some fifty boarders. I cannot tell you how many dwellings there are, for I have not counted them; some are of logs, some of brick, some framed, and some are
3696-406: Is comparable to or better in audio quality than a standard analog broadcast". Despite the various actions, AM band audiences continued to contract, and the number of stations began to slowly decline. A 2009 FCC review reported that "The story of AM radio over the last 50 years has been a transition from being the dominant form of audio entertainment for all age groups to being almost non-existent to
3828-457: Is land and 1.73 square miles (4.48 km ) is covered by water. It is 850 feet (260 m) above sea level at the confluence of the Raccoon and Des Moines Rivers. In November 2005, Des Moines voters approved a measure that allowed the city to annex parcels of land in the northeast, southeast, and southern corners of Des Moines without agreement by local residents, particularly areas bordering
3960-502: Is largely arbitrary. Listed below are some of the early AM radio broadcasts, which, due to their irregular schedules and limited purposes, can be classified as "experimental": People who weren't around in the Twenties when radio exploded can't know what it meant, this milestone for mankind. Suddenly, with radio, there was instant human communication. No longer were our homes isolated and lonely and silent. The world came into our homes for
4092-592: Is located on, and named after, the Des Moines River , which likely was adapted from the early French name, Rivière des Moines, meaning "River of the Monks ". The city's population was 214,133 as of the 2020 census . The six-county metropolitan area is ranked 81st in terms of population in the United States , with 709,466 residents according to the 2020 census by the United States Census Bureau , and
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4224-536: Is off Ingraham Hill Road in Binghamton, among the towers for other broadcast stations in the Binghamton area. WNBF is also heard on 250-watt FM translator W221EJ at 92.1 MHz . Weekdays begin with two local shows, First News with Don Morgan followed by Binghamton Now with Bob Joseph . The rest of the weekday schedule is made up of nationally syndicated conservative talk programs: The Dan Bongino Show , The Sean Hannity Show , The Mark Levin Show , CBS Eye on
4356-734: Is one of the Southern Tier 's oldest radio stations. Although the station has traditionally traced its founding to 1928, the year it moved to Binghamton, it was first licensed on February 7, 1927, to the Howitt-Wood Radio Company (Lyle E. Howitt and H. L. Wood) at 117 West Main Street in Endicott, New York, with 50 watts on 1460 kHz, operating from the Elvin Theater. The WNBF call letters were randomly assigned from
4488-645: Is simpler than later transmission systems. An AM receiver detects amplitude variations in the radio waves at a particular frequency, then amplifies changes in the signal voltage to operate a loudspeaker or earphone . However, the simplicity of AM transmission also makes it vulnerable to "static" ( radio noise , radio frequency interference ) created by both natural atmospheric electrical activity such as lightning, and electrical and electronic equipment, including fluorescent lights, motors and vehicle ignition systems. In large urban centers, AM radio signals can be severely disrupted by metal structures and tall buildings. As
4620-643: Is the largest metropolitan area fully located within the state. Des Moines is a major center of the United States insurance industry and has a sizable financial-services and publishing business base. The city is the headquarters for the Principal Financial Group , Ruan Transportation, TMC Transportation, EMC Insurance Companies, and Wellmark Blue Cross Blue Shield . Other major corporations such as Wells Fargo , Cognizant , Voya Financial , Nationwide Mutual Insurance Company , ACE Limited , Bayer , and Corteva have large operations in or near
4752-578: The Electronic Industries Association (EIA) and the National Association of Broadcasters (NAB) with the intention of helping AM stations, especially ones with musical formats, become more competitive with FM broadcasters by promoting better quality receivers. However, the stereo AM and AMAX initiatives had little impact, and a 2015 review of these events concluded that Initially the consumer manufacturers made
4884-625: The Emergency Alert System (EAS). Some automakers have been eliminating AM radio from their electric vehicles (EVs) due to interference from the electric motors , but the lawmakers argue that this is a safety risk and that car owners should have access to AM radio regardless of the type of vehicle they drive. The proposed legislation would require all new vehicles to include AM radio at no additional charge, and it would also require automakers that have already eliminated AM radio to inform customers of alternatives. AM radio technology
5016-493: The Federal Emergency Management Agency (FEMA) expressed concerns that this would reduce the effectiveness of emergency communications. In May 2023, a bipartisan group of lawmakers in the United States introduced legislation making it illegal for automakers to eliminate AM radio from their cars. The lawmakers argue that AM radio is an important tool for public safety due to being a component of
5148-491: The Iowa Highway 5 / U.S. 65 bypass. The annexations became official on June 26, 2009, as 5,174 acres (20.94 km ) and around 868 new residents were added to the city of Des Moines. An additional 759 acres (3.07 km ) were voluntarily annexed to the city over that same period. The skyline of Des Moines changed in the 1970s and the 1980s, when several new skyscrapers were built. Additional skyscrapers were built in
5280-431: The electrolytic detector and thermionic diode ( Fleming valve ) were invented by Reginald Fessenden and John Ambrose Fleming , respectively. Most important, in 1904–1906 the crystal detector , the simplest and cheapest AM detector, was developed by G. W. Pickard . Homemade crystal radios spread rapidly during the next 15 years, providing ready audiences for the first radio broadcasts. One limitation of crystals sets
5412-430: The " capture effect " means that the dominant signal needs to only be about twice as strong as the interfering one. To allow room for more stations on the mediumwave broadcast band in the United States, in June 1989 the FCC adopted a National Radio Systems Committee (NRSC) standard that limited maximum transmitted audio bandwidth to 10.2 kHz, limiting occupied bandwidth to 20.4 kHz. The former audio limitation
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5544-603: The 1930s, most of the major radio stations in the country were affiliated with networks owned by two companies, NBC and CBS . In 1934, a third national network, the Mutual Radio Network , was formed as a cooperative owned by its stations. A second country which quickly adopted network programming was the United Kingdom, and its national network quickly became a prototype for a state-managed monopoly of broadcasting. A rising interest in radio broadcasting by
5676-660: The 1940s two new broadcast media, FM radio and television , began to provide extensive competition with the established broadcasting services. The AM radio industry suffered a serious loss of audience and advertising revenue, and coped by developing new strategies. Network broadcasting gave way to format broadcasting: instead of broadcasting the same programs all over the country, stations individually adopted specialized formats which appealed to different audiences, such as regional and local news, sports, "talk" programs, and programs targeted at minorities. Instead of live music, most stations began playing less expensive recorded music. In
5808-496: The 1990s, including Iowa's tallest. Before then, the 19-story Equitable Building , from 1924, was the tallest building in the city and the tallest building in Iowa. The 25-story Financial Center was completed in 1973 and the 36-story Ruan Center was completed in 1974. They were later joined by the 33-story Des Moines Marriott Hotel (1981), the 25-story HUB Tower and 25-story Plaza Building (1985). Iowa's tallest building, Principal Financial Group 's 45-story tower at 801 Grand
5940-532: The AM radio industry in the United States developed technology for broadcasting in stereo . Other nations adopted AM stereo, most commonly choosing Motorola's C-QUAM, and in 1993 the United States also made the C-QUAM system its standard, after a period allowing four different standards to compete. The selection of a single standard improved acceptance of AM stereo , however overall there was limited adoption of AM stereo worldwide, and interest declined after 1990. With
6072-531: The British public pressured the government to reintroduce the service, following its suspension in 1920. However, the government also wanted to avoid what it termed the "chaotic" U.S. experience of allowing large numbers of stations to operate with few restrictions. There were also concerns about broadcasting becoming dominated by the Marconi company. Arrangements were made for six large radio manufacturers to form
6204-477: The Des Moines Plan, comprising an elected mayor and four commissioners, all elected at-large , who were responsible for public works, public property, public safety, and finance. Considered progressive at the time, it diluted the votes of ethnic and national minorities, who generally could not command a majority to elect a candidate of their choice. That form of government was scrapped in 1950 in favor of
6336-611: The Des Moines Public Library, designed by renowned architect David Chipperfield of London, opened on April 8, 2006. The World Food Prize Foundation, which is based in Des Moines, completed adaptation and restoration of the former Des Moines Public Library building in October 2011. The former library now serves as the home and headquarters of the Norman Borlaug /World Food Prize Hall of Laureates. At
6468-732: The Des Moines River. Based on archaeological evidence, the junction of the Des Moines and Raccoon Rivers has attracted humans for at least 7,000 years. Several prehistoric occupation areas have been identified by archaeologists in downtown Des Moines . Discovered in December 2010, the " Palace " is an expansive 7,000-year-old site found during excavations prior to construction of the new wastewater treatment plant in southeast Des Moines. It contains well-preserved house deposits and numerous graves. More than 6,000 artifacts were found at this site. State of Iowa archaeologist John Doershuk
6600-479: The Howitt-Wood Radio Company one of first construction permits for a commercial FM station. Originally on 44.9 MHz as W49BN, it later became WNBF-FM on 100.5 MHz. The license for this original WNBF-FM was cancelled on August 11, 1952. In early 1941 station ownership was transferred to the Wylie B. Jones Advertising Agency. On March 29, 1941, most of the stations on 1500 kHz, including WNBF, moved to 1490 kHz, with
6732-720: The Polk County Administrative Building, with a newer addition); and the City Hall are surviving examples of the 1900–1910 buildings. They form the Civic Center Historic District . The ornate riverfront balustrades that line the Des Moines and Raccoon Rivers were built by the federal Civilian Conservation Corps in the mid-1930s, during the Great Depression under Democratic President Franklin D. Roosevelt , as
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#17327808821556864-544: The State of Iowa Historical Museum (1987). The Des Moines skywalk also began to take shape during the 1980s. The skywalk system is 4 miles (6.4 km) long and connects many downtown buildings. In the early 21st century, the city has had more major construction in the downtown area. The new Science Center of Iowa and Blank IMAX Dome Theater and the Iowa Events Center opened in 2005. The new central branch of
6996-411: The Twenties when radio exploded can't know what it meant, this milestone for mankind. Suddenly, with radio, there was instant human communication. No longer were our homes isolated and lonely and silent. The world came into our homes for the first time. Music came pouring in. Laughter came in. News came in. The world shrank, with radio. The idea of broadcasting — the unrestricted transmission of signals to
7128-427: The U.S., for example) subject to international agreements. Des Moines Des Moines ( / d ə ˈ m ɔɪ n / də- MOYN ) is the capital and most populous city in the U.S. state of Iowa . It is the county seat of Polk County with parts extending into Warren County . It was incorporated on September 22, 1851, as Fort Des Moines , which was shortened to "Des Moines" in 1857. It
7260-694: The United States and France this led to a small market of receiver lines geared for jewelers who needed accurate time to set their clocks, including the Ondophone in France, and the De Forest RS-100 Jewelers Time Receiver in the United States The ability to pick up time signal broadcasts, in addition to Morse code weather reports and news summaries, also attracted the interest of amateur radio enthusiasts. It
7392-558: The World with John Batchelor and Red Eye Radio . Weekend programming includes shows on health, money, car repair, home improvement, a Saturday oldies show and a Sunday morning polka music show. Syndicated weekend programs include The Kim Komando Show , At Home with Gary Sullivan , The Mike Gallagher Show and Sunday Night with Bill Cunningham . It also carries Binghamton Rumble Ponies minor league baseball games. Most hours begin with an update from ABC News Radio . WNBF
7524-533: The age of 18 living with them, 43.7% were married couples living together, 12.6% had a female householder with no husband present, and 39.5% were non-families. 31.9% of all households were made up of individuals, and 10.2% had someone living alone who was 65 years of age or older. The average household size was 2.39 and the average family size was 3.04. The age distribution was 24.8% under the age of 18, 10.6% from 18 to 24, 31.8% from 25 to 44, 20.4% from 45 to 64, and 12.4% who were 65 years of age or older. The median age
7656-476: The ages of 18 and 24; 29.4% were from 25 to 44; 23.9% were from 45 to 64; and 11% were 65 years of age or older. The gender makeup of the city was 48.9% male and 51.1% female. As of the 2000 census, there were 198,682 people, 80,504 households, and 48,704 families in the city. The population density was 2,621.3 inhabitants per square mile (1,012.1/km ). There were 85,067 housing units at an average density of 1,122.3 per square mile (433.3/km ). The racial makeup of
7788-523: The antenna wire. This meant that the full transmitter power flowed through the microphone, and even using water cooling, the power handling ability of the microphones severely limited the power of the transmissions. Ultimately only a small number of large and powerful Alexanderson alternators would be developed. However, they would be almost exclusively used for long-range radiotelegraph communication, and occasionally for radiotelephone experimentation, but were never used for general broadcasting. Almost all of
7920-420: The area, mining coal from the riverbank for the fort's blacksmith. Settlers occupied the abandoned fort and nearby areas. On May 25, 1846, the state legislature designated Fort Des Moines as the seat of Polk County. Arozina Perkins, a school teacher who spent the winter of 1850–1851 in the town of Fort Des Moines, was not favorably impressed: This is one of the strangest looking "cities" I ever saw... This town
8052-482: The audience has continued to decline. In 1987, the elimination of the Fairness Doctrine requirement meant that talk shows, which were commonly carried by AM stations, could adopt a more focused presentation on controversial topics, without the distraction of having to provide airtime for any contrasting opinions. In addition, satellite distribution made it possible for programs to be economically carried on
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#17327808821558184-734: The center of North America and far removed from large bodies of water, the Des Moines area has a hot summer type humid continental climate ( Köppen Dfa ), with warm to hot, humid summers and cold, dry winters. Summer temperatures can often climb into the 90 °F (32 °C) range, occasionally reaching 100 °F (38 °C). Humidity can be high in spring and summer, with frequent afternoon thunderstorms . Fall brings pleasant temperatures and colorful fall foliage . Winters vary from moderately cold to bitterly cold, with low temperatures venturing below 0 °F (−18 °C) quite often. Snowfall averages 36.5 inches (93 cm) per season, and annual precipitation averages 36.55 inches (928 mm), with
8316-404: The characteristics of arc-transmitters . Fessenden attempted to sell this form of radiotelephone for point-to-point communication, but was unsuccessful. Fessenden's work with high-frequency spark transmissions was only a temporary measure. His ultimate plan for creating an audio-capable transmitter was to redesign an electrical alternator , which normally produced alternating current of at most
8448-719: The city for unincorporated areas not merged with the city proper was 66.2% White , 15.5% African Americans , 0.5% Native American , 4.0% Asian , and 2.6% from Two or more races . People of Hispanic or Latino origin, of any race, made up 12.1% of the population. The city's racial make up during the 2010 census was 76.4% White , 10.2% African American , 0.5% Native American , 4.4% Asian (1.2% Vietnamese, 0.9% Laotian, 0.4% Burmese, 0.3% Asian Indian, 0.3% Thai, 0.2% Chinese, 0.2% Cambodian, 0.2% Filipino, 0.1% Hmong, 0.1% Korean, 0.1% Nepalese), 0.1% Pacific Islander , 5.0% from other races , and 3.4% from two or more races. People of Hispanic or Latino origin, of any race, formed 12.0% of
8580-432: The city included 252 people incarcerated in adult correctional facilities and 2,378 people in student housing. Of the 87,958 households, 28.0% had children under the age of 18; 35.5% were married couples living together; 31.3% had a female householder with no spouse or partner present. 35.3% of households consisted of individuals and 11.0% had someone living alone who was 65 years of age or older. The average household size
8712-407: The city was 82.3% white , 8.07% Black , 0.35% American Indian , 3.50% Asian, 0.05% Pacific Islander , 3.52% from other races , and 2.23% from two or more races. 6.61% of the population were Hispanic or Latino of any race. 20.9% were of German , 10.3% Irish, 9.1% "American" and 8.0% English ancestry, according to Census 2000 . There were 80,504 households, out of which 29.5% had children under
8844-403: The commission estimated that fewer than 250 AM stations were transmitting hybrid mode signals. On October 27, 2020, the FCC voted to allow AM stations to eliminate their analog transmissions and convert to all-digital operation, with the requirement that stations making the change had to continue to make programming available over "at least one free over-the-air digital programming stream that
8976-522: The construction of a fort on the site where the Des Moines and Raccoon Rivers merge. Allen wanted to use the name Fort Raccoon; however, the U.S. War Department preferred Fort Des Moines. The fort was built to control the Sauk and Meskwaki peoples, whom the government had moved to the area from their traditional lands in eastern Iowa. The fort was abandoned in 1846 after the Sauk and Meskwaki were removed from
9108-465: The construction permit for a new WNBF-FM (now WHWK ) on 98.1 MHz, which began broadcasting in 1956. Triangle also owned TV Guide magazine. In 1972, Stoner Broadcasting, based in Des Moines , bought WNBF-AM-FM, and Gateway Communications, publishers of The Record of Bergen County, New Jersey , bought WNBF-TV. Citadel Broadcasting acquired WNBF and its FM counterpart, WHWK, in 1999. In 2021, an FM translator W221EJ signed on at 92.1 FM to rebroadcast
9240-475: The continued migration of AM stations away from music to news, sports, and talk formats, receiver manufacturers saw little reason to adopt the more expensive stereo tuners, and thus radio stations have little incentive to upgrade to stereo transmission. In countries where the use of directional antennas is common, such as the United States, transmitter sites consisting of multiple towers often occupy large tracts of land that have significantly increased in value over
9372-437: The continuous wave AM transmissions made prior to 1915 were made by versions of the arc converter transmitter, which had been initially developed by Valdemar Poulsen in 1903. Arc transmitters worked by producing a pulsating electrical arc in an enclosed hydrogen atmosphere. They were much more compact than alternator transmitters, and could operate on somewhat higher transmitting frequencies. However, they suffered from some of
9504-434: The decades, to the point that the value of land exceeds that of the station itself. This sometimes results in the sale of the transmitter site, with the station relocating to a more distant shared site using significantly less power, or completely shutting down operations. The ongoing development of alternative transmission systems, including Digital Audio Broadcasting (DAB), satellite radio, and HD (digital) radio, continued
9636-567: The decline of the popularity of the traditional broadcast technologies. These new options, including the introduction of Internet streaming, particularly resulted in the reduction of shortwave transmissions, as international broadcasters found ways to reach their audiences more easily. In 2022 it was reported that AM radio was being removed from a number of electric vehicle (EV) models, including from cars manufactured by Tesla, Audi, Porsche, BMW and Volvo, reportedly due to automakers concerns that an EV's higher electromagnetic interference can disrupt
9768-569: The demonstration witnesses, which stated "[Radio] Telephony is admirably adapted for transmitting news, stock quotations, music, race reports, etc. simultaneously over a city, on account of the fact that no wires are needed and a single apparatus can distribute to ten thousand subscribers as easily as to a few. It is proposed to erect stations for this purpose in the large cities here and abroad." However, other than two holiday transmissions reportedly made shortly after these demonstrations, Fessenden does not appear to have conducted any radio broadcasts for
9900-418: The entire country east of the Des Moines River. Crops were utterly destroyed, houses and fences swept away." The city started to rebuild from scratch. On September 22, 1851, Des Moines was incorporated as a city; the charter was approved by voters on October 18. In 1857, the name "Fort Des Moines" was shortened to "Des Moines", and it was designated as the second state capital, previously at Iowa City . Growth
10032-648: The expectation is that listeners will primarily be tuning into the FM signal rather than the nominally "primary" AM station. A 2020 review noted that "for many owners, keeping their AM stations on the air now is pretty much just about retaining their FM translator footprint rather than keeping the AM on the air on its own merits". In 2018 the FCC, led by then-Commission Chairman Ajit Pai , proposed greatly reducing signal protection for 50 kW Class A " clear channel " stations. This would allow co-channel secondary stations to operate with higher powers, especially at night. However,
10164-445: The fall of 1900, he successfully transmitted speech over a distance of about 1.6 kilometers (one mile), which appears to have been the first successful audio transmission using radio signals. However, at this time the sound was far too distorted to be commercially practical. For a time he continued working with more sophisticated high-frequency spark transmitters, including versions that used compressed air, which began to take on some of
10296-401: The first time. Music came pouring in. Laughter came in. News came in. The world shrank, with radio. Following World War I, the number of stations providing a regular broadcasting service greatly increased, primarily due to advances in vacuum-tube technology. In response to ongoing activities, government regulators eventually codified standards for which stations could make broadcasts intended for
10428-624: The general public, for example, in the United States formal recognition of a "broadcasting service" came with the establishment of regulations effective December 1, 1921, and Canadian authorities created a separate category of "radio-telephone broadcasting stations" in April 1922. However, there were numerous cases of entertainment broadcasts being presented on a regular schedule before their formal recognition by government regulators. Some early examples include: Because most longwave radio frequencies were used for international radiotelegraph communication,
10560-417: The general public, or to have even given additional thought about the potential of a regular broadcast service, and in a 1908 article providing a comprehensive review of the potential uses for his radiotelephone invention, he made no references to broadcasting. Because there was no way to amplify electrical currents at this time, modulation was usually accomplished by a carbon microphone inserted directly in
10692-621: The implementation of the North American Regional Broadcasting Agreement . In 1942, WNBF moved to 1290 kHz, with a power increase from 250 to 5,000 watts. In 1946, the station owners became Clark Associates, Inc. In 1949 a 384-foot (117 m) transmission tower was constructed for use by both the AM and FM radio stations, plus a newly authorized television station, WNBF-TV channel 12 (now WBNG-TV ). In 1955, Triangle Publications purchased WNBF-AM-TV and
10824-488: The isolation of rural life. Political officials could now speak directly to millions of citizens. One of the first to take advantage of this was American president Franklin Roosevelt , who became famous for his fireside chats during the Great Depression . However, broadcasting also provided the means to use propaganda as a powerful government tool, and contributed to the rise of fascist and communist ideologies. In
10956-411: The lack of any way to amplify the signals meant they were somewhat weak. On December 21, 1906, Fessenden made an extensive demonstration of the new alternator-transmitter at Brant Rock, Massachusetts, showing its utility for point-to-point wireless telephony, including interconnecting his stations to the wire telephone network. As part of the demonstration, speech was transmitted 18 kilometers (11 miles) to
11088-419: The late 1960s and 1970s, top 40 rock and roll stations in the U.S. and Canada such as WABC and CHUM transmitted highly processed and extended audio to 11 kHz, successfully attracting huge audiences. For young people, listening to AM broadcasts and participating in their music surveys and contests was the social media of the time. In the late 1970s, spurred by the exodus of musical programming to FM stations,
11220-472: The lowest insurance premium taxes in the nation at 1%, and does not charge any premium taxes on qualified life insurance plans, making the state attractive to insurance business. Des Moines has been referred to as the "Hartford of the West" and "Insurance Capital" because of this. Principal is one of two Fortune 500 companies with headquarters in Iowa (the other being Casey's General Stores ), ranking 201st on
11352-554: The magazine's list in 2020. As a center of financial and insurance services, other major corporations headquartered outside of Iowa have a presence in the Des Moines Metro area, including Wells Fargo , Voya Financial , and Electronic Data Systems (EDS). The Meredith Corporation , a leading publishing and marketing company, was also based in Des Moines prior to its acquisition by IAC and merger with Dotdash in 2021. Meredith published Better Homes and Gardens , one of
11484-399: The marketplace decide" which was best. The lack of a common standard resulted in consumer confusion and increased the complexity and cost of producing AM stereo receivers. In 1993, the FCC again revised its policy, by selecting C-QUAM as the sole AM stereo implementation. In 1993, the FCC also endorsed, although it did not make mandatory, AMAX broadcasting standards that were developed by
11616-432: The message, spreading it broadcast to receivers in all directions". However, it was recognized that this would involve significant financial issues, as that same year The Electrician also commented "did not Prof. Lodge forget that no one wants to pay for shouting to the world on a system by which it would be impossible to prevent non-subscribers from benefiting gratuitously?" On January 1, 1902, Nathan Stubblefield gave
11748-579: The metropolitan area. In recent years, Microsoft , Hewlett-Packard , and Facebook have built data-processing and logistical facilities in the Des Moines area. Des Moines is an important city in U.S. presidential politics; as the state's capital, it is the site of the first caucuses of the presidential primary cycle. Many presidential candidates set up campaign headquarters in Des Moines. A 2007 article in The New York Times said, "If you have any desire to witness presidential candidates in
11880-499: The monks". One popular interpretation of "Des Moines" concludes that it refers to a group of French Trappist monks , who in the 17th century lived in huts built on top of what is now known as the ancient Monks Mound at Cahokia , the major center of Mississippian culture , which developed in what is present-day Illinois, east of the Mississippi River and the city of St. Louis . This was some 200 miles (320 km) from
12012-413: The most close-up and intimate of settings, there is arguably no better place to go than Des Moines." Des Moines takes its name from Fort Des Moines (1843–46), which was named for the Des Moines River . This was adopted from the name given by French colonists . Des Moines ( pronounced [de mwan] ; formerly [de mwɛn] ) translates literally to either "from the monks" or "of
12144-448: The multiple incompatible AM stereo systems, and failure of the manufacturers (including the auto makers) to effectively promote AMAX radios, coupled with the ever-increasing background of noise in the band, the general public soon lost interest and moved on to other media. On June 8, 1988, an International Telecommunication Union (ITU)-sponsored conference held at Rio de Janeiro, Brazil adopted provisions, effective July 1, 1990, to extend
12276-537: The necessity of having to transmit a high power carrier wave to overcome ground losses, and the large antenna radiators required at the low broadcast frequencies, but can be sent over long distances via the ionosphere at night; however, they are much more susceptible to interference, and often have lower audio fidelity. Thus, AM broadcasters tend to specialize in spoken-word formats, such as talk radio , all-news radio and sports radio , with music formats primarily for FM and digital stations. People who weren't around in
12408-405: The new frequencies. It was now estimated that the expanded band could accommodate around 300 U.S. stations. However, it turned out that the number of possible station reassignments was much lower, with a 2006 accounting reporting that, out of 4,758 licensed U.S. AM stations, only 56 were now operating on the expanded band. Moreover, despite an initial requirement that by the end of five years either
12540-428: The new policy, by 2011 there were approximately 500 in operation, and as of 2020 approximately 2,800 of the 4,570 licensed AM stations were rebroadcasting on one or more FM translators. In 2009 the FCC stated that "We do not intend to allow these cross-service translators to be used as surrogates for FM stations". However, based on station slogans, especially in the case of recently adopted musical formats, in most cases
12672-411: The original station or its expanded band counterpart had to cease broadcasting, as of 2015 there were 25 cases where the original standard band station was still on the air, despite also operating as an expanded band station. HD Radio is a digital audio broadcasting method developed by iBiquity . In 2002 its "hybrid mode", which simultaneously transmits a standard analog signal as well as a digital one,
12804-433: The overheating issues of needing to insert microphones directly in the transmission antenna circuit. Vacuum tube transmitters also provided high-quality AM signals, and could operate on higher transmitting frequencies than alternator and arc transmitters. Non-governmental radio transmissions were prohibited in many countries during World War I, but AM radiotelephony technology advanced greatly due to wartime research, and after
12936-429: The population (9.4% Mexican, 0.7% Salvadoran, 0.3% Guatemalan, 0.3% Puerto Rican, 0.1% Honduran, 0.1% Ecuadorian, 0.1% Cuban, 0.1% Spaniard, 0.1% Spanish). Non-Hispanic Whites were 70.5% of the population in 2010. Des Moines also has a sizeable South Sudanese community. There were 81,369 households, of which 31.6% had children under the age of 18 living with them, 38.9% were married couples living together, 14.2% had
13068-412: The poverty line, including 14.9% of those under age 18 and 7.6% of those ages 65 or over. Many insurance companies are headquartered in Des Moines, including the Principal Financial Group , EMC Insurance Group, Fidelity & Guaranty Life , Allied Insurance , GuideOne Insurance , Wellmark Blue Cross Blue Shield of Iowa, FBL Financial Group , and American Republic Insurance Company. Iowa has one of
13200-441: The primary early developer of AM technology is Canadian-born inventor Reginald Fessenden . The original spark-gap radio transmitters were impractical for transmitting audio, since they produced discontinuous pulses known as " damped waves ". Fessenden realized that what was needed was a new type of radio transmitter that produced steady "undamped" (better known as " continuous wave ") signals, which could then be "modulated" to reflect
13332-478: The racial counts and placed in their own category) was 60.99% (130,599) White alone (non-Hispanic) , 11.46% (24,538) Black alone (non-Hispanic) , 0.28% (597) Native American alone (non-Hispanic) , 6.70% (14,348) Asian alone (non-Hispanic) , 0.06% (124) Pacific Islander alone (non-Hispanic) , 0.38% (817) Other Race alone (non-Hispanic) , 4.50% (9,630) Multiracial or Mixed Race (non-Hispanic) , and 15.64% (33,480) Hispanic or Latino . The 2020 census population of
13464-650: The reception of AM transmissions and hurt the listening experience, among other reasons. However the United States Congress has introduced a bill to require all vehicles sold in the US to have an AM receiver to receive emergency broadcasts. The FM broadcast band was established in 1941 in the United States, and at the time some suggested that the AM band would soon be eliminated. In 1948 wide-band FM's inventor, Edwin H. Armstrong , predicted that "The broadcasters will set up FM stations which will parallel, carry
13596-461: The remains of the old dragoon houses... The people support two papers and there are several dry goods shops. I have been into but four of them... Society is as varied as the buildings are. There are people from nearly every state, and Dutch, Swedes, etc. In May 1851, much of the town was destroyed during the Flood of 1851 . "The Des Moines and Raccoon Rivers rose to an unprecedented height, inundating
13728-799: The same deficiencies. The lack of any means to amplify electrical currents meant that, like the alternator transmitters, modulation was usually accomplished by a microphone inserted directly in the antenna wire, which again resulted in overheating issues, even with the use of water-cooled microphones. Thus, transmitter powers tended to be limited. The arc was also somewhat unstable, which reduced audio quality. Experimenters who used arc transmitters for their radiotelephone research included Ernst Ruhmer , Quirino Majorana , Charles "Doc" Herrold , and Lee de Forest . Advances in vacuum tube technology (called "valves" in British usage), especially after around 1915, revolutionized radio technology. Vacuum tube devices could be used to amplify electrical currents, which overcame
13860-400: The same program, as over their AM stations... eventually the day will come, of course, when we will no longer have to build receivers capable of receiving both types of transmission, and then the AM transmitters will disappear." However, FM stations actually struggled for many decades, and it was not until 1978 that FM listenership surpassed that of AM stations. Since then the AM band's share of
13992-542: The scale of vice and degradation, than all their intercourse with the whites for the ten years previous". After official removal , the Meskwaki continued to return to Des Moines until around 1857. Archaeological excavations have shown that many fort-related features survived under what is now Martin Luther King Jr. Parkway and First Street. Soldiers stationed at Fort Des Moines opened the first coal mines in
14124-432: The signal of WNBF 1290. Over its long history, WNBF has been home to some of the biggest names in area broadcasting, such as Bill Parker, John Leslie, Roger Neel and Bernard Fionte. 42°03′29″N 75°57′15″W / 42.05806°N 75.95417°W / 42.05806; -75.95417 AM broadcasting The earliest experimental AM transmissions began in the early 1900s. However, widespread AM broadcasting
14256-410: The sounds being transmitted. Fessenden's basic approach was disclosed in U.S. Patent 706,737, which he applied for on May 29, 1901, and was issued the next year. It called for the use of a high-speed alternator (referred to as "an alternating-current dynamo") that generated "pure sine waves" and produced "a continuous train of radiant waves of substantially uniform strength", or, in modern terminology,
14388-556: The state and shifted to the Indian Territory. The Sauk and Meskwaki did not fare well in Des Moines. The illegal whiskey trade, combined with the destruction of traditional lifeways, led to severe problems for their society. One newspaper reported: "It is a fact that the location of Fort Des Moines among the Sac and Fox Indians (under its present commander) for the last two years, had corrupted them more and lowered them deeper in
14520-411: The technology for AM broadcasting in stereo was challenging due to the need to limit the transmissions to a 20 kHz bandwidth, while also making the transmissions backward compatible with existing non-stereo receivers. In 1990, the FCC authorized an AM stereo standard developed by Magnavox, but two years later revised its decision to instead approve four competing implementations, saying it would "let
14652-401: The translator stations are not permitted to originate programming when the "primary" AM station is broadcasting, they are permitted to do so during nighttime hours for AM stations licensed for daytime-only operation. Prior to the adoption of the new policy, as of March 18, 2009, the FCC had issued 215 Special Temporary Authority grants for FM translators relaying AM stations. After creation of
14784-616: The turn of the 20th century, encouraged by the Civic Committee of the Des Moines Women's Club , Des Moines undertook a " City Beautiful " project in which large Beaux Arts public buildings and fountains were constructed along the Des Moines River. The former Des Moines Public Library building (now the home of the World Food Prize ); the United States central Post Office , built by the federal government (now
14916-496: The upper end of the Region 2 AM broadcast band, by adding ten frequencies which spanned from 1610 kHz to 1700 kHz. At this time it was suggested that as many as 500 U.S. stations could be assigned to the new frequencies. On April 12, 1990, the FCC voted to begin the process of populating the expanded band, with the main priority being the reduction of interference on the existing AM band, by transferring selected stations to
15048-548: The war the availability of tubes sparked a great increase in the number of amateur radio stations experimenting with AM transmission of news or music. Vacuum tubes remained the central technology of radio for 40 years, until transistors began to dominate in the late 1950s, and are still used in the highest power broadcast transmitters. Unlike telegraph and telephone systems, which used completely different types of equipment, most radio receivers were equally suitable for both radiotelegraph and radiotelephone reception. In 1903 and 1904
15180-404: The youngest demographic groups. Among persons aged 12–24, AM accounts for only 4% of listening, while FM accounts for 96%. Among persons aged 25–34, AM accounts for only 9% of listening, while FM accounts for 91%. The median age of listeners to the AM band is 57 years old, a full generation older than the median age of FM listeners." In 2009, the FCC made a major regulatory change, when it adopted
15312-506: Was $ 33,699 (+/- $ 740). Approximately, 12.1% of families and 16.0% of the population were below the poverty line , including 24.3% of those under the age of 18 and 9.8% of those ages 65 or over. As of the census of 2010, there were 203,433 people, 81,369 households, and 47,491 families residing in the city. Population density was 2,515.6 inhabitants per square mile (971.3/km ). There were 88,729 housing units at an average density of 1,097.2 per square mile (423.6/km ). The racial makeup of
15444-572: Was 15 kHz resulting in bandwidth of 30 kHz. Another common limitation on AM fidelity is the result of receiver design, although some efforts have been made to improve this, notably through the AMAX standards adopted in the United States. AM broadcasts are used on several frequency bands. The allocation of these bands is governed by the ITU 's Radio Regulations and, on the national level, by each country's telecommunications administration (the FCC in
15576-605: Was 2,428.4 per square mile (937.6/km ). There were 95,082 housing units at an average density of 1,078.3 per square mile (416.3/km ). The racial makeup (including Hispanics in the racial counts) was 64.54% (138,200) white or European American (60.99% non-Hispanic white ), 11.68% (25,011) black or African-American , 0.69% (1,474) Native American or Alaska Native , 6.76% (14,474) Asian , 0.06% (135) Pacific Islander or Native Hawaiian , 6.62% (14,178) from other races , and 9.65% (20,661) from two or more races . The racial and ethnic makeup (where Hispanics are excluded from
15708-441: Was 2.5 and the average family size was 3.3. The percent of those with a bachelor's degree or higher was estimated to be 19.9% of the population. Of the population age 25 and over, 86.7% were high school graduates or higher and 27.9% had a bachelor's degree or higher. 23.5% of the population was under the age of 18, 10.4% from 18 to 24, 29.6% from 25 to 44, 23.1% from 45 to 64, and 13.5% were 65 years of age or older. The median age
15840-405: Was 34 years. For every 100 females, there were 93.8 males. For every 100 females age 18 and over, there were 90.5 males. The median income for a household in the city was $ 38,408, and the median income for a family was $ 46,590. Males had a median income of $ 31,712 versus $ 25,832 for females. The per capita income for the city was $ 19,467. About 7.9% of families and 11.4% of the population were below
15972-473: Was 34.8 years. For every 100 females, there were 102.7 males. For every 100 females ages 18 and older, there were 104.4 males. The 2016-2020 5-year American Community Survey estimates show that the median household income was $ 54,843 (with a margin of error of +/- $ 1,544) and the median family income was $ 66,420 (+/- $ 1,919). Males had a median income of $ 38,326 (+/- $ 1,405) versus $ 29,855 (+/- $ 1,327) for females. The median income for those above 16 years old
16104-565: Was about 1.7% of the city's population in 1910. By 1880, Des Moines had a population of 22,408, making it Iowa's largest city. It displaced the three Mississippi River ports: Burlington, Dubuque, and Davenport, that had alternated holding the position since the territorial period. Des Moines has remained Iowa's most populous city. In 1910, the Census Bureau reported Des Moines' population as 97.3% white and 2.7% black, reflecting its early settlement pattern primarily by ethnic Europeans. At
16236-474: Was approved by the FCC for use by AM stations, initially only during daytime hours, due to concerns that during the night its wider bandwidth would cause unacceptable interference to stations on adjacent frequencies. In 2007 nighttime operation was also authorized. The number of hybrid mode AM stations is not exactly known, because the FCC does not keep track of the stations employing the system, and some authorized stations have later turned it off. But as of 2020
16368-510: Was assisted by University of Iowa archaeologists at this dig. At least three Late Prehistoric villages, dating from about AD 1300 to 1700, stood in or near what developed later as downtown Des Moines. In addition, 15 to 18 prehistoric Native American mounds were observed in the area by early settlers. All have been destroyed during development of the city. Des Moines traces its origins to May 1843, when Captain James Allen supervised
16500-643: Was built in 1991, and the 19-story EMC Insurance Building was erected in 1997. During this time period, the Civic Center of Greater Des Moines (1979) was developed; it hosts Broadway shows and special events. Also constructed were the Greater Des Moines Botanical Garden (1979), a large city botanical garden/greenhouse on the east side of the river; the Polk County Convention Complex (1985), and
16632-400: Was immediately recognized that, much like the telegraph had preceded the invention of the telephone, the ability to make audio radio transmissions would be a significant technical advance. Despite this knowledge, it still took two decades to perfect the technology needed to make quality audio transmissions. In addition, the telephone had rarely been used for distributing entertainment, outside of
16764-703: Was not established until the 1920s, following the development of vacuum tube receivers and transmitters. AM radio remained the dominant method of broadcasting for the next 30 years, a period called the " Golden Age of Radio ", until television broadcasting became widespread in the 1950s and received much of the programming previously carried by radio. Later, AM radio's audiences declined greatly due to competition from FM ( frequency modulation ) radio, Digital Audio Broadcasting (DAB), satellite radio , HD (digital) radio , Internet radio , music streaming services , and podcasting . Compared to FM or digital transmissions , AM transmissions are more expensive to transmit due to
16896-532: Was recorded in 1960), as highway construction led to new residential construction outside the city. The population was 198,682 in 2000 and grew slightly to 200,538 in 2009. The growth of the outlying suburbs has continued, and the overall metropolitan-area population is over 700,000 today. During the Great Flood of 1993 , heavy rains throughout June and early July caused the Des Moines and Raccoon Rivers to rise above flood stage levels. The Des Moines Water Works
17028-654: Was slow during the Civil War period, but the city exploded in size and importance after a railroad link was completed in 1866. In 1864, the Des Moines Coal Company was organized to begin the first systematic mining in the region. Its first mine, north of town on the river's west side, was exhausted by 1873. The Black Diamond mine, near the south end of the West Seventh Street Bridge, sank a 150-foot (46 m) mine shaft to reach
17160-440: Was submerged by floodwaters during the early morning hours of July 11, 1993, leaving an estimated 250,000 people without running water for 12 days and without drinking water for 20 days. Des Moines suffered major flooding again in June 2008 with a major levee breach. The Des Moines River is controlled upstream by Saylorville Reservoir . In both 1993 and 2008, the flooding river overtopped the reservoir spillway. Today, Des Moines
17292-473: Was the first organization to create a radio network, and also to promote commercial advertising, which it called "toll" broadcasting. Its flagship station, WEAF (now WFAN) in New York City, sold blocks of airtime to commercial sponsors that developed entertainment shows containing commercial messages . AT&T held a monopoly on quality telephone lines, and by 1924 had linked 12 stations in Eastern cities into
17424-406: Was the lack of amplifying the signals, so listeners had to use earphones , and it required the development of vacuum-tube receivers before loudspeakers could be used. The dynamic cone loudspeaker , invented in 1924, greatly improved audio frequency response over the previous horn speakers, allowing music to be reproduced with good fidelity. AM radio offered the highest sound quality available in
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