WLS is a commercial AM radio station in Chicago, Illinois. Owned by Cumulus Media, through licensee Radio License Holdings LLC, the station airs a talk radio format. WLS has its studios in the NBC Tower on North Columbus Drive in the city's Streeterville neighborhood, its non-directional broadcast tower is located on the southern edge of Tinley Park, Illinois. WLS is a Class A station broadcasting on the clear-channel frequency of 890 kHz with 50,000 watts of power using C-QUAM AM Stereo; the station's daytime groundwave service contour covers portions of five states while at night its signal reaches 38 states via skywave. The station's programming is available to listeners in the Chicago metropolitan area with an HD Radio receiver via a simulcast on the HD2 subchannel of sister station WLS-FM. Despite different owners and affiliations, 89 WLS, ABC owned-and-operated WLS-TV and ESPN Radio owned-and-operated WMVP maintain a strong partnership. WLS's weekday programming consists of local hosts and nationally syndicated shows such as Rush Limbaugh, Mark Levin, Chris Plante, John Batchelor, "Red Eye Radio" and "This Morning, America's First News with Gordon Deal."
Limbaugh is syndicated by Premiere Networks. Most of the other syndicated shows on WLS come from a subsidiary of Cumulus Media. Local hosts include Mancow Muller in morning drive time and John Howell to host a news round up in the evening drive. Weekends feature programs on real estate, auto repair and paid brokered programming. Syndicated weekend shows include Kim Komando, Bob Brinker, Jim Bohannon, Ric Edelman and Larry Kudlow. Most hours begin with national news from Westwood One News. Starting in 2016, WLS had been the flagship station of the Chicago White Sox baseball team and the Chicago Bulls basketball team, but when parent company Cumulus Media filed for Chapter 11 bankruptcy protection in November 2017, the White Sox terminated the contract with the station after the 2017 season ended, while the Bulls contract for the remainder of the 2017–18 season was terminated. The Bulls moved to Entercom-owned sports radio station AM 670 WSCR, while the White Sox signed a deal with talk station AM 720 WGN.
In the 2015-16 season, WLS carried Notre Dame Fighting Irish college basketball games. In 2016, Notre Dame moved to AM 1000 WMVP. In the 1920s, Sears and Company was a major retail and mail order company. To get farmers and people in rural communities to buy radio sets from its catalogs, Sears bought time on radio stations, decided to form its own station. Just before the permanent station was ready, Sears began broadcasts on March 21, 1924 as WBBX with noon programs using the WMAQ studios. WLS was one of the original 50,000-watt Class I-A clear-channel stations which did not share its frequency of 870 AM with any other station during nighttime hours, when AM radio signals can travel long distances via skywave. Sears broadcast test transmissions from its own studios on April 9, 10 and 11, 1924, using the call sign WES. Sears operated its station at the company's corporate headquarters on Chicago's West Side, where the company's mail order business was located. On April 12, 1924, the station commenced using the call letters WLS, broadcasting from its new studios in the Sherman House Hotel in downtown Chicago.
The station's transmitter was located outside of Crete, Illinois. On April 19, the station aired its first National Barn Dance; the station shared time on the frequency with WCBD until November 11, 1928, at which point it began sharing time with WENR. In 1931, the station's power was increased from 5,000 watts to 50,000 watts, the station began sharing the transmitter of WENR near Downers Grove, Illinois. In 1938, the station's transmitter was moved to Illinois. Sears opened the station in 1924 as a service to farmers and subsequently sold it to the Prairie Farmer magazine in 1928; the station moved to the Prairie Farmer Building on West Washington in Chicago, where it remained for 32 years. For a few months after ABC's 1960 purchase of it and the format change, the "bright new sound" that began in May 1960 was broadcast from the Prairie Farmer Building. WLS didn't make the move to downtown Michigan Avenue's Stone Container Building, located at 360 North Michigan Avenue, until October of that year.
Thirty years it would move once more, to 190 North State in downtown Chicago. It was the scene of the National Barn Dance, which featured Gene Autry, Pat Buttram, George Gobel, and, second only to the Grand Ole Opry in presenting country music and humor; the station experimented in many forms of news broadcasting, including weather and crop reports. Its most famous news broadcast was the eyewitness report of the Hindenburg disaster by Herbert Morrison. Morrison and engineer Charles Nehlsen had been sent to New Jersey by WLS to cover the arrival of the Hindenburg for delayed broadcast, their recordings aired the next day on May 7, 1937, the first time that recordings of a news event were broadcast. Starting in the 1930s, WLS was an affiliate of the Blue Network of the National Broadcasting Company, as such aired the popular Fibber McGee and Molly and Lum and Abner comedy programs during their early years; when the Federal Communications Commission forced NBC to sell the Blue Network, WLS maintained its affiliation with the network under its new identity, the American Broadcasting Company.
Under this affiliation, some programs from the network that were not commercially sponsored or which were sched
Medium wave is the part of the medium frequency radio band used for AM radio broadcasting. For Europe the MW band ranges from 526.5 kHz to 1606.5 kHz, using channels spaced every 9 kHz, in North America an extended MW broadcast band ranges from 525 kHz to 1705 kHz, using 10 kHz spaced channels. The term is a historic one, dating from the early 20th century, when the radio spectrum was divided on the basis of the wavelength of the waves into long wave, medium wave, short wave radio bands. Wavelengths in this band are long enough that radio waves are not blocked by buildings and hills and can propagate beyond the horizon following the curvature of the Earth. Practical groundwave reception extends to 200–300 miles, with greater distances over terrain with higher ground conductivity, greatest distances over salt water. Most broadcast stations use groundwave to cover their listening area. Medium waves can reflect off charged particle layers in the ionosphere and return to Earth at much greater distances.
At night in winter months and at times of low solar activity, the lower ionospheric D layer disappears. When this happens, MW radio waves can be received many hundreds or thousands of miles away as the signal will be reflected by the higher F layer; this can allow long-distance broadcasting, but can interfere with distant local stations. Due to the limited number of available channels in the MW broadcast band, the same frequencies are re-allocated to different broadcasting stations several hundred miles apart. On nights of good skywave propagation, the skywave signals of a distant station may interfere with the signals of local stations on the same frequency. In North America, the North American Regional Broadcasting Agreement sets aside certain channels for nighttime use over extended service areas via skywave by a few specially licensed AM broadcasting stations; these channels are called clear channels, they are required to broadcast at higher powers of 10 to 50 kW. Broadcasting in the United States was restricted to two wavelengths: "entertainment" was broadcast at 360 meters, with stations required to switch to 485 meters when broadcasting weather forecasts, crop price reports and other government reports.
This arrangement had numerous practical difficulties. Early transmitters were technically crude and impossible to set on their intended frequency and if two stations in the same part of the country broadcast the resultant interference meant that neither could be heard clearly; the Commerce Department intervened in such cases but left it up to stations to enter into voluntary timesharing agreements amongst themselves. The addition of a third "entertainment" wavelength, 400 meters, did little to solve this overcrowding. In 1923, the Commerce Department realized that as more and more stations were applying for commercial licenses, it was not practical to have every station broadcast on the same three wavelengths. On 15 May 1923, Commerce Secretary Herbert Hoover announced a new bandplan which set aside 81 frequencies, in 10 kHz steps, from 550 kHz to 1350 kHz; each station would be assigned one frequency, no longer having to broadcast weather and government reports on a different frequency than entertainment.
Class A and B stations were segregated into sub-bands. Today in most of the Americas, mediumwave broadcast stations are separated by 10 kHz and have two sidebands of up to ±5 kHz in theory. In the rest of the world, the separation is 9 kHz, with sidebands of ±4.5 kHz. Both provide adequate audio quality for voice, but are insufficient for high-fidelity broadcasting, common on the VHF FM bands. In the US and Canada the maximum transmitter power is restricted to 50 kilowatts, while in Europe there are medium wave stations with transmitter power up to 2 megawatts daytime. Most United States AM radio stations are required by the Federal Communications Commission to shut down, reduce power, or employ a directional antenna array at night in order to avoid interference with each other due to night-time only long-distance skywave propagation; those stations which shut down at night are known as "daytimers". Similar regulations are in force for Canadian stations, administered by Industry Canada. In Europe, each country is allocated a number of frequencies.
In most cases there are two power limits: a lower one for omnidirectional and a higher one for directional radiation with minima in certain directions. The power limit can be depending on daytime and it is possible, that a station may not work at nighttime, because it would produce too much interference. Other countries may only operate low-powered transmitters on the same frequency, again subject to agreement. For example, Russia operates a high-powered transmitter, located in its Kaliningrad exclave and used for external broadcasting, on 1386 kHz; the same frequency is used by low-powered local radio stations in the United Kingdom, which has 250 medium-wave transmitters of 1 kW and over. International mediumwave broadcasting in Europe has decreased markedly with
The ionosphere is the ionized part of Earth's upper atmosphere, from about 60 km to 1,000 km altitude, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation, it forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth; as early as 1839, the German mathematician and physicist Carl Friedrich Gauss postulated that an electrically conducting region of the atmosphere could account for observed variations of Earth's magnetic field. Sixty years Guglielmo Marconi received the first trans-Atlantic radio signal on December 12, 1901, in St. John's, Newfoundland using a 152.4 m kite-supported antenna for reception. The transmitting station in Poldhu, used a spark-gap transmitter to produce a signal with a frequency of 500 kHz and a power of 100 times more than any radio signal produced; the message received was three dits, the Morse code for the letter S.
To reach Newfoundland the signal would have to bounce off the ionosphere twice. Dr. Jack Belrose has contested this, based on theoretical and experimental work. However, Marconi did achieve transatlantic wireless communications in Glace Bay, Nova Scotia, one year later. In 1902, Oliver Heaviside proposed the existence of the Kennelly–Heaviside layer of the ionosphere which bears his name. Heaviside's proposal included means by which radio signals are transmitted around the Earth's curvature. Heaviside's proposal, coupled with Planck's law of black-body radiation, may have hampered the growth of radio astronomy for the detection of electromagnetic waves from celestial bodies until 1932. In 1902, Arthur Edwin Kennelly discovered some of the ionosphere's radio-electrical properties. In 1912, the U. S. Congress imposed the Radio Act of 1912 on amateur radio operators, limiting their operations to frequencies above 1.5 MHz. The government thought; this led to the discovery of HF radio propagation via the ionosphere in 1923.
In 1926, Scottish physicist Robert Watson-Watt introduced the term ionosphere in a letter published only in 1969 in Nature: We have in quite recent years seen the universal adoption of the term'stratosphere'..and..the companion term'troposphere'... The term'ionosphere', for the region in which the main characteristic is large scale ionisation with considerable mean free paths, appears appropriate as an addition to this series. In the early 1930s, test transmissions of Radio Luxembourg inadvertently provided evidence of the first radio modification of the ionosphere. Edward V. Appleton was awarded a Nobel Prize in 1947 for his confirmation in 1927 of the existence of the ionosphere. Lloyd Berkner first measured the density of the ionosphere; this permitted the first complete theory of short-wave radio propagation. Maurice V. Wilkes and J. A. Ratcliffe researched the topic of radio propagation of long radio waves in the ionosphere. Vitaly Ginzburg has developed a theory of electromagnetic wave propagation in plasmas such as the ionosphere.
In 1962, the Canadian satellite Alouette 1 was launched to study the ionosphere. Following its success were Alouette 2 in 1965 and the two ISIS satellites in 1969 and 1971, further AEROS-A and -B in 1972 and 1975, all for measuring the ionosphere. On July 26, 1963 the first operational geosynchronous satellite Syncom 2 was launched; the board radio beacons on this satellite enabled – for the first time – the measurement of total electron content variation along a radio beam from geostationary orbit to an earth receiver. Australian geophysicist Elizabeth Essex-Cohen from 1969 onwards was using this technique to monitor the atmosphere above Australia and Antarctica; the ionosphere is a shell of electrons and electrically charged atoms and molecules that surrounds the Earth, stretching from a height of about 50 km to more than 1,000 km. It exists due to ultraviolet radiation from the Sun; the lowest part of the Earth's atmosphere, the troposphere extends from the surface to about 10 km. Above, the stratosphere, followed by the mesosphere.
In the stratosphere incoming solar radiation creates the ozone layer. At heights of above 80 km, in the thermosphere, the atmosphere is so thin that free electrons can exist for short periods of time before they are captured by a nearby positive ion; the number of these free electrons is sufficient to affect radio propagation. This portion of the atmosphere is ionized and contains a plasma, referred to as the ionosphere. Ultraviolet, X-ray and shorter wavelengths of solar radiation are ionizing, since photons at these frequencies contain sufficient energy to dislodge an electron from a neutral gas atom or molecule upon absorption. In this process the light electron obtains a high velocity so that the temperature of the created electronic gas is much higher than the one of ions and neutrals; the reverse process to ionization is recombination, in which a free electron is "captured" by a positive ion. Recombination occurs spontaneously, causes the emission of a photon carrying away the energy produced upon recombination.
As gas density increases at lower altitudes, the recombination process prevails, since the gas molecules and ions are closer together. The balance between these two processes determines th
Panasonic Corporation known as Matsushita Electric Industrial Co. Ltd. is a Japanese multinational electronics corporation headquartered in Kadoma, Japan. The company was founded in 1918 as a producer of lightbulb sockets and has grown to become one of the largest Japanese electronics producers alongside Sony, Toshiba and Canon Inc. In addition to electronics, it offers non-electronic products and services such as home renovation services. Panasonic is the world's fourth-largest television manufacturer by 2012 market share. Panasonic has a primary listing on the Tokyo Stock Exchange and is a constituent of the Nikkei 225 and TOPIX indices, it has a secondary listing on the Nagoya Stock Exchange. From 1935 to October 1, 2008, the company name was "Matsushita Electric Industrial Co. Ltd." On January 10, 2008, the company announced that it would change its name to "Panasonic Corporation", in effect on October 1, 2008, to conform with its global brand name "Panasonic". The name change was approved at a shareholders' meeting on June 26, 2008 after consultation with the Matsushita family.
Panasonic was founded in 1918 by Kōnosuke Matsushita as a vendor of duplex lamp sockets. In the 1920's Matsushita began launching products. In 1927, he produced a line of bicycle lamps that were the first to be marketed with the "National" brand name. During World War II the company operated factories in Japan and other parts of Asia which produced electrical components and appliances such as light fixtures, electric irons, wireless equipment and its first vacuum tubes. After the war, Panasonic regrouped as a Keiretsu and began to supply the post-war boom in Japan with radios and appliances, as well as bicycles. Matsushita's brother-in-law, Toshio Iue, founded Sanyo as a subcontractor for components after World War II. Sanyo grew to become a competitor to Panasonic, but was acquired by Panasonic in December 2009. In 1961, Matsushita met American dealers; the company began producing television sets for the U. S. market under the Panasonic brand name, expanded the use of the brand to Europe in 1979.
The company used the National brand outside North America from the 1950s to the 1970s. The inability to use the National brand name led to the creation of the Panasonic brand in the United States. Over the next several decades Panasonic released additional products, including black and white TV's, electrical blenders, rice cookers, color TV's and microwave ovens; the company debuted a hi-fidelity audio speaker in Japan in 1965 with the brand Technics. This line of high quality stereo components became worldwide favorites, the most famous products being its turntables, such as the SL-1200 record player, known for its high performance and durability. Throughout the 1970s and early 1980s, Panasonic continued to produce high-quality specialized electronics for niche markets such as shortwave radios, developed its successful line of stereo receivers, CD players and other components. In 1973, Matsushita established "Anam National", joint venture with Anam Group in South Korea. In 1983, Matsushita launched the Panasonic Senior Partner, the first IBM PC compatible Japanese-made computer.
In November 1990, Matsushita agreed to acquire the American media company MCA Inc. for US$6.59 billion. Matsushita subsequently sold 80% of MCA to Seagram Company for US$7 billion in April 1995. In 1998, Matsushita sold Anam National to Anam Electronics. On May 2, 2002, Panasonic Canada marked its 35th anniversary in that country by giving $5 million to help build a "music city" on Toronto's waterfront. On January 19, 2006, Panasonic announced that it would stop producing analog televisions from the next month, in order to concentrate on digital televisions. In 2008, all models of electric shavers from the Panasonic factory were called Panasonic shavers, they dropped Matsushita and National from their name, regardless of worldwide or Japanese markets. On November 3, 2008, Panasonic and Sanyo announced that they were holding merger talks, which resulted in the acquisition of Sanyo by Panasonic; the merger was completed in December 2009, resulted in a corporation with revenues of over ¥11.2 trillion.
With the announcement that Pioneer would exit the production of its Kuro plasma HDTV displays, Panasonic purchased many of the patents and incorporated these technologies into its own plasma displays. In April 2011, it was announced that Panasonic would cut its work force by 40,000 by the end of fiscal 2012 in a bid to streamline overlapping operations; the curtailment is about 10 percent of its group work force. In October 2011, Panasonic announced that it would trim its money-losing TV business by ceasing production of Plasma TVs at its plant in Amagasaki, Hyogo Prefecture by March 2012, cutting 1,000 jobs in the process. In January 2012, Panasonic announced that it had struck a deal with Myspace on its new venture, Myspace TV. Myspace TV will allow users to watch live television while chatting with other users on a laptop, tablet or the television itself. With the partnership, Myspace TV will be integrated into Panasonic Viera televisions. On May 11, 2012, Panasonic announced plans to acquire a 76.2% stake in FirePro Systems, an India-based company in infrastructure protection and security solutions such as fire alarm, fire suppression, video surveillance and building management.
In line with company prediction of a net loss of 765 billion yen, on November 5, 2012, the shares fell to the lowest level since February 1975 to 388 yen. In 2012, the sh
Microwaves are a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter. Different sources define different frequency ranges as microwaves. A more common definition in radio engineering is the range between 100 GHz. In all cases, microwaves include the entire SHF band at minimum. Frequencies in the microwave range are referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations; the prefix micro- in microwave is not meant to suggest a wavelength in the micrometer range. Rather, it indicates that microwaves are "small", compared to the radio waves used prior to microwave technology; the boundaries between far infrared, terahertz radiation and ultra-high-frequency radio waves are arbitrary and are used variously between different fields of study. Microwaves travel by line-of-sight. At the high end of the band they are absorbed by gases in the atmosphere, limiting practical communication distances to around a kilometer.
Microwaves are used in modern technology, for example in point-to-point communication links, wireless networks, microwave radio relay networks, radar and spacecraft communication, medical diathermy and cancer treatment, remote sensing, radio astronomy, particle accelerators, industrial heating, collision avoidance systems, garage door openers and keyless entry systems, for cooking food in microwave ovens. Microwaves occupy a place in the electromagnetic spectrum with frequency above ordinary radio waves, below infrared light: In descriptions of the electromagnetic spectrum, some sources classify microwaves as radio waves, a subset of the radio wave band; this is an arbitrary distinction. Microwaves travel by line-of-sight paths. Although at the low end of the band they can pass through building walls enough for useful reception rights of way cleared to the first Fresnel zone are required. Therefore, on the surface of the Earth, microwave communication links are limited by the visual horizon to about 30–40 miles.
Microwaves are absorbed by moisture in the atmosphere, the attenuation increases with frequency, becoming a significant factor at the high end of the band. Beginning at about 40 GHz, atmospheric gases begin to absorb microwaves, so above this frequency microwave transmission is limited to a few kilometers. A spectral band structure causes absorption peaks at specific frequencies. Above 100 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that it is in effect opaque, until the atmosphere becomes transparent again in the so-called infrared and optical window frequency ranges. In a microwave beam directed at an angle into the sky, a small amount of the power will be randomly scattered as the beam passes through the troposphere. A sensitive receiver beyond the horizon with a high gain antenna focused on that area of the troposphere can pick up the signal; this technique has been used at frequencies between 0.45 and 5 GHz in tropospheric scatter communication systems to communicate beyond the horizon, at distances up to 300 km.
The short wavelengths of microwaves allow omnidirectional antennas for portable devices to be made small, from 1 to 20 centimeters long, so microwave frequencies are used for wireless devices such as cell phones, cordless phones, wireless LANs access for laptops, Bluetooth earphones. Antennas used include short whip antennas, rubber ducky antennas, sleeve dipoles, patch antennas, the printed circuit inverted F antenna used in cell phones, their short wavelength allows narrow beams of microwaves to be produced by conveniently small high gain antennas from a half meter to 5 meters in diameter. Therefore, beams of microwaves are used for point-to-point communication links, for radar. An advantage of narrow beams is that they don't interfere with nearby equipment using the same frequency, allowing frequency reuse by nearby transmitters. Parabolic antennas are the most used directive antennas at microwave frequencies, but horn antennas, slot antennas and dielectric lens antennas are used. Flat microstrip antennas are being used in consumer devices.
Another directive antenna practical at microwave frequencies is the phased array, a computer-controlled array of antennas which produces a beam which can be electronically steered in different directions. At microwave frequencies, the transmission lines which are used to carry lower frequency radio waves to and from antennas, such as coaxial cable and parallel wire lines, have excessive power losses, so when low attenuation is required microwaves are carried by metal pipes called waveguides. Due to the high cost and maintenance requirements of waveguide runs, in many microwave antennas the output stage of the transmitter or the RF front end of the receiver is located at the antenna; the term microwave has a more technical meaning in electromagnetics and circuit theory. Apparatus and techniques may
KMOX is an AM radio station affiliated with CBS News Radio and broadcasting from St. Louis, Missouri. Owned by Entercom, it is a 50,000-watt class A clear channel radio station, according to the North American Regional Broadcasting Agreement, signed by the U. S. Canada and Mexico; this permits KMOX's nighttime signal to be heard in most of the central U. S. and into Mexico and Canada. Its daytime signal provides at least secondary coverage to most of eastern and central Missouri, much of west-central Illinois. KMOX refers to itself as The Voice of St. Louis. KMOX's transmitter is located in Illinois; the KMOX studio is located at 1220 Olive Street in the Park Pacific Building at Olive Street and Tucker Boulevard. Entercom has studios and offices there for its two other St. Louis radio stations, KYKY and KEZK-FM. For many years, KMOX broadcast using C-QUAM AM stereo, but stereo transmissions ended in the spring of 2000; the station now broadcasts an HD Radio signal. The Federal Communications Commission requires a digital license for HD broadcasting.
KMOX, along with WSDZ, are responsible for the activation of the Greater St. Louis Emergency Alert System for hazardous weather, disaster declarations, etc. KMOX was started in the early days of broadcasting by a group of businessmen incorporated as The Voice of St. Louis Inc. According to the station's official website, the KMOX call letters were assigned by the Federal Radio Commission; the station's owners had hoped to be assigned KVSL, for "Voice of St. Louis." The owners applied for KMO, but those call letters had been in use by KMO in Tacoma since 1922. KMOX signed on December 24, 1925; the "X" was added because the starting date was "X "mas eve. Although a local legend states the call letters mean Kirkwood, Missouri On Xmas, the K was the assigned first call letter of all new radio stations west of the Mississippi River. In 1927, the station gave prominent coverage to the Charles Lindbergh flight across the Atlantic, in his plane, The Spirit of St. Louis; that same year, KMOX became one of the first 16 stations in the CBS network.
Two years CBS bought KMOX, began the process of getting approval to build a 50,000-watt transmitter tower. When completed, it gave the now-clear-channel station a signal that could be heard as far away as New Zealand and the Arctic Circle, making it one of the first international radio stations, its signal has been picked up in South Africa. In 1933, KMOX covered the first post-Prohibition case of Budweiser beer leaving the Anheuser-Busch St. Louis brewery for the White House, a story carried nationally by CBS. During the 1930s and 1940s, KMOX was one of several St. Louis stations broadcasting Cardinals and Browns baseball games. KMOX lost broadcasting rights in 1948 when a new Cardinals radio network was formed by the team, but by the 1950s, it became the flagship station of that network. During the 1950s, the station's slogan was "k-mocks", pronouncing the way the station's call letters are spelled. In 1955 Robert Hyland Jr became a role he held for nearly forty years, it was Hyland who leveraged KMOX's relationship with the Cardinals.
On February 29 of that year, Jack Buck hosted the first "At Your Service" program, which included an interview with Eleanor Roosevelt. That program, like the sports talk programs that soon followed, pioneered a format for radio dependent on interviews, guest appearances, calls from listeners. After Hyland died in 1992, Rod Zimmerman was named general manager, he departed in 1998 to manage WBBM Radio in Chicago. KMOX picked up Costas Coast to Coast in 1994. In July of that year Bob Costas began hosting a sports call-in show on the station. Karen Carroll was general manager from 1998 until 2003, when Tom Langmyer was promoted to the top position. Langmyer left in 2005 to become vice president/general manager of WGN Radio in Chicago. Dave Ervin managed the station from 2005 to 2008. John Sheehan, who oversees sister stations KEZK and KYKY is the station's current Market Manager for CBS. KMOX started broadcasting in HD Radio in May 2006; the station's emphasis had shifted away from broadcasting St. Louis professional sports teams.
In 2000, the St. Louis Blues hockey team moved to KTRS after having been on KMOX for all but three of the team's 33 seasons, but it would return starting in the 2006–07 season. In 2006, the Cardinals' broadcasts moved to KTRS 550 AM after 52 seasons on KMOX after the team purchased controlling interest in KTRS. On September 1, 2010, the Cardinals announced the return of broadcasts to KMOX, starting in the 2011 baseball season. KMOX aired the Missouri Tigers basketball games for many years. Starting in the Fall 2011, the Tigers moved their basketball and news & talk programs to KTRS. On January 30, 2012, Jon Grayson's "Overnight America", based at KMOX, airing on CBS stations WCCO Minneapolis and KDKA Pittsburgh, became a nationally syndicated program with several dozen stations airing it across the country. On February 2, 2017, CBS Radio announced; the merger was approved on November 9, 2017, was consummated on the 17th, ending KMOX's 88 years of CBS ownership. KMOX has had a long history of broadcasting sports.
In 1926, it broadcast the Cardinals-Yankees World Series, starting the next season the station was carrying Cardinals' games. KMOX's most famous sports figure was Jack Buck, who w
Very high frequency
High frequency is the ITU designation for the range of radio frequency electromagnetic waves from 30 to 300 megahertz, with corresponding wavelengths of ten meters to one meter. Frequencies below VHF are denoted high frequency, the next higher frequencies are known as ultra high frequency. Common uses for radio waves in the VHF band are FM radio broadcasting, television broadcasting, two way land mobile radio systems, long range data communication up to several tens of kilometers with radio modems, amateur radio, marine communications. Air traffic control communications and air navigation systems work at distances of 100 kilometres or more to aircraft at cruising altitude. In the Americas and many other parts of the world, VHF Band I was used for the transmission of analog television; as part of the worldwide transition to digital terrestrial television most countries require broadcasters to air television in the VHF range using digital rather than analog format. Radio waves in the VHF band propagate by line-of-sight and ground-bounce paths.
They do not follow the contour of the Earth as ground waves and so are blocked by hills and mountains, although because they are weakly refracted by the atmosphere they can travel somewhat beyond the visual horizon out to about 160 km. They can penetrate building walls and be received indoors, although in urban areas reflections from buildings cause multipath propagation, which can interfere with television reception. Atmospheric radio noise and interference from electrical equipment is less of a problem in the band than at lower frequencies; the VHF band is the first band at which efficient transmitting antennas are small enough that they can be mounted on vehicles and portable devices, so the band is used for two-way land mobile radio systems, such as walkie-talkies, two way radio communication with aircraft and ships. When conditions are right, VHF waves can travel long distances by tropospheric ducting due to refraction by temperature gradients in the atmosphere. For analog TV, VHF transmission range is a function of transmitter power, receiver sensitivity, distance to the horizon, since VHF signals propagate under normal conditions as a near line-of-sight phenomenon.
The distance to the radio horizon is extended over the geometric line of sight to the horizon, as radio waves are weakly bent back toward the Earth by the atmosphere. An approximation to calculate the line-of-sight horizon distance is: distance in nautical miles = 1.23 × A f where A f is the height of the antenna in feet distance in kilometers = 12.746 × A m where A m is the height of the antenna in meters. These approximations are only valid for antennas at heights that are small compared to the radius of the Earth, they may not be accurate in mountainous areas, since the landscape may not be transparent enough for radio waves. In engineered communications systems, more complex calculations are required to assess the probable coverage area of a proposed transmitter station; the accuracy of these calculations for digital TV signals is being debated. VHF is the first band at which wavelengths are small enough that efficient transmitting antennas are short enough to mount on vehicles and handheld devices, a quarter wave whip antenna at VHF frequencies is 25 cm to 2.5 meter long.
So the VHF and UHF wavelengths are used for two-way radios in vehicles and handheld transceivers and walkie-talkies. Portable radios use whips or rubber ducky antennas, while base stations use larger fiberglass whips or collinear arrays of vertical dipoles. For directional antennas, the Yagi antenna is the most used as a high gain or "beam" antenna. For television reception, the Yagi is used, as well as the log-periodic antenna due to its wider bandwidth. Helical and turnstile antennas are used for satellite communication since they employ circular polarization. For higher gain, multiple Yagis or helicals can be mounted together to make array antennas. Vertical collinear arrays of dipoles can be used to make high gain omnidirectional antennas, in which more of the antenna's power is radiated in horizontal directions. Television and FM broadcasting stations use collinear arrays of specialized dipole antennas such as batwing antennas. Certain subparts of the VHF band have the same use around the world.
Some national uses are detailed below. 50–54 MHz: Amateur Radio 6-meter band. 108–118 MHz: Air navigation beacons VOR and Instrument Landing System localizer. 118–137 MHz: Airband for air traffic control, AM, 121.5 MHz is emergency frequency 144–148 MHz: Amateur Radio 2-meter band. The VHF TV band in Australia was allocated channels 1 to 10-with channels 2, 7 and 9 assigned for the initial services in Sydney and Melbourne, the same channels were assigned in Brisbane and Perth. Other capital cities and regional areas used a combination of these and other frequencies as available; the initial commercial services in Hobart and Darwin were allocated channels 6 and 8 rather than 7 or 9. By the early 1960s it became apparent that the 10 VHF channels were insufficient to support the growth of television services; this was rectified by the addition of th