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117-624: The Federal Radio Commission ( FRC ) was a government agency that regulated United States radio communication from its creation in 1927 until 1934, when it was succeeded by the Federal Communications Commission (FCC) . The FRC was established by the Radio Act of 1927 , which replaced the Radio Act of 1912 after the earlier law was found to lack sufficient oversight provisions, especially for regulating broadcasting stations. In addition to increased regulatory powers,

234-471: A directional antenna transmits radio waves in a beam in a particular direction, or receives waves from only one direction. Radio waves travel at the speed of light in vacuum and at slightly lower velocity in air. The other types of electromagnetic waves besides radio waves, infrared , visible light , ultraviolet , X-rays and gamma rays , can also carry information and be used for communication. The wide use of radio waves for telecommunication

351-418: A microphone , a video signal representing moving images from a video camera , or a digital signal consisting of a sequence of bits representing binary data from a computer. The modulation signal is applied to a radio transmitter . In the transmitter, an electronic oscillator generates an alternating current oscillating at a radio frequency , called the carrier wave because it serves to generate

468-497: A radar screen . Doppler radar can measure a moving object's velocity, by measuring the change in frequency of the return radio waves due to the Doppler effect . Radar sets mainly use high frequencies in the microwave bands, because these frequencies create strong reflections from objects the size of vehicles and can be focused into narrow beams with compact antennas. Parabolic (dish) antennas are widely used. In most radars

585-474: A " push to talk " button on their radio which switches off the receiver and switches on the transmitter. Or the radio link may be full duplex , a bidirectional link using two radio channels so both people can talk at the same time, as in a cell phone. One way, unidirectional radio transmission is called simplex . This is radio communication between a spacecraft and an Earth-based ground station, or another spacecraft. Communication with spacecraft involves

702-627: A Service Regulation specifying that "Radiotelegrams shall show in the preamble that the service is 'Radio ' ". The switch to radio in place of wireless took place slowly and unevenly in the English-speaking world. Lee de Forest helped popularize the new word in the United States—in early 1907, he founded the DeForest Radio Telephone Company, and his letter in the 22 June 1907 Electrical World about

819-571: A bit later the Columbia Broadcasting System ) (CBS) — that were in the process of dominating broadcasting, other than a statement in section 3 that "The Commission shall have the authority to make special regulations applicable to stations engaged in chain broadcasting". In early 1928 it became clear that the FRC needed more than a single year to perform its tasks, and its tenure was extended for an additional year. In December 1929

936-440: A check on the commission's power, "censorship" of station programming was not allowed, although extreme language was prohibited: "Sec. 29. Nothing in this Act shall be understood or construed to give the licensing authority the power of censorship over the radio communications or signals transmitted by any radio station, and no regulation or condition shall be promulgated or fixed by the licensing authority which shall interfere with

1053-412: A controller device control the actions of a remote device. The existence of radio waves was first proven by German physicist Heinrich Hertz on 11 November 1886. In the mid-1890s, building on techniques physicists were using to study electromagnetic waves, Italian physicist Guglielmo Marconi developed the first apparatus for long-distance radio communication, sending a wireless Morse Code message to

1170-424: A fast-changing environment. To aid decision-making, he sponsored a series of four national conferences from 1922 to 1925, where invited industry leaders participated in setting standards for radio in general. During his tenure Hoover was aware that some of his actions were on shaky legal ground, given the limited powers assigned to him by the 1912 Act. In particular, in 1921 the department had tried to refuse to issue

1287-421: A given bandwidth than analog modulation , by using data compression algorithms, which reduce redundancy in the data to be sent, and more efficient modulation. Other reasons for the transition is that digital modulation has greater noise immunity than analog, digital signal processing chips have more power and flexibility than analog circuits, and a wide variety of types of information can be transmitted using

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1404-548: A government license, such as the general radiotelephone operator license in the US, obtained by taking a test demonstrating adequate technical and legal knowledge of safe radio operation. Exceptions to the above rules allow the unlicensed operation by the public of low power short-range transmitters in consumer products such as cell phones, cordless phones , wireless devices , walkie-talkies , citizens band radios , wireless microphones , garage door openers , and baby monitors . In

1521-587: A large economic cost, but it can also be life-threatening (for example, in the case of interference with emergency communications or air traffic control ). To prevent interference between different users, the emission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU), which allocates bands in the radio spectrum for different uses. Radio transmitters must be licensed by governments, under

1638-595: A metal conductor called an antenna . As they travel farther from the transmitting antenna, radio waves spread out so their signal strength ( intensity in watts per square meter) decreases (see Inverse-square law ), so radio transmissions can only be received within a limited range of the transmitter, the distance depending on the transmitter power, the antenna radiation pattern , receiver sensitivity, background noise level, and presence of obstructions between transmitter and receiver . An omnidirectional antenna transmits or receives radio waves in all directions, while

1755-427: A more limited information-carrying capacity and so work best with audio signals (speech and music), and the sound quality can be degraded by radio noise from natural and artificial sources. The shortwave bands have a greater potential range but are more subject to interference by distant stations and varying atmospheric conditions that affect reception. In the very high frequency band, greater than 30 megahertz,

1872-470: A primitive spark-gap transmitter . Experiments by Hertz and physicists Jagadish Chandra Bose , Oliver Lodge , Lord Rayleigh , and Augusto Righi , among others, showed that radio waves like light demonstrated reflection, refraction , diffraction , polarization , standing waves , and traveled at the same speed as light, confirming that both light and radio waves were electromagnetic waves, differing only in frequency. In 1895, Guglielmo Marconi developed

1989-420: A public audience. Analog audio is the earliest form of radio broadcast. AM broadcasting began around 1920. FM broadcasting was introduced in the late 1930s with improved fidelity . A broadcast radio receiver is called a radio . Most radios can receive both AM and FM. Television broadcasting is the transmission of moving images by radio, which consist of sequences of still images, which are displayed on

2106-459: A radio signal is usually concentrated in narrow frequency bands called sidebands ( SB ) just above and below the carrier frequency. The width in hertz of the frequency range that the radio signal occupies, the highest frequency minus the lowest frequency, is called its bandwidth ( BW ). For any given signal-to-noise ratio , an amount of bandwidth can carry the same amount of information ( data rate in bits per second) regardless of where in

2223-489: A receiver that is typically colocated with the transmitter. In radio navigation systems such as GPS and VOR , a mobile navigation instrument receives radio signals from multiple navigational radio beacons whose position is known, and by precisely measuring the arrival time of the radio waves the receiver can calculate its position on Earth. In wireless radio remote control devices like drones , garage door openers , and keyless entry systems , radio signals transmitted from

2340-533: A recipient over a kilometer away in 1895, and the first transatlantic signal on 12 December 1901. The first commercial radio broadcast was transmitted on 2 November 1920, when the live returns of the Harding-Cox presidential election were broadcast by Westinghouse Electric and Manufacturing Company in Pittsburgh, under the call sign KDKA . The emission of radio waves is regulated by law, coordinated by

2457-673: A reference to the radiotelegraph and radiotelegraphy . The use of radio as a standalone word dates back to at least 30 December 1904, when instructions issued by the British Post Office for transmitting telegrams specified that "The word 'Radio'... is sent in the Service Instructions." This practice was universally adopted, and the word "radio" introduced internationally, by the 1906 Berlin Radiotelegraphic Convention, which included

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2574-732: A renewal license to a point-to-point radiotelegraph station in New York City, operated by the Intercity Radio Company, on the grounds that it was causing excessive interference to earlier radiotelegraph stations operating nearby. Intercity appealed, and in 1923 the Court of Appeals of the District of Columbia sided with Intercity, stating the 1912 Act did not provide for licensing decisions at "the discretion of an executive officer". The Department of Commerce planned to request

2691-550: A review by the Supreme Court, but the case was rendered moot when Intercity decided to shut down the New York City station. Still, it had raised significant questions about the extent of Hoover's authority. A secord, ultimately successful, challenge occurred in 1926. The Zenith Radio Corporation in late 1925 established a high-powered radio station, WJAZ , with a transmitter site outside Chicago, Illinois. After being informed that there might not be an available frequency for

2808-479: A schedule of just two hours per week, his tone soon changed. At this time the United States had an informal agreement with Canada that six designated AM band frequencies would be used exclusively by Canadian stations. In early January 1926, McDonald directed WJAZ to move from its 930 kHz assignment to 910 kHz, one of the restricted Canadian frequencies, and begin expanded hours of operation. Invoking

2925-446: A screen on a television receiver (a "television" or TV) along with a synchronized audio (sound) channel. Television ( video ) signals occupy a wider bandwidth than broadcast radio ( audio ) signals. Analog television , the original television technology, required 6 MHz, so the television frequency bands are divided into 6 MHz channels, now called "RF channels". The current television standard, introduced beginning in 2006,

3042-441: A smaller bandwidth than the old analog channels, saving scarce radio spectrum space. Therefore, each of the 6 MHz analog RF channels now carries up to 7 DTV channels – these are called "virtual channels". Digital television receivers have different behavior in the presence of poor reception or noise than analog television, called the " digital cliff " effect. Unlike analog television, in which increasingly poor reception causes

3159-416: A television (video) signal has a greater data rate than an audio signal . The radio spectrum , the total range of radio frequencies that can be used for communication in a given area, is a limited resource. Each radio transmission occupies a portion of the total bandwidth available. Radio bandwidth is regarded as an economic good which has a monetary cost and is in increasing demand. In some parts of

3276-400: A transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraft and missiles, a beam of radio waves emitted by a radar transmitter reflects off the target object, and the reflected waves reveal the object's location to

3393-652: A transmitter to control the actions of a device at a remote location. Remote control systems may also include telemetry channels in the other direction, used to transmit real-time information on the state of the device back to the control station. Uncrewed spacecraft are an example of remote-controlled machines, controlled by commands transmitted by satellite ground stations . Most handheld remote controls used to control consumer electronics products like televisions or DVD players actually operate by infrared light rather than radio waves, so are not examples of radio remote control. A security concern with remote control systems

3510-435: A variety of license classes depending on use, and are restricted to certain frequencies and power levels. In some classes, such as radio and television broadcasting stations, the transmitter is given a unique identifier consisting of a string of letters and numbers called a call sign , which must be used in all transmissions. In order to adjust, maintain, or internally repair radiotelephone transmitters, individuals must hold

3627-413: Is amplified in the transmitter and applied to a transmitting antenna which radiates the energy as radio waves. The radio waves carry the information to the receiver location. At the receiver, the radio wave induces a tiny oscillating voltage in the receiving antenna which is a weaker replica of the current in the transmitting antenna. This voltage is applied to the radio receiver , which amplifies

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3744-703: Is spoofing , in which an unauthorized person transmits an imitation of the control signal to take control of the device. Examples of radio remote control: Radio jamming is the deliberate radiation of radio signals designed to interfere with the reception of other radio signals. Jamming devices are called "signal suppressors" or "interference generators" or just jammers. During wartime, militaries use jamming to interfere with enemies' tactical radio communication. Since radio waves can pass beyond national borders, some totalitarian countries which practice censorship use jamming to prevent their citizens from listening to broadcasts from radio stations in other countries. Jamming

3861-445: Is a digital format called high-definition television (HDTV), which transmits pictures at higher resolution, typically 1080 pixels high by 1920 pixels wide, at a rate of 25 or 30 frames per second. Digital television (DTV) transmission systems, which replaced older analog television in a transition beginning in 2006, use image compression and high-efficiency digital modulation such as OFDM and 8VSB to transmit HDTV video within

3978-402: Is a legally qualified candidate for any public office to use a broadcasting station, he shall afford equal opportunities to all other such candidates for that office in the use of such broadcasting station, and the licensing authority shall make rules and regulations to carry this provision into effect: Provided, That such licensee shall have no power of censorship over the material broadcast under

4095-433: Is an audio transceiver , a receiver and transmitter in the same device, used for bidirectional person-to-person voice communication with other users with similar radios. An older term for this mode of communication is radiotelephony . The radio link may be half-duplex , as in a walkie-talkie , using a single radio channel in which only one radio can transmit at a time, so different users take turns talking, pressing

4212-410: Is called "tuning". The oscillating radio signal from the desired station causes the tuned circuit to resonate , oscillate in sympathy, and it passes the signal on to the rest of the receiver. Radio signals at other frequencies are blocked by the tuned circuit and not passed on. A modulated radio wave, carrying an information signal, occupies a range of frequencies . The information ( modulation ) in

4329-427: Is called an uplink , while a link that transmits data from the spacecraft to the ground is called a downlink. Radar is a radiolocation method used to locate and track aircraft, spacecraft, missiles, ships, vehicles, and also to map weather patterns and terrain. A radar set consists of a transmitter and receiver. The transmitter emits a narrow beam of radio waves which is swept around the surrounding space. When

4446-565: Is in radio clocks and watches, which include an automated receiver that periodically (usually weekly) receives and decodes the time signal and resets the watch's internal quartz clock to the correct time, thus allowing a small watch or desk clock to have the same accuracy as an atomic clock. Government time stations are declining in number because GPS satellites and the Internet Network Time Protocol (NTP) provide equally accurate time standards. A two-way radio

4563-417: Is mainly due to their desirable propagation properties stemming from their longer wavelength. In radio communication systems, information is carried across space using radio waves. At the sending end, the information to be sent is converted by some type of transducer to a time-varying electrical signal called the modulation signal. The modulation signal may be an audio signal representing sound from

4680-600: Is not censorship." Denied this station, Brinkley moved his operations to a series of powerful Mexican outlets located on the U.S. border, which helped to lead to implementation of the North American Regional Broadcasting Agreement in 1941. KGEF was a broadcasting station first licensed in late 1926 to Trinity Methodist Church, South, in downtown Los Angeles. Its programming was dominated by long denunciations made by pastor Robert "Fighting Bob" Shuler , who stated that he operated

4797-524: Is the one-way transmission of information from a transmitter to receivers belonging to a public audience. Since the radio waves become weaker with distance, a broadcasting station can only be received within a limited distance of its transmitter. Systems that broadcast from satellites can generally be received over an entire country or continent. Older terrestrial radio and television are paid for by commercial advertising or governments. In subscription systems like satellite television and satellite radio

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4914-540: Is usually accomplished by a powerful transmitter which generates noise on the same frequency as the target transmitter. US Federal law prohibits the nonmilitary operation or sale of any type of jamming devices, including ones that interfere with GPS, cellular, Wi-Fi and police radars. ELF 3 Hz/100 Mm 30 Hz/10 Mm SLF 30 Hz/10 Mm 300 Hz/1 Mm ULF 300 Hz/1 Mm 3 kHz/100 km James Herbert Wilkerson James Herbert Wilkerson (December 11, 1869 – September 30, 1948)

5031-595: The International Telecommunication Union (ITU), which allocates frequency bands in the radio spectrum for various uses. The word radio is derived from the Latin word radius , meaning "spoke of a wheel, beam of light, ray". It was first applied to communications in 1881 when, at the suggestion of French scientist Ernest Mercadier  [ fr ] , Alexander Graham Bell adopted radiophone (meaning "radiated sound") as an alternate name for his photophone optical transmission system. Following Hertz's discovery of

5148-473: The U.S. Court of Appeals denied his appeal, stating "This contention is without merit. There has been no attempt on the part of the commission to subject any part of appellant's broadcasting matter to scrutiny prior to its release. In considering the question whether the public interest, convenience, or necessity will be served by a renewal of appellant's license, the commission has merely exercised its undoubted right to take note of appellant's past conduct, which

5265-504: The ionosphere without refraction , and at microwave frequencies the high-gain antennas needed to focus the radio energy into a narrow beam pointed at the receiver are small and take up a minimum of space in a satellite. Portions of the UHF , L , C , S , k u and k a band are allocated for space communication. A radio link that transmits data from the Earth's surface to a spacecraft

5382-400: The radio spectrum into 12 bands, each beginning at a wavelength which is a power of ten (10 ) metres, with corresponding frequency of 3 times a power of ten, and each covering a decade of frequency or wavelength. Each of these bands has a traditional name: It can be seen that the bandwidth , the range of frequencies, contained in each band is not equal but increases exponentially as

5499-531: The 1920s with the introduction of broadcasting. Electromagnetic waves were predicted by James Clerk Maxwell in his 1873 theory of electromagnetism , now called Maxwell's equations , who proposed that a coupled oscillating electric field and magnetic field could travel through space as a wave, and proposed that light consisted of electromagnetic waves of short wavelength . On 11 November 1886, German physicist Heinrich Hertz , attempting to confirm Maxwell's theory, first observed radio waves he generated using

5616-492: The 1927 Act included a general declaration about the need to equitably distribute station assignments, stating: "In considering applications for licenses and renewals of licenses, when and in so far as there is a demand for the same, the licensing authority shall make such a distribution of licenses, bands of frequency of wave lengths, periods of time for operation, and of power among the different States and communities as to give fair, efficient, and equitable radio service to each of

5733-846: The Communications Act contained provisions very similar to the Radio Act of 1927, and the FCC largely took over the operations and precedents of the FRC. The law also transferred jurisdiction over communications common carriers, such as telephone and telegraph companies, from the Interstate Commerce Commission to the FCC. Radio In radio communication , used in radio and television broadcasting , cell phones, two-way radios , wireless networking , and satellite communication , among numerous other uses, radio waves are used to carry information across space from

5850-399: The Court of Appeals of the District of Columbia ruled that restricting WGY's hours "was unreasonable and not in the public interest, convenience or necessity" The U.S. Supreme Court agreed to take the FRC's appeal, but following oral arguments declined to issue a ruling, after deciding that under current legislation it did not have oversight, thus allowing the lower court ruling to stand. KFKB

5967-474: The Earth's atmosphere has less of an effect on the range of signals, and line-of-sight propagation becomes the principal mode. These higher frequencies permit the great bandwidth required for television broadcasting. Since natural and artificial noise sources are less present at these frequencies, high-quality audio transmission is possible, using frequency modulation . Radio broadcasting means transmission of audio (sound) to radio receivers belonging to

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6084-628: The FRC decisions reviewed by the courts were upheld, however a notable exception involved WGY in Schenectady, New York, a long established high-powered station owned by General Electric. Under the November 11, 1928, reassignment plan, WGY was limited to daytime hours plus evening hours until sunset in Oakland, California, where KGO, transmitting on the same frequency, was located. Previously, WGY had operated with unlimited hours. On February 25, 1929,

6201-625: The FRC introduced the standard that, in order to receive a license, a radio station had to be shown to be "in the public interest, convenience, or necessity". Although radio communication (originally known as "wireless telegraphy") was developed in the late 1890s, it was largely unregulated in the United States until the passage of the Radio Act of 1912 . This law set up procedures for the Department of Commerce to license radio transmitters, which initially consisted primarily of maritime and amateur stations. The broadcasting of news and entertainment to

6318-734: The FRC issued General Order 32, which notified 164 stations that the initial review had found their justification for receiving a license insufficient, and they would have to attend a hearing in Washington, D.C. Moreover, "At this hearing, unless you can make an affirmative showing that public interest, convenience, or necessity will be served by the granting of your application, it will be finally denied." Many low-powered independent stations were eliminated, although eighty-one stations did survive, most with reduced power. Educational stations fared particularly poorly. They were usually required to share frequencies with commercial stations and operate during

6435-490: The FRC to crack down on "vulgar" language — for example the profanity-filled rants of William K. Henderson on KWKH in Shreveport, Louisiana. But it also led to First Amendment free speech disputes over the appropriateness of some FRC actions. A forerunner of the FCC's later " equal-time rule " required stations to give equal opportunities for political candidates: "Sec 18. If any licensee shall permit any person who

6552-459: The Government, through agencies established by Congress, may not refuse a renewal license to one who has abused it to broadcast defamatory and untrue matter. In that case there is not a denial of the freedom of speech but merely the application of the regulatory power of Congress in a field within the scope of its legislative authority". The court also ruled that denying license renewal as not in

6669-592: The Intercity Radio Company case rulings, Zenith ignored the Commerce Department's order to return WJAZ to its assigned frequency. On January 20, 1926, a federal court suit, United States versus Zenith Radio Corporation and E. F. McDonald , was filed in Chicago. McDonald expected a narrow ruling in his favor, claiming that only a small number of stations, including WJAZ, held the "Class D Developmental" licenses that were free from normal restrictions. However,

6786-508: The US, these fall under Part 15 of the Federal Communications Commission (FCC) regulations. Many of these devices use the ISM bands , a series of frequency bands throughout the radio spectrum reserved for unlicensed use. Although they can be operated without a license, like all radio equipment these devices generally must be type-approved before the sale. Below are some of the most important uses of radio, organized by function. Broadcasting

6903-525: The United States by the end of the year. The number of reserved transmitting frequencies also expanded, and by 1925, the "broadcast band" consisted of the frequencies from 550 kHz to 1500 kHz, in ten kHz steps. Herbert Hoover became the Secretary of Commerce in March 1921, and thus assumed primary responsibility for shaping radio broadcasting during its earliest days, which was a difficult task in

7020-420: The absence of federal regulation, stations were taking their individual disputes to the courts, which began to render decisions favoring incumbent stations. This effectively was granting established stations "property rights" in the use of their assignments, which the government wanted to avoid, because it generally considered the radio spectrum to be a public resource. Despite the recognition that new legislation

7137-428: The actual outcome was sweeping. On April 16, 1926, Judge James H. Wilkerson 's ruling stated that, under the 1912 Act, the Commerce Department in fact could not limit the number of broadcasting licenses issued, or designate station frequencies. The government reviewed whether to try to appeal this decision, but Acting Attorney General William J. Donovan's analysis concurred with the court's decision. The immediate result

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7254-405: The air simultaneously without interfering with each other because each transmitter's radio waves oscillate at a different rate, in other words, each transmitter has a different frequency , measured in hertz (Hz), kilohertz (kHz), megahertz (MHz) or gigahertz (GHz). The receiving antenna typically picks up the radio signals of many transmitters. The receiver uses tuned circuits to select

7371-423: The average listener is difficult to judge, but the term "chaos" started to appear in discussions. Prior to the early 1926 adverse ruling on the Commerce Department's regulatory authority, there had been numerous efforts in the U.S. Congress to replace the Radio Act of 1912 with a more comprehensive bill, but none of these efforts made much headway. The need for new legislation gained additional importance because, in

7488-414: The beam strikes a target object, radio waves are reflected back to the receiver. The direction of the beam reveals the object's location. Since radio waves travel at a constant speed close to the speed of light , by measuring the brief time delay between the outgoing pulse and the received "echo", the range to the target can be calculated. The targets are often displayed graphically on a map display called

7605-438: The commission had to monitor whether in heavily populated areas a decision would cause a zone or state to exceed its calculated quota. In cases where two or more stations shared a common frequency on a timesharing basis, a station could petition the FRC to have its hours of operation increased by having the other stations deleted. A prominent example under the FRC's jurisdiction occurred when a Gary, Indiana station, WJKS, proposed

7722-512: The commission's mandate was extended indefinitely. The FRC's regulatory activities, and the public's knowledge of its work, primarily focused on broadcasting stations. However, in 1932, in addition to 625 broadcasting stations, the commission oversaw numerous other station classifications, including approximately thirty thousand amateur radio stations, two thousand ship stations, and one thousand fixed-point land stations. On February 25, 1928, Charles Jenkins Laboratories of Washington, DC , became

7839-668: The continuous waves which were needed for audio modulation , so radio was used for person-to-person commercial, diplomatic and military text messaging. Starting around 1908 industrial countries built worldwide networks of powerful transoceanic transmitters to exchange telegram traffic between continents and communicate with their colonies and naval fleets. During World War I the development of continuous wave radio transmitters, rectifying electrolytic, and crystal radio receiver detectors enabled amplitude modulation (AM) radiotelephony to be achieved by Reginald Fessenden and others, allowing audio to be transmitted. On 2 November 1920,

7956-442: The control of the United States over all the channels of interstate and foreign radio transmission; and to provide for the use of such channels, but not the ownership thereof, by individuals, firms, or corporations, for limited periods of time, under licenses granted by Federal authority, and no such license shall be construed to create any right, beyond the terms, conditions, and periods of the license." Some technical duties remained

8073-466: The customer pays a monthly fee. In these systems, the radio signal is encrypted and can only be decrypted by the receiver, which is controlled by the company and can be deactivated if the customer does not pay. Broadcasting uses several parts of the radio spectrum, depending on the type of signals transmitted and the desired target audience. Longwave and medium wave signals can give reliable coverage of areas several hundred kilometers across, but have

8190-547: The daytime, which was considered of limited value for adult education. With the roster of stations now reduced to a somewhat more manageable level, the FRC next embarked on a major reorganization of broadcasting station frequency assignments. On August 30, 1928, the Commission issued General Order 40, which defined a "broadcast band" consisting of 96 frequencies from 550 to 1500 kHz. Six frequencies were restricted for exclusive use Canadian stations, leaving 90 available for

8307-483: The deletion of its two timeshare partners, WIBO and WPCC, both located in Chicago, Illinois. A major justification was that Indiana was currently under-quota based on the Davis Amendment provisions, while Illinois had exceeded its allocation. The commission ruled in favor of WJKS, however the Court of Appeals of the District of Columbia reversed the decision, calling it "arbitrary and capricious". The FRC appealed

8424-570: The existence of radio waves in 1886, the term Hertzian waves was initially used for this radiation. The first practical radio communication systems, developed by Marconi in 1894–1895, transmitted telegraph signals by radio waves, so radio communication was first called wireless telegraphy . Up until about 1910 the term wireless telegraphy also included a variety of other experimental systems for transmitting telegraph signals without wires, including electrostatic induction , electromagnetic induction and aquatic and earth conduction , so there

8541-413: The first commercial radio broadcast was transmitted by Westinghouse Electric and Manufacturing Company in Pittsburgh, under the call sign KDKA featuring live coverage of the Harding-Cox presidential election . Radio waves are radiated by electric charges undergoing acceleration . They are generated artificially by time-varying electric currents , consisting of electrons flowing back and forth in

8658-601: The first holder of a television license. The most critical issue the FRC faced at the time of its creation was an excess of broadcasting stations, which now numbered 732, all on the AM band. (The FM broadcast band would not be created until 1941). There were some significant technical restraints on the number of stations that could operate simultaneously. At night, a change in the ionosphere allows radio signals, especially from more powerful stations, to travel hundreds of kilometers. In addition, at this time transmitter frequency stability

8775-481: The first meeting of the commission created by this Act, all the powers and authority vested in the commission under the terms of this Act, except as to the revocation of licenses, shall be vested in and exercised by the Secretary of Commerce; except that thereafter the commission shall have power and jurisdiction to act upon and determine any and all matters brought before it under the terms of this section." Acting as

8892-592: The first radio communication system, using a spark-gap transmitter to send Morse code over long distances. By December 1901, he had transmitted across the Atlantic Ocean. Marconi and Karl Ferdinand Braun shared the 1909 Nobel Prize in Physics "for their contributions to the development of wireless telegraphy". During radio's first two decades, called the radiotelegraphy era, the primitive radio transmitters could only transmit pulses of radio waves, not

9009-618: The frequency increases; each band contains ten times the bandwidth of the preceding band. The term "tremendously low frequency" (TLF) has been used for wavelengths from 1–3 Hz (300,000–100,000 km), though the term has not been defined by the ITU. The airwaves are a resource shared by many users. Two radio transmitters in the same area that attempt to transmit on the same frequency will interfere with each other, causing garbled reception, so neither transmission may be received clearly. Interference with radio transmissions can not only have

9126-509: The general public, which began to be developed early 1920s, was not foreseen by this legislation. The first Commerce Department regulations specifically addressing broadcasting were adopted on December 1, 1921, when two wavelengths were set aside for stations making broadcasts intended for a general audience: 360 meters (833 kHz) for "entertainment", and 485 meters (619 kHz) for "market and weather reports". The number of broadcasting stations grew tremendously in 1922, numbering over 500 in

9243-442: The granting thereof was in the public interest ; that the programs broadcast by its principal speaker were sensational rather than instructive and in two instances he had been convicted of attempting over the radio to obstruct orderly administration of public justice". The Court of Appeals of the District of Columbia affirmed the Commission's decision and held that, despite First Amendment protections: "...this does not mean that

9360-519: The grounds that it should have been given a full-time authorization, but lost. Even though the station was government owned, the Federal Radio Commission said that city ownership did not give the station any special standing under the "public interest, convenience, and necessity" standard. However, the case was viewed as representative of the preferences given to commercial interests above those of non-commercial stations. Section 9 of

9477-427: The limitations of the 1912 act, the FRC was given the power to grant and deny licenses, assign station frequencies and power levels, and issue fines for violations. The opening paragraph of the Radio Act of 1927 summarized its objectives as: "...this Act is intended to regulate all forms of interstate and foreign radio transmissions and communications within the United States, its Territories and possessions; to maintain

9594-402: The longest transmission distances of any radio links, up to billions of kilometers for interplanetary spacecraft . In order to receive the weak signals from distant spacecraft, satellite ground stations use large parabolic "dish" antennas up to 25 metres (82 ft) in diameter and extremely sensitive receivers. High frequencies in the microwave band are used, since microwaves pass through

9711-530: The lower court decision to the Supreme Court, stating that the issue impacted 116 separate cases pending before it. A unanimous Supreme Court overturned the District Court, and ruled in FRC's favor, upholding the validity of the Davis Amendment provisions. WIBO made a final attempt to convince the FRC that the expression of strong ties to Indiana by WJKS was fraudulent, and WJKS's owners were really attempting to establish another Chicago station. This appeal

9828-472: The need for legal restrictions warned that "Radio chaos will certainly be the result until such stringent regulation is enforced." The United States Navy would also play a role. Although its translation of the 1906 Berlin Convention used the terms wireless telegraph and wireless telegram , by 1912 it began to promote the use of radio instead. The term started to become preferred by the general public in

9945-505: The picture quality to gradually degrade, in digital television picture quality is not affected by poor reception until, at a certain point, the receiver stops working and the screen goes black. Government standard frequency and time signal services operate time radio stations which continuously broadcast extremely accurate time signals produced by atomic clocks , as a reference to synchronize other clocks. Examples are BPC , DCF77 , JJY , MSF , RTZ , TDF , WWV , and YVTO . One use

10062-517: The provisions of this paragraph. No obligation is hereby imposed upon any licensee to allow the use of its station by any such candidate." The Radio Act of 1927 did not authorize the Federal Radio Commission to make any rules regulating advertising , although section 19 required advertisers to properly identify themselves. There was almost no mention of the radio networks — notably the National Broadcasting Company (NBC) and,

10179-478: The public interest did not violate the Fifth Amendment's prohibition of "taking of property" without due process of law. This ruling became final after a petition for writ of certiorari requesting review by United States Supreme Court was denied. Under the November 11, 1928, reorganization, WNYC , the municipal station of New York City, was given a half-time, low-power assignment. The station appealed on

10296-451: The radio frequency spectrum it is located, so bandwidth is a measure of information-carrying capacity . The bandwidth required by a radio transmission depends on the data rate of the information (modulation signal) being sent, and the spectral efficiency of the modulation method used; how much data it can transmit in each kilohertz of bandwidth. Different types of information signals carried by radio have different data rates. For example,

10413-409: The radio signal desired out of all the signals picked up by the antenna and reject the others. A tuned circuit (also called resonant circuit or tank circuit) acts like a resonator , similar to a tuning fork . It has a natural resonant frequency at which it oscillates. The resonant frequency of the receiver's tuned circuit is adjusted by the user to the frequency of the desired radio station; this

10530-451: The radio spectrum, the right to use a frequency band or even a single radio channel is bought and sold for millions of dollars. So there is an incentive to employ technology to minimize the bandwidth used by radio services. A slow transition from analog to digital radio transmission technologies began in the late 1990s. Part of the reason for this is that digital modulation can often transmit more information (a greater data rate) in

10647-456: The radio waves that carry the information through the air. The modulation signal is used to modulate the carrier, varying some aspect of the carrier wave, impressing the information in the modulation signal onto the carrier. Different radio systems use different modulation methods: Many other types of modulation are also used. In some types, a carrier wave is not transmitted but just one or both modulation sidebands . The modulated carrier

10764-526: The responsibility of the Radio Division of the Department of Commerce, and because Congress failed to provide funding for a staff, during the FRC's first year the commission was heavily dependent on support from Commerce personnel. Moreover, most of the FRC's work was expected to be completed within one year, and the original intention was that a majority of its functions would then revert to the Secretary of Commerce: "Sec 5. From and after one year after

10881-453: The right of free speech by means of radio communications. No person within the jurisdiction of the United States shall utter any obscene, indecent, or profane language by means of radio communication." However, the "public interest, convenience, or necessity" standard allowed the Commission to take into consideration program content when renewing licenses, and the ability to take away a license provided some degree of content control. This allowed

10998-481: The same digital modulation. Because it is a fixed resource which is in demand by an increasing number of users, the radio spectrum has become increasingly congested in recent decades, and the need to use it more effectively is driving many additional radio innovations such as trunked radio systems , spread spectrum (ultra-wideband) transmission, frequency reuse , dynamic spectrum management , frequency pooling, and cognitive radio . The ITU arbitrarily divides

11115-678: The same." The 1928 reauthorization strengthened this mandate, by including a provision, known as the " Davis Amendment " after its sponsor Representative Ewin L. Davis (D-Tennessee), that required "a fair and equitable allocation of licenses, wave lengths, time for operation, and station power to each of the States, the District of Columbia, the Territories and possessions of the United States within each zone, according to population". This resulted in an additional degree of complexity, for in addition to stations being judged on their individual merits,

11232-407: The slightly fewer than 600 U.S. stations. The new assignments went into effect on November 11, 1928. Forty of the available frequencies were reserved for high-powered "clear channel" stations, which in most cases had only a single station with an exclusive nationwide assignment. Although generally accepted as being successful on a technical level of reducing interference and improving reception, there

11349-431: The standard of transmitting on frequencies evenly divided by 10 kHz. The FRC conducted a review and census of the existing stations, then notified them that if they wished to remain on the air they had to file a formal license application by January 15, 1928, as the first step in determining whether they met the new "public interest, convenience, or necessity" standard. After reviewing the applications, on May 25, 1928,

11466-454: The station in order to "make it hard for the bad man to do wrong in the community", but his strident broadcasts soon became very controversial. After a 1931 evaluation of the station's renewal application, chief examiner Ellis A. Yost expressed misgivings about Shuler's "extremely indiscreet" broadcasts, but recommended approval. However, a review by the Commission concluded that the station should be deleted, because it "...could not determine that

11583-470: The station to use, company president E. F. McDonald proposed that, because they only wanted to broadcast two hours a week, they would be happy with an assignment on 930 kHz that was limited to 10:00 p.m. to midnight Central time on Thursday nights, when the only other station on the frequency, KOA in Denver, Colorado, was normally off the air. Despite McDonald's initial expression of satisfaction with

11700-401: The station was primarily being run as "a mere adjunct of a particular business". (In one of Brinkley's programs he read listener mail describing medical issues, then recommended medication of dubious value, identified by numbers, over the air. Listeners had to visit a Brinkley "kick back" pharmacy to purchase these items.) Brinkley appealed on the grounds that this was prohibited censorship, but

11817-431: The transmitting antenna also serves as the receiving antenna; this is called a monostatic radar . A radar which uses separate transmitting and receiving antennas is called a bistatic radar . Radiolocation is a generic term covering a variety of techniques that use radio waves to find the location of objects, or for navigation. Radio remote control is the use of electronic control signals sent by radio waves from

11934-477: The trial, informant Edward J. O'Hare told IRS agent Frank J. Wilson that Capone's outfit had a complete list of prospective jurors. 10 of the jurors' names and addresses O'Hare provided appeared on the jury list. When they relayed it to Wilkerson, he responded that he hadn't received his jury list yet, but would call them when he did. The names on O'Hare's list matched exactly the names on Wilkerson's list, but Wilkerson seemed to be unconcerned, telling them to bring

12051-510: The weak radio signal so it is stronger, then demodulates it, extracting the original modulation signal from the modulated carrier wave. The modulation signal is converted by a transducer back to a human-usable form: an audio signal is converted to sound waves by a loudspeaker or earphones, a video signal is converted to images by a display , while a digital signal is applied to a computer or microprocessor, which interacts with human users. The radio waves from many transmitters pass through

12168-764: Was a United States district judge of the United States District Court for the Northern District of Illinois . Born in Savannah, Missouri , Wilkerson received an Artium Baccalaureus degree from DePauw University in 1889. He was in private practice in Chicago, Illinois from 1893 to 1922. He was a member of the Illinois House of Representatives in 1902, and was a county attorney of Cook County, Illinois from 1903 to 1904. He

12285-598: Was a need for a more precise term referring exclusively to electromagnetic radiation. The French physicist Édouard Branly , who in 1890 developed the radio wave detecting coherer , called it in French a radio-conducteur . The radio- prefix was later used to form additional descriptive compound and hyphenated words, especially in Europe. For example, in early 1898 the British publication The Practical Engineer included

12402-401: Was a popular Milford, Kansas broadcasting station, licensed to an organization controlled by John R. Brinkley, known as "The Goat Gland Doctor" due to his promotion of "sexual rejuvenation" surgery that included implantation of slivers of goat testes. In 1930 the Federal Radio Commission denied his request for renewal, primarily on the grounds that, instead of being operated as a public service,

12519-771: Was a special assistant to the Attorney General of the United States from 1906 to 1911, and was then the United States Attorney for the Northern District of Illinois from 1911 to 1914. He was Chairman of the Illinois Public Utilities Commission from 1919 to 1921. On July 11, 1922, Wilkerson was nominated by President Warren G. Harding to a seat on the United States District Court for the Northern District of Illinois vacated by Judge Kenesaw Mountain Landis . Wilkerson

12636-473: Was also a perception that large companies and their stations had received the best assignments. Commissioner Ira E. Robinson publicly dissented, stating that: "Having opposed and voted against the plan and the allocations made thereunder, I deem it unethical and improper to take part in hearings for the modification of same". Some later economic analysis has concluded that the early radio regulation policies reflected regulatory capture and rent-seeking . Most of

12753-536: Was brought to the Senate floor on January 28, 1927, and, as a compromise, specified that a five member commission would be given the power to reorganize radio regulation, but most of its duties would end after one year. After a month of debates this bill was passed on February 18, 1927, as the Radio Act of 1927, and signed into law by President Calvin Coolidge on February 23, 1927. The Commission's organizational meeting

12870-480: Was confirmed by the United States Senate on July 18, 1922, and received his commission the same day. He assumed senior status on December 31, 1940, serving in that capacity until his death on September 30, 1948. On November 24, 1931, Wilkerson sentenced Al Capone to 11 years in prison for tax evasion. Capone would often engage in jury tampering , and about two weeks before the scheduled start of

12987-401: Was deferred, so they initially participated without pay. In October 1927 Dillon died and Bellows resigned. During the next month Bullard died, and Harold Lafount and Sam Pickard were appointed. It was not until March 1928, after Caldwell was approved by a one vote margin and Ira E. Robinson was appointed as chairman, that all five commissioner posts were filled with confirmed members. To rectify

13104-711: Was held on March 15. The Radio Act of 1927 subdivided the country into five geographical zones, and specified that one commissioner would be appointed who resided within each zone. Terms were initially for up to six years, although this was later reduced to one year, and no more than three commissioners could be members of the same political party. The FRC's commissioners, by zone, from 1927 to 1934 were: The five initial appointments, made by President Coolidge on March 2, 1927, were: Admiral William H. G. Bullard as chairman, Colonel John F. Dillon, Eugene O. Sykes, Henry A. Bellows, and Orestes H. Caldwell. Bullard, Dillon and Sykes were confirmed on March 4, but action on Bellows and Caldwell

13221-501: Was limiting the number of stations operating concurrently, which meant restricting some stations to daytime-only operation, and in many cases requiring time-sharing, where up to four stations in a given region had to divide up the hours each used on a single frequency. On May 3, 1927, the FRC made the first of a series of temporary frequency assignments, which served to reassign the stations operating on Canadian frequencies, and also eliminate "split-frequency" operations that fell outside of

13338-566: Was needed, there was a lack of consensus whether it should increase the authority of the Secretary of Commerce, which opponents argued would create a too-powerful "Radio Czar", or if an independent regulatory body was needed, which some disputed was unneeded and overly expansive. The legislation ultimately passed was known as the Dill-White Bill, which was proposed and sponsored by Senator Clarence Dill (D-Washington) and Representative Wallace H. White Jr. (R-Maine) on December 21, 1926. It

13455-446: Was often limited, which meant that stations broadcasting on nominally the same frequency often were actually slightly offset from each other, which produced piercing high-pitched "heterodyne" interference at even greater distances than the mixing of their audio. Another tool that was not yet available was directional antennas that could restrict signals to specified directions. Overall, the main tools available for insuring quality reception

13572-425: Was that, until Congress passed new legislation, the Commerce Department could not limit the number of new broadcasting stations, which were now free to operate on any frequency and use any power they wished. Many stations showed restraint, while others took the opportunity to increase powers and move to new frequencies (derisively called "wave jumping"). The extent to which this new environment resulted in disruption for

13689-452: Was unsuccessful, and both WIBO and WPCC had to cease broadcasting. In 1934 the Davis Amendment provisions were carried over to the FCC, but they were repealed on June 5, 1936. In 1944 WJKS, after changing its call letters to WIND , moved from Gary to Chicago. The Communications Act of 1934 abolished the Federal Radio Commission and transferred jurisdiction over radio licensing to the new Federal Communications Commission (FCC). Title III of

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