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80-469: WWVA may refer to: WWVA (AM) , a radio station (1170 AM) licensed to Wheeling, West Virginia, United States WOVK-FM , a radio station (98.7 FM) licensed to Wheeling, West Virginia, United States which originally held the WWVA-FM callsign from 1947 into the 1970s WWVA Jamboree , also known as Jamboree USA and currently known as The Wheeling Jamboree ,

160-416: A capacitance , as antennas shorter than a quarter-wavelength have capacitive reactance . Many early crystal sets did not have a tuning capacitor, and relied instead on the capacitance inherent in the wire antenna (in addition to significant parasitic capacitance in the coil ) to form the tuned circuit with the coil. The earliest crystal receivers did not have a tuned circuit at all, and just consisted of

240-492: A pencil lead for a detector. The lead point touching the semiconducting oxide coating (magnetite) on the blade formed a crude point-contact diode. By carefully adjusting the pencil lead on the surface of the blade, they could find spots capable of rectification. The sets were dubbed " foxhole radios " by the popular press, and they became part of the folklore of World War II . In some German-occupied countries during WW2 there were widespread confiscations of radio sets from

320-447: A zincite ( zinc oxide ) crystal he gained amplification. This was a negative resistance phenomenon, decades before the development of the tunnel diode . After the first experiments, Losev built regenerative and superheterodyne receivers, and even transmitters. A crystodyne could be produced under primitive conditions; it could be made in a rural forge, unlike vacuum tubes and modern semiconductor devices. However, this discovery

400-485: A Two-Circuit Radio Receiving Equipment With Crystal Detector , which was published the same year and is still frequently built by enthusiasts today. In the beginning of the 20th century, radio had little commercial use, and radio experimentation was a hobby for many people. Some historians consider the autumn of 1920 to be the beginning of commercial radio broadcasting for entertainment purposes. Pittsburgh station KDKA , owned by Westinghouse , received its license from

480-478: A coil, changing the inductance in a tuned circuit. Earlier crystal radios suffered from severely reduced Q, and resulting selectivity, from the electrical load of the earphone or earpiece. Furthermore, with its efficient earpiece, the "rocket radio" did not require a large antenna to gather enough signal. With much higher Q, it could typically tune in several strong local stations, while an earlier radio might only receive one station, possibly with other stations heard in

560-399: A connection to ground (the earth) as a return circuit for the current. The ground wire was attached to a radiator, water pipe, or a metal stake driven into the ground. In early days if an adequate ground connection could not be made a counterpoise was sometimes used. A good ground is more important for crystal sets than it is for powered receivers, as crystal sets are designed to have

640-401: A contact between a mineral and a metal was discovered in 1874 by Karl Ferdinand Braun . Crystals were first used as a detector of radio waves in 1894 by Jagadish Chandra Bose , in his microwave optics experiments. They were first used as a demodulator for radio communication reception in 1902 by G. W. Pickard . Crystal radios were the first widely used type of radio receiver, and

720-589: A country music program WBZY , a radio station (105.7 FM) licensed to Canton, Georgia, United States, which held the call sign WWVA-FM from 2005 to 2013 Walla Walla Valley Academy , a Seventh-day Adventist high school in College Place, Washington White Waltham Village Association , Village Association of a small village in Berkshire, England Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

800-402: A crude Schottky diode that allowed current to flow better in one direction than in the opposite direction. Modern crystal sets use modern semiconductor diodes . The crystal functions as an envelope detector , rectifying the alternating current radio signal to a pulsing direct current , the peaks of which trace out the audio signal, so it can be converted to sound by the earphone, which

880-402: A crystal detector connected between the antenna and ground, with an earphone across it. Since this circuit lacked any frequency-selective elements besides the broad resonance of the antenna, it had little ability to reject unwanted stations, so all stations within a wide band of frequencies were heard in the earphone (in practice the most powerful usually drowns out the others). It was used in

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960-419: A crystal radio with common household items. To minimize the cost, many of the plans suggested winding the tuning coil on empty pasteboard containers such as oatmeal boxes, which became a common foundation for homemade radios. In early 1920s Russia , Oleg Losev was experimenting with applying voltage biases to various kinds of crystals for the manufacturing of radio detectors. The result was astonishing: with

1040-420: A crystal set has insufficient power for a loudspeaker ). However they are passive receivers, while other radios use an amplifier powered by current from a battery or wall outlet to make the radio signal louder. Thus, crystal sets produce rather weak sound and must be listened to with sensitive earphones, and can receive stations only within a limited range of the transmitter. The rectifying property of

1120-413: A crystal, usually a thin wire or metal probe that contacts the crystal, and the stand or enclosure that holds those components in place. The most common crystal used is a small piece of galena ; pyrite was also often used, as it was a more easily adjusted and stable mineral, and quite sufficient for urban signal strengths. Several other minerals also performed well as detectors. Another benefit of crystals

1200-468: A division of Columbia Pictures , Coca-Cola , Price Broadcasting, Osborn Communications, Atlantic Star Communications, AMFM Inc., and Clear Channel Communications. WWVA's broadcast history includes the airing of such notable live broadcasts as President Dwight D. Eisenhower 's 1952 visit to the Wheeling area. In the 1980s, WWVA briefly enjoyed a reputation as one of the leading radio news operations in

1280-507: A feed wire attached in the center or at one end leading down to the receiver. However, more often, random lengths of wire dangling out windows are used. A popular practice in early days (particularly among apartment dwellers) was to use existing large metal objects, such as bedsprings , fire escapes , and barbed wire fences as antennas. The wire antennas used with crystal receivers are monopole antennas which develop their output voltage with respect to ground. The receiver thus requires

1360-451: A fraction of the coil's turns. This reduced the impedance loading of the tuned circuit, as well as improving the impedance match with the detector. In more sophisticated crystal receivers, the tuning coil is replaced with an adjustable air core antenna coupling transformer which improves the selectivity by a technique called loose coupling . This consists of two magnetically coupled coils of wire, one (the primary ) attached to

1440-491: A low input impedance needed to transfer power efficiently from the antenna. A low resistance ground connection (preferably below 25 Ω) is necessary because any resistance in the ground reduces available power from the antenna. In contrast, modern receivers are voltage-driven devices, with high input impedance, hence little current flows in the antenna/ground circuit. Also, mains powered receivers are grounded adequately through their power cords, which are in turn attached to

1520-429: A publication entitled Construction and Operation of a Simple Homemade Radio Receiving Outfit . This article showed how almost any family having a member who was handy with simple tools could make a radio and tune into weather, crop prices, time, news and the opera. This design was significant in bringing radio to the general public. NBS followed that with a more selective two-circuit version, Construction and Operation of

1600-413: A rocket, typically imported from Japan, was introduced, and gained moderate popularity. It used a piezoelectric crystal earpiece (described later in this article), a ferrite core to reduce the size of the tuning coil (also described later), and a small germanium fixed diode, which did not require adjustment. To tune in stations, the user moved the rocket nosepiece, which, in turn, moved a ferrite core inside

1680-406: A single tuned circuit. However, the looser coupling also reduced the power of the signal passed to the second circuit. The transformer was made with adjustable coupling, to allow the listener to experiment with various settings to gain the best reception. One design common in early days, called a "loose coupler", consisted of a smaller secondary coil inside a larger primary coil. The smaller coil

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1760-552: A technological explosion around 1920 that evolved into today's radio broadcasting industry. Early radio telegraphy used spark gap and arc transmitters as well as high-frequency alternators running at radio frequencies . The coherer was the first means of detecting a radio signal. These, however, lacked the sensitivity to detect weak signals. In the early 20th century, various researchers discovered that certain metallic minerals , such as galena , could be used to detect radio signals. Indian physicist Jagadish Chandra Bose

1840-683: A variety of common objects, such as blue steel razor blades and lead pencils , rusty needles, and pennies In these, a semiconducting layer of oxide or sulfide on the metal surface is usually responsible for the rectifying action. In modern sets, a semiconductor diode is used for the detector, which is much more reliable than a crystal detector and requires no adjustments. Germanium diodes (or sometimes Schottky diodes ) are used instead of silicon diodes, because their lower forward voltage drop (roughly 0.3 V compared to 0.6 V ) makes them more sensitive. All semiconductor detectors function rather inefficiently in crystal receivers, because

1920-631: Is an American AM radio station in Wheeling, West Virginia . The station is owned by iHeartMedia, Inc. and uses the moniker "The Big One". It is West Virginia's only class A 50,000–watt clear-channel station , sharing the frequency's Class A status with KOTV in Tulsa, Oklahoma , and KJNP in North Pole, Alaska. Its transmitter site is located at a three-tower facility in St. Clairsville, Ohio . During

2000-418: Is connected to the detector. The rectified current from the detector has radio frequency pulses from the carrier frequency in it, which are blocked by the high inductive reactance and do not pass well through the coils of early date earphones. Hence, a small capacitor called a bypass capacitor is often placed across the earphone terminals; its low reactance at radio frequency bypasses these pulses around

2080-620: Is the second-longest running program in radio history ( The Grand Ole Opry on WSM Nashville is the oldest, having first aired in 1925). However, the Jamboree was dropped from WWVA's schedule in December 2008, and went to WKKX for a time. In 2015 it was picked up by community station WWOV-LP /101.1. On August 4, 2010, a severe thunderstorm, classified as a "down burst" by the National Weather Service, pushed through

2160-733: The Boy Scouts mainly as a way of learning about the technology of radio. They are still sold as educational devices, and there are groups of enthusiasts devoted to their construction. Crystal radios receive amplitude modulated (AM) signals, although FM designs have been built. They can be designed to receive almost any radio frequency band, but most receive the AM broadcast band. A few receive shortwave bands, but strong signals are required. The first crystal sets received wireless telegraphy signals broadcast by spark-gap transmitters at frequencies as low as 20 kHz. Crystal radio

2240-703: The Jamboree became the centerpiece of an all-contemporary country western format starting on November 8, 1965, a format that saw ratings skyrocket weeks after it debuted. "This is WWVA, the big country" was their signature. In 1970 the studios and the Jamboree moved to the Capitol Music Hall , a civic center that is the largest in West Virginia . This country music format lasted until 1997 when WWVA abandoned it in favor of news/talk. Assumption of ownership by Clear Channel Communications resulted in

2320-569: The United States Department of Commerce just in time to broadcast the Harding-Cox presidential election returns. In addition to reporting on special events, broadcasts to farmers of crop price reports were an important public service in the early days of radio. In 1921, factory-made radios were very expensive. Since less-affluent families could not afford to own one, newspapers and magazines carried articles on how to build

2400-436: The wireless telegraphy era could be received at hundreds of miles, and crystal receivers were even used for transoceanic communication during that period. Commercial passive receiver development was abandoned with the advent of reliable vacuum tubes around 1920, and subsequent crystal radio research was primarily done by radio amateurs and hobbyists. Many different circuits have been used. The following sections discuss

2480-460: The U.S. The Clear Channel Wheeling stations were initially slated to be sold to Florida-based GoodRadio.TV LLC in May 2007, but the deal soon collapsed prior to FCC approval. Crystal sets Crystal radios are the simplest type of radio receiver and can be made with a few inexpensive parts, such as a wire for an antenna, a coil of wire, a capacitor, a crystal detector, and earphones (because

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2560-512: The Wheeling area knocking the 3–tower array, located in nearby St. Clairsville, Ohio , to the ground. The station was taken completely off the air and took its programming to sister station WBBD on August 5. On August 5, 2010, at 10:30 pm, transmissions on 1170 AM were restored using temporary equipment. On November 16, 2006, WWVA, WOVK , WVKF , WKWK , WEGW and WBBD were announced for sale as part of Clear Channel's divestiture of almost 450 small and middle-market radio properties in

2640-690: The addition of such hosts as Rush Limbaugh and Glenn Beck . A series of cost-cutting moves in January 2004 resulted in the elimination of both local talk hosts (George Kellas and Jim Harrington) and most of the news department. Coinciding with this was an attempt to relocate the station to Stow, Ohio , under an FCC major construction permit four weeks later. This application was withdrawn in August 2004. Since then, much of WWVA's programming emulates regional sister station WHLO in Akron, Ohio . One local link to

2720-429: The antenna and ground and the other (the secondary ) attached to the rest of the circuit. The current from the antenna creates an alternating magnetic field in the primary coil, which induced a current in the secondary coil which was then rectified and powered the earphone. Each of the coils functions as a tuned circuit ; the primary coil resonated with the capacitance of the antenna (or sometimes another capacitor), and

2800-404: The antenna was connected across only a portion of the tuning coil's turns. This made the tuning coil act as an impedance matching transformer (in an autotransformer connection) in addition to providing the tuning function. The antenna's low resistance was increased (transformed) by a factor equal to the square of the turns ratio (the ratio of the number of turns the antenna was connected to, to

2880-438: The background. For listening in areas where an electric outlet was not available, the "rocket radio" served as an alternative to the vacuum tube portable radios of the day, which required expensive and heavy batteries. Children could hide "rocket radios" under the covers, to listen to radio when their parents thought they were sleeping. Children could take the radios to public swimming pools and listen to radio when they got out of

2960-407: The capacitance (C), or both, "tuning" the circuit to the frequencies of different radio stations. In the lowest-cost sets, the inductor was made variable via a spring contact pressing against the windings that could slide along the coil, thereby introducing a larger or smaller number of turns of the coil into the circuit, varying the inductance . Alternatively, a variable capacitor is used to tune

3040-431: The circuit. Some modern crystal sets use a ferrite core tuning coil, in which a ferrite magnetic core is moved into and out of the coil, thereby varying the inductance by changing the magnetic permeability (this eliminated the less reliable mechanical contact). The antenna is an integral part of the tuned circuit and its reactance contributes to determining the circuit's resonant frequency. Antennas usually act as

3120-456: The civilian population. This led determined listeners to build their own clandestine receivers which often amounted to little more than a basic crystal set. Anyone doing so risked imprisonment or even death if caught, and in most of Europe the signals from the BBC (or other allied stations) were not strong enough to be received on such a set. In the late 1950s, the compact "rocket radio", shaped like

3200-547: The country, and won several national news reporting awards under the leadership of prominent broadcast journalists such as Jim Forsyth and Colleen Marshall, but that reputation faded in the 1990s. Harvey, however, remained on the station's schedule, as did the legendary Jamboree USA and Jamboree in the Hills broadcasts. The WWVA Jamboree broadcasts started on January 7, 1933, and were even transmitted to troops abroad during World War II . Under Basic Communications ownership,

3280-663: The day, a single non-directional tower beams its full power to northern West Virginia, at night, power is fed to all three towers in a directional pattern to protect KOTV. WWVA is one of the Local Primary 1 Emergency Alert System stations in the Wheeling area. The BloomDaddy Experience hosts the AM-Drive portion of WWVA. The Glenn Beck Program , The Sean Hannity Show and The Clay Travis and Buck Sexton Show air in late-mornings, middays, afternoons and early evenings, respectively. WWVA airs paid religious programming in

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3360-447: The detection curve producing more signal voltage at the expense of less signal current (higher impedance). There is a limit to the benefit that this produces, depending on the other impedances of the radio. This improved sensitivity was caused by moving the DC operating point to a more desirable voltage-current operating point (impedance) on the junction's I-V curve . The battery did not power

3440-471: The earliest days of radio, when only one or two stations were within a crystal set's limited range. An important principle used in crystal radio design to transfer maximum power to the earphone is impedance matching . The maximum power is transferred from one part of a circuit to another when the impedance of one circuit is the complex conjugate of that of the other; this implies that the two circuits should have equal resistance. However, in crystal sets,

3520-439: The earphone to ground. In some sets the earphone cord had enough capacitance that this component could be omitted. Only certain sites on the crystal surface functioned as rectifying junctions, and the device was very sensitive to the pressure of the crystal-wire contact, which could be disrupted by the slightest vibration. Therefore, a usable contact point had to be found by trial and error before each use. The operator dragged

3600-414: The earphones were the most costly component. The early earphones used with wireless-era crystal sets had moving iron drivers that worked in a way similar to the horn loudspeakers of the period. Each earpiece contained a permanent magnet about which was a coil of wire which formed a second electromagnet . Both magnetic poles were close to a steel diaphragm of the speaker. When the audio signal from

3680-490: The earth through the building wiring. The tuned circuit , consisting of a coil and a capacitor connected together, acts as a resonator , similar to a tuning fork. Electric charge, induced in the antenna by the radio waves, flows rapidly back and forth between the plates of the capacitor through the coil. The circuit has a high impedance at the desired radio signal's frequency, but a low impedance at all other frequencies. Hence, signals at undesired frequencies pass through

3760-417: The great sensitivity of human hearing , which can detect sounds with an intensity of only 10 W /cm . Therefore, crystal receivers have to be designed to convert the energy from the radio waves into sound waves as efficiently as possible. Even so, they are usually only able to receive stations within distances of about 25 miles for AM broadcast stations, although the radiotelegraphy signals used during

3840-423: The impedance of the antenna-ground system (around 10–200 ohms ) is usually lower than the impedance of the receiver's tuned circuit (thousands of ohms at resonance), and also varies depending on the quality of the ground attachment, length of the antenna, and the frequency to which the receiver is tuned. Therefore, in improved receiver circuits, in order to match the antenna impedance to the receiver's impedance,

3920-455: The late evenings and Coast to Coast AM in the overnight hours. This Morning, America's First News with Gordon Deal is also carried in the early morning hours. WWVA produces Extension Calling , a local agricultural education program recorded by Ohio State University and West Virginia University extension agents, aired Sunday mornings for over 40 years. WWVA began broadcasting at 2 a.m. on December 13, 1926, when John Stroebel threw

4000-404: The low voltage input to the detector is too low to result in much difference between forward better conduction direction, and the reverse weaker conduction. To improve the sensitivity of some of the early crystal detectors, such as silicon carbide, a small forward bias voltage was applied across the detector by a battery and potentiometer . The bias moves the diode's operating point higher on

4080-577: The main type used during the wireless telegraphy era. Sold and homemade by the millions, the inexpensive and reliable crystal radio was a major driving force in the introduction of radio to the public, contributing to the development of radio as an entertainment medium with the beginning of radio broadcasting around 1920. Around 1920, crystal sets were superseded by the first amplifying receivers, which used vacuum tubes . With this technological advance, crystal sets became obsolete for commercial use but continued to be built by hobbyists, youth groups, and

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4160-420: The others. The crystal detector demodulates the radio frequency signal, extracting the modulation (the audio signal which represents the sound waves) from the radio frequency carrier wave . In early receivers, a type of crystal detector often used was a " cat whisker detector ". The point of contact between the wire and the crystal acted as a semiconductor diode . The cat whisker detector constituted

4240-433: The parts of a crystal radio in greater detail. The antenna converts the energy in the electromagnetic radio waves to an alternating electric current in the antenna, which is connected to the tuning coil. Since, in a crystal radio, all the power comes from the antenna, it is important that the antenna collect as much power from the radio wave as possible. The larger an antenna, the more power it can intercept. Antennas of

4320-420: The radio was passed through the electromagnet's windings, current was caused to flow in the coil which created a varying magnetic field that augmented or diminished that due to the permanent magnet. This varied the force of attraction on the diaphragm, causing it to vibrate. The vibrations of the diaphragm push and pull on the air in front of it, creating sound waves. Standard headphones used in telephone work had

4400-415: The radio, but only provided the biasing voltage which required little power. The requirements for earphones used in crystal sets are different from earphones used with modern audio equipment. They have to be efficient at converting the electrical signal energy to sound waves, while most modern earphones sacrifice efficiency in order to gain high fidelity reproduction of the sound. In early homebuilt sets,

4480-413: The receiver low selectivity . The crystal detector worsened the problem, because it has relatively low resistance , thus it "loaded" the tuned circuit, drawing significant current and thus damping the oscillations, reducing its Q factor so it allowed through a broader band of frequencies. In many circuits, the selectivity was improved by connecting the detector and earphone circuit to a tap across only

4560-437: The rest of the circuit. One or both of the coils usually had several taps which could be selected with a switch, allowing adjustment of the number of turns of that transformer and hence the "turns ratio". Coupling transformers were difficult to adjust, because the three adjustments, the tuning of the primary circuit, the tuning of the secondary circuit, and the coupling of the coils, were all interactive, and changing one affected

4640-459: The rocket radio declined in popularity. While it never regained the popularity and general use that it enjoyed at its beginnings, the crystal radio circuit is still used. The Boy Scouts have kept the construction of a radio set in their program since the 1920s. A large number of prefabricated novelty items and simple kits could be found through the 1950s and 1960s, and many children with an interest in electronics built one. Building crystal radios

4720-463: The secondary coil resonated with the tuning capacitor. Both the primary and secondary were tuned to the frequency of the station. The two circuits interacted to form a resonant transformer . Reducing the coupling between the coils, by physically separating them so that less of the magnetic field of one intersects the other, reduces the mutual inductance , narrows the bandwidth, and results in much sharper, more selective tuning than that produced by

4800-478: The spring of 1944, powered personal radio receivers were strictly prohibited as the Germans had equipment that could detect the local oscillator signal of superheterodyne receivers. Crystal sets lack power driven local oscillators, hence they could not be detected. Some resourceful soldiers constructed "crystal" sets from discarded materials to listen to news and music. One type used a blue steel razor blade and

4880-437: The square of its distance from the radio transmitter . Even for a powerful commercial broadcasting station , if it is more than a few miles from the receiver the power received by the antenna is very small, typically measured in microwatts or nanowatts . In modern crystal sets, signals as weak as 50 picowatts at the antenna can be heard. Crystal radios can receive such weak signals without using amplification only due to

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4960-463: The station sounded loudest in the earphone. One of the drawbacks of crystal sets is that they are vulnerable to interference from stations near in frequency to the desired station. Often two or more stations are heard simultaneously. This is because the simple tuned circuit does not reject nearby signals well; it allows a wide band of frequencies to pass through, that is, it has a large bandwidth (low Q factor ) compared to modern receivers, giving

5040-524: The station's past was the afternoon drive show hosted by former sportscaster Steve Novotney, but he was also fired from WWVA in November 2006. At the time, the only local talk show remaining on WWVA was Saturday Sports Day with John Simonson, but WWVA, then in negotiations with new ownership, made a bold move when they paid more money to David Bloomquist to export his Bloomdaddy Experience from rival local station, WKKX in late May/early June 2007. The move

5120-402: The subject. A crystal radio can be thought of as a radio receiver reduced to its essentials. It consists of at least these components: As a crystal radio has no power supply, the sound power produced by the earphone comes solely from the transmitter of the radio station being received, via the radio waves captured by the antenna. The power available to a receiving antenna decreases with

5200-616: The switch that sent power to a home-built 50-watt transmitter in the basement of his home. One week earlier, the Commerce Department granted a broadcast license on 860 kHz to the radio station WWVA. In its first year of operation, it broadcast to listeners with home-made crystal sets , principally from Stroebel's own home. The call letters are derived from the words Wheeling, West Virginia (WWVA), as U.S. postal codes were once written out with three letters such as WVA for West Virginia, hence Wheeling, WVA became "WWVA". Through

5280-521: The title WWVA . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=WWVA&oldid=978189764 " Categories : Disambiguation pages Broadcast call sign disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages WWVA (AM) WWVA (1170 kHz , NewsRadio 1170 )

5360-442: The total number of turns of the coil), to match the resistance across the tuned circuit. In the "two-slider" circuit, popular during the wireless era, both the antenna and the detector circuit were attached to the coil with sliding contacts, allowing (interactive) adjustment of both the resonant frequency and the turns ratio. Alternatively a multiposition switch was used to select taps on the coil. These controls were adjusted until

5440-413: The tuned circuit to ground, while the desired frequency is instead passed on to the detector (diode) and stimulates the earpiece and is heard. The frequency of the station received is the resonant frequency f of the tuned circuit, determined by the capacitance C of the capacitor and the inductance L of the coil: The circuit can be adjusted to different frequencies by varying the inductance (L),

5520-636: The type commonly used with crystal sets are most effective when their length is close to a multiple of a quarter- wavelength of the radio waves they are receiving. Since the length of the waves used with crystal radios is very long ( AM broadcast band waves are 182–566 metres or 597–1,857 feet long) the antenna is made as long as possible, from a long wire , in contrast to the whip antennas or ferrite loopstick antennas used in modern radios. Serious crystal radio hobbyists use "inverted L" and "T" type antennas , consisting of hundreds of feet of wire suspended as high as possible between buildings or trees, with

5600-421: The water, clipping the ground wire to a chain link fence surrounding the pool. The rocket radio was also used as an emergency radio, because it did not require batteries or an AC outlet. The rocket radio was available in several rocket styles, as well as other styles that featured the same basic circuit. Transistor radios had become available at the time, but were expensive. Once those radios dropped in price,

5680-414: The wire across the crystal surface until a radio station or "static" sounds were heard in the earphones. Alternatively, some radios (circuit, right) used a battery-powered buzzer attached to the input circuit to adjust the detector. The spark at the buzzer's electrical contacts served as a weak source of static, so when the detector began working, the buzzing could be heard in the earphones. The buzzer

5760-543: The years, WWVA has been granted several power increases. In May 1941, the FCC moved WWVA to 1170, and in August of that same year, granted it the highest power for AM stations: 50,000 watts. With the increase, WWVA became the most powerful AM station in the entire state of West Virginia . WWVA has changed hands many times over the years. Past owners include Fidelity Investments , West Virginia Broadcasting Corporation, Storer Broadcasting , Basic Communications, Screen Gems Radio -

5840-405: Was a craze in the 1920s, and again in the 1950s. Recently, hobbyists have started designing and building examples of the early instruments. Much effort goes into the visual appearance of these sets as well as their performance. Annual crystal radio 'DX' contests (long distance reception) and building contests allow these set owners to compete with each other and form a community of interest in

5920-527: Was controversial (even though the reason given by WKKX to let Bloomquist go was in connection with the Don Imus Rutgers controversy that transpired on MSNBC around that same time), as WKKX members appeared bitter about the exit. Clear Channel began to syndicate Bloomdaddy through the northeast and midwest after the cancellation of The War Room with Quinn and Rose in November 2013. The Original Wheeling Radio Jamboree (formerly Jamboree USA )

6000-459: Was first to use a crystal as a radio wave detector, using galena detectors to receive microwaves starting around 1894. In 1901, Bose filed for a U.S. patent for "A Device for Detecting Electrical Disturbances" that mentioned the use of a galena crystal; this was granted in 1904, #755840. On August 30, 1906, Greenleaf Whittier Pickard filed a patent for a silicon crystal detector, which was granted on November 20, 1906. A crystal detector includes

6080-423: Was invented by a long, partly obscure chain of discoveries in the late 19th century that gradually evolved into more and more practical radio receivers in the early 20th century. The earliest practical use of crystal radio was to receive Morse code radio signals transmitted from spark-gap transmitters by early amateur radio experimenters. As electronics evolved, the ability to send voice signals by radio caused

6160-421: Was mounted on a rack so it could be slid linearly in or out of the larger coil. If radio interference was encountered, the smaller coil would be slid further out of the larger, loosening the coupling, narrowing the bandwidth, and thereby rejecting the interfering signal. The antenna coupling transformer also functioned as an impedance matching transformer , that allowed a better match of the antenna impedance to

6240-461: Was not supported by the authorities and was soon forgotten; no device was produced in mass quantity beyond a few examples for research. In addition to mineral crystals, the oxide coatings of many metal surfaces act as semiconductors (detectors) capable of rectification. Crystal radios have been improvised using detectors made from rusty nails, corroded pennies, and many other common objects. When Allied troops were halted near Anzio, Italy during

6320-399: Was that they could demodulate amplitude modulated signals. This device brought radiotelephones and voice broadcast to a public audience. Crystal sets represented an inexpensive and technologically simple method of receiving these signals at a time when the embryonic radio broadcasting industry was beginning to grow. In 1922 the (then named) United States Bureau of Standards released

6400-462: Was then turned off, and the radio tuned to the desired station. Galena (lead sulfide) was the most common crystal used, but various other types of crystals were also used, the most common being iron pyrite (fool's gold, FeS 2 ), silicon , molybdenite (MoS 2 ), silicon carbide (carborundum, SiC), and a zincite - bornite (ZnO-Cu 5 FeS 4 ) crystal-to-crystal junction trade-named Perikon . Crystal radios have also been improvised from

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