Crystal radio - Knowledge

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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 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 the background.

1695:) is actual audio information, and 91% is just rectified DC voltage. <correction> The 30% figure is the standard used for radio testing, and is based on the average modulation factor for speech. Properly-designed and managed AM transmitters can be run to 100% modulation on peaks without causing distortion or "splatter" (excess sideband energy that radiates outside of the intended signal bandwidth). Given that the audio signal is unlikely to be at peak all the time, the ratio of energy is, in practice, even greater. Considerable effort was made to convert this DC voltage into sound energy. Some earlier attempts include a one- 61: 1777: 1795: 564: 2685:"Im Mai 1901 habe ich einige Versuche im Laboratorium gemacht und dabei gefunden, daß in der Tat ein Fernhörer, der in einen aus Psilomelan und Elementen bestehenden Kreis eingeschaltet war, deutliche und scharfe Laute gab, wenn dem Kreise schwache schnelle Schwingungen zugeführt wurden. Das Ergebnis wurde nachgeprüft, und zwar mit überraschend gutem Erfolg, an den Stationen für drahtlose Telegraphie, an welchen zu dieser Zeit auf den Straßburger Forts von der Königlichen Preußischen Luftschiffer-Abteilung unter Leitung des Hauptmannes von Sigsfeld gearbeitet wurde." 1853: 1762: 1353: 1185: 1817: 1193: 1140: 607: 2687:(In May 1901, I did some experiments in the lab and thereby found that in fact an earphone, which was connected in a circuit consisting of psilomelane and batteries, produced clear and strong sounds when weak, rapid oscillations were introduced to the circuit. The result was verified – and indeed with surprising success – at the stations for wireless telegraphy, which, at this time, were operated at the Strasbourg forts by the Royal Prussian Airship-Department under the direction of Capt. von Sigsfeld.) 816: 1750: 1087: 1726: 920: 279: 1865: 1308: 615: 1835: 219: 1176:, 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 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. 665:, and allows radio waves at that frequency to pass through to the detector while largely blocking waves at other frequencies. One or both of the coil or capacitor is adjustable, allowing the circuit to be tuned to different frequencies. In some circuits a capacitor is not used and the antenna serves this function, as an antenna that is shorter than a quarter-wavelength of the radio waves it is meant to receive is capacitive. 1554: 469: 1136:

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 the station sounded loudest in the earphone.

1289: 6046: 1522:. The bias moves the diode's operating point higher on 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 1297: 1096: 6056: 227: 1535: 870:, consisting of hundreds of feet of wire suspended as high as possible between buildings or trees, with 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 6035: 45: 728: 6066: 1738: 1255:, narrows the bandwidth, and results in much sharper, more selective tuning than that produced by 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. 546:

thought they were sleeping. Children could take the radios to public swimming pools and listen to radio when they got out of 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.

381:. 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, 1630:

to match the low impedance of the speaker to the circuit. Similarly, modern low-impedance (8 Ω) earphones cannot be used unmodified in crystal sets because the receiver does not produce enough current to drive them. They are sometimes used by adding an audio transformer to match their impedance

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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 the earliest days of radio, when only one or two stations were within a crystal

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The circuit can be adjusted to different frequencies by varying the inductance (L), 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

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at the desired radio signal's frequency, but a low impedance at all other frequencies. Hence, signals at undesired frequencies pass through 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

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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

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In the late 1950s, the compact "rocket radio", shaped like 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),

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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

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that allows the passage of low frequencies, but blocks the higher frequencies. In that case a bypass capacitor is not needed (although in practice a small one of around 0.68 to 1 nF is often used to help improve quality), but instead a 10–100 kΩ resistor must be added in parallel with the

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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

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there were widespread confiscations of radio sets from 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

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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 the type commonly used

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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 the total number of turns of the coil), to match the resistance

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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

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All semiconductor detectors function rather inefficiently in crystal receivers, because 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

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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 a crystal radio with common household items. To minimize the cost, many of the plans suggested winding the tuning coil on empty

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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 was then turned off, and the radio tuned to the desired station.

1336:) of the amplitude (hence the term amplitude modulation, AM) of the waves. This signal cannot be converted to sound by the earphone, because the audio excursions are the same on both sides of the axis, averaging out to zero, which would result in no net motion of the earphone's diaphragm. 1585:

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 a low

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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

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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

1270:, that allowed a better match of the antenna impedance to 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". 1227:) 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 1067:

The earliest crystal receivers did not have a tuned circuit at all, and just consisted of 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

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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.

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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.

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with the capacitance of the antenna (or sometimes another capacitor), and 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

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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.

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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

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Braun patented an R.F. detector in 1906. See: (Ferdinand Braun), "Wellenempfindliche Kontaktstelle" (R.F. sensitive contact), Deutsches Reichspatent DE 178,871, (filed: Feb. 18, 1906 ; issued: Oct. 22, 1906). Available on-line at:

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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 the others.

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crystal with electrodes attached to each side, glued to a light diaphragm. When the audio signal from the radio set is applied to the electrodes, it causes the crystal to vibrate, vibrating the diaphragm. Crystal earphones are designed as

783:/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 235: 1156:

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

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is often placed across the earphone terminals; its low reactance at radio frequency bypasses these pulses around the earphone to ground. In some sets the earphone cord had enough capacitance that this component could be omitted.

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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

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amplifier in 1966. Sometimes efforts to recover this power are confused with other efforts to produce a more efficient detection. This history continues now with designs as elaborate as "inverted two-wave switching power unit".

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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 was that they could

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that plug directly into the ear canal of the wearer, coupling the sound more efficiently to the eardrum. Their resistance is much higher (typically megohms) so they do not greatly "load" the tuned circuit, allowing increased

1104:"Two slider" crystal radio circuit. and example from 1920s. The two sliding contacts on the coil allowed the impedance of the radio to be adjusted to match the antenna as the radio was tuned, resulting in stronger reception. 1126:

Therefore, in improved receiver circuits, in order to match the antenna impedance to the receiver's impedance, the antenna was connected across only a portion of the tuning coil's turns. This made the tuning coil act as an

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In 1908, Wichi Torikata of the Imperial Japanese Electrotechnical Laboratory of the Ministry of Communications in Tokyo was granted Japanese patent 15,345 for the “Koseki” detector, consisting of crystals of zincite and

4261:"The cat's-whisker detector is a primitive point-contact diode. A point-contact junction is the simplest implementation of a Schottky diode, which is a majority-carrier device formed by a metal-semiconductor junction." 123:

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.

898:(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 339:

A crystal detector includes 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

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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, the impedance of the antenna-ground system (around 10–200

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crystal radio marketed to children. The earphone is on left. The antenna wire, right, has a clip to attach to metal objects such as a bedspring, which serve as an additional antenna to improve reception.

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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.

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and modern semiconductor devices. However, this discovery was not supported by the authorities and was soon forgotten; no device was produced in mass quantity beyond a few examples for research.

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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

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A crystal radio tuned to a strong local transmitter can be used as a power source for a second amplified receiver of a distant station that cannot be heard without amplification.

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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

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There is a long history of unsuccessful attempts and unverified claims to recover the power in the carrier of the received signal itself. Conventional crystal sets use half-wave

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respond better with a local battery while others do not require it...but with practically any crystal it aids in obtaining the sensitive adjustment to employ a local battery...

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of the radio station being received, via the radio waves captured by the antenna. The power available to a receiving antenna decreases with the square of its distance from the

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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

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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.

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Commercial passive receiver development was abandoned with the advent of reliable vacuum tubes around 1920, and subsequent crystal radio research was primarily done by

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Bose was first to use crystals for electromagnetic wave detection, using galena detectors to receive microwaves starting around 1894 and receiving a patent in 1904

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The crystal conducts current better in one direction than the other, producing a signal whose amplitude does not average to zero but varies with the audio signal.

4358: 2723:(1843–1933) of Washington, D.C., a retired general of the US Army's Signal Corps, received a patent for a carborundum R.F. detector. See: Dunwoody, Henry H. C. 2701:(4) : 556–563. In these experiments, Braun applied a cat whisker to various semiconducting crystals and observed that current flowed in only one direction. 480:(detectors) capable of rectification. Crystal radios have been improvised using detectors made from rusty nails, corroded pennies, and many other common objects. 3364:

Marconi used carborundum detectors for a time around 1907 in his first commercial transatlantic wireless link between Newfoundland, Canada and Clifton, Ireland.

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One design common in early days, called a "loose coupler", consisted of a smaller secondary coil inside a larger primary coil. The smaller coil was mounted on a

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experimenters. As electronics evolved, the ability to send voice signals by radio caused a technological explosion around 1920 that evolved into today's radio

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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.

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era before 1920, crystal receivers were "state of the art", and sophisticated models were produced. After 1920 crystal sets became the cheap alternative to

1060:. 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 1428:

operator dragged the wire across the crystal surface until a radio station or "static" sounds were heard in the earphones. Alternatively, some radios

472:"Foxhole radio" used on the Italian Front in World War 2. It uses a pencil lead attached to a safety pin pressing against a razor blade for a detector. 1834: 1510:) 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. 406: 902:

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 a low

4731: 175:. With this technological advance, crystal sets became obsolete for commercial use but continued to be built by hobbyists, youth groups, and the 6012: 1816: 6007: 5997: 5977: 5779: 3737: 3276: 2587: 2555: 2417: 2094: 2035: 1999: 6090: 402: 282:

Type 'C' Form 'A' twin detector crystal radio set, manufactured by British Thomson Houston Ltd. in 1924, kept at the Museum of the radio -

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Long distance transoceanic stations of the era used wavelengths of 10,000 to 20,000 meters, correstponding to frequencies of 15 to 30 kHz.

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is used for the detector, which is much more reliable than a crystal detector and requires no adjustments. Germanium diodes (or sometimes

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to convert the audio signal to sound waves so they can be heard. The low power produced by a crystal receiver is insufficient to power a

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during the spring of 1944, powered personal radio receivers were strictly prohibited as the Germans had equipment that could detect the

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While it never regained the popularity and general use that it enjoyed at its beginnings, the crystal radio circuit is still used. The

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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

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and hobbyists. Many different circuits have been used. The following sections discuss the parts of a crystal radio in greater detail.

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Inductively-coupled circuit with impedance matching. This type was used in most quality crystal receivers in the early 20th century.

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era could be received at hundreds of miles, and crystal receivers were even used for transoceanic communication during that period.

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to its audio frequency modulation. The detector's audio frequency output is converted to sound by the earphone. Early sets used a "

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had become available at the time, but were expensive. Once those radios dropped in price, the rocket radio declined in popularity.

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of the receiver. The piezoelectric earphone's higher resistance, in parallel with its capacitance of around 9 pF, creates a

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receivers are grounded adequately through their power cords, which are in turn attached to the earth through the building wiring.

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Braun also states that he had been researching the conductive properties of semiconductors since 1874. See: Braun, F. (1874)

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from the radio was passed through the electromagnet's windings, current was caused to flow in the coil which created a varying

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Ian L. Sanders. Tickling the Crystal – Domestic British Crystal Sets of the 1920s; Volumes 1–5. BVWS Books (2000–2010).

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A crystal radio can be thought of as a radio receiver reduced to its essentials. It consists of at least these components:

563: 5784: 2720: 2501: 1158: 759:, if it is more than a few miles from the receiver the power received by the antenna is very small, typically measured in 6069: 4518: 3151: 6059: 5820: 5717: 5260: 5027: 1025:

slide along the coil, thereby introducing a larger or smaller number of turns of the coil into the circuit, varying the

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Greenleaf Whittier Pickard's US Patent 836,531 "Means for receiving intelligence communicated by electric waves" diagram

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The rocket radio was available in several rocket styles, as well as other styles that featured the same basic circuit.

6049: 5556: 4996: 2113: 743:, consisting of a piece of galena with a thin wire in contact with it on a part of the crystal, making a diode contact 2936: 1391:

that allowed current to flow better in one direction than in the opposite direction. Modern crystal sets use modern

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was the first means of detecting a radio signal. These, however, lacked the sensitivity to detect weak signals.

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Zinc Negative Resistance RF Amplifier for Crystal Sets and Regenerative Receivers Uses No Tubes or Transistors

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In 1924, Losev's (also spelled "Lossev" and "Lossew") research was publicized in several French publications:

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crystal detectors were used in receivers in greater numbers than any other type of detector after about 1907.

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Pictorial diagram from 1922 showing the circuit of a crystal radio. This common circuit did not use a tuning

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This article is about unpowered radio receivers. For crystal-controlled oscillators (as used in radios), see

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Circuit with detector bias battery to improve sensitivity and buzzer to aid in adjustment of the cat whisker

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of the radio waves they are receiving. Since the length of the waves used with crystal radios is very long (

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from all the radio signals received by the antenna. The tuned circuit consists of a coil of wire (called an

299: 112: 3862:. US: Prepared by US National Bureau of Standards, United States Army Signal Corps. 1922. pp. 421–425. 1139: 5800: 5586: 5401: 5346: 5341: 5154: 5119: 3757: 2647:"Construction and Operation of a Simple Homemade Radio Receiving Outfit, Bureau of Standards Circular 120" 1526:. The battery did not power the radio, but only provided the biasing voltage which required little power. 815: 606: 484: 433:

to various kinds of crystals for the manufacturing of radio detectors. The result was astonishing: with a

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can be approximately doubled by connecting a battery across its terminals to give approximately 0.2 volt

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One of the drawbacks of crystal sets is that they are vulnerable to interference from stations near in

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As a crystal radio has no power supply, the sound power produced by the earphone comes solely from the

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which develop their output voltage with respect to ground. The receiver thus requires a connection to

159:. Crystal radios were the first widely used type of radio receiver, and the main type used during the 5616: 5576: 5546: 5303: 5238: 5129: 3817: 3729: 3723: 2767: 2734:

received a patent for his R.F. detector consisting of tellurium and silicon. See: Louis W. Austin,

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A crystodyne could be produced under primitive conditions; it could be made in a rural forge, unlike

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Practical Wireless Telegraphy: A complete text book for students of radio communication, Revised Ed

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allow these set owners to compete with each other and form a community of interest in the subject.

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pasteboard containers such as oatmeal boxes, which became a common foundation for homemade radios.

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reproduction of the sound. In early homebuilt sets, the earphones were the most costly component.

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layer of oxide or sulfide on the metal surface is usually responsible for the rectifying action.

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A bypass capacitor is used to remove the radio frequency carrier pulses, leaving the audio signal

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In more sophisticated crystal receivers, the tuning coil is replaced with an adjustable air core

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An important principle used in crystal radio design to transfer maximum power to the earphone is

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Radio Hook-ups: A Reference and Record Book of Circuits Used for Connecting Wireless Instruments

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Radio hook-ups: a reference and record book of circuits used for connecting wireless instruments

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Amateur-built crystal receiver with "loose coupler" antenna transformer, Belfast, around 1914

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English-language publications noticed the French articles and also publicized Losev's work:

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with crystal sets are most effective when their length is close to a multiple of a quarter-

383:

Construction and Operation of a Two-Circuit Radio Receiving Equipment With Crystal Detector

5526: 5381: 5149: 5112: 4905: 4646: 4345: 3979: 3665:

Radio Communication Pamphlet No. 40: The Principles Underlying Radio Communication, 2nd Ed

3651: 3613: 3570: 3317: 3064: 2505: 2495: 1647: 1615: 1464: 1412: 1322: 1300: 1259: 1132: 903: 788: 784: 776: 627: 496: 450: 295: 199: 191: 38: 5124: 4881: 3411: 3293: 2610: 385:, which was published the same year and is still frequently built by enthusiasts today. 4835: 4828: 4821: 4181: 4037: 4001: 3680: 3438: 2771: 2626: 2192: 771:

at the antenna can be heard. Crystal radios can receive such weak signals without using

171:

Around 1920, crystal sets were superseded by the first amplifying receivers, which used

5724: 5596: 5571: 5531: 5501: 5376: 5211: 5097: 4003:

Practical Wireless Telegraphy: A complete text book for students of radio communication

3549: 3545:

Radio Reception: A simple and complete explanation of the principles of radio telephony

3485: 1622:

Although the low power produced by crystal radios is typically insufficient to drive a

1582: 1553: 1507: 1408: 1388: 1248: 1115: 1052:

contributes to determining the circuit's resonant frequency. Antennas usually act as a

468: 357: 336:

filed a patent for a silicon crystal detector, which was granted on November 20, 1906.

49: 4842: 2646: 6084: 5873: 5646: 5636: 5551: 5441: 5436: 5426: 5411: 5233: 5092: 4981: 4893:

Section 1 links to "Crystal Radio Set Systems: Design, Measurements and Improvement".

4848:

PA Kinzie (1996). Crystal Radio: History, Fundamentals, and Design. Xtal Set Society.

3885: 1601: 1574: 1547: 1519: 1496: 1228: 1201: 1038: 932: 924: 804: 756: 736: 669: 650: 510: 477: 324: 4468: 3268:

Planar Microwave Engineering: A practical guide to theory, measurement, and circuits

2356: 2276: 2086:

Revolution in Miniature: The history and impact of semiconductor electronics, 2nd Ed

1296: 5751: 5591: 5536: 5466: 5431: 5366: 5265: 5255: 5107: 4913: 3008: 2950:

Victor Gabel (October 1 & 8, 1924) "The crystal as a generator and amplifier,"

2671:, a manganese oxide ore, as an R.F. detector: Ferdinand Braun (December 27, 1906) 1895: 1578: 1376: 1372: 1364: 1329: 1325: 1034: 860: 856: 844: 681: 568: 525: 446: 361: 267: 4898: 4097: 2123:

Crystal fire: the invention of the transistor and the birth of the information age

1654:

factor of only 30% by voltage at peaks, no more than 9% of received signal power (

1383:". The point of contact between the wire and the crystal acted as a semiconductor 1114:. The maximum power is transferred from one part of a circuit to another when the 1041:

is moved into and out of the coil, thereby varying the inductance by changing the

476:

In addition to mineral crystals, the oxide coatings of many metal surfaces act as

4858: 4852: 3564: 2825:, US patent no. 836,531 (filed: August 30, 1906 ; issued: November 20, 1905) 5951: 5601: 5511: 5496: 5456: 5416: 5275: 3058: 2668: 2604: 2523: 2488: 1913: 1713: 1627: 1623: 1566: 1456: 1444: 1288: 1204: 1095: 1053: 956: 908: 879: 875: 780: 748: 720: 595: 533:(or other allied stations) were not strong enough to be received on such a set. 505: 501: 457: 313:

In the early 20th century, various researchers discovered that certain metallic

283: 195: 172: 152: 108: 4450: 2727:

U. S. patent 837,616 (filed: March 23, 1906 ; issued: December 4, 1906).

2705: 2498: 2348: 2258: 1577:. Both magnetic poles were close to a steel diaphragm of the speaker. When the 708:

was the component that gave crystal radios their name. Modern sets use modern

226: 5956: 5663: 5361: 5270: 5226: 5196: 5174: 5164: 5139: 4526: 2664: 1885: 1696: 1651: 1534: 1368: 1333: 1026: 963: 840: 828: 685: 677: 635: 438: 426: 390: 350: 255: 4829:

The Wireless Experimenter's Manual: Incorporating how to Conduct a Radio Club

3859:

The Principles Underlying Radio Communication, 2nd Ed., Radio pamphlet no. 40

3543: 2822: 2809: 2735: 2724: 2471: 5941: 5406: 5221: 4421: 3803: 3241: 3170:

Revolution in Miniature: The History and Impact of Semiconductor Electronics

2288: 1643: 1523: 1416: 1400: 1153: 1069: 940: 936: 871: 772: 760: 732: 658: 646: 575: 394: 128: 116: 4949: 4548: 2812:, US patent no. 755,840 (filed: September 30, 1901; issued: March 29, 1904) 712:, although some hobbyists still experiment with crystal or other detectors. 44: 17: 4973: 3891:

The science of radio: with MATLAB and Electronics Workbench demonstrations

727: 5936: 5926: 5843: 5668: 5491: 4752:

Polyakov, V. T. (2001). "3.3.2 Питание полем мощных станций".

3679:

Hausmann, Erich; Goldsmith, Alfred Norton; Hazeltine, Louis Alan (1922).

2756:"The work of Jagadis Chandra Bose: 100 years of millimeter-wave research" 2475: 2177:"The work of Jagadis Chandra Bose: 100 years of millimeter-wave research" 1606: 1172:

The crystal detector worsened the problem, because it has relatively low

1162: 867: 768: 764: 716: 654: 587: 514: 202:

bands, but strong signals are required. The first crystal sets received

100: 4957: 4459: 3834: 2738:

US patent 846,081 (filed: Oct. 27, 1906 ; issued: March 5, 1907).

2267: 1870:

Polish Detefon brand radio, 1930–1939, using a "cartridge" type crystal

1782:

Marconi Type 106 crystal receiver used for transatlantic communication,

851:

or 597–1,857 feet long) the antenna is made as long as possible, from a

234: 5931: 5916: 4594:

Manual of Wireless Telegraphy for the Use of Naval Electricians, Vol. 2

1908: 1472: 1468: 1452: 434: 314: 307: 132: 4843:

Construction and operation of a simple homemade radio receiving outfit

2779: 2200: 379:

Construction and Operation of a Simple Homemade Radio Receiving Outfit

5961: 5921: 5243: 5035: 4988: 1767: 1570: 1492: 1440: 1247:

between the coils, by physically separating them so that less of the

701: 422: 345: 341: 318: 190:

designs have been built. They can be designed to receive almost any

89: 1600:, which are much more sensitive and also smaller. They consist of a 1321:

radio signal from the tuned circuit. The rapid oscillations are the

1743:

Australian signallers using a Marconi Mk III crystal receiver, 1916

1379:. In early receivers, a type of crystal detector often used was a " 5946: 5883: 5191: 4875:

A website with lots of information on early radio and crystal sets

2445: 1533: 1384: 1351: 1306: 1295: 1287: 1191: 1183: 1138: 918: 848: 814: 613: 605: 591: 562: 488: 467: 277: 233: 225: 217: 136: 93: 59: 43: 2823:"Means for receiving intelligence communicated by electric waves" 151:, in his microwave optics experiments. They were first used as a 5888: 2911:

I. Podliasky (May 25, 1924) (Crystal detectors as oscillators),

430: 37:"Crystal set" redirects here. For the Australian rock band, see 4992: 4859:

The Design and Implementation of Low-Power CMOS Radio Receivers

3976:

Crystal Radio Set Systems: Design, Measurement, and Improvement

3019: 5134: 4799: 2253:. New York: Inst. of Electrical and Electronic Engineers: 64. 1120: 583: 530: 250:

Crystal radio was invented by a long, partly obscure chain of

88:, originally made from a piece of crystalline mineral such as 2835:

http://www.crystalradio.net/crystalplans/xximages/nsb_120.pdf

2027:

Gonzo gizmos: Projects and devices to channel your inner geek

1858:

German Heliogen brand radio showing "basket-weave" coil, 1935

1731:

Soldier listening to a crystal radio during World War I, 1914

1048:

The antenna is an integral part of the tuned circuit and its

1033:

is used to tune the circuit. Some modern crystal sets use a

700:" consisting of a small piece of crystalline mineral such as 4889: 4760:] (in Russian). Moscow: Knizhnai͡a palata. p. 256. 3668:. United States Bureau of Standards. 1922. pp. 309–311. 2846:

http://www.crystalradio.net/crystalplans/xximages/nbs121.pdf

2706:

Foundation for German communication and related technologies

1561:

The early earphones used with wireless-era crystal sets had

449:. After the first experiments, Losev built regenerative and 4966:

http://uv201.com/Radio_Pages/Pre-1921/crystal_detectors.htm

4006:(Revised ed.). New York: Wireless Press, Inc. p. 2458: 1375:

which represents the sound waves) from the radio frequency

4445:(4). Inst. of Electrical and Electronic Engineers: 64–65. 4330: 3872: 3709: 2433: 1631:

with the higher impedance of the driving antenna circuit.

907:

little current flows in the antenna/ground circuit. Also,

567:

Crystal radio used as a backup receiver on a World War II

4899:

Semiconductor archeology or tribute to unknown precursors

4874: 3435:

a list of circuits from the wireless era can be found in

2059:

The Design and Implementation of Low Power CMOS Receivers

1518:

voltage was applied across the detector by a battery and

3063:. New York: Scientific American Publishing Co. pp. 2609:. New York: Scientific American Publishing Co. pp. 1626:, some homemade 1960s sets have used one, with an audio 1223:) attached to the antenna and ground and the other (the 1165:) compared to modern receivers, giving the receiver low 1045:(this eliminated the less reliable mechanical contact). 4622:. New York: Wireless Press, Inc. pp. 134–135, 140. 3167:

Braun, Agnès; Braun, Ernest; MacDonald, Stuart (1982).

2409:

The Cool Gent: The Nine Lives of Radio Legend Herb Kent

1716:

radios, used in emergencies and by youth and the poor.

1266:

The antenna coupling transformer also functioned as an

1143:

Direct-coupled circuit with taps for impedance matching

827:

The antenna converts the energy in the electromagnetic

779:, which can detect sounds with an intensity of only 10 4853:

The Design of CMOS Radio-Frequency Integrated Circuits

4289:

The Design of CMOS Radio-Frequency Integrated Circuits

4231:(4). New York: Popular Science Publishing Co.: 206–209 3751: 3749: 2625:

Morecroft, John H.; A. Pinto; Walter A. Curry (1921).

2406:

Kent, Herb; David Smallwood; Richard M. Daley (2009).

1573:

about which was a coil of wire which formed a second

1064:

in the coil) to form the tuned circuit with the coil.

735:, but used the capacitance of the antenna to form the 4758:

Receiving techniques. Simple receivers for AM signals

3682:

Radio Phone Receiving: A Practical Book for Everybody

2716:

Other inventors who patented crystal R.F. detectors:

2582:. The Alternative Electronics Press. pp. 20–23. 1770:-A crystal set used by US Signal Corps in World War I 1660: 1056:, as antennas shorter than a quarter-wavelength have 978: 923:

The earliest crystal receiver circuit did not have a

866:

Serious crystal radio hobbyists use "inverted L" and

4525:. Kev's Vintage Radio and Hi-Fi page. Archived from 3372:. Institution of Electrical Engineers. p. 191. 3153:

Wireless Telegraph Construction for Amateurs, 3rd Ed

2760:

IEEE Transactions on Microwave Theory and Techniques

2181:

IEEE Transactions on Microwave Theory and Techniques

1514:

crystal detectors, such as silicon carbide, a small

513:" by the popular press, and they became part of the 107:(because a crystal set has insufficient power for a 5970: 5907: 5829: 5793: 5750: 5691: 5625: 5334: 5026: 4885:

History and Technical Information on Crystal Radios

3443:. US: The Norman W. Henley publishing co. pp. 1569:of the period. Each earpiece contained a permanent 52:, with earphones. The device at top is the radio's 4754:Техника радиоприёма. Простые приёмники АМ сигналов 2986:, pp. 294–295, 431 (September 1924). See also the 2649:. U.S. Government Printing Office. April 24, 1922. 2547:22 Radio and Receiver Projects for the Evil Genius 2126:. US: W. W. Norton & Company. pp. 19–21. 1991:22 Radio and Receiver Projects for the Evil Genius 1687: 1014:{\displaystyle f={\frac {1}{2\pi {\sqrt {LC}}}}\,} 1013: 890:The wire antennas used with crystal receivers are 445:phenomenon, decades before the development of the 222:A family listening to a crystal radio in the 1920s 4631: 4629: 4597:. Washington DC: US Naval Institute. p. 131. 2961:O. Lossev (October 1924) "Oscillating crystals," 2379:The Third Element: A Brief History of Electronics 1994:. US: McGraw-Hill Professional. pp. 40, 44. 1332:(the sound) is contained in the slow variations ( 4838:. The Norman W. Henley publishing co.; 67 pages. 4747: 4745: 4292:. UK: Cambridge University Press. pp. 4–6. 4134:(6). New York: Doubleday Page & Co.: 480–483 3949:. New York: John Wiley & Sons. p. 269. 2693:(On current conduction through metal sulfides), 2436:, Birmingham, Alabama, US. Retrieved 2010-01-18. 1387:. The cat whisker detector constituted a crude 823:, a common wire antenna used with crystal radios 767:. In modern crystal sets, signals as weak as 50 586:in the 1920s, and again in the 1950s. Recently, 246:" taught Americans how to build a crystal radio. 4369:(6). New York: The Gage Publishing Co.: 393–394 4341: 4339: 3921:. UK: Cambridge University Press. p. 218. 3337:"Jack Binn's 10 commandments for the radio fan" 3271:. UK: Cambridge Univ. Press. pp. 297–304. 1303:used in modern crystal radios (about 3 mm long) 4499:. Prof. Kenneth Kuhn website, Univ. of Alabama 4422:Crystal Plans and Circuits, Stay Tuned website 3767:. Prof. Kenneth Kuhn website, Univ. of Alabama 3508: 3506: 3504: 3502: 3173:. Cambridge University Press. pp. 11–12. 3089:. Prof. Kenneth Kuhn website, Univ. of Alabama 2691:"Ueber die Stromleitung durch Schwefelmetalle" 2673:"Ein neuer Wellenanzeiger (Unipolar-Detektor)" 2309:. UK: Cambridge University Press. p. 44. 1962:. US: McGraw-Hill Professional. pp. 7–9. 441:) crystal he gained amplification. This was a 103:of wire, a capacitor, a crystal detector, and 56:. A second pair of earphone jacks is provided. 27:Simple radio receiver circuit for AM reception 5004: 4845:", Bureau of Standards, C-120: Apr. 24, 1922. 4681:The Principles Underlying Radio Communication 4570:The Principles Underlying Radio Communication 4042:. London: Longman's Green & Co. pp. 3945:Alley, Charles L.; Kenneth W. Atwood (1973). 3852: 3850: 3848: 3846: 3844: 3842: 2867:A history of the world semiconductor industry 2089:. UK: Cambridge Univ. Press. pp. 11–12. 1983: 1981: 1979: 155:for radio communication reception in 1902 by 8: 4857:Derek K. Shaeffer and Thomas H. Lee (1999). 4326: 4324: 4248:H. V. Johnson, A Vacation Radio Pocket Set. 3835:Crystal Radios and Plans, Stay Tuned website 3722:Hayt, William H.; Kemmerly, Jack E. (1971). 3542:Marx, Harry J.; Adrian Van Muffling (1922). 3300:. Dept. of Physics, Georgia State University 2550:. US: McGraw-Hill Professional. p. 39. 2412:. US: Chicago Review Press. pp. 13–14. 2343:(3). US: Institute of Radio Engineers: 184. 1840:Swedish "box" crystal radio with earphones, 6019:Global telecommunications regulation bodies 4214: 4212: 3347:(5). New York: Modern Publishing Co.: 42–43 2856:Bondi, Victor."American Decades: 1930–1939" 2631:. New York: John Wiley & Sons. p. 2571: 2569: 2567: 2448:midnightscience.com . Retrieved 2010-01-18. 2056:Schaeffer, Derek K.; Thomas H. Lee (1999). 2051: 2049: 2047: 1367:the radio frequency signal, extracting the 775:only due to the great sensitivity of human 704:with a fine wire touching its surface. The 6055: 5011: 4997: 4989: 4961:How to build a sensitive crystal receiver? 4186:. US: Government Printing Office. p. 4057: 4055: 4053: 3218: 3216: 3214: 3212: 2675:(A new R.F. detector (one-way detector)), 2331:Marriott, Robert H. (September 17, 1915). 2298: 2296: 1483:) crystal-to-crystal junction trade-named 4931:Asquin, Don; Rabjohn, Gord (April 2012). 4458: 4411:(1). New York: Radcraft Publications: 730 4091: 4089: 4087: 4085: 3145: 3143: 2266: 2108: 2106: 1677: 1671: 1659: 1565:that worked in a way similar to the horn 1495:, rusty needles, and pennies In these, a 1251:of one intersects the other, reduces the 1010: 997: 985: 977: 618:Circuit diagram of a simple crystal radio 610:Block diagram of a crystal radio receiver 524:In some German-occupied countries during 321:, could be used to detect radio signals. 4950:http://www.crystal-radio.eu/endiodes.htm 4926:Details of crystals used in crystal sets 4331:Hausmann, Goldsmith & Hazeltine 1922 3940: 3938: 3873:Hausmann, Goldsmith & Hazeltine 1922 3710:Hausmann, Goldsmith & Hazeltine 1922 3596:(10). New York: Clarke Publishing Co.: 9 3524:. Kenneth Kuhn website, Univ. of Alabama 3405: 3403: 3401: 3399: 3397: 3395: 3393: 3391: 3389: 3330: 3328: 3326: 2579:The New Radio Receiver Building Handbook 2153:. US: John Wiley and Sons. p. 333. 2083:Braun, Ernest; Stuart MacDonald (1982). 2030:. US: Chicago Review Press. p. 85. 1552: 955:of the tuned circuit, determined by the 726: 688:). The crystal detector functions as a 429:was experimenting with applying voltage 244:A simple homemade radio receiving outfit 48:Swedish crystal radio from 1922 made by 4974:http://www.sparkmuseum.com/DETECTOR.HTM 4359:"Radio Apparatus – What is it made of?" 4124:"The Selective Double-Circuit Receiver" 4039:Textbook on Wireless Telegraphy, Vol. 1 3631:. US: Forgotten Books. pp. 18–22. 3569:. New York: Funk and Wagnalls. p. 2993:. (It was Hugo Gernsback, publisher of 2401: 2399: 2019: 2017: 2015: 2013: 2011: 1959:Old Time Radios! Restoration and Repair 1939: 1721: 594:(long distance reception) and building 4357:Hirsch, William Crawford (June 1922). 3260: 3258: 3256: 3254: 3252: 3250: 3110:, New York: McGraw-Hill, 1948, pp. 3–4 2810:"Detector for electrical disturbances" 1951: 1949: 1947: 1945: 1943: 661:connected together. The circuit has a 210:at frequencies as low as 20 kHz. 4958:http://www.crystal-radio.eu/engev.htm 4824:. D. Van Nostrand company. 267 pages. 4609:Certain crystals if this combination 3915:Smith, K. c. a.; R. E. Alley (1992). 3126:. Rosenberg Publishing. p. 103. 2937:"Oscillating and Amplifying Crystals" 2683:(52) : 1199–1200. From p. 1119: 2337:Proc. of the Inst. Of Radio Engineers 115:receivers, while other radios use an 7: 6065: 3918:Electrical circuits: An introduction 3725:Engineering Circuit Analysis, 2nd Ed 3685:. D. Van Nostrand Company. pp. 2997:, who coined the term "crystodyne".) 403:United States Department of Commerce 4221:"Radio Detectors and How They Work" 4068:. Forgotten Books. pp. 23–25. 3548:. US: G.P. Putnam's sons. pp. 2974:The Wireless World and Radio Review 2963:The Wireless World and Radio Review 2952:The Wireless World and Radio Review 2941:The Wireless World and Radio Review 2893:, September 1924, pp. 294–295, 431. 692:, demodulating the radio frequency 4841:JL Preston and HA Wheeler (1922) " 4591:Robison, Samuel Shelburne (1911). 4399:Gernsback, Hugo (September 1944). 4252:, vol. II, no. 3, p. 42, Jul. 1914 4219:Campbell, John W. (October 1944). 4122:Hogan, John V. L. (October 1922). 4062:Collins, Archie Frederick (1922). 3728:. New York: McGraw-Hill. pp. 3625:Collins, Archie Frederick (1922). 3484:. personal website. Archived from 3156:. D. Van Nostrand Co. p. 199. 739:with the coil. The detector was a 645:(tuned circuit) which selects the 453:receivers, and even transmitters. 25: 4933:"High Performance Crystal Radios" 3816:Blanchard, T. A. (October 1962). 2972:Round and Rust (August 19, 1925) 2628:Principles of Radio Communication 2333:"United States Radio Development" 755:. Even for a powerful commercial 407:Harding-Cox presidential election 375:United States Bureau of Standards 92:. This component is now called a 6064: 6054: 6045: 6044: 6033: 5654:Free-space optical communication 4696:"Build a Matchbox Crystal Radio" 4488:Kuhn, Kenneth A. (Jan 6, 2008). 4315:Text-book on Wireless Telegraphy 4180:US Signal Corps (October 1916). 3894:. US: Springer. pp. 60–62. 3756:Kuhn, Kenneth A. (Jan 6, 2008). 3482:Ian Purdie's Amateur Radio Pages 3225:"Build a Matchbox Crystal Radio" 3194:Fette, Bruce A. (Dec 27, 2008). 3078:Kuhn, Kenneth A. (Jan 6, 2008). 2518:Solomon, Larry J. (2007-12-30). 2459:Stay Tuned Crystal Radio website 1888: 1863: 1851: 1833: 1815: 1793: 1775: 1760: 1748: 1736: 1724: 1311:How the crystal detector works. 1094: 1085: 1037:tuning coil, in which a ferrite 680:the radio signal to extract the 401:, received its license from the 377:released a publication entitled 143:. Crystals were first used as a 131:property of a contact between a 4584:The sensitivity of the Perikon 4346:Lescarboura (1922), pp. 143–146 4201:Marx & Van Muffling (1922) 4165:Marx & Van Muffling (1922) 4021:Marx & Van Muffling (1922) 3584:Putnam, Robert (October 1922). 3057:Lescarboura, Austin C. (1922). 2935:Hugh S. Pocock (June 11, 1924) 2603:Lescarboura, Austin C. (1922). 2478:website . Retrieved 2010-01-18. 2382:. AuthorHouse. pp. 44–45. 1395:. The crystal functions as an 258:radio signals transmitted from 4792:"High Sensitivity Crystal Set" 4616:Bucher, Elmer Eustace (1921). 4000:Bucher, Elmer Eustace (1921). 3947:Electronic Engineering, 3rd Ed 3785:Clifford, Martin (July 1986). 3652:Lescarboura, 1922, pp. 102–104 3563:Williams, Henry Smith (1922). 3466:is a collection of 12 circuits 3461:The Boy's Book of Crystal Sets 3437:Sleeper, Milton Blake (1922). 3196:"RF Basics: Radio Propagation" 3150:Morgan, Alfred Powell (1914). 2922:M. Vingradow (September 1924) 2508:journal. Retrieved 2010-01-18. 2434:Birmingham Crystal Radio Group 1268:impedance matching transformer 1129:impedance matching transformer 939:connected together, acts as a 582:Building crystal radios was a 405:just in time to broadcast the 1: 4834:Milton Blake Sleeper (1922). 4827:Elmer Eustice Bucher (1920). 4065:The Radio Amateur's Hand Book 3970:Tongue, Ben H. (2007-11-06). 3628:The Radio Amateur's Hand Book 3590:Tractor and Gas Engine Review 3513:Kuhn, Kenneth (Dec 9, 2007). 3418:. Alan Klase personal website 3335:Binns, Jack (November 1922). 3106:H. C. Torrey, C. A. Whitmer, 2721:Henry Harrison Chase Dunwoody 2695:Annalen der Physik und Chemie 2677:Elektrotechnische Zeitschrift 2024:Field, Simon Quellen (2003). 1841: 1823: 1805: 1800:Homemade "loose coupler" set 1783: 935:, consisting of a coil and a 356:signals. This device brought 6040:Telecommunication portal 5821:Telecommunications equipment 4790:Cutler, Bob (January 2007). 4433:Douglas, Alan (April 1981). 4267:. Riley Shaw's personal blog 4265:"The cat's-whisker detector" 3978:. Ben Tongue. Archived from 3586:"Make the aerial a good one" 2924:"Lés Détecteurs Générateurs" 2821:Greenleaf Whittier Pickard, 2725:"Wireless-telegraph system," 2544:Petruzellis, Thomas (2007). 2499:Antique Wireless Association 2245:Douglas, Alan (April 1981). 1988:Petruzellis, Thomas (2007). 1755:Marconi Type 103 crystal set 948:the station received is the 290:Early radio telegraphy used 6091:History of radio technology 5557:Alexander Stepanovich Popov 4890:Ben Tongue's Technical Talk 4822:Elements of Radiotelegraphy 4780:Radio-Electronics, 1966, №2 4388:Stanley (1919), pp. 311–318 3515:"Antenna and Ground System" 2754:Emerson, D. T. (Dec 1997). 2306:The Evolution of Technology 2175:Emerson, D. T. (Dec 1997). 723:, hence earphones are used. 194:band, but most receive the 6142: 5261:Telecommunications history 4694:Payor, Steve (June 1989). 4647:Lescarboura (1922), p. 285 4451:10.1109/mspec.1981.6369482 4401:"Foxhole emergency radios" 4263:Shaw, Riley (April 2015). 4151:Alley & Atwood (1973) 3818:"Vestpocket Crystal Radio" 3223:Payor, Steve (June 1989). 2980:"The Crystodyne principle" 2887:"The Crystodyne Principle" 2576:Williams, Lyle R. (2006). 2489:Designing a DX crystal set 2349:10.1109/jrproc.1917.217311 2259:10.1109/MSPEC.1981.6369482 2062:. Springer. pp. 3–4. 1538:Modern crystal radio with 1467:(carborundum, SiC), and a 1407:radio signal to a pulsing 1281: 334:Greenleaf Whittier Pickard 300:high-frequency alternators 147:of radio waves in 1894 by 139:was discovered in 1874 by 119:powered by current from a 36: 29: 6028: 5869:Public Switched Telephone 5681:telecommunication circuit 5642:Fiber-optic communication 5387:Francis Blake (telephone) 5182:Optical telecommunication 4983:The Crystal Set Perfected 4938:. Ottawa Electronics Club 4658:Collins (1922), pp. 27–28 4497:Crystal Radio Engineering 3787:"The early days of radio" 3765:Crystal Radio Engineering 3522:Crystal Radio Engineering 3120:Jensen, Peter R. (2003). 3087:Crystal Radio Engineering 3037:electronics-tutorials.com 2147:Sarkar, Tapan K. (2006). 1688:{\displaystyle P=U^{2}/R} 1557:1600 ohm magnetic headset 962:of the capacitor and the 373:In 1922 the (then named) 5780:Orbital angular-momentum 5217:Satellite communications 5056:Communications satellite 4909:". earthlink.net/~lenyr. 4882:Hobbydyne Crystal Radios 4820:Ellery W. Stone (1919). 4753: 4096:Wenzel, Charles (1995). 4036:Stanley, Rupert (1919). 3614:Lescarboura 1922, p. 100 3412:"Crystal Set Design 102" 2303:Basalla, George (1988). 1956:Carr, Joseph J. (1990). 1822:Crystal radio, Germany, 1593:Modern crystal sets use 1284:Crystal detector (radio) 1219:coils of wire, one (the 791:signals used during the 487:troops were halted near 6106:Amateur radio receivers 5659:Molecular communication 5482:Gardiner Greene Hubbard 5311:Undersea telegraph line 5046:Cable protection system 4286:Lee, Thomas H. (2004). 4250:Electrical Experimenter 3458:May, Walter J. (1954). 3410:Klase, Alan R. (1998). 3366:Beauchamp, Ken (2001). 3265:Lee, Thomas H. (2004). 3031:Purdie, Ian C. (2001). 2908:, no. 28, p. 139 (1924) 2461:. Retrieved 2010-01-18. 2376:Corbin, Alfred (2006). 1432:used a battery-powered 1292:Galena crystal detector 1215:. This consists of two 863:used in modern radios. 847:band waves are 182–566 787:stations, although the 186:(AM) signals, although 182:Crystal radios receive 6121:Bangladeshi inventions 5801:Communication protocol 5587:Charles Sumner Tainter 5402:Walter Houser Brattain 5347:Edwin Howard Armstrong 5155:Information revolution 4851:Thomas H. Lee (2004). 4732:High Power Crystal Set 4669:Williams (1922), p. 79 4435:"The Crystal Detector" 4153:Electronic Engineering 4102:Crystal radio circuits 4098:"Simple crystal radio" 3294:"Threshold of hearing" 2988:October 1924 issue of 2808:Jagadis Chunder Bose, 2247:"The crystal detector" 1689: 1558: 1542: 1540:piezoelectric earphone 1357: 1349: 1304: 1293: 1211:by a technique called 1197: 1189: 1148:Problem of selectivity 1144: 1015: 928: 824: 744: 619: 611: 571: 473: 287: 260:spark-gap transmitters 247: 231: 223: 208:spark-gap transmitters 74:crystal radio receiver 69: 57: 54:cat's whisker detector 5775:Polarization-division 5507:Narinder Singh Kapany 5472:Erna Schneider Hoover 5392:Jagadish Chandra Bose 5372:Alexander Graham Bell 5103:online video platform 4636:Field 2003, pp. 93–94 4519:"The Crystal Set 5/6" 4363:The Electrical Record 3478:"A Basic Crystal Set" 3369:History of Telegraphy 3198:. RF Engineer Network 1924:Electrolytic detector 1690: 1635:Use as a power source 1556: 1537: 1355: 1310: 1299: 1291: 1195: 1187: 1142: 1073:set's limited range. 1062:parasitic capacitance 1043:magnetic permeability 1016: 922: 855:, in contrast to the 818: 730: 617: 609: 566: 471: 329:Jagadish Chandra Bose 281: 237: 229: 221: 206:signals broadcast by 149:Jagadish Chandra Bose 111:). However they are 63: 47: 5617:Vladimir K. Zworykin 5577:Almon Brown Strowger 5547:Charles Grafton Page 5202:Prepaid mobile phone 5130:Electrical telegraph 4922:Roger Lapthorn G3XBM 4916:. November 20, 2002. 3476:Purdie, Ian (1999). 3464:. London: Bernard's. 3020:1950s Crystal Radios 3009:Rocket Crystal Radio 2865:Peter Robin Morris, 2732:Louis Winslow Austin 2661:Karl Ferdinand Braun 2446:The Xtal Set Society 1804:,museum in Florida, 1658: 1393:semiconductor diodes 1381:cat whisker detector 1238:resonant transformer 1217:magnetically coupled 1058:capacitive reactance 1029:. Alternatively, a 976: 882:fences as antennas. 757:broadcasting station 741:cat whisker detector 710:semiconductor diodes 698:cat whisker detector 198:band. A few receive 141:Karl Ferdinand Braun 5567:Johann Philipp Reis 5326:Wireless revolution 5288:The Telephone Cases 5145:Hydraulic telegraph 4912:Nyle Steiner K7NS, 4737:Popular Electronics 4720:Field (2003), p. 94 4700:Popular Electronics 3229:Popular Electronics 3060:Radio for Everybody 3033:"Crystal Radio Set" 2958: : 2ff, 47ff. 2772:1997ITMTT..45.2267E 2606:Radio for Everybody 2520:"FM Crystal Radios" 2487:Mike Tuggle (2003) 2457:Darryl Boyd (2006) 2432:Jack Bryant (2009) 2232:History of wireless 2193:1997ITMTT..45.2267E 2150:History of wireless 1710:wireless telegraphy 1563:moving iron drivers 1504:semiconductor diode 1405:alternating current 1319:amplitude modulated 1231:; the primary coil 1207:which improves the 793:wireless telegraphy 694:alternating current 690:square law detector 443:negative resistance 354:amplitude modulated 242:1922 Circular 120 " 240:Bureau of Standards 204:wireless telegraphy 184:amplitude modulated 161:wireless telegraphy 5765:Frequency-division 5742:Telephone exchange 5612:Charles Wheatstone 5542:Jun-ichi Nishizawa 5517:Innocenzo Manzetti 5452:Reginald Fessenden 5187:Optical telegraphy 5020:Telecommunications 4904:2013-03-17 at the 4551:. crystal-radio.eu 4523:The Crystal Corner 3758:"Resonant Circuit" 3108:Crystal Rectifiers 2504:2010-05-23 at the 2494:2010-01-24 at the 2289:Stay Tuned website 1685: 1619:earphone's input. 1559: 1543: 1502:In modern sets, a 1358: 1350: 1305: 1294: 1198: 1190: 1180:Inductive coupling 1145: 1112:impedance matching 1077:Impedance matching 1031:variable capacitor 1011: 950:resonant frequency 929: 861:loopstick antennas 825: 821:inverted-L antenna 745: 663:resonant frequency 620: 612: 572: 474: 288: 248: 232: 224: 166:radio broadcasting 70: 58: 32:Crystal oscillator 6126:Indian inventions 6116:Electronic design 6096:Radio electronics 6078: 6077: 5816:Store and forward 5811:Data transmission 5725:Network switching 5676:Transmission line 5522:Guglielmo Marconi 5487:Internet pioneers 5352:Mohamed M. Atalla 5321:Whistled language 4969:Crystal Detectors 4730:Walter B. Ford, " 4572:(1922), p.439-440 4517:Hadgraft, Peter. 4490:"Diode Detectors" 3822:Radio-Electronics 3791:Radio Electronics 3739:978-0-07-027382-5 3318:Lescarboura, 1922 3278:978-0-521-83526-8 2928:L'Onde Electrique 2913:Radio Électricité 2780:10.1109/22.643830 2766:(12): 2267–2273. 2589:978-1-84728-526-3 2557:978-0-07-148929-4 2419:978-1-55652-774-6 2234:, pp. 94, 291–308 2201:10.1109/22.643830 2187:(12): 2267–2273. 2096:978-0-521-28903-0 2037:978-1-55652-520-9 2001:978-0-07-148929-4 1904:Batteryless radio 1598:crystal earpieces 1447:(fool's gold, FeS 1397:envelope detector 1253:mutual inductance 1008: 1005: 892:monopole antennas 868:"T" type antennas 753:radio transmitter 632:electric currents 553:Transistor radios 529:signals from the 304:radio frequencies 16:(Redirected from 6133: 6111:Receiver (radio) 6068: 6067: 6058: 6057: 6048: 6047: 6038: 6037: 6036: 5909:Notable networks 5899:Wireless network 5839:Cellular network 5831:Types of network 5806:Computer network 5693:Network topology 5607:Thomas A. Watson 5462:Oliver Heaviside 5447:Philo Farnsworth 5422:Daniel Davis Jr. 5397:Charles Bourseul 5357:John Logie Baird 5066:Data compression 5061:Computer network 5013: 5006: 4999: 4990: 4946: 4944: 4943: 4937: 4809: 4808: 4796: 4787: 4781: 4778: 4772: 4771: 4749: 4740: 4734:", August 1960, 4728: 4722: 4717: 4711: 4710: 4708: 4707: 4691: 4685: 4677: 4671: 4666: 4660: 4655: 4649: 4644: 4638: 4633: 4624: 4623: 4605: 4599: 4598: 4580: 4574: 4566: 4560: 4559: 4557: 4556: 4544: 4538: 4537: 4535: 4534: 4514: 4508: 4507: 4505: 4504: 4494: 4485: 4479: 4478: 4476: 4475: 4462: 4430: 4424: 4419: 4417: 4416: 4396: 4390: 4385: 4379: 4378: 4376: 4374: 4354: 4348: 4343: 4334: 4333:, pp. 60–61 4328: 4319: 4310: 4304: 4303: 4283: 4277: 4276: 4274: 4272: 4259: 4253: 4246: 4240: 4239: 4237: 4236: 4216: 4207: 4205:, p. 43, fig. 22 4198: 4192: 4191: 4177: 4171: 4162: 4156: 4149: 4143: 4142: 4140: 4139: 4119: 4113: 4112: 4110: 4109: 4093: 4080: 4079: 4059: 4048: 4047: 4033: 4027: 4018: 4012: 4011: 3997: 3991: 3990: 3988: 3987: 3967: 3961: 3960: 3942: 3933: 3932: 3912: 3906: 3905: 3882: 3876: 3870: 3864: 3863: 3854: 3837: 3832: 3830: 3829: 3813: 3807: 3801: 3799: 3798: 3782: 3776: 3775: 3773: 3772: 3762: 3753: 3744: 3743: 3719: 3713: 3707: 3701: 3700: 3676: 3670: 3669: 3660: 3654: 3649: 3643: 3642: 3622: 3616: 3611: 3605: 3604: 3602: 3601: 3581: 3575: 3574: 3560: 3554: 3553: 3539: 3533: 3532: 3530: 3529: 3519: 3510: 3497: 3496: 3494: 3493: 3473: 3467: 3465: 3455: 3449: 3448: 3433: 3427: 3426: 3424: 3423: 3407: 3384: 3383: 3362: 3356: 3355: 3353: 3352: 3332: 3321: 3315: 3309: 3308: 3306: 3305: 3289: 3283: 3282: 3262: 3245: 3239: 3237: 3236: 3220: 3207: 3206: 3204: 3203: 3191: 3185: 3184: 3164: 3158: 3157: 3147: 3138: 3137: 3117: 3111: 3104: 3098: 3097: 3095: 3094: 3084: 3075: 3069: 3068: 3054: 3048: 3047: 3045: 3044: 3028: 3022: 3017: 3011: 3006: 3000: 2919: : 196–197. 2900: 2894: 2884: 2878: 2863: 2857: 2854: 2848: 2843: 2837: 2832: 2826: 2819: 2813: 2806: 2800: 2799: 2797: 2796: 2751: 2745: 2714: 2708: 2657: 2651: 2650: 2643: 2637: 2636: 2621: 2615: 2614: 2600: 2594: 2593: 2573: 2562: 2561: 2541: 2535: 2534: 2532: 2531: 2522:. Archived from 2515: 2509: 2485: 2479: 2468: 2462: 2455: 2449: 2443: 2437: 2430: 2424: 2423: 2403: 2394: 2393: 2373: 2367: 2366: 2364: 2363: 2327: 2321: 2320: 2300: 2291: 2286: 2284: 2283: 2270: 2242: 2236: 2227: 2221: 2220: 2218: 2217: 2171: 2165: 2164: 2144: 2138: 2137: 2118:Lillian Hoddeson 2114:Riordan, Michael 2110: 2101: 2100: 2080: 2074: 2073: 2053: 2042: 2041: 2021: 2006: 2005: 1985: 1974: 1973: 1953: 1929:History of radio 1919:Detector (radio) 1898: 1893: 1892: 1891: 1867: 1855: 1846: 1843: 1837: 1828: 1825: 1819: 1810: 1807: 1797: 1788: 1785: 1779: 1764: 1752: 1740: 1728: 1694: 1692: 1691: 1686: 1681: 1676: 1675: 1430:(circuit, right) 1421:bypass capacitor 1346: 1340: 1315: 1278:Crystal detector 1202:antenna coupling 1098: 1089: 1020: 1018: 1017: 1012: 1009: 1007: 1006: 998: 986: 836:electric current 706:crystal detector 643:resonant circuit 602:Basic principles 493:local oscillator 464:"Foxhole radios" 296:arc transmitters 86:crystal detector 76:, also called a 21: 6141: 6140: 6136: 6135: 6134: 6132: 6131: 6130: 6101:Types of radios 6081: 6080: 6079: 6074: 6034: 6032: 6024: 5966: 5903: 5825: 5789: 5746: 5695: 5687: 5628: 5621: 5527:Robert Metcalfe 5382:Tim Berners-Lee 5330: 5150:Information Age 5022: 5017: 4977:Radio Detectors 4941: 4939: 4935: 4930: 4920:Crystal Set DX? 4906:Wayback Machine 4870: 4817: 4815:Further reading 4812: 4794: 4789: 4788: 4784: 4779: 4775: 4768: 4755: 4751: 4750: 4743: 4729: 4725: 4718: 4714: 4705: 4703: 4693: 4692: 4688: 4678: 4674: 4667: 4663: 4656: 4652: 4645: 4641: 4634: 4627: 4615: 4606: 4602: 4590: 4581: 4577: 4567: 4563: 4554: 4552: 4547:Kleijer, Dick. 4546: 4545: 4541: 4532: 4530: 4516: 4515: 4511: 4502: 4500: 4492: 4487: 4486: 4482: 4473: 4471: 4432: 4431: 4427: 4414: 4412: 4398: 4397: 4393: 4386: 4382: 4372: 4370: 4356: 4355: 4351: 4344: 4337: 4329: 4322: 4313:Stanley (1919) 4311: 4307: 4300: 4285: 4284: 4280: 4270: 4268: 4262: 4260: 4256: 4247: 4243: 4234: 4232: 4225:Popular Science 4218: 4217: 4210: 4203:Radio Reception 4199: 4195: 4183:Radiotelegraphy 4179: 4178: 4174: 4167:Radio Reception 4163: 4159: 4150: 4146: 4137: 4135: 4128:Radio Broadcast 4121: 4120: 4116: 4107: 4105: 4095: 4094: 4083: 4076: 4061: 4060: 4051: 4035: 4034: 4030: 4023:Radio Reception 4019: 4015: 3999: 3998: 3994: 3985: 3983: 3969: 3968: 3964: 3957: 3944: 3943: 3936: 3929: 3914: 3913: 3909: 3902: 3884: 3883: 3879: 3871: 3867: 3856: 3855: 3840: 3827: 3825: 3815: 3814: 3810: 3796: 3794: 3784: 3783: 3779: 3770: 3768: 3760: 3755: 3754: 3747: 3740: 3721: 3720: 3716: 3708: 3704: 3697: 3678: 3677: 3673: 3662: 3661: 3657: 3650: 3646: 3639: 3624: 3623: 3619: 3612: 3608: 3599: 3597: 3583: 3582: 3578: 3566:Practical Radio 3562: 3561: 3557: 3541: 3540: 3536: 3527: 3525: 3517: 3512: 3511: 3500: 3491: 3489: 3475: 3474: 3470: 3457: 3456: 3452: 3436: 3434: 3430: 3421: 3419: 3409: 3408: 3387: 3380: 3365: 3363: 3359: 3350: 3348: 3341:Popular Science 3334: 3333: 3324: 3316: 3312: 3303: 3301: 3291: 3290: 3286: 3279: 3264: 3263: 3248: 3234: 3232: 3222: 3221: 3210: 3201: 3199: 3193: 3192: 3188: 3181: 3166: 3165: 3161: 3149: 3148: 3141: 3134: 3123:Wireless at War 3119: 3118: 3114: 3105: 3101: 3092: 3090: 3082: 3077: 3076: 3072: 3056: 3055: 3051: 3042: 3040: 3030: 3029: 3025: 3018: 3014: 3007: 3003: 2969: : 93–96. 2926:, pp. 433–448, 2901: 2897: 2885: 2881: 2864: 2860: 2855: 2851: 2844: 2840: 2833: 2829: 2820: 2816: 2807: 2803: 2794: 2792: 2790: 2753: 2752: 2748: 2715: 2711: 2702: 2688: 2686: 2684: 2658: 2654: 2645: 2644: 2640: 2624: 2622: 2618: 2602: 2601: 2597: 2590: 2575: 2574: 2565: 2558: 2543: 2542: 2538: 2529: 2527: 2517: 2516: 2512: 2506:Wayback Machine 2496:Wayback Machine 2486: 2482: 2469: 2465: 2456: 2452: 2444: 2440: 2431: 2427: 2420: 2405: 2404: 2397: 2390: 2375: 2374: 2370: 2361: 2359: 2330: 2328: 2324: 2317: 2302: 2301: 2294: 2281: 2279: 2244: 2243: 2239: 2228: 2224: 2215: 2213: 2211: 2174: 2172: 2168: 2161: 2146: 2145: 2141: 2134: 2112: 2111: 2104: 2097: 2082: 2081: 2077: 2070: 2055: 2054: 2045: 2038: 2023: 2022: 2009: 2002: 1987: 1986: 1977: 1970: 1955: 1954: 1941: 1937: 1894: 1889: 1887: 1884: 1879: 1878: 1877: 1874: 1868: 1859: 1856: 1847: 1844: 1838: 1829: 1826: 1820: 1811: 1808: 1798: 1789: 1786: 1780: 1771: 1765: 1756: 1753: 1744: 1741: 1732: 1729: 1706: 1667: 1656: 1655: 1650:signals have a 1637: 1532: 1508:Schottky diodes 1482: 1478: 1465:silicon carbide 1462: 1450: 1413:radio frequency 1344: 1338: 1323:radio frequency 1313: 1301:Germanium diode 1286: 1280: 1182: 1150: 1133:autotransformer 1108: 1107: 1106: 1105: 1101: 1100: 1099: 1091: 1090: 1079: 990: 974: 973: 917: 904:input impedance 888: 813: 801: 789:radiotelegraphy 649:of the desired 634:are induced by 604: 561: 539: 497:superheterodyne 466: 451:superheterodyne 421:In early 1920s 419: 371: 369:1920s and 1930s 362:voice broadcast 358:radiotelephones 276: 216: 192:radio frequency 42: 39:The Crystal Set 35: 28: 23: 22: 15: 12: 11: 5: 6139: 6137: 6129: 6128: 6123: 6118: 6113: 6108: 6103: 6098: 6093: 6083: 6082: 6076: 6075: 6073: 6072: 6062: 6052: 6042: 6029: 6026: 6025: 6023: 6022: 6015: 6010: 6005: 6000: 5995: 5994: 5993: 5988: 5980: 5974: 5972: 5968: 5967: 5965: 5964: 5959: 5954: 5949: 5944: 5939: 5934: 5929: 5924: 5919: 5913: 5911: 5905: 5904: 5902: 5901: 5896: 5891: 5886: 5881: 5876: 5871: 5866: 5861: 5856: 5851: 5846: 5841: 5835: 5833: 5827: 5826: 5824: 5823: 5818: 5813: 5808: 5803: 5797: 5795: 5791: 5790: 5788: 5787: 5782: 5777: 5772: 5767: 5762: 5760:Space-division 5756: 5754: 5748: 5747: 5745: 5744: 5739: 5738: 5737: 5732: 5722: 5721: 5720: 5710: 5705: 5699: 5697: 5689: 5688: 5686: 5685: 5684: 5683: 5673: 5672: 5671: 5661: 5656: 5651: 5650: 5649: 5639: 5633: 5631: 5623: 5622: 5620: 5619: 5614: 5609: 5604: 5599: 5597:Camille Tissot 5594: 5589: 5584: 5579: 5574: 5572:Claude Shannon 5569: 5564: 5562:Tivadar Puskás 5559: 5554: 5549: 5544: 5539: 5534: 5532:Antonio Meucci 5529: 5524: 5519: 5514: 5509: 5504: 5502:Charles K. Kao 5499: 5494: 5489: 5484: 5479: 5477:Harold Hopkins 5474: 5469: 5464: 5459: 5454: 5449: 5444: 5439: 5434: 5429: 5424: 5419: 5414: 5409: 5404: 5399: 5394: 5389: 5384: 5379: 5377:Emile Berliner 5374: 5369: 5364: 5359: 5354: 5349: 5344: 5338: 5336: 5332: 5331: 5329: 5328: 5323: 5318: 5316:Videotelephony 5313: 5308: 5307: 5306: 5301: 5291: 5284: 5279: 5273: 5268: 5263: 5258: 5253: 5252: 5251: 5246: 5241: 5231: 5230: 5229: 5219: 5214: 5212:Radiotelephone 5209: 5204: 5199: 5194: 5189: 5184: 5179: 5178: 5177: 5167: 5162: 5157: 5152: 5147: 5142: 5137: 5132: 5127: 5122: 5117: 5116: 5115: 5110: 5105: 5100: 5098:Internet video 5090: 5089: 5088: 5083: 5078: 5073: 5063: 5058: 5053: 5048: 5043: 5038: 5032: 5030: 5024: 5023: 5018: 5016: 5015: 5008: 5001: 4993: 4987: 4986: 4979: 4971: 4963: 4955: 4947: 4928: 4923: 4917: 4910: 4894: 4886: 4878: 4869: 4868:External links 4866: 4865: 4864: 4861: 4855: 4849: 4846: 4839: 4832: 4825: 4816: 4813: 4811: 4810: 4782: 4773: 4766: 4741: 4723: 4712: 4686: 4683:(1922), p. 441 4672: 4661: 4650: 4639: 4625: 4600: 4575: 4561: 4539: 4509: 4480: 4425: 4391: 4380: 4349: 4335: 4320: 4305: 4298: 4278: 4254: 4241: 4208: 4193: 4172: 4157: 4144: 4114: 4081: 4074: 4049: 4028: 4013: 3992: 3962: 3955: 3934: 3927: 3907: 3900: 3886:Nahin, Paul J. 3877: 3865: 3838: 3808: 3777: 3745: 3738: 3714: 3702: 3695: 3671: 3655: 3644: 3637: 3617: 3606: 3576: 3555: 3534: 3498: 3468: 3450: 3428: 3385: 3378: 3357: 3322: 3310: 3292:Nave, C. Rod. 3284: 3277: 3246: 3208: 3186: 3179: 3159: 3139: 3132: 3112: 3099: 3080:"Introduction" 3070: 3049: 3023: 3012: 3001: 2999: 2998: 2977: 2976:, pp. 217–218. 2970: 2959: 2948: 2931: 2930: 2920: 2909: 2895: 2879: 2858: 2849: 2838: 2827: 2814: 2801: 2789:978-0986488511 2788: 2746: 2744: 2743: 2739: 2728: 2709: 2652: 2638: 2616: 2595: 2588: 2563: 2556: 2536: 2510: 2480: 2472:Crystal Radios 2463: 2450: 2438: 2425: 2418: 2395: 2388: 2368: 2322: 2315: 2292: 2237: 2230:Sarkar (2006) 2222: 2209: 2166: 2159: 2139: 2132: 2102: 2095: 2075: 2068: 2043: 2036: 2007: 2000: 1975: 1968: 1938: 1936: 1933: 1932: 1931: 1926: 1921: 1916: 1911: 1906: 1900: 1899: 1883: 1880: 1876: 1875: 1869: 1862: 1860: 1857: 1850: 1848: 1839: 1832: 1830: 1821: 1814: 1812: 1799: 1792: 1790: 1781: 1774: 1772: 1766: 1759: 1757: 1754: 1747: 1745: 1742: 1735: 1733: 1730: 1723: 1720: 1719: 1718: 1705: 1702: 1684: 1680: 1674: 1670: 1666: 1663: 1636: 1633: 1583:magnetic field 1531: 1528: 1497:semiconducting 1480: 1476: 1460: 1448: 1409:direct current 1389:Schottky diode 1282:Main article: 1279: 1276: 1249:magnetic field 1213:loose coupling 1181: 1178: 1149: 1146: 1103: 1102: 1093: 1092: 1084: 1083: 1082: 1081: 1080: 1078: 1075: 1022: 1021: 1004: 1001: 996: 993: 989: 984: 981: 916: 913: 887: 884: 819:Diagram of an 812: 809: 805:radio amateurs 800: 797: 725: 724: 713: 666: 639: 603: 600: 560: 557: 538: 537:"Rocket Radio" 535: 511:foxhole radios 478:semiconductors 465: 462: 418: 415: 370: 367: 275: 272: 215: 212: 82:radio receiver 80:, is a simple 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 6138: 6127: 6124: 6122: 6119: 6117: 6114: 6112: 6109: 6107: 6104: 6102: 6099: 6097: 6094: 6092: 6089: 6088: 6086: 6071: 6063: 6061: 6053: 6051: 6043: 6041: 6031: 6030: 6027: 6020: 6016: 6014: 6011: 6009: 6006: 6004: 6001: 5999: 5996: 5992: 5989: 5987: 5984: 5983: 5981: 5979: 5976: 5975: 5973: 5969: 5963: 5960: 5958: 5955: 5953: 5950: 5948: 5945: 5943: 5940: 5938: 5935: 5933: 5930: 5928: 5925: 5923: 5920: 5918: 5915: 5914: 5912: 5910: 5906: 5900: 5897: 5895: 5892: 5890: 5887: 5885: 5882: 5880: 5877: 5875: 5872: 5870: 5867: 5865: 5862: 5860: 5857: 5855: 5852: 5850: 5847: 5845: 5842: 5840: 5837: 5836: 5834: 5832: 5828: 5822: 5819: 5817: 5814: 5812: 5809: 5807: 5804: 5802: 5799: 5798: 5796: 5792: 5786: 5785:Code-division 5783: 5781: 5778: 5776: 5773: 5771: 5770:Time-division 5768: 5766: 5763: 5761: 5758: 5757: 5755: 5753: 5749: 5743: 5740: 5736: 5733: 5731: 5728: 5727: 5726: 5723: 5719: 5716: 5715: 5714: 5711: 5709: 5706: 5704: 5701: 5700: 5698: 5696:and switching 5694: 5690: 5682: 5679: 5678: 5677: 5674: 5670: 5667: 5666: 5665: 5662: 5660: 5657: 5655: 5652: 5648: 5647:optical fiber 5645: 5644: 5643: 5640: 5638: 5637:Coaxial cable 5635: 5634: 5632: 5630: 5624: 5618: 5615: 5613: 5610: 5608: 5605: 5603: 5600: 5598: 5595: 5593: 5590: 5588: 5585: 5583: 5580: 5578: 5575: 5573: 5570: 5568: 5565: 5563: 5560: 5558: 5555: 5553: 5552:Radia Perlman 5550: 5548: 5545: 5543: 5540: 5538: 5535: 5533: 5530: 5528: 5525: 5523: 5520: 5518: 5515: 5513: 5510: 5508: 5505: 5503: 5500: 5498: 5495: 5493: 5490: 5488: 5485: 5483: 5480: 5478: 5475: 5473: 5470: 5468: 5465: 5463: 5460: 5458: 5455: 5453: 5450: 5448: 5445: 5443: 5442:Lee de Forest 5440: 5438: 5437:Thomas Edison 5435: 5433: 5430: 5428: 5427:Donald Davies 5425: 5423: 5420: 5418: 5415: 5413: 5412:Claude Chappe 5410: 5408: 5405: 5403: 5400: 5398: 5395: 5393: 5390: 5388: 5385: 5383: 5380: 5378: 5375: 5373: 5370: 5368: 5365: 5363: 5360: 5358: 5355: 5353: 5350: 5348: 5345: 5343: 5340: 5339: 5337: 5333: 5327: 5324: 5322: 5319: 5317: 5314: 5312: 5309: 5305: 5302: 5300: 5297: 5296: 5295: 5292: 5290: 5289: 5285: 5283: 5280: 5277: 5274: 5272: 5269: 5267: 5264: 5262: 5259: 5257: 5256:Smoke signals 5254: 5250: 5247: 5245: 5242: 5240: 5237: 5236: 5235: 5234:Semiconductor 5232: 5228: 5225: 5224: 5223: 5220: 5218: 5215: 5213: 5210: 5208: 5205: 5203: 5200: 5198: 5195: 5193: 5190: 5188: 5185: 5183: 5180: 5176: 5173: 5172: 5171: 5168: 5166: 5163: 5161: 5158: 5156: 5153: 5151: 5148: 5146: 5143: 5141: 5138: 5136: 5133: 5131: 5128: 5126: 5123: 5121: 5118: 5114: 5111: 5109: 5106: 5104: 5101: 5099: 5096: 5095: 5094: 5093:Digital media 5091: 5087: 5084: 5082: 5079: 5077: 5074: 5072: 5069: 5068: 5067: 5064: 5062: 5059: 5057: 5054: 5052: 5049: 5047: 5044: 5042: 5039: 5037: 5034: 5033: 5031: 5029: 5025: 5021: 5014: 5009: 5007: 5002: 5000: 4995: 4994: 4991: 4985: 4984: 4980: 4978: 4975: 4972: 4970: 4967: 4964: 4962: 4959: 4956: 4954: 4951: 4948: 4934: 4929: 4927: 4924: 4921: 4918: 4915: 4911: 4908: 4907: 4903: 4900: 4895: 4892: 4891: 4887: 4884: 4883: 4879: 4877: 4876: 4872: 4871: 4867: 4862: 4860: 4856: 4854: 4850: 4847: 4844: 4840: 4837: 4833: 4830: 4826: 4823: 4819: 4818: 4814: 4806: 4802: 4801: 4793: 4786: 4783: 4777: 4774: 4769: 4767:5-94074-056-1 4763: 4759: 4748: 4746: 4742: 4739: 4738: 4733: 4727: 4724: 4721: 4716: 4713: 4701: 4697: 4690: 4687: 4684: 4682: 4676: 4673: 4670: 4665: 4662: 4659: 4654: 4651: 4648: 4643: 4640: 4637: 4632: 4630: 4626: 4621: 4620: 4613: 4610: 4604: 4601: 4596: 4595: 4588: 4585: 4579: 4576: 4573: 4571: 4565: 4562: 4550: 4543: 4540: 4529:on 2010-07-20 4528: 4524: 4520: 4513: 4510: 4498: 4491: 4484: 4481: 4470: 4466: 4461: 4456: 4452: 4448: 4444: 4440: 4439:IEEE Spectrum 4436: 4429: 4426: 4423: 4410: 4406: 4402: 4395: 4392: 4389: 4384: 4381: 4368: 4364: 4360: 4353: 4350: 4347: 4342: 4340: 4336: 4332: 4327: 4325: 4321: 4318: 4316: 4309: 4306: 4301: 4299:0-521-83539-9 4295: 4291: 4290: 4282: 4279: 4266: 4258: 4255: 4251: 4245: 4242: 4230: 4226: 4222: 4215: 4213: 4209: 4206: 4204: 4197: 4194: 4189: 4185: 4184: 4176: 4173: 4169: 4168: 4161: 4158: 4154: 4148: 4145: 4133: 4129: 4125: 4118: 4115: 4104:. techlib.com 4103: 4099: 4092: 4090: 4088: 4086: 4082: 4077: 4075:1-60680-119-8 4071: 4067: 4066: 4058: 4056: 4054: 4050: 4045: 4041: 4040: 4032: 4029: 4025: 4024: 4017: 4014: 4009: 4005: 4004: 3996: 3993: 3982:on 2016-06-04 3981: 3977: 3973: 3966: 3963: 3958: 3956:0-471-02450-3 3952: 3948: 3941: 3939: 3935: 3930: 3928:0-521-37769-2 3924: 3920: 3919: 3911: 3908: 3903: 3901:0-387-95150-4 3897: 3893: 3892: 3887: 3881: 3878: 3874: 3869: 3866: 3861: 3860: 3853: 3851: 3849: 3847: 3845: 3843: 3839: 3836: 3823: 3819: 3812: 3809: 3805: 3792: 3788: 3781: 3778: 3766: 3759: 3752: 3750: 3746: 3741: 3735: 3731: 3727: 3726: 3718: 3715: 3711: 3706: 3703: 3698: 3696:1-110-37159-4 3692: 3688: 3684: 3683: 3675: 3672: 3667: 3666: 3659: 3656: 3653: 3648: 3645: 3640: 3638:1-60680-119-8 3634: 3630: 3629: 3621: 3618: 3615: 3610: 3607: 3595: 3591: 3587: 3580: 3577: 3572: 3568: 3567: 3559: 3556: 3551: 3547: 3546: 3538: 3535: 3523: 3516: 3509: 3507: 3505: 3503: 3499: 3488:on 2009-10-29 3487: 3483: 3479: 3472: 3469: 3463: 3462: 3454: 3451: 3446: 3442: 3441: 3432: 3429: 3417: 3413: 3406: 3404: 3402: 3400: 3398: 3396: 3394: 3392: 3390: 3386: 3381: 3375: 3371: 3370: 3361: 3358: 3346: 3342: 3338: 3331: 3329: 3327: 3323: 3319: 3314: 3311: 3299: 3295: 3288: 3285: 3280: 3274: 3270: 3269: 3261: 3259: 3257: 3255: 3253: 3251: 3247: 3243: 3230: 3226: 3219: 3217: 3215: 3213: 3209: 3197: 3190: 3187: 3182: 3176: 3172: 3171: 3163: 3160: 3155: 3154: 3146: 3144: 3140: 3135: 3129: 3125: 3124: 3116: 3113: 3109: 3103: 3100: 3088: 3081: 3074: 3071: 3066: 3062: 3061: 3053: 3050: 3038: 3034: 3027: 3024: 3021: 3016: 3013: 3010: 3005: 3002: 2996: 2992: 2991: 2985: 2981: 2978: 2975: 2971: 2968: 2964: 2960: 2957: 2953: 2949: 2946: 2942: 2938: 2934: 2933: 2929: 2925: 2921: 2918: 2914: 2910: 2907: 2904: 2903: 2899: 2896: 2892: 2888: 2883: 2880: 2876: 2875:0-86341-227-0 2872: 2869:, IET, 1990, 2868: 2862: 2859: 2853: 2850: 2847: 2842: 2839: 2836: 2831: 2828: 2824: 2818: 2815: 2811: 2805: 2802: 2791: 2785: 2781: 2777: 2773: 2769: 2765: 2761: 2757: 2750: 2747: 2740: 2737: 2733: 2729: 2726: 2722: 2718: 2717: 2713: 2710: 2707: 2700: 2696: 2692: 2682: 2678: 2674: 2670: 2666: 2662: 2659:In May 1901, 2656: 2653: 2648: 2642: 2639: 2634: 2630: 2629: 2620: 2617: 2612: 2608: 2607: 2599: 2596: 2591: 2585: 2581: 2580: 2572: 2570: 2568: 2564: 2559: 2553: 2549: 2548: 2540: 2537: 2526:on 2007-12-30 2525: 2521: 2514: 2511: 2507: 2503: 2500: 2497: 2493: 2490: 2484: 2481: 2477: 2473: 2467: 2464: 2460: 2454: 2451: 2447: 2442: 2439: 2435: 2429: 2426: 2421: 2415: 2411: 2410: 2402: 2400: 2396: 2391: 2389:1-4208-9084-0 2385: 2381: 2380: 2372: 2369: 2358: 2354: 2350: 2346: 2342: 2338: 2334: 2326: 2323: 2318: 2316:0-521-29681-1 2312: 2308: 2307: 2299: 2297: 2293: 2290: 2278: 2274: 2269: 2264: 2260: 2256: 2252: 2251:IEEE Spectrum 2248: 2241: 2238: 2235: 2233: 2226: 2223: 2212: 2210:9780986488511 2206: 2202: 2198: 2194: 2190: 2186: 2182: 2178: 2170: 2167: 2162: 2160:0-471-71814-9 2156: 2152: 2151: 2143: 2140: 2135: 2133:0-393-31851-6 2129: 2125: 2124: 2119: 2115: 2109: 2107: 2103: 2098: 2092: 2088: 2087: 2079: 2076: 2071: 2069:0-7923-8518-7 2065: 2061: 2060: 2052: 2050: 2048: 2044: 2039: 2033: 2029: 2028: 2020: 2018: 2016: 2014: 2012: 2008: 2003: 1997: 1993: 1992: 1984: 1982: 1980: 1976: 1971: 1969:0-8306-3342-1 1965: 1961: 1960: 1952: 1950: 1948: 1946: 1944: 1940: 1934: 1930: 1927: 1925: 1922: 1920: 1917: 1915: 1912: 1910: 1907: 1905: 1902: 1901: 1897: 1886: 1881: 1873: 1866: 1861: 1854: 1849: 1836: 1831: 1818: 1813: 1803: 1796: 1791: 1778: 1773: 1769: 1763: 1758: 1751: 1746: 1739: 1734: 1727: 1722: 1717: 1715: 1711: 1703: 1701: 1698: 1682: 1678: 1672: 1668: 1664: 1661: 1653: 1649: 1645: 1640: 1634: 1632: 1629: 1625: 1620: 1617: 1613: 1608: 1603: 1602:piezoelectric 1599: 1596: 1595:piezoelectric 1591: 1589: 1584: 1580: 1576: 1575:electromagnet 1572: 1568: 1564: 1555: 1551: 1549: 1548:high fidelity 1541: 1536: 1529: 1527: 1525: 1521: 1520:potentiometer 1517: 1511: 1509: 1505: 1500: 1498: 1494: 1490: 1486: 1474: 1470: 1466: 1458: 1454: 1446: 1442: 1438: 1435: 1431: 1425: 1422: 1418: 1414: 1410: 1406: 1402: 1398: 1394: 1390: 1386: 1382: 1378: 1374: 1370: 1366: 1363: 1354: 1347: 1341: 1335: 1331: 1327: 1324: 1320: 1316: 1309: 1302: 1298: 1290: 1285: 1277: 1275: 1271: 1269: 1264: 1261: 1256: 1254: 1250: 1246: 1243:Reducing the 1241: 1239: 1234: 1230: 1229:tuned circuit 1226: 1222: 1218: 1214: 1210: 1206: 1203: 1194: 1186: 1179: 1177: 1175: 1170: 1168: 1164: 1160: 1155: 1147: 1141: 1137: 1134: 1130: 1124: 1122: 1117: 1113: 1097: 1088: 1076: 1074: 1071: 1065: 1063: 1059: 1055: 1051: 1046: 1044: 1040: 1039:magnetic core 1036: 1032: 1028: 1002: 999: 994: 991: 987: 982: 979: 972: 971: 970: 969:of the coil: 968: 965: 961: 958: 954: 951: 946: 942: 938: 934: 933:tuned circuit 926: 925:tuned circuit 921: 915:Tuned circuit 914: 912: 910: 909:mains powered 905: 901: 897: 893: 885: 883: 881: 877: 873: 869: 864: 862: 858: 857:whip antennas 854: 850: 846: 842: 837: 834: 830: 822: 817: 810: 808: 806: 798: 796: 794: 790: 786: 782: 778: 774: 773:amplification 770: 766: 762: 758: 754: 750: 742: 738: 737:tuned circuit 734: 729: 722: 718: 714: 711: 707: 703: 699: 695: 691: 687: 683: 679: 675: 671: 670:semiconductor 667: 664: 660: 656: 652: 651:radio station 648: 644: 640: 637: 633: 629: 625: 624: 623: 616: 608: 601: 599: 597: 593: 592:'DX' contests 589: 585: 580: 577: 570: 565: 558: 556: 554: 550: 547: 543: 536: 534: 532: 527: 522: 520: 516: 512: 507: 503: 498: 494: 490: 486: 481: 479: 470: 463: 461: 459: 454: 452: 448: 444: 440: 436: 432: 428: 424: 416: 414: 410: 408: 404: 400: 396: 392: 386: 384: 380: 376: 368: 366: 363: 359: 355: 352: 347: 343: 337: 335: 330: 326: 322: 320: 316: 311: 309: 305: 301: 297: 293: 286:(Switzerland) 285: 280: 273: 271: 269: 265: 264:amateur radio 261: 257: 253: 245: 241: 236: 228: 220: 213: 211: 209: 205: 201: 197: 193: 189: 185: 180: 178: 174: 169: 168:around 1920. 167: 162: 158: 157:G. W. Pickard 154: 150: 146: 142: 138: 134: 130: 125: 122: 118: 114: 110: 106: 102: 97: 95: 91: 87: 83: 79: 75: 67: 62: 55: 51: 46: 40: 33: 19: 5752:Multiplexing 5627:Transmission 5592:Nikola Tesla 5582:Henry Sutton 5537:Samuel Morse 5467:Robert Hooke 5432:Amos Dolbear 5367:John Bardeen 5286: 5266:Telautograph 5170:Mobile phone 5125:Edholm's law 5108:social media 5041:Broadcasting 4982: 4976: 4968: 4960: 4952: 4940:. Retrieved 4897: 4888: 4880: 4873: 4804: 4798: 4785: 4776: 4757: 4735: 4726: 4715: 4704:. Retrieved 4699: 4689: 4680: 4675: 4664: 4653: 4642: 4618: 4611: 4608: 4603: 4593: 4586: 4583: 4578: 4569: 4564: 4553:. Retrieved 4542: 4531:. Retrieved 4527:the original 4522: 4512: 4501:. Retrieved 4496: 4483: 4472:. Retrieved 4460:10366/158938 4442: 4438: 4428: 4413:. Retrieved 4408: 4404: 4394: 4383: 4371:. Retrieved 4366: 4362: 4352: 4314: 4308: 4288: 4281: 4269:. Retrieved 4257: 4249: 4244: 4233:. Retrieved 4228: 4224: 4202: 4196: 4182: 4175: 4170:, pp. 96–101 4166: 4160: 4152: 4147: 4136:. Retrieved 4131: 4127: 4117: 4106:. Retrieved 4101: 4064: 4038: 4031: 4022: 4016: 4002: 3995: 3984:. Retrieved 3980:the original 3975: 3965: 3946: 3917: 3910: 3890: 3880: 3875:, p. 57 3868: 3858: 3826:. Retrieved 3821: 3811: 3795:. Retrieved 3790: 3780: 3769:. Retrieved 3764: 3724: 3717: 3712:, p. 48 3705: 3681: 3674: 3664: 3658: 3647: 3627: 3620: 3609: 3598:. Retrieved 3593: 3589: 3579: 3565: 3558: 3544: 3537: 3526:. Retrieved 3521: 3490:. Retrieved 3486:the original 3481: 3471: 3460: 3453: 3439: 3431: 3420:. Retrieved 3415: 3368: 3360: 3349:. Retrieved 3344: 3340: 3313: 3302:. Retrieved 3298:HyperPhysics 3297: 3287: 3267: 3233:. Retrieved 3228: 3200:. Retrieved 3189: 3169: 3162: 3152: 3122: 3115: 3107: 3102: 3091:. Retrieved 3086: 3073: 3059: 3052: 3041:. Retrieved 3039:. Ian Purdie 3036: 3026: 3015: 3004: 2994: 2989: 2983: 2973: 2966: 2962: 2955: 2951: 2944: 2940: 2927: 2916: 2912: 2905: 2898: 2890: 2882: 2866: 2861: 2852: 2841: 2830: 2817: 2804: 2793:. Retrieved 2763: 2759: 2749: 2712: 2698: 2694: 2680: 2676: 2655: 2641: 2627: 2619: 2605: 2598: 2578: 2546: 2539: 2528:. Retrieved 2524:the original 2513: 2483: 2466: 2453: 2441: 2428: 2408: 2378: 2371: 2360:. Retrieved 2340: 2336: 2325: 2305: 2280:. Retrieved 2268:10366/158938 2250: 2240: 2231: 2225: 2214:. Retrieved 2184: 2180: 2169: 2149: 2142: 2122: 2085: 2078: 2058: 2026: 1990: 1958: 1896:Radio portal 1871: 1801: 1707: 1641: 1638: 1621: 1592: 1579:audio signal 1567:loudspeakers 1560: 1544: 1516:forward bias 1512: 1501: 1493:lead pencils 1489:razor blades 1484: 1439: 1429: 1426: 1377:carrier wave 1373:audio signal 1360:The crystal 1359: 1343: 1337: 1330:audio signal 1326:carrier wave 1312: 1272: 1265: 1257: 1244: 1242: 1224: 1220: 1212: 1199: 1171: 1151: 1125: 1109: 1066: 1047: 1035:ferrite core 1023: 966: 959: 952: 930: 900:counterpoise 889: 876:fire escapes 865: 845:AM broadcast 826: 802: 785:AM broadcast 746: 682:audio signal 621: 581: 573: 569:Liberty ship 551: 548: 544: 540: 523: 519:World War II 489:Anzio, Italy 482: 475: 458:vacuum tubes 455: 447:tunnel diode 420: 411: 399:Westinghouse 387: 382: 378: 372: 338: 323: 312: 289: 268:broadcasting 249: 243: 196:AM broadcast 181: 173:vacuum tubes 170: 126: 98: 77: 73: 71: 5952:NPL network 5664:Radio waves 5602:Alfred Vail 5512:Hedy Lamarr 5497:Dawon Kahng 5457:Elisha Gray 5417:Yogen Dalal 5342:Nasir Ahmed 5276:Teleprinter 5140:Heliographs 4807:(1): 31–??. 4405:Radio-Craft 2947:: 299–300. 2906:Radio Revue 2736:"Receiver," 2669:psilomelane 2613:, 110, 268. 1914:Demodulator 1845: 1925 1827: 1924 1809: 1920 1787: 1917 1714:vacuum tube 1708:During the 1628:transformer 1624:loudspeaker 1612:selectivity 1457:molybdenite 1445:iron pyrite 1365:demodulates 1209:selectivity 1205:transformer 1167:selectivity 1054:capacitance 957:capacitance 880:barbed wire 859:or ferrite 833:alternating 829:radio waves 749:transmitter 721:loudspeaker 678:demodulates 636:radio waves 559:Later years 506:pencil lead 502:razor blade 397:, owned by 302:running at 298:as well as 284:Monteceneri 274:Early years 252:discoveries 153:demodulator 109:loudspeaker 78:crystal set 18:Crystal set 6085:Categories 5998:Antarctica 5957:Toasternet 5879:Television 5362:Paul Baran 5294:Television 5278:(teletype) 5271:Telegraphy 5249:transistor 5227:Phryctoria 5197:Photophone 5175:Smartphone 5165:Mass media 4942:2016-09-27 4706:2010-05-28 4555:2010-05-27 4533:2010-05-28 4503:2009-12-07 4474:2010-03-28 4415:2010-03-14 4235:2010-03-06 4138:2010-02-10 4108:2009-12-07 3986:2010-02-07 3828:2010-08-19 3804:Stay Tuned 3797:2010-07-19 3771:2009-12-07 3600:2010-01-18 3528:2009-12-07 3492:2010-02-27 3422:2010-02-07 3379:0852967926 3351:2010-01-18 3304:2009-12-06 3242:Stay Tuned 3235:2010-05-28 3202:2010-01-18 3180:0521289033 3133:1922013846 3093:2009-12-07 3043:2009-12-05 2995:Radio News 2990:Radio News 2984:Radio News 2891:Radio News 2795:2010-01-19 2665:Strasbourg 2530:2022-02-20 2474:, Klase's 2362:2010-01-19 2282:2010-03-14 2216:2010-01-19 1935:References 1697:transistor 1652:modulation 1644:rectifiers 1401:rectifying 1369:modulation 1334:modulation 1174:resistance 1027:inductance 964:inductance 872:bedsprings 841:wavelength 761:microwatts 686:modulation 576:Boy Scouts 495:signal of 439:zinc oxide 427:Oleg Losev 417:Crystodyne 391:Pittsburgh 351:demodulate 332:30, 1906, 327:physicist 317:, such as 270:industry. 256:Morse code 177:Boy Scouts 129:rectifying 64:1970s-era 5982:Americas 5971:Locations 5942:Internet2 5703:Bandwidth 5407:Vint Cerf 5304:streaming 5282:Telephone 5222:Semaphore 5113:streaming 2730:In 1907, 2719:In 1906, 2470:Al Klase 1588:impedance 1530:Earphones 1524:I-V curve 1419:called a 1417:capacitor 1233:resonated 1225:secondary 1159:bandwidth 1154:frequency 1116:impedance 1070:resonance 1050:reactance 995:π 945:impedance 941:resonator 937:capacitor 853:long wire 769:picowatts 765:nanowatts 733:capacitor 659:capacitor 647:frequency 630:in which 588:hobbyists 292:spark gap 262:by early 200:shortwave 117:amplifier 105:earphones 6050:Category 5937:Internet 5927:CYCLADES 5844:Ethernet 5794:Concepts 5718:terminal 5669:wireless 5492:Bob Kahn 5335:Pioneers 5160:Internet 5051:Cable TV 4902:Archived 4549:"Diodes" 4469:44288637 4317:, p. 282 4155:, p. 318 3888:(2001). 3416:Skywaves 3320:, p. 144 2742:bornite. 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