50:
531:
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.
1766:
1684:) 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-
1784:
553:
1842:
1751:
1342:
1174:
1806:
1182:
2674:"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."
1129:
596:
805:
1739:
1076:
1715:
268:
909:
1854:
1297:
604:
2676:(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.)
1824:
208:
1543:
458:
1278:
6035:
1286:
1085:
1165:, 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.
6045:
216:
654:, 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.
1524:
6024:
1125:
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.
1511:. 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
34:
6055:
717:
1727:
859:, 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
1244:, 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.
535:
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.
370:. 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,
1619:
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
1061:
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
1013:
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
936:
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
895:
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
530:
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),
320:
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
1607:
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
1416:
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
517:
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
827:
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
1124:
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
534:
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
1502:
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
401:
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
1425:
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.
1325:) 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.
1574:
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
224:
497:
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
1534:
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
1259:, 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".
1216:) 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
1056:
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
1251:
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.
377:
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.
1579:, often 75 Ω, and required more current than a crystal radio could supply. Therefore, the type used with crystal set radios (and other sensitive equipment) was wound with more turns of finer wire giving it a high impedance of 2000–8000 Ω.
1224:
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
1112:) is usually lower than the impedance of the receiver's tuned circuit (thousands of ohms at resonance), and also varies depending on the quality of the ground attachment, length of the antenna, and the frequency to which the receiver is tuned.
567:
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.
152:
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
2692:
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:
1262:
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.
1593:
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
772:/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
1145:
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
1412:
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.
488:
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
3448:
1688:
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".
337:
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
1598:
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
1093:"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.
1115:
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
2730:
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
4250:"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."
112:
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.
887:(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
328:
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
1107:
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
57:
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.
353:
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.
449:
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.
932:, similar to a tuning fork. Electric charge, induced in the antenna by the radio waves, flows rapidly back and forth between the plates of the capacitor through the coil. The circuit has a high
1008:
73:, popular in the early days of radio. It uses only the power of the received radio signal to produce sound, needing no external power. It is named for its most important component, a
579:
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
1879:
1628:
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.
243:
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
1765:
1631:
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
1400:, the peaks of which trace out the audio signal, so it can be converted to sound by the earphone, which is connected to the detector. The rectified current from the detector has
4601:
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...
740:
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
1404:
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
168:
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.
1682:
792:
Commercial passive receiver development was abandoned with the advent of reliable vacuum tubes around 1920, and subsequent crystal radio research was primarily done by
1783:
2162:
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
1841:
1331:
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.
4347:
2712:(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.
2690:(4) : 556–563. In these experiments, Braun applied a cat whisker to various semiconducting crystals and observed that current flowed in only one direction.
1853:
469:(detectors) capable of rectification. Crystal radios have been improvised using detectors made from rusty nails, corroded pennies, and many other common objects.
3353:
Marconi used carborundum detectors for a time around 1907 in his first commercial transatlantic wireless link between
Newfoundland, Canada and Clifton, Ireland.
1247:
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
255:
experimenters. As electronics evolved, the ability to send voice signals by radio caused a technological explosion around 1920 that evolved into today's radio
398:
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.
4921:
1701:
era before 1920, crystal receivers were "state of the art", and sophisticated models were produced. After 1920 crystal sets became the cheap alternative to
5299:
1049:. 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
1750:
1726:
1417:
operator dragged the wire across the crystal surface until a radio station or "static" sounds were heard in the earphones. Alternatively, some radios
461:"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.
1499:) 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.
891:
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
4720:
164:. With this technological advance, crystal sets became obsolete for commercial use but continued to be built by hobbyists, youth groups, and the
1714:
6007:
5979:
5974:
4999:
271:
Type 'C' Form 'A' twin detector crystal radio set, manufactured by
British Thomson Houston Ltd. in 1924, kept at the Museum of the radio -
2612:
Long distance transoceanic stations of the era used wavelengths of 10,000 to 20,000 meters, correstponding to frequencies of 15 to 30 kHz.
1823:
1495:
is used for the detector, which is much more reliable than a crystal detector and requires no adjustments. Germanium diodes (or sometimes
708:
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
480:
during the spring of 1944, powered personal radio receivers were strictly prohibited as the
Germans had equipment that could detect the
563:
While it never regained the popularity and general use that it enjoyed at its beginnings, the crystal radio circuit is still used. The
88:
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
796:
and hobbyists. Many different circuits have been used. The following sections discuss the parts of a crystal radio in greater detail.
3960:
4914:
1177:
Inductively-coupled circuit with impedance matching. This type was used in most quality crystal receivers in the early 20th century.
784:
era could be received at hundreds of miles, and crystal receivers were even used for transoceanic communication during that period.
685:
to its audio frequency modulation. The detector's audio frequency output is converted to sound by the earphone. Early sets used a "
3110:
544:
had become available at the time, but were expensive. Once those radios dropped in price, the rocket radio declined in popularity.
395:
3466:
3157:
1603:
of the receiver. The piezoelectric earphone's higher resistance, in parallel with its capacitance of around 9 pF, creates a
900:
receivers are grounded adequately through their power cords, which are in turn attached to the earth through the building wiring.
6001:
2678:
Braun also states that he had been researching the conductive properties of semiconductors since 1874. See: Braun, F. (1874)
1570:
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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5986:
5966:
5768:
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2083:
2024:
1988:
1805:
4908:
4852:
Ian L. Sanders. Tickling the
Crystal – Domestic British Crystal Sets of the 1920s; Volumes 1–5. BVWS Books (2000–2010).
4581:
6079:
2508:
2480:
1432:(lead sulfide) was the most common crystal used, but various other types of crystals were also used, the most common being
611:
A crystal radio can be thought of as a radio receiver reduced to its essentials. It consists of at least these components:
391:
5133:
2490:
748:, if it is more than a few miles from the receiver the power received by the antenna is very small, typically measured in
6058:
5991:
5837:
4507:
3140:
1014:
slide along the coil, thereby introducing a larger or smaller number of turns of the coil into the circuit, varying the
964:
219:
Greenleaf
Whittier Pickard's US Patent 836,531 "Means for receiving intelligence communicated by electric waves" diagram
5763:
2776:
538:
The rocket radio was available in several rocket styles, as well as other styles that featured the same basic circuit.
1738:
732:, consisting of a piece of galena with a thin wire in contact with it on a part of the crystal, making a diode contact
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4286:
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that allowed current to flow better in one direction than in the opposite direction. Modern crystal sets use modern
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4992:
3961:"Practical considerations, helpful definitions of terms and useful explanations of some concepts used in this site"
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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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3366:
3167:
3120:
2912:
4903:
Zinc
Negative Resistance RF Amplifier for Crystal Sets and Regenerative Receivers Uses No Tubes or Transistors
2891:
In 1924, Losev's (also spelled "Lossev" and "Lossew") research was publicized in several French publications:
2661:
2318:
crystal detectors were used in receivers in greater numbers than any other type of detector after about 1907.
5773:
2709:
1147:
720:
Pictorial diagram from 1922 showing the circuit of a crystal radio. This common circuit did not use a tuning
19:
This article is about unpowered radio receivers. For crystal-controlled oscillators (as used in radios), see
4423:
2235:
1345:
Circuit with detector bias battery to improve sensitivity and buzzer to aid in adjustment of the cat whisker
832:
of the radio waves they are receiving. Since the length of the waves used with crystal radios is very long (
642:
from all the radio signals received by the antenna. The tuned circuit consists of a coil of wire (called an
6048:
5809:
5706:
5249:
5044:
5016:
3851:. US: Prepared by US National Bureau of Standards, United States Army Signal Corps. 1922. pp. 421–425.
888:
387:
228:
3746:
2636:"Construction and Operation of a Simple Homemade Radio Receiving Outfit, Bureau of Standards Circular 120"
1515:. The battery did not power the radio, but only provided the biasing voltage which required little power.
1226:
422:
to various kinds of crystals for the manufacturing of radio detectors. The result was astonishing: with a
6038:
5545:
4985:
4478:
2102:
4576:
can be approximately doubled by connecting a battery across its terminals to give approximately 0.2 volt
4276:
6114:
6104:
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5897:
5819:
5758:
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3021:
1141:
One of the drawbacks of crystal sets is that they are vulnerable to interference from stations near in
736:
As a crystal radio has no power supply, the sound power produced by the earphone comes solely from the
322:
145:
3068:
883:
which develop their output voltage with respect to ground. The receiver thus requires a connection to
148:. Crystal radios were the first widely used type of radio receiver, and the main type used during the
49:
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received a patent for his R.F. detector consisting of tellurium and silicon. See: Louis W. Austin,
1369:
686:
445:
A crystodyne could be produced under primitive conditions; it could be made in a rural forge, unlike
42:
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552:
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4608:
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.
402:
pasteboard containers such as oatmeal boxes, which became a common foundation for homemade radios.
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4668:
4557:
4112:
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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.
1337:
A bypass capacitor is used to remove the radio frequency carrier pulses, leaving the audio signal
1189:
In more sophisticated crystal receivers, the tuning coil is replaced with an adjustable air core
1099:
An important principle used in crystal radio design to transfer maximum power to the earphone is
1038:
288:
101:
4825:
Radio Hook-ups: A Reference and Record Book of Circuits Used for Connecting Wireless Instruments
3574:
3429:
Radio hook-ups: a reference and record book of circuits used for connecting wireless instruments
2823:
1476:. Crystal radios have also been improvised from a variety of common objects, such as blue steel
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2218:
2165:
2110:
2073:
2014:
1978:
1912:
1504:
1422:
1341:
1185:
Amateur-built crystal receiver with "loose coupler" antenna transformer, Belfast, around 1914
1162:
1050:
317:
280:
248:
196:
165:
137:
109:
5024:
2921:
English-language publications noticed the French articles and also publicized Losev's work:
2046:
1946:
1173:
5605:
5565:
5535:
5292:
5227:
5049:
4657:
2756:
2720:
2649:
2177:
1576:
1307:
1181:
1046:
933:
884:
828:
with crystal sets are most effective when their length is close to a multiple of a quarter-
729:
372:
Construction and Operation of a Two-Circuit Radio Receiving Equipment With Crystal Detector
176:
172:
129:
4635:
4334:
3968:
3654:
Radio Communication Pamphlet No. 40: The Principles Underlying Radio Communication, 2nd Ed
3640:
3602:
3559:
3306:
3053:
8:
5615:
5555:
5314:
5276:
5074:
5059:
4870:
4725:
3400:
3282:
2599:
1698:
1600:
1551:
1492:
1393:
1381:
1197:
1155:
841:
821:
781:
698:
682:
678:
431:
374:, which was published the same year and is still frequently built by enthusiasts today.
342:
192:
149:
4824:
4817:
4810:
4170:
4026:
3990:
3669:
3427:
2760:
2615:
2181:
1128:
760:
at the antenna can be heard. Crystal radios can receive such weak signals without using
160:
Around 1920, crystal sets were superseded by the first amplifying receivers, which used
5842:
5799:
5730:
5600:
5530:
5505:
5440:
5287:
5008:
4453:
3992:
Practical Wireless Telegraphy: A complete text book for students of radio communication
3538:
3534:
Radio Reception: A simple and complete explanation of the principles of radio telephony
3474:
2341:
2261:
1611:
Although the low power produced by crystal radios is typically insufficient to drive a
1256:
1117:
1100:
1041:
contributes to determining the circuit's resonant frequency. Antennas usually act as a
1019:
938:
809:
804:
651:
595:
325:
filed a patent for a silicon crystal detector, which was granted on November 20, 1906.
154:
20:
4831:
2635:
5882:
5804:
5718:
5701:
5664:
5510:
5340:
5309:
5175:
5069:
4970:
4882:
Section 1 links to "Crystal Radio Set Systems: Design, Measurements and Improvement".
4837:
PA Kinzie (1996). Crystal Radio: History, Fundamentals, and Design. Xtal Set Society.
4750:
4282:
4058:
3939:
3911:
3884:
3722:
3679:
3621:
3362:
3261:
3163:
3116:
2859:
2772:
2572:
2540:
2402:
2372:
2299:
2193:
2143:
2116:
2079:
2052:
2020:
1984:
1952:
1892:
1477:
1385:
1241:
1205:
741:
292:
54:
5550:
4457:
3257:
Planar Microwave Engineering: A practical guide to theory, measurement, and circuits
2345:
2265:
2075:
Revolution in Miniature: The history and impact of semiconductor electronics, 2nd Ed
5887:
5847:
5827:
5794:
5723:
5681:
5595:
5450:
5435:
5410:
5385:
5345:
5195:
5054:
5039:
4902:
4443:
4435:
2997:
2939:
Victor Gabel (October 1 & 8, 1924) "The crystal as a generator and amplifier,"
2764:
2660:, a manganese oxide ore, as an R.F. detector: Ferdinand Braun (December 27, 1906)
2333:
2251:
2243:
2185:
2106:
1917:
1907:
1586:
1583:
1528:
1409:
1350:
1221:
1075:
880:
824:
694:
662:
631:
620:
541:
507:
481:
267:
240:
133:
93:
74:
70:
4887:
4086:
2112:
Crystal fire: the invention of the transistor and the birth of the information age
1643:
factor of only 30% by voltage at peaks, no more than 9% of received signal power (
1372:". The point of contact between the wire and the crystal acted as a semiconductor
1103:. The maximum power is transferred from one part of a circuit to another when the
1030:
is moved into and out of the coil, thereby varying the inductance by changing the
465:
In addition to mineral crystals, the oxide coatings of many metal surfaces act as
5515:
5370:
5138:
5113:
5101:
4894:
4847:
4841:
3553:
2814:, US patent no. 836,531 (filed: August 30, 1906 ; issued: November 20, 1905)
2494:
2484:
1636:
1604:
1453:
1401:
1311:
1296:
1289:
1248:
1121:
908:
892:
777:
773:
765:
616:
485:
439:
284:
188:
180:
27:
3047:
2593:
2512:
2477:
522:(or other allied stations) were not strong enough to be received on such a set.
302:
In the early 20th century, various researchers discovered that certain metallic
5713:
5585:
5560:
5520:
5490:
5365:
5200:
5153:
5128:
5086:
4439:
2716:
U. S. patent 837,616 (filed: March 23, 1906 ; issued: December 4, 1906).
2694:
2487:
2337:
2247:
1571:
1566:. Both magnetic poles were close to a steel diaphragm of the speaker. When the
1496:
1397:
1377:
1237:
1104:
697:
was the component that gave crystal radios their name. Modern sets use modern
603:
346:
38:
4515:
207:
6073:
5862:
5635:
5625:
5540:
5430:
5425:
5415:
5400:
5222:
5081:
4818:
The Wireless Experimenter's Manual: Incorporating how to Conduct a Radio Club
3874:
3848:
The Principles Underlying Radio Communication, 2nd Ed., Radio pamphlet no. 40
3532:
2811:
2798:
2724:
2713:
2460:
1590:
1563:
1536:
1508:
1485:
1217:
1190:
1027:
921:
913:
793:
745:
725:
658:
639:
499:
466:
313:
4410:
3792:
3230:
3159:
Revolution in Miniature: The History and Impact of Semiconductor Electronics
2277:
5740:
5580:
5525:
5455:
5420:
5355:
5254:
5244:
5096:
4938:
4537:
2801:, US patent no. 755,840 (filed: September 30, 1901; issued: March 29, 1904)
1884:
1567:
1365:
1361:
1353:
1318:
1314:
1023:
849:
845:
833:
701:, although some hobbyists still experiment with crystal or other detectors.
670:
557:
514:
435:
350:
256:
4962:
3880:
The science of radio: with MATLAB and Electronics Workbench demonstrations
5940:
5590:
5500:
5485:
5445:
5405:
5264:
4741:
Polyakov, V. T. (2001). "3.3.2 Питание полем мощных станций".
3668:
Hausmann, Erich; Goldsmith, Alfred Norton; Hazeltine, Louis Alan (1922).
2745:"The work of Jagadis Chandra Bose: 100 years of millimeter-wave research"
2657:
2464:
2166:"The work of Jagadis Chandra Bose: 100 years of millimeter-wave research"
1902:
1702:
1616:
1612:
1555:
1542:
1445:
1433:
1193:
1161:
The crystal detector worsened the problem, because it has relatively low
1042:
945:
897:
868:
864:
769:
737:
709:
584:
494:
490:
457:
446:
272:
191:
bands, but strong signals are required. The first crystal sets received
184:
161:
141:
97:
4946:
4448:
3823:
2727:
US patent 846,081 (filed: Oct. 27, 1906 ; issued: March 5, 1907).
2256:
1859:
Polish Detefon brand radio, 1930–1939, using a "cartridge" type crystal
1771:
Marconi Type 106 crystal receiver used for transatlantic communication,
840:
or 597–1,857 feet long) the antenna is made as long as possible, from a
5945:
5652:
5350:
5259:
5215:
5185:
5163:
4583:
Manual of Wireless Telegraphy for the Use of Naval Electricians, Vol. 2
2653:
1685:
1640:
1357:
1322:
1285:
1015:
952:
829:
817:
674:
666:
624:
427:
415:
379:
339:
244:
4832:
Construction and operation of a simple homemade radio receiving outfit
2768:
2189:
368:
Construction and Operation of a Simple Homemade Radio Receiving Outfit
5930:
5395:
5210:
4977:
1632:
1512:
1405:
1389:
1236:
between the coils, by physically separating them so that less of the
1142:
1058:
929:
925:
860:
761:
749:
721:
647:
635:
564:
383:
179:
designs have been built. They can be designed to receive almost any
117:
105:
1589:, which are much more sensitive and also smaller. They consist of a
1310:
radio signal from the tuned circuit. The rapid oscillations are the
1277:
1084:
5925:
5915:
5832:
5657:
5480:
2394:
1732:
Australian signallers using a Marconi Mk III crystal receiver, 1916
1595:
1368:. In early receivers, a type of crystal detector often used was a "
1151:
856:
757:
753:
705:
643:
576:
503:
215:
89:
4864:
A website with lots of information on early radio and crystal sets
2434:
1523:
5920:
5905:
5123:
2812:"Means for receiving intelligence communicated by electric waves"
1897:
1461:
1457:
1441:
423:
303:
296:
140:, in his microwave optics experiments. They were first used as a
121:
2900:
I. Podliasky (May 25, 1924) (Crystal detectors as oscillators),
2613:
33:
26:"Crystal set" redirects here. For the Australian rock band, see
5950:
5910:
5232:
4848:
The Design and Implementation of Low-Power CMOS Radio Receivers
3965:
Crystal Radio Set Systems: Design, Measurement, and Improvement
3008:
1756:
1559:
1481:
1429:
716:
690:
411:
334:
330:
307:
78:
2242:. New York: Inst. of Electrical and Electronic Engineers: 64.
239:
Crystal radio was invented by a long, partly obscure chain of
223:
77:, originally made from a piece of crystalline mineral such as
5935:
5872:
5180:
2824:
http://www.crystalradio.net/crystalplans/xximages/nsb_120.pdf
2016:
Gonzo gizmos: Projects and devices to channel your inner geek
1847:
German Heliogen brand radio showing "basket-weave" coil, 1935
1720:
Soldier listening to a crystal radio during World War I, 1914
1373:
1037:
The antenna is an integral part of the tuned circuit and its
1022:
is used to tune the circuit. Some modern crystal sets use a
837:
689:" consisting of a small piece of crystalline mineral such as
580:
477:
125:
82:
4878:
4749:] (in Russian). Moscow: Knizhnai͡a palata. p. 256.
3657:. United States Bureau of Standards. 1922. pp. 309–311.
2835:
http://www.crystalradio.net/crystalplans/xximages/nbs121.pdf
2695:
Foundation for German communication and related technologies
1550:
The early earphones used with wireless-era crystal sets had
438:. After the first experiments, Losev built regenerative and
5877:
4955:
http://uv201.com/Radio_Pages/Pre-1921/crystal_detectors.htm
3995:(Revised ed.). New York: Wireless Press, Inc. p.
2447:
1364:
which represents the sound waves) from the radio frequency
419:
4434:(4). Inst. of Electrical and Electronic Engineers: 64–65.
4319:
3861:
3698:
3667:
2422:
1620:
with the higher impedance of the driving antenna circuit.
896:
little current flows in the antenna/ground circuit. Also,
556:
Crystal radio used as a backup receiver on a World War II
4888:
Semiconductor archeology or tribute to unknown precursors
4863:
4788:
3424:
a list of circuits from the wireless era can be found in
2048:
The Design and Implementation of Low Power CMOS Receivers
1507:
voltage was applied across the detector by a battery and
1109:
572:
519:
3052:. New York: Scientific American Publishing Co. pp.
2598:. New York: Scientific American Publishing Co. pp.
1615:, some homemade 1960s sets have used one, with an audio
1212:) attached to the antenna and ground and the other (the
1154:) compared to modern receivers, giving the receiver low
1034:(this eliminated the less reliable mechanical contact).
4611:. New York: Wireless Press, Inc. pp. 134–135, 140.
3530:
3156:
Braun, Agnès; Braun, Ernest; MacDonald, Stuart (1982).
2398:
The Cool Gent: The Nine Lives of Radio Legend Herb Kent
2101:
1705:
radios, used in emergencies and by youth and the poor.
1255:
The antenna coupling transformer also functioned as an
1132:
Direct-coupled circuit with taps for impedance matching
816:
The antenna converts the energy in the electromagnetic
768:, which can detect sounds with an intensity of only 10
4842:
The Design of CMOS Radio-Frequency Integrated Circuits
4278:
The Design of CMOS Radio-Frequency Integrated Circuits
4220:(4). New York: Popular Science Publishing Co.: 206–209
3933:
3740:
3738:
2614:
Morecroft, John H.; A. Pinto; Walter A. Curry (1921).
2395:
Kent, Herb; David Smallwood; Richard M. Daley (2009).
2044:
1562:
about which was a coil of wire which formed a second
1053:
in the coil) to form the tuned circuit with the coil.
724:, but used the capacitance of the antenna to form the
4747:
Receiving techniques. Simple receivers for AM signals
3671:
Radio Phone Receiving: A Practical Book for Everybody
2705:
Other inventors who patented crystal R.F. detectors:
2571:. The Alternative Electronics Press. pp. 20–23.
2071:
1759:-A crystal set used by US Signal Corps in World War I
1649:
1045:, as antennas shorter than a quarter-wavelength have
967:
912:
The earliest crystal receiver circuit did not have a
855:
Serious crystal radio hobbyists use "inverted L" and
4514:. Kev's Vintage Radio and Hi-Fi page. Archived from
3361:. Institution of Electrical Engineers. p. 191.
3142:
Wireless Telegraph Construction for Amateurs, 3rd Ed
2749:
IEEE Transactions on Microwave Theory and Techniques
2170:
IEEE Transactions on Microwave Theory and Techniques
1874:
1503:
crystal detectors, such as silicon carbide, a small
502:" by the popular press, and they became part of the
96:(because a crystal set has insufficient power for a
4874:
History and Technical Information on Crystal Radios
3735:
3432:. US: The Norman W. Henley publishing co. pp.
3155:
1558:of the period. Each earpiece contained a permanent
41:, with earphones. The device at top is the radio's
4743:Техника радиоприёма. Простые приёмники АМ сигналов
2975:, pp. 294–295, 431 (September 1924). See also the
2638:. U.S. Government Printing Office. April 24, 1922.
2536:22 Radio and Receiver Projects for the Evil Genius
2115:. US: W. W. Norton & Company. pp. 19–21.
1980:22 Radio and Receiver Projects for the Evil Genius
1676:
1003:{\displaystyle f={\frac {1}{2\pi {\sqrt {LC}}}}\,}
1002:
879:The wire antennas used with crystal receivers are
434:phenomenon, decades before the development of the
211:A family listening to a crystal radio in the 1920s
4620:
4618:
4586:. Washington DC: US Naval Institute. p. 131.
2950:O. Lossev (October 1924) "Oscillating crystals,"
2368:The Third Element: A Brief History of Electronics
1983:. US: McGraw-Hill Professional. pp. 40, 44.
1321:(the sound) is contained in the slow variations (
6071:
4827:. The Norman W. Henley publishing co.; 67 pages.
4736:
4734:
4281:. UK: Cambridge University Press. pp. 4–6.
4123:(6). New York: Doubleday Page & Co.: 480–483
3938:. New York: John Wiley & Sons. p. 269.
3903:
2682:(On current conduction through metal sulfides),
2425:, Birmingham, Alabama, US. Retrieved 2010-01-18.
1376:. The cat whisker detector constituted a crude
812:, a common wire antenna used with crystal radios
756:. In modern crystal sets, signals as weak as 50
575:in the 1920s, and again in the 1950s. Recently,
235:" taught Americans how to build a crystal radio.
4358:(6). New York: The Gage Publishing Co.: 393–394
4330:
4328:
4168:
3910:. UK: Cambridge University Press. p. 218.
3326:"Jack Binn's 10 commandments for the radio fan"
3260:. UK: Cambridge Univ. Press. pp. 297–304.
1292:used in modern crystal radios (about 3 mm long)
4615:
4488:. Prof. Kenneth Kuhn website, Univ. of Alabama
4411:Crystal Plans and Circuits, Stay Tuned website
3756:. Prof. Kenneth Kuhn website, Univ. of Alabama
3497:
3495:
3493:
3491:
3162:. Cambridge University Press. pp. 11–12.
3078:. Prof. Kenneth Kuhn website, Univ. of Alabama
2680:"Ueber die Stromleitung durch Schwefelmetalle"
2662:"Ein neuer Wellenanzeiger (Unipolar-Detektor)"
2298:. UK: Cambridge University Press. p. 44.
1951:. US: McGraw-Hill Professional. pp. 7–9.
430:) crystal he gained amplification. This was a
92:of wire, a capacitor, a crystal detector, and
45:. A second pair of earphone jacks is provided.
16:Simple radio receiver circuit for AM reception
4993:
4919:
4834:", Bureau of Standards, C-120: Apr. 24, 1922.
4731:
4670:The Principles Underlying Radio Communication
4559:The Principles Underlying Radio Communication
4031:. London: Longman's Green & Co. pp.
3934:Alley, Charles L.; Kenneth W. Atwood (1973).
3841:
3839:
3837:
3835:
3833:
3831:
2856:A history of the world semiconductor industry
2078:. UK: Cambridge Univ. Press. pp. 11–12.
1972:
1970:
1968:
452:
144:for radio communication reception in 1902 by
4846:Derek K. Shaeffer and Thomas H. Lee (1999).
4325:
4315:
4313:
4237:H. V. Johnson, A Vacation Radio Pocket Set.
3824:Crystal Radios and Plans, Stay Tuned website
3711:Hayt, William H.; Kemmerly, Jack E. (1971).
3710:
3531:Marx, Harry J.; Adrian Van Muffling (1922).
3289:. Dept. of Physics, Georgia State University
2539:. US: McGraw-Hill Professional. p. 39.
2526:
2401:. US: Chicago Review Press. pp. 13–14.
2332:(3). US: Institute of Radio Engineers: 184.
1829:Swedish "box" crystal radio with earphones,
6008:Global telecommunications regulation bodies
4203:
4201:
3488:
3336:(5). New York: Modern Publishing Co.: 42–43
3045:
3039:
2845:Bondi, Victor."American Decades: 1930–1939"
2620:. New York: John Wiley & Sons. p.
2591:
2560:
2558:
2556:
2532:
2437:midnightscience.com . Retrieved 2010-01-18.
2045:Schaeffer, Derek K.; Thomas H. Lee (1999).
2040:
2038:
2036:
1976:
1356:the radio frequency signal, extracting the
764:only due to the great sensitivity of human
693:with a fine wire touching its surface. The
525:
6044:
5000:
4986:
4950:How to build a sensitive crystal receiver?
4175:. US: Government Printing Office. p.
4046:
4044:
4042:
3828:
3207:
3205:
3203:
3201:
2664:(A new R.F. detector (one-way detector)),
2320:Marriott, Robert H. (September 17, 1915).
2287:
2285:
1965:
1472:) crystal-to-crystal junction trade-named
4920:Asquin, Don; Rabjohn, Gord (April 2012).
4470:
4447:
4400:(1). New York: Radcraft Publications: 730
4387:
4310:
4080:
4078:
4076:
4074:
3804:
3798:
3354:
3347:
3134:
3132:
2255:
2097:
2095:
1554:that worked in a way similar to the horn
1484:, rusty needles, and pennies In these, a
1240:of one intersects the other, reduces the
1136:
999:
607:Circuit diagram of a simple crystal radio
599:Block diagram of a crystal radio receiver
513:In some German-occupied countries during
310:, could be used to detect radio signals.
4939:http://www.crystal-radio.eu/endiodes.htm
4915:Details of crystals used in crystal sets
4740:
4565:
4499:
4320:Hausmann, Goldsmith & Hazeltine 1922
4207:
4198:
3929:
3927:
3862:Hausmann, Goldsmith & Hazeltine 1922
3773:
3699:Hausmann, Goldsmith & Hazeltine 1922
3585:(10). New York: Clarke Publishing Co.: 9
3551:
3513:. Kenneth Kuhn website, Univ. of Alabama
3394:
3392:
3390:
3388:
3386:
3384:
3382:
3380:
3378:
3319:
3317:
3315:
2568:The New Radio Receiver Building Handbook
2564:
2553:
2319:
2142:. US: John Wiley and Sons. p. 333.
2072:Braun, Ernest; Stuart MacDonald (1982).
2033:
2019:. US: Chicago Review Press. p. 85.
1623:
1541:
1522:
1340:
1295:
1284:
1276:
1180:
1172:
1127:
944:of the tuned circuit, determined by the
907:
803:
715:
677:). The crystal detector functions as a
602:
594:
551:
456:
418:was experimenting with applying voltage
266:
233:A simple homemade radio receiving outfit
222:
214:
206:
48:
37:Swedish crystal radio from 1922 made by
32:
4963:http://www.sparkmuseum.com/DETECTOR.HTM
4590:
4579:
4421:
4348:"Radio Apparatus – What is it made of?"
4113:"The Selective Double-Circuit Receiver"
4050:
4039:
4028:Textbook on Wireless Telegraphy, Vol. 1
4024:
3620:. US: Forgotten Books. pp. 18–22.
3613:
3558:. New York: Funk and Wagnalls. p.
3425:
3198:
2982:. (It was Hugo Gernsback, publisher of
2742:
2506:
2500:
2390:
2388:
2291:
2282:
2233:
2227:
2163:
2008:
2006:
2004:
2002:
2000:
1948:Old Time Radios! Restoration and Repair
583:(long distance reception) and building
6072:
5007:
4778:
4604:
4346:Hirsch, William Crawford (June 1922).
4345:
4339:
4084:
4071:
3988:
3958:
3572:
3464:
3249:
3247:
3245:
3243:
3241:
3239:
3138:
3129:
3108:
3102:
3099:, New York: McGraw-Hill, 1948, pp. 3–4
3019:
2799:"Detector for electrical disturbances"
2364:
2135:
2092:
1940:
1938:
1936:
1934:
1932:
650:connected together. The circuit has a
199:at frequencies as low as 20 kHz.
4981:
4947:http://www.crystal-radio.eu/engev.htm
4813:. D. Van Nostrand company. 267 pages.
4682:
4598:Certain crystals if this combination
4110:
3924:
3904:Smith, K. c. a.; R. E. Alley (1992).
3873:
3398:
3375:
3323:
3312:
3211:
3182:
3149:
3115:. Rosenberg Publishing. p. 103.
2926:"Oscillating and Amplifying Crystals"
2672:(52) : 1199–1200. From p. 1119:
2326:Proc. of the Inst. Of Radio Engineers
2129:
2012:
1168:
1065:
104:receivers, while other radios use an
6054:
4505:
4476:
4251:
3907:Electrical circuits: An introduction
3744:
3714:Engineering Circuit Analysis, 2nd Ed
3674:. D. Van Nostrand Company. pp.
3524:
3501:
3066:
2986:, who coined the term "crystodyne".)
2385:
1997:
1944:
392:United States Department of Commerce
4535:
4274:
4210:"Radio Detectors and How They Work"
4057:. Forgotten Books. pp. 23–25.
3537:. US: G.P. Putnam's sons. pp.
3446:
3253:
3236:
2963:The Wireless World and Radio Review
2952:The Wireless World and Radio Review
2941:The Wireless World and Radio Review
2930:The Wireless World and Radio Review
2882:, September 1924, pp. 294–295, 431.
1929:
1266:
681:, demodulating the radio frequency
590:
13:
4830:JL Preston and HA Wheeler (1922) "
4803:
4580:Robison, Samuel Shelburne (1911).
4388:Gernsback, Hugo (September 1944).
4241:, vol. II, no. 3, p. 42, Jul. 1914
4208:Campbell, John W. (October 1944).
4111:Hogan, John V. L. (October 1922).
4051:Collins, Archie Frederick (1922).
3717:. New York: McGraw-Hill. pp.
3614:Collins, Archie Frederick (1922).
3473:. personal website. Archived from
3145:. D. Van Nostrand Co. p. 199.
728:with the coil. The detector was a
634:(tuned circuit) which selects the
442:receivers, and even transmitters.
357:
14:
6126:
4922:"High Performance Crystal Radios"
4856:
3805:Blanchard, T. A. (October 1962).
2961:Round and Rust (August 19, 1925)
2617:Principles of Radio Communication
2322:"United States Radio Development"
744:. Even for a powerful commercial
396:Harding-Cox presidential election
364:United States Bureau of Standards
81:. This component is now called a
6053:
6043:
6034:
6033:
6022:
5643:Free-space optical communication
4772:
4763:
4713:
4702:
4685:"Build a Matchbox Crystal Radio"
4676:
4662:
4651:
4640:
4629:
4551:
4529:
4477:Kuhn, Kenneth A. (Jan 6, 2008).
4304:Text-book on Wireless Telegraphy
4169:US Signal Corps (October 1916).
3883:. US: Springer. pp. 60–62.
3745:Kuhn, Kenneth A. (Jan 6, 2008).
3471:Ian Purdie's Amateur Radio Pages
3280:
3214:"Build a Matchbox Crystal Radio"
3183:Fette, Bruce A. (Dec 27, 2008).
3067:Kuhn, Kenneth A. (Jan 6, 2008).
2507:Solomon, Larry J. (2007-12-30).
2448:Stay Tuned Crystal Radio website
1877:
1852:
1840:
1822:
1804:
1782:
1764:
1749:
1737:
1725:
1713:
1300:How the crystal detector works.
1083:
1074:
1026:tuning coil, in which a ferrite
903:
669:the radio signal to extract the
390:, received its license from the
366:released a publication entitled
132:. Crystals were first used as a
120:property of a contact between a
4573:The sensitivity of the Perikon
4415:
4381:
4370:
4335:Lescarboura (1922), pp. 143–146
4295:
4268:
4244:
4231:
4190:Marx & Van Muffling (1922)
4183:
4162:
4154:Marx & Van Muffling (1922)
4147:
4134:
4104:
4018:
4010:Marx & Van Muffling (1922)
4003:
3982:
3952:
3897:
3867:
3855:
3767:
3704:
3692:
3661:
3645:
3634:
3607:
3596:
3573:Putnam, Robert (October 1922).
3566:
3545:
3458:
3440:
3418:
3300:
3274:
3176:
3089:
3060:
3046:Lescarboura, Austin C. (1922).
3013:
3002:
2991:
2924:Hugh S. Pocock (June 11, 1924)
2885:
2869:
2848:
2839:
2828:
2817:
2804:
2791:
2736:
2699:
2642:
2628:
2606:
2592:Lescarboura, Austin C. (1922).
2585:
2470:
2467:website . Retrieved 2010-01-18.
2453:
2440:
2428:
2415:
2371:. AuthorHouse. pp. 44–45.
2358:
2312:
1384:. The crystal functions as an
247:radio signals transmitted from
4781:"High Sensitivity Crystal Set"
4605:Bucher, Elmer Eustace (1921).
3989:Bucher, Elmer Eustace (1921).
3936:Electronic Engineering, 3rd Ed
3774:Clifford, Martin (July 1986).
3641:Lescarboura, 1922, pp. 102–104
3552:Williams, Henry Smith (1922).
3455:is a collection of 12 circuits
3450:The Boy's Book of Crystal Sets
3426:Sleeper, Milton Blake (1922).
3185:"RF Basics: Radio Propagation"
3139:Morgan, Alfred Powell (1914).
2911:M. Vingradow (September 1924)
2497:journal. Retrieved 2010-01-18.
2423:Birmingham Crystal Radio Group
2212:
2156:
2065:
1257:impedance matching transformer
1118:impedance matching transformer
928:connected together, acts as a
571:Building crystal radios was a
547:
394:just in time to broadcast the
262:
1:
4823:Milton Blake Sleeper (1922).
4816:Elmer Eustice Bucher (1920).
4054:The Radio Amateur's Hand Book
3959:Tongue, Ben H. (2007-11-06).
3617:The Radio Amateur's Hand Book
3579:Tractor and Gas Engine Review
3502:Kuhn, Kenneth (Dec 9, 2007).
3407:. Alan Klase personal website
3324:Binns, Jack (November 1922).
3095:H. C. Torrey, C. A. Whitmer,
2710:Henry Harrison Chase Dunwoody
2684:Annalen der Physik und Chemie
2666:Elektrotechnische Zeitschrift
2013:Field, Simon Quellen (2003).
1923:
1830:
1812:
1794:
1789:Homemade "loose coupler" set
1772:
924:, consisting of a coil and a
405:
345:signals. This device brought
6029:Telecommunication portal
5810:Telecommunications equipment
4779:Cutler, Bob (January 2007).
4422:Douglas, Alan (April 1981).
4256:. Riley Shaw's personal blog
4254:"The cat's-whisker detector"
3967:. Ben Tongue. Archived from
3575:"Make the aerial a good one"
2913:"Lés Détecteurs Générateurs"
2810:Greenleaf Whittier Pickard,
2714:"Wireless-telegraph system,"
2533:Petruzellis, Thomas (2007).
2488:Antique Wireless Association
2234:Douglas, Alan (April 1981).
1977:Petruzellis, Thomas (2007).
1744:Marconi Type 103 crystal set
1518:
937:the station received is the
279:Early radio telegraphy used
7:
6080:History of radio technology
5546:Alexander Stepanovich Popov
4879:Ben Tongue's Technical Talk
4811:Elements of Radiotelegraphy
4769:Radio-Electronics, 1966, №2
4377:Stanley (1919), pp. 311–318
3504:"Antenna and Ground System"
2743:Emerson, D. T. (Dec 1997).
2295:The Evolution of Technology
2164:Emerson, D. T. (Dec 1997).
1870:
712:, hence earphones are used.
183:band, but most receive the
10:
6131:
5250:Telecommunications history
4683:Payor, Steve (June 1989).
4636:Lescarboura (1922), p. 285
4440:10.1109/mspec.1981.6369482
4390:"Foxhole emergency radios"
4252:Shaw, Riley (April 2015).
4140:Alley & Atwood (1973)
3807:"Vestpocket Crystal Radio"
3212:Payor, Steve (June 1989).
2969:"The Crystodyne principle"
2876:"The Crystodyne Principle"
2565:Williams, Lyle R. (2006).
2478:Designing a DX crystal set
2338:10.1109/jrproc.1917.217311
2248:10.1109/MSPEC.1981.6369482
2051:. Springer. pp. 3–4.
1692:
1527:Modern crystal radio with
1456:(carborundum, SiC), and a
1396:radio signal to a pulsing
1270:
799:
323:Greenleaf Whittier Pickard
289:high-frequency alternators
202:
136:of radio waves in 1894 by
128:was discovered in 1874 by
108:powered by current from a
25:
18:
6017:
5959:
5896:
5858:Public Switched Telephone
5818:
5782:
5739:
5680:
5670:telecommunication circuit
5631:Fiber-optic communication
5614:
5376:Francis Blake (telephone)
5323:
5171:Optical telecommunication
5015:
4972:The Crystal Set Perfected
4927:. Ottawa Electronics Club
4647:Collins (1922), pp. 27–28
4486:Crystal Radio Engineering
3776:"The early days of radio"
3754:Crystal Radio Engineering
3511:Crystal Radio Engineering
3109:Jensen, Peter R. (2003).
3076:Crystal Radio Engineering
3026:electronics-tutorials.com
2136:Sarkar, Tapan K. (2006).
1677:{\displaystyle P=U^{2}/R}
1546:1600 ohm magnetic headset
951:of the capacitor and the
874:
787:
362:In 1922 the (then named)
5769:Orbital angular-momentum
5206:Satellite communications
5045:Communications satellite
4898:". earthlink.net/~lenyr.
4871:Hobbydyne Crystal Radios
4809:Ellery W. Stone (1919).
4742:
4085:Wenzel, Charles (1995).
4025:Stanley, Rupert (1919).
3603:Lescarboura 1922, p. 100
3401:"Crystal Set Design 102"
2292:Basalla, George (1988).
1945:Carr, Joseph J. (1990).
1811:Crystal radio, Germany,
1582:Modern crystal sets use
1273:Crystal detector (radio)
1208:coils of wire, one (the
780:signals used during the
476:troops were halted near
6095:Amateur radio receivers
5648:Molecular communication
5471:Gardiner Greene Hubbard
5300:Undersea telegraph line
5035:Cable protection system
4275:Lee, Thomas H. (2004).
4239:Electrical Experimenter
3447:May, Walter J. (1954).
3399:Klase, Alan R. (1998).
3355:Beauchamp, Ken (2001).
3254:Lee, Thomas H. (2004).
3020:Purdie, Ian C. (2001).
2897:, no. 28, p. 139 (1924)
2450:. Retrieved 2010-01-18.
2365:Corbin, Alfred (2006).
1421:used a battery-powered
1281:Galena crystal detector
1204:. This consists of two
852:used in modern radios.
836:band waves are 182–566
776:stations, although the
175:(AM) signals, although
171:Crystal radios receive
6110:Bangladeshi inventions
5790:Communication protocol
5576:Charles Sumner Tainter
5391:Walter Houser Brattain
5336:Edwin Howard Armstrong
5144:Information revolution
4840:Thomas H. Lee (2004).
4721:High Power Crystal Set
4658:Williams (1922), p. 79
4424:"The Crystal Detector"
4142:Electronic Engineering
4091:Crystal radio circuits
4087:"Simple crystal radio"
3283:"Threshold of hearing"
2977:October 1924 issue of
2797:Jagadis Chunder Bose,
2236:"The crystal detector"
1678:
1547:
1531:
1529:piezoelectric earphone
1346:
1338:
1293:
1282:
1200:by a technique called
1186:
1178:
1137:Problem of selectivity
1133:
1004:
917:
813:
733:
608:
600:
560:
462:
276:
249:spark-gap transmitters
236:
220:
212:
197:spark-gap transmitters
63:crystal radio receiver
58:
46:
43:cat's whisker detector
5764:Polarization-division
5496:Narinder Singh Kapany
5461:Erna Schneider Hoover
5381:Jagadish Chandra Bose
5361:Alexander Graham Bell
5092:online video platform
4625:Field 2003, pp. 93–94
4508:"The Crystal Set 5/6"
4352:The Electrical Record
3467:"A Basic Crystal Set"
3358:History of Telegraphy
3187:. RF Engineer Network
1913:Electrolytic detector
1679:
1624:Use as a power source
1545:
1526:
1344:
1299:
1288:
1280:
1184:
1176:
1131:
1062:set's limited range.
1051:parasitic capacitance
1032:magnetic permeability
1005:
911:
844:, in contrast to the
807:
719:
606:
598:
555:
460:
318:Jagadish Chandra Bose
270:
226:
218:
210:
195:signals broadcast by
138:Jagadish Chandra Bose
100:). However they are
52:
36:
5606:Vladimir K. Zworykin
5566:Almon Brown Strowger
5536:Charles Grafton Page
5191:Prepaid mobile phone
5119:Electrical telegraph
4911:Roger Lapthorn G3XBM
4905:. November 20, 2002.
3465:Purdie, Ian (1999).
3453:. London: Bernard's.
3009:1950s Crystal Radios
2998:Rocket Crystal Radio
2854:Peter Robin Morris,
2721:Louis Winslow Austin
2650:Karl Ferdinand Braun
2435:The Xtal Set Society
1793:,museum in Florida,
1647:
1382:semiconductor diodes
1370:cat whisker detector
1227:resonant transformer
1206:magnetically coupled
1047:capacitive reactance
1018:. Alternatively, a
965:
871:fences as antennas.
746:broadcasting station
730:cat whisker detector
699:semiconductor diodes
687:cat whisker detector
187:band. A few receive
130:Karl Ferdinand Braun
5556:Johann Philipp Reis
5315:Wireless revolution
5277:The Telephone Cases
5134:Hydraulic telegraph
4901:Nyle Steiner K7NS,
4726:Popular Electronics
4709:Field (2003), p. 94
4689:Popular Electronics
3218:Popular Electronics
3049:Radio for Everybody
3022:"Crystal Radio Set"
2947: : 2ff, 47ff.
2761:1997ITMTT..45.2267E
2595:Radio for Everybody
2509:"FM Crystal Radios"
2476:Mike Tuggle (2003)
2446:Darryl Boyd (2006)
2421:Jack Bryant (2009)
2221:History of wireless
2182:1997ITMTT..45.2267E
2139:History of wireless
1699:wireless telegraphy
1552:moving iron drivers
1493:semiconductor diode
1394:alternating current
1308:amplitude modulated
1220:; the primary coil
1196:which improves the
782:wireless telegraphy
683:alternating current
679:square law detector
432:negative resistance
343:amplitude modulated
231:1922 Circular 120 "
229:Bureau of Standards
193:wireless telegraphy
173:amplitude modulated
150:wireless telegraphy
5754:Frequency-division
5731:Telephone exchange
5601:Charles Wheatstone
5531:Jun-ichi Nishizawa
5506:Innocenzo Manzetti
5441:Reginald Fessenden
5176:Optical telegraphy
5009:Telecommunications
4893:2013-03-17 at the
4540:. crystal-radio.eu
4512:The Crystal Corner
3747:"Resonant Circuit"
3097:Crystal Rectifiers
2493:2010-05-23 at the
2483:2010-01-24 at the
2278:Stay Tuned website
1674:
1608:earphone's input.
1548:
1532:
1491:In modern sets, a
1347:
1339:
1294:
1283:
1187:
1179:
1169:Inductive coupling
1134:
1101:impedance matching
1066:Impedance matching
1020:variable capacitor
1000:
939:resonant frequency
918:
850:loopstick antennas
814:
810:inverted-L antenna
734:
652:resonant frequency
609:
601:
561:
463:
277:
237:
221:
213:
155:radio broadcasting
59:
47:
21:Crystal oscillator
6115:Indian inventions
6105:Electronic design
6085:Radio electronics
6067:
6066:
5805:Store and forward
5800:Data transmission
5714:Network switching
5665:Transmission line
5511:Guglielmo Marconi
5476:Internet pioneers
5341:Mohamed M. Atalla
5310:Whistled language
4958:Crystal Detectors
4719:Walter B. Ford, "
4561:(1922), p.439-440
4506:Hadgraft, Peter.
4479:"Diode Detectors"
3811:Radio-Electronics
3780:Radio Electronics
3728:978-0-07-027382-5
3307:Lescarboura, 1922
3267:978-0-521-83526-8
2917:L'Onde Electrique
2902:Radio Électricité
2769:10.1109/22.643830
2755:(12): 2267–2273.
2578:978-1-84728-526-3
2546:978-0-07-148929-4
2408:978-1-55652-774-6
2223:, pp. 94, 291–308
2190:10.1109/22.643830
2176:(12): 2267–2273.
2085:978-0-521-28903-0
2026:978-1-55652-520-9
1990:978-0-07-148929-4
1893:Batteryless radio
1587:crystal earpieces
1436:(fool's gold, FeS
1386:envelope detector
1242:mutual inductance
997:
994:
881:monopole antennas
857:"T" type antennas
742:radio transmitter
621:electric currents
542:Transistor radios
518:signals from the
293:radio frequencies
6122:
6100:Receiver (radio)
6057:
6056:
6047:
6046:
6037:
6036:
6027:
6026:
6025:
5898:Notable networks
5888:Wireless network
5828:Cellular network
5820:Types of network
5795:Computer network
5682:Network topology
5596:Thomas A. Watson
5451:Oliver Heaviside
5436:Philo Farnsworth
5411:Daniel Davis Jr.
5386:Charles Bourseul
5346:John Logie Baird
5055:Data compression
5050:Computer network
5002:
4995:
4988:
4979:
4978:
4935:
4933:
4932:
4926:
4798:
4797:
4785:
4776:
4770:
4767:
4761:
4760:
4738:
4729:
4723:", August 1960,
4717:
4711:
4706:
4700:
4699:
4697:
4696:
4680:
4674:
4666:
4660:
4655:
4649:
4644:
4638:
4633:
4627:
4622:
4613:
4612:
4594:
4588:
4587:
4569:
4563:
4555:
4549:
4548:
4546:
4545:
4533:
4527:
4526:
4524:
4523:
4503:
4497:
4496:
4494:
4493:
4483:
4474:
4468:
4467:
4465:
4464:
4451:
4419:
4413:
4408:
4406:
4405:
4385:
4379:
4374:
4368:
4367:
4365:
4363:
4343:
4337:
4332:
4323:
4322:, pp. 60–61
4317:
4308:
4299:
4293:
4292:
4272:
4266:
4265:
4263:
4261:
4248:
4242:
4235:
4229:
4228:
4226:
4225:
4205:
4196:
4194:, p. 43, fig. 22
4187:
4181:
4180:
4166:
4160:
4151:
4145:
4138:
4132:
4131:
4129:
4128:
4108:
4102:
4101:
4099:
4098:
4082:
4069:
4068:
4048:
4037:
4036:
4022:
4016:
4007:
4001:
4000:
3986:
3980:
3979:
3977:
3976:
3956:
3950:
3949:
3931:
3922:
3921:
3901:
3895:
3894:
3871:
3865:
3859:
3853:
3852:
3843:
3826:
3821:
3819:
3818:
3802:
3796:
3790:
3788:
3787:
3771:
3765:
3764:
3762:
3761:
3751:
3742:
3733:
3732:
3708:
3702:
3696:
3690:
3689:
3665:
3659:
3658:
3649:
3643:
3638:
3632:
3631:
3611:
3605:
3600:
3594:
3593:
3591:
3590:
3570:
3564:
3563:
3549:
3543:
3542:
3528:
3522:
3521:
3519:
3518:
3508:
3499:
3486:
3485:
3483:
3482:
3462:
3456:
3454:
3444:
3438:
3437:
3422:
3416:
3415:
3413:
3412:
3396:
3373:
3372:
3351:
3345:
3344:
3342:
3341:
3321:
3310:
3304:
3298:
3297:
3295:
3294:
3278:
3272:
3271:
3251:
3234:
3228:
3226:
3225:
3209:
3196:
3195:
3193:
3192:
3180:
3174:
3173:
3153:
3147:
3146:
3136:
3127:
3126:
3106:
3100:
3093:
3087:
3086:
3084:
3083:
3073:
3064:
3058:
3057:
3043:
3037:
3036:
3034:
3033:
3017:
3011:
3006:
3000:
2995:
2989:
2908: : 196–197.
2889:
2883:
2873:
2867:
2852:
2846:
2843:
2837:
2832:
2826:
2821:
2815:
2808:
2802:
2795:
2789:
2788:
2786:
2785:
2740:
2734:
2703:
2697:
2646:
2640:
2639:
2632:
2626:
2625:
2610:
2604:
2603:
2589:
2583:
2582:
2562:
2551:
2550:
2530:
2524:
2523:
2521:
2520:
2511:. Archived from
2504:
2498:
2474:
2468:
2457:
2451:
2444:
2438:
2432:
2426:
2419:
2413:
2412:
2392:
2383:
2382:
2362:
2356:
2355:
2353:
2352:
2316:
2310:
2309:
2289:
2280:
2275:
2273:
2272:
2259:
2231:
2225:
2216:
2210:
2209:
2207:
2206:
2160:
2154:
2153:
2133:
2127:
2126:
2107:Lillian Hoddeson
2103:Riordan, Michael
2099:
2090:
2089:
2069:
2063:
2062:
2042:
2031:
2030:
2010:
1995:
1994:
1974:
1963:
1962:
1942:
1918:History of radio
1908:Detector (radio)
1887:
1882:
1881:
1880:
1856:
1844:
1835:
1832:
1826:
1817:
1814:
1808:
1799:
1796:
1786:
1777:
1774:
1768:
1753:
1741:
1729:
1717:
1683:
1681:
1680:
1675:
1670:
1665:
1664:
1419:(circuit, right)
1410:bypass capacitor
1335:
1329:
1304:
1267:Crystal detector
1191:antenna coupling
1087:
1078:
1009:
1007:
1006:
1001:
998:
996:
995:
987:
975:
825:electric current
695:crystal detector
632:resonant circuit
591:Basic principles
482:local oscillator
453:"Foxhole radios"
285:arc transmitters
75:crystal detector
65:, also called a
6130:
6129:
6125:
6124:
6123:
6121:
6120:
6119:
6090:Types of radios
6070:
6069:
6068:
6063:
6023:
6021:
6013:
5955:
5892:
5814:
5778:
5735:
5684:
5676:
5617:
5610:
5516:Robert Metcalfe
5371:Tim Berners-Lee
5319:
5139:Information Age
5011:
5006:
4966:Radio Detectors
4930:
4928:
4924:
4909:Crystal Set DX?
4895:Wayback Machine
4859:
4806:
4804:Further reading
4801:
4783:
4777:
4773:
4768:
4764:
4757:
4744:
4739:
4732:
4718:
4714:
4707:
4703:
4694:
4692:
4681:
4677:
4667:
4663:
4656:
4652:
4645:
4641:
4634:
4630:
4623:
4616:
4595:
4591:
4570:
4566:
4556:
4552:
4543:
4541:
4536:Kleijer, Dick.
4534:
4530:
4521:
4519:
4504:
4500:
4491:
4489:
4481:
4475:
4471:
4462:
4460:
4420:
4416:
4403:
4401:
4386:
4382:
4375:
4371:
4361:
4359:
4344:
4340:
4333:
4326:
4318:
4311:
4302:Stanley (1919)
4300:
4296:
4289:
4273:
4269:
4259:
4257:
4249:
4245:
4236:
4232:
4223:
4221:
4214:Popular Science
4206:
4199:
4192:Radio Reception
4188:
4184:
4172:Radiotelegraphy
4167:
4163:
4156:Radio Reception
4152:
4148:
4139:
4135:
4126:
4124:
4117:Radio Broadcast
4109:
4105:
4096:
4094:
4083:
4072:
4065:
4049:
4040:
4023:
4019:
4012:Radio Reception
4008:
4004:
3987:
3983:
3974:
3972:
3957:
3953:
3946:
3932:
3925:
3918:
3902:
3898:
3891:
3872:
3868:
3860:
3856:
3845:
3844:
3829:
3816:
3814:
3803:
3799:
3785:
3783:
3772:
3768:
3759:
3757:
3749:
3743:
3736:
3729:
3709:
3705:
3697:
3693:
3686:
3666:
3662:
3651:
3650:
3646:
3639:
3635:
3628:
3612:
3608:
3601:
3597:
3588:
3586:
3571:
3567:
3555:Practical Radio
3550:
3546:
3529:
3525:
3516:
3514:
3506:
3500:
3489:
3480:
3478:
3463:
3459:
3445:
3441:
3423:
3419:
3410:
3408:
3397:
3376:
3369:
3352:
3348:
3339:
3337:
3330:Popular Science
3322:
3313:
3305:
3301:
3292:
3290:
3279:
3275:
3268:
3252:
3237:
3223:
3221:
3210:
3199:
3190:
3188:
3181:
3177:
3170:
3154:
3150:
3137:
3130:
3123:
3112:Wireless at War
3107:
3103:
3094:
3090:
3081:
3079:
3071:
3065:
3061:
3044:
3040:
3031:
3029:
3018:
3014:
3007:
3003:
2996:
2992:
2958: : 93–96.
2915:, pp. 433–448,
2890:
2886:
2874:
2870:
2853:
2849:
2844:
2840:
2833:
2829:
2822:
2818:
2809:
2805:
2796:
2792:
2783:
2781:
2779:
2741:
2737:
2704:
2700:
2691:
2677:
2675:
2673:
2647:
2643:
2634:
2633:
2629:
2611:
2607:
2590:
2586:
2579:
2563:
2554:
2547:
2531:
2527:
2518:
2516:
2505:
2501:
2495:Wayback Machine
2485:Wayback Machine
2475:
2471:
2458:
2454:
2445:
2441:
2433:
2429:
2420:
2416:
2409:
2393:
2386:
2379:
2363:
2359:
2350:
2348:
2317:
2313:
2306:
2290:
2283:
2270:
2268:
2232:
2228:
2217:
2213:
2204:
2202:
2200:
2161:
2157:
2150:
2134:
2130:
2123:
2100:
2093:
2086:
2070:
2066:
2059:
2043:
2034:
2027:
2011:
1998:
1991:
1975:
1966:
1959:
1943:
1930:
1926:
1883:
1878:
1876:
1873:
1868:
1867:
1866:
1863:
1857:
1848:
1845:
1836:
1833:
1827:
1818:
1815:
1809:
1800:
1797:
1787:
1778:
1775:
1769:
1760:
1754:
1745:
1742:
1733:
1730:
1721:
1718:
1695:
1666:
1660:
1656:
1648:
1645:
1644:
1639:signals have a
1626:
1521:
1497:Schottky diodes
1471:
1467:
1454:silicon carbide
1451:
1439:
1402:radio frequency
1333:
1327:
1312:radio frequency
1302:
1290:Germanium diode
1275:
1269:
1171:
1139:
1122:autotransformer
1097:
1096:
1095:
1094:
1090:
1089:
1088:
1080:
1079:
1068:
986:
979:
974:
966:
963:
962:
906:
893:input impedance
877:
802:
790:
778:radiotelegraphy
638:of the desired
623:are induced by
593:
550:
528:
486:superheterodyne
455:
440:superheterodyne
410:In early 1920s
408:
360:
358:1920s and 1930s
351:voice broadcast
347:radiotelephones
265:
205:
181:radio frequency
31:
28:The Crystal Set
24:
17:
12:
11:
5:
6128:
6118:
6117:
6112:
6107:
6102:
6097:
6092:
6087:
6082:
6065:
6064:
6062:
6061:
6051:
6041:
6031:
6018:
6015:
6014:
6012:
6011:
6004:
5999:
5994:
5989:
5984:
5983:
5982:
5977:
5969:
5963:
5961:
5957:
5956:
5954:
5953:
5948:
5943:
5938:
5933:
5928:
5923:
5918:
5913:
5908:
5902:
5900:
5894:
5893:
5891:
5890:
5885:
5880:
5875:
5870:
5865:
5860:
5855:
5850:
5845:
5840:
5835:
5830:
5824:
5822:
5816:
5815:
5813:
5812:
5807:
5802:
5797:
5792:
5786:
5784:
5780:
5779:
5777:
5776:
5771:
5766:
5761:
5756:
5751:
5749:Space-division
5745:
5743:
5737:
5736:
5734:
5733:
5728:
5727:
5726:
5721:
5711:
5710:
5709:
5699:
5694:
5688:
5686:
5678:
5677:
5675:
5674:
5673:
5672:
5662:
5661:
5660:
5650:
5645:
5640:
5639:
5638:
5628:
5622:
5620:
5612:
5611:
5609:
5608:
5603:
5598:
5593:
5588:
5586:Camille Tissot
5583:
5578:
5573:
5568:
5563:
5561:Claude Shannon
5558:
5553:
5551:Tivadar Puskás
5548:
5543:
5538:
5533:
5528:
5523:
5521:Antonio Meucci
5518:
5513:
5508:
5503:
5498:
5493:
5491:Charles K. Kao
5488:
5483:
5478:
5473:
5468:
5466:Harold Hopkins
5463:
5458:
5453:
5448:
5443:
5438:
5433:
5428:
5423:
5418:
5413:
5408:
5403:
5398:
5393:
5388:
5383:
5378:
5373:
5368:
5366:Emile Berliner
5363:
5358:
5353:
5348:
5343:
5338:
5333:
5327:
5325:
5321:
5320:
5318:
5317:
5312:
5307:
5305:Videotelephony
5302:
5297:
5296:
5295:
5290:
5280:
5273:
5268:
5262:
5257:
5252:
5247:
5242:
5241:
5240:
5235:
5230:
5220:
5219:
5218:
5208:
5203:
5201:Radiotelephone
5198:
5193:
5188:
5183:
5178:
5173:
5168:
5167:
5166:
5156:
5151:
5146:
5141:
5136:
5131:
5126:
5121:
5116:
5111:
5106:
5105:
5104:
5099:
5094:
5089:
5087:Internet video
5079:
5078:
5077:
5072:
5067:
5062:
5052:
5047:
5042:
5037:
5032:
5027:
5021:
5019:
5013:
5012:
5005:
5004:
4997:
4990:
4982:
4976:
4975:
4968:
4960:
4952:
4944:
4936:
4917:
4912:
4906:
4899:
4883:
4875:
4867:
4858:
4857:External links
4855:
4854:
4853:
4850:
4844:
4838:
4835:
4828:
4821:
4814:
4805:
4802:
4800:
4799:
4771:
4762:
4755:
4730:
4712:
4701:
4675:
4672:(1922), p. 441
4661:
4650:
4639:
4628:
4614:
4589:
4564:
4550:
4528:
4498:
4469:
4414:
4380:
4369:
4338:
4324:
4309:
4294:
4287:
4267:
4243:
4230:
4197:
4182:
4161:
4146:
4133:
4103:
4070:
4063:
4038:
4017:
4002:
3981:
3951:
3944:
3923:
3916:
3896:
3889:
3875:Nahin, Paul J.
3866:
3854:
3827:
3797:
3766:
3734:
3727:
3703:
3691:
3684:
3660:
3644:
3633:
3626:
3606:
3595:
3565:
3544:
3523:
3487:
3457:
3439:
3417:
3374:
3367:
3346:
3311:
3299:
3281:Nave, C. Rod.
3273:
3266:
3235:
3197:
3175:
3168:
3148:
3128:
3121:
3101:
3088:
3069:"Introduction"
3059:
3038:
3012:
3001:
2990:
2988:
2987:
2966:
2965:, pp. 217–218.
2959:
2948:
2937:
2920:
2919:
2909:
2898:
2884:
2868:
2847:
2838:
2827:
2816:
2803:
2790:
2778:978-0986488511
2777:
2735:
2733:
2732:
2728:
2717:
2698:
2641:
2627:
2605:
2584:
2577:
2552:
2545:
2525:
2499:
2469:
2461:Crystal Radios
2452:
2439:
2427:
2414:
2407:
2384:
2377:
2357:
2311:
2304:
2281:
2226:
2219:Sarkar (2006)
2211:
2198:
2155:
2148:
2128:
2121:
2091:
2084:
2064:
2057:
2032:
2025:
1996:
1989:
1964:
1957:
1927:
1925:
1922:
1921:
1920:
1915:
1910:
1905:
1900:
1895:
1889:
1888:
1872:
1869:
1865:
1864:
1858:
1851:
1849:
1846:
1839:
1837:
1828:
1821:
1819:
1810:
1803:
1801:
1788:
1781:
1779:
1770:
1763:
1761:
1755:
1748:
1746:
1743:
1736:
1734:
1731:
1724:
1722:
1719:
1712:
1709:
1708:
1707:
1694:
1691:
1673:
1669:
1663:
1659:
1655:
1652:
1625:
1622:
1572:magnetic field
1520:
1517:
1486:semiconducting
1469:
1465:
1449:
1437:
1398:direct current
1378:Schottky diode
1271:Main article:
1268:
1265:
1238:magnetic field
1202:loose coupling
1170:
1167:
1138:
1135:
1092:
1091:
1082:
1081:
1073:
1072:
1071:
1070:
1069:
1067:
1064:
1011:
1010:
993:
990:
985:
982:
978:
973:
970:
905:
902:
876:
873:
808:Diagram of an
801:
798:
794:radio amateurs
789:
786:
714:
713:
702:
655:
628:
592:
589:
549:
546:
527:
526:"Rocket Radio"
524:
500:foxhole radios
467:semiconductors
454:
451:
407:
404:
359:
356:
264:
261:
204:
201:
71:radio receiver
69:, is a simple
15:
9:
6:
4:
3:
2:
6127:
6116:
6113:
6111:
6108:
6106:
6103:
6101:
6098:
6096:
6093:
6091:
6088:
6086:
6083:
6081:
6078:
6077:
6075:
6060:
6052:
6050:
6042:
6040:
6032:
6030:
6020:
6019:
6016:
6009:
6005:
6003:
6000:
5998:
5995:
5993:
5990:
5988:
5985:
5981:
5978:
5976:
5973:
5972:
5970:
5968:
5965:
5964:
5962:
5958:
5952:
5949:
5947:
5944:
5942:
5939:
5937:
5934:
5932:
5929:
5927:
5924:
5922:
5919:
5917:
5914:
5912:
5909:
5907:
5904:
5903:
5901:
5899:
5895:
5889:
5886:
5884:
5881:
5879:
5876:
5874:
5871:
5869:
5866:
5864:
5861:
5859:
5856:
5854:
5851:
5849:
5846:
5844:
5841:
5839:
5836:
5834:
5831:
5829:
5826:
5825:
5823:
5821:
5817:
5811:
5808:
5806:
5803:
5801:
5798:
5796:
5793:
5791:
5788:
5787:
5785:
5781:
5775:
5774:Code-division
5772:
5770:
5767:
5765:
5762:
5760:
5759:Time-division
5757:
5755:
5752:
5750:
5747:
5746:
5744:
5742:
5738:
5732:
5729:
5725:
5722:
5720:
5717:
5716:
5715:
5712:
5708:
5705:
5704:
5703:
5700:
5698:
5695:
5693:
5690:
5689:
5687:
5685:and switching
5683:
5679:
5671:
5668:
5667:
5666:
5663:
5659:
5656:
5655:
5654:
5651:
5649:
5646:
5644:
5641:
5637:
5636:optical fiber
5634:
5633:
5632:
5629:
5627:
5626:Coaxial cable
5624:
5623:
5621:
5619:
5613:
5607:
5604:
5602:
5599:
5597:
5594:
5592:
5589:
5587:
5584:
5582:
5579:
5577:
5574:
5572:
5569:
5567:
5564:
5562:
5559:
5557:
5554:
5552:
5549:
5547:
5544:
5542:
5541:Radia Perlman
5539:
5537:
5534:
5532:
5529:
5527:
5524:
5522:
5519:
5517:
5514:
5512:
5509:
5507:
5504:
5502:
5499:
5497:
5494:
5492:
5489:
5487:
5484:
5482:
5479:
5477:
5474:
5472:
5469:
5467:
5464:
5462:
5459:
5457:
5454:
5452:
5449:
5447:
5444:
5442:
5439:
5437:
5434:
5432:
5431:Lee de Forest
5429:
5427:
5426:Thomas Edison
5424:
5422:
5419:
5417:
5416:Donald Davies
5414:
5412:
5409:
5407:
5404:
5402:
5401:Claude Chappe
5399:
5397:
5394:
5392:
5389:
5387:
5384:
5382:
5379:
5377:
5374:
5372:
5369:
5367:
5364:
5362:
5359:
5357:
5354:
5352:
5349:
5347:
5344:
5342:
5339:
5337:
5334:
5332:
5329:
5328:
5326:
5322:
5316:
5313:
5311:
5308:
5306:
5303:
5301:
5298:
5294:
5291:
5289:
5286:
5285:
5284:
5281:
5279:
5278:
5274:
5272:
5269:
5266:
5263:
5261:
5258:
5256:
5253:
5251:
5248:
5246:
5245:Smoke signals
5243:
5239:
5236:
5234:
5231:
5229:
5226:
5225:
5224:
5223:Semiconductor
5221:
5217:
5214:
5213:
5212:
5209:
5207:
5204:
5202:
5199:
5197:
5194:
5192:
5189:
5187:
5184:
5182:
5179:
5177:
5174:
5172:
5169:
5165:
5162:
5161:
5160:
5157:
5155:
5152:
5150:
5147:
5145:
5142:
5140:
5137:
5135:
5132:
5130:
5127:
5125:
5122:
5120:
5117:
5115:
5112:
5110:
5107:
5103:
5100:
5098:
5095:
5093:
5090:
5088:
5085:
5084:
5083:
5082:Digital media
5080:
5076:
5073:
5071:
5068:
5066:
5063:
5061:
5058:
5057:
5056:
5053:
5051:
5048:
5046:
5043:
5041:
5038:
5036:
5033:
5031:
5028:
5026:
5023:
5022:
5020:
5018:
5014:
5010:
5003:
4998:
4996:
4991:
4989:
4984:
4983:
4980:
4974:
4973:
4969:
4967:
4964:
4961:
4959:
4956:
4953:
4951:
4948:
4945:
4943:
4940:
4937:
4923:
4918:
4916:
4913:
4910:
4907:
4904:
4900:
4897:
4896:
4892:
4889:
4884:
4881:
4880:
4876:
4873:
4872:
4868:
4866:
4865:
4861:
4860:
4851:
4849:
4845:
4843:
4839:
4836:
4833:
4829:
4826:
4822:
4819:
4815:
4812:
4808:
4807:
4795:
4791:
4790:
4782:
4775:
4766:
4758:
4756:5-94074-056-1
4752:
4748:
4737:
4735:
4728:
4727:
4722:
4716:
4710:
4705:
4690:
4686:
4679:
4673:
4671:
4665:
4659:
4654:
4648:
4643:
4637:
4632:
4626:
4621:
4619:
4610:
4609:
4602:
4599:
4593:
4585:
4584:
4577:
4574:
4568:
4562:
4560:
4554:
4539:
4532:
4518:on 2010-07-20
4517:
4513:
4509:
4502:
4487:
4480:
4473:
4459:
4455:
4450:
4445:
4441:
4437:
4433:
4429:
4428:IEEE Spectrum
4425:
4418:
4412:
4399:
4395:
4391:
4384:
4378:
4373:
4357:
4353:
4349:
4342:
4336:
4331:
4329:
4321:
4316:
4314:
4307:
4305:
4298:
4290:
4288:0-521-83539-9
4284:
4280:
4279:
4271:
4255:
4247:
4240:
4234:
4219:
4215:
4211:
4204:
4202:
4195:
4193:
4186:
4178:
4174:
4173:
4165:
4158:
4157:
4150:
4143:
4137:
4122:
4118:
4114:
4107:
4093:. techlib.com
4092:
4088:
4081:
4079:
4077:
4075:
4066:
4064:1-60680-119-8
4060:
4056:
4055:
4047:
4045:
4043:
4034:
4030:
4029:
4021:
4014:
4013:
4006:
3998:
3994:
3993:
3985:
3971:on 2016-06-04
3970:
3966:
3962:
3955:
3947:
3945:0-471-02450-3
3941:
3937:
3930:
3928:
3919:
3917:0-521-37769-2
3913:
3909:
3908:
3900:
3892:
3890:0-387-95150-4
3886:
3882:
3881:
3876:
3870:
3863:
3858:
3850:
3849:
3842:
3840:
3838:
3836:
3834:
3832:
3825:
3812:
3808:
3801:
3794:
3781:
3777:
3770:
3755:
3748:
3741:
3739:
3730:
3724:
3720:
3716:
3715:
3707:
3700:
3695:
3687:
3685:1-110-37159-4
3681:
3677:
3673:
3672:
3664:
3656:
3655:
3648:
3642:
3637:
3629:
3627:1-60680-119-8
3623:
3619:
3618:
3610:
3604:
3599:
3584:
3580:
3576:
3569:
3561:
3557:
3556:
3548:
3540:
3536:
3535:
3527:
3512:
3505:
3498:
3496:
3494:
3492:
3477:on 2009-10-29
3476:
3472:
3468:
3461:
3452:
3451:
3443:
3435:
3431:
3430:
3421:
3406:
3402:
3395:
3393:
3391:
3389:
3387:
3385:
3383:
3381:
3379:
3370:
3364:
3360:
3359:
3350:
3335:
3331:
3327:
3320:
3318:
3316:
3308:
3303:
3288:
3284:
3277:
3269:
3263:
3259:
3258:
3250:
3248:
3246:
3244:
3242:
3240:
3232:
3219:
3215:
3208:
3206:
3204:
3202:
3186:
3179:
3171:
3165:
3161:
3160:
3152:
3144:
3143:
3135:
3133:
3124:
3118:
3114:
3113:
3105:
3098:
3092:
3077:
3070:
3063:
3055:
3051:
3050:
3042:
3027:
3023:
3016:
3010:
3005:
2999:
2994:
2985:
2981:
2980:
2974:
2970:
2967:
2964:
2960:
2957:
2953:
2949:
2946:
2942:
2938:
2935:
2931:
2927:
2923:
2922:
2918:
2914:
2910:
2907:
2903:
2899:
2896:
2893:
2892:
2888:
2881:
2877:
2872:
2865:
2864:0-86341-227-0
2861:
2858:, IET, 1990,
2857:
2851:
2842:
2836:
2831:
2825:
2820:
2813:
2807:
2800:
2794:
2780:
2774:
2770:
2766:
2762:
2758:
2754:
2750:
2746:
2739:
2729:
2726:
2722:
2718:
2715:
2711:
2707:
2706:
2702:
2696:
2689:
2685:
2681:
2671:
2667:
2663:
2659:
2655:
2651:
2648:In May 1901,
2645:
2637:
2631:
2623:
2619:
2618:
2609:
2601:
2597:
2596:
2588:
2580:
2574:
2570:
2569:
2561:
2559:
2557:
2548:
2542:
2538:
2537:
2529:
2515:on 2007-12-30
2514:
2510:
2503:
2496:
2492:
2489:
2486:
2482:
2479:
2473:
2466:
2462:
2456:
2449:
2443:
2436:
2431:
2424:
2418:
2410:
2404:
2400:
2399:
2391:
2389:
2380:
2378:1-4208-9084-0
2374:
2370:
2369:
2361:
2347:
2343:
2339:
2335:
2331:
2327:
2323:
2315:
2307:
2305:0-521-29681-1
2301:
2297:
2296:
2288:
2286:
2279:
2267:
2263:
2258:
2253:
2249:
2245:
2241:
2240:IEEE Spectrum
2237:
2230:
2224:
2222:
2215:
2201:
2199:9780986488511
2195:
2191:
2187:
2183:
2179:
2175:
2171:
2167:
2159:
2151:
2149:0-471-71814-9
2145:
2141:
2140:
2132:
2124:
2122:0-393-31851-6
2118:
2114:
2113:
2108:
2104:
2098:
2096:
2087:
2081:
2077:
2076:
2068:
2060:
2058:0-7923-8518-7
2054:
2050:
2049:
2041:
2039:
2037:
2028:
2022:
2018:
2017:
2009:
2007:
2005:
2003:
2001:
1992:
1986:
1982:
1981:
1973:
1971:
1969:
1960:
1958:0-8306-3342-1
1954:
1950:
1949:
1941:
1939:
1937:
1935:
1933:
1928:
1919:
1916:
1914:
1911:
1909:
1906:
1904:
1901:
1899:
1896:
1894:
1891:
1890:
1886:
1875:
1862:
1855:
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1843:
1838:
1825:
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1807:
1802:
1792:
1785:
1780:
1767:
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1758:
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1735:
1728:
1723:
1716:
1711:
1710:
1706:
1704:
1700:
1690:
1687:
1671:
1667:
1661:
1657:
1653:
1650:
1642:
1638:
1634:
1629:
1621:
1618:
1614:
1609:
1606:
1602:
1597:
1592:
1591:piezoelectric
1588:
1585:
1584:piezoelectric
1580:
1578:
1573:
1569:
1565:
1564:electromagnet
1561:
1557:
1553:
1544:
1540:
1538:
1537:high fidelity
1530:
1525:
1516:
1514:
1510:
1509:potentiometer
1506:
1500:
1498:
1494:
1489:
1487:
1483:
1479:
1475:
1463:
1459:
1455:
1447:
1443:
1435:
1431:
1427:
1424:
1420:
1414:
1411:
1407:
1403:
1399:
1395:
1391:
1387:
1383:
1379:
1375:
1371:
1367:
1363:
1359:
1355:
1352:
1343:
1336:
1330:
1324:
1320:
1316:
1313:
1309:
1305:
1298:
1291:
1287:
1279:
1274:
1264:
1260:
1258:
1253:
1250:
1245:
1243:
1239:
1235:
1232:Reducing the
1230:
1228:
1223:
1219:
1218:tuned circuit
1215:
1211:
1207:
1203:
1199:
1195:
1192:
1183:
1175:
1166:
1164:
1159:
1157:
1153:
1149:
1144:
1130:
1126:
1123:
1119:
1113:
1111:
1106:
1102:
1086:
1077:
1063:
1060:
1054:
1052:
1048:
1044:
1040:
1035:
1033:
1029:
1028:magnetic core
1025:
1021:
1017:
991:
988:
983:
980:
976:
971:
968:
961:
960:
959:
958:of the coil:
957:
954:
950:
947:
943:
940:
935:
931:
927:
923:
922:tuned circuit
915:
914:tuned circuit
910:
904:Tuned circuit
901:
899:
898:mains powered
894:
890:
886:
882:
872:
870:
866:
862:
858:
853:
851:
847:
846:whip antennas
843:
839:
835:
831:
826:
823:
819:
811:
806:
797:
795:
785:
783:
779:
775:
771:
767:
763:
762:amplification
759:
755:
751:
747:
743:
739:
731:
727:
726:tuned circuit
723:
718:
711:
707:
703:
700:
696:
692:
688:
684:
680:
676:
672:
668:
664:
660:
659:semiconductor
656:
653:
649:
645:
641:
640:radio station
637:
633:
629:
626:
622:
618:
614:
613:
612:
605:
597:
588:
586:
582:
581:'DX' contests
578:
574:
569:
566:
559:
554:
545:
543:
539:
536:
532:
523:
521:
516:
511:
509:
505:
501:
496:
492:
487:
483:
479:
475:
470:
468:
459:
450:
448:
443:
441:
437:
433:
429:
425:
421:
417:
413:
403:
399:
397:
393:
389:
385:
381:
375:
373:
369:
365:
355:
352:
348:
344:
341:
336:
332:
326:
324:
319:
315:
311:
309:
305:
300:
298:
294:
290:
286:
282:
275:(Switzerland)
274:
269:
260:
258:
254:
253:amateur radio
250:
246:
242:
234:
230:
225:
217:
209:
200:
198:
194:
190:
186:
182:
178:
174:
169:
167:
163:
158:
157:around 1920.
156:
151:
147:
146:G. W. Pickard
143:
139:
135:
131:
127:
123:
119:
114:
111:
107:
103:
99:
95:
91:
86:
84:
80:
76:
72:
68:
64:
56:
51:
44:
40:
35:
29:
22:
5741:Multiplexing
5616:Transmission
5581:Nikola Tesla
5571:Henry Sutton
5526:Samuel Morse
5456:Robert Hooke
5421:Amos Dolbear
5356:John Bardeen
5275:
5255:Telautograph
5159:Mobile phone
5114:Edholm's law
5097:social media
5030:Broadcasting
4971:
4965:
4957:
4949:
4941:
4929:. Retrieved
4886:
4877:
4869:
4862:
4793:
4787:
4774:
4765:
4746:
4724:
4715:
4704:
4693:. Retrieved
4688:
4678:
4669:
4664:
4653:
4642:
4631:
4607:
4600:
4597:
4592:
4582:
4575:
4572:
4567:
4558:
4553:
4542:. Retrieved
4531:
4520:. Retrieved
4516:the original
4511:
4501:
4490:. Retrieved
4485:
4472:
4461:. Retrieved
4449:10366/158938
4431:
4427:
4417:
4402:. Retrieved
4397:
4393:
4383:
4372:
4360:. Retrieved
4355:
4351:
4341:
4303:
4297:
4277:
4270:
4258:. Retrieved
4246:
4238:
4233:
4222:. Retrieved
4217:
4213:
4191:
4185:
4171:
4164:
4159:, pp. 96–101
4155:
4149:
4141:
4136:
4125:. Retrieved
4120:
4116:
4106:
4095:. Retrieved
4090:
4053:
4027:
4020:
4011:
4005:
3991:
3984:
3973:. Retrieved
3969:the original
3964:
3954:
3935:
3906:
3899:
3879:
3869:
3864:, p. 57
3857:
3847:
3815:. Retrieved
3810:
3800:
3784:. Retrieved
3779:
3769:
3758:. Retrieved
3753:
3713:
3706:
3701:, p. 48
3694:
3670:
3663:
3653:
3647:
3636:
3616:
3609:
3598:
3587:. Retrieved
3582:
3578:
3568:
3554:
3547:
3533:
3526:
3515:. Retrieved
3510:
3479:. Retrieved
3475:the original
3470:
3460:
3449:
3442:
3428:
3420:
3409:. Retrieved
3404:
3357:
3349:
3338:. Retrieved
3333:
3329:
3302:
3291:. Retrieved
3287:HyperPhysics
3286:
3276:
3256:
3222:. Retrieved
3217:
3189:. Retrieved
3178:
3158:
3151:
3141:
3111:
3104:
3096:
3091:
3080:. Retrieved
3075:
3062:
3048:
3041:
3030:. Retrieved
3028:. Ian Purdie
3025:
3015:
3004:
2993:
2983:
2978:
2972:
2962:
2955:
2951:
2944:
2940:
2933:
2929:
2916:
2905:
2901:
2894:
2887:
2879:
2871:
2855:
2850:
2841:
2830:
2819:
2806:
2793:
2782:. Retrieved
2752:
2748:
2738:
2701:
2687:
2683:
2669:
2665:
2644:
2630:
2616:
2608:
2594:
2587:
2567:
2535:
2528:
2517:. Retrieved
2513:the original
2502:
2472:
2455:
2442:
2430:
2417:
2397:
2367:
2360:
2349:. Retrieved
2329:
2325:
2314:
2294:
2269:. Retrieved
2257:10366/158938
2239:
2229:
2220:
2214:
2203:. Retrieved
2173:
2169:
2158:
2138:
2131:
2111:
2074:
2067:
2047:
2015:
1979:
1947:
1885:Radio portal
1860:
1790:
1696:
1630:
1627:
1610:
1581:
1568:audio signal
1556:loudspeakers
1549:
1533:
1505:forward bias
1501:
1490:
1482:lead pencils
1478:razor blades
1473:
1428:
1418:
1415:
1366:carrier wave
1362:audio signal
1349:The crystal
1348:
1332:
1326:
1319:audio signal
1315:carrier wave
1301:
1261:
1254:
1246:
1233:
1231:
1213:
1209:
1201:
1188:
1160:
1140:
1114:
1098:
1055:
1036:
1024:ferrite core
1012:
955:
948:
941:
919:
889:counterpoise
878:
865:fire escapes
854:
834:AM broadcast
815:
791:
774:AM broadcast
735:
671:audio signal
610:
570:
562:
558:Liberty ship
540:
537:
533:
529:
512:
508:World War II
478:Anzio, Italy
471:
464:
447:vacuum tubes
444:
436:tunnel diode
409:
400:
388:Westinghouse
376:
371:
367:
361:
327:
312:
301:
278:
257:broadcasting
238:
232:
185:AM broadcast
170:
162:vacuum tubes
159:
115:
87:
66:
62:
60:
5941:NPL network
5653:Radio waves
5591:Alfred Vail
5501:Hedy Lamarr
5486:Dawon Kahng
5446:Elisha Gray
5406:Yogen Dalal
5331:Nasir Ahmed
5265:Teleprinter
5129:Heliographs
4796:(1): 31–??.
4394:Radio-Craft
2936:: 299–300.
2895:Radio Revue
2725:"Receiver,"
2658:psilomelane
2602:, 110, 268.
1903:Demodulator
1834: 1925
1816: 1924
1798: 1920
1776: 1917
1703:vacuum tube
1697:During the
1617:transformer
1613:loudspeaker
1601:selectivity
1446:molybdenite
1434:iron pyrite
1354:demodulates
1198:selectivity
1194:transformer
1156:selectivity
1043:capacitance
946:capacitance
869:barbed wire
848:or ferrite
822:alternating
818:radio waves
738:transmitter
710:loudspeaker
667:demodulates
625:radio waves
548:Later years
495:pencil lead
491:razor blade
386:, owned by
291:running at
287:as well as
273:Monteceneri
263:Early years
241:discoveries
142:demodulator
98:loudspeaker
67:crystal set
6074:Categories
5987:Antarctica
5946:Toasternet
5868:Television
5351:Paul Baran
5283:Television
5267:(teletype)
5260:Telegraphy
5238:transistor
5216:Phryctoria
5186:Photophone
5164:Smartphone
5154:Mass media
4931:2016-09-27
4695:2010-05-28
4544:2010-05-27
4522:2010-05-28
4492:2009-12-07
4463:2010-03-28
4404:2010-03-14
4224:2010-03-06
4127:2010-02-10
4097:2009-12-07
3975:2010-02-07
3817:2010-08-19
3793:Stay Tuned
3786:2010-07-19
3760:2009-12-07
3589:2010-01-18
3517:2009-12-07
3481:2010-02-27
3411:2010-02-07
3368:0852967926
3340:2010-01-18
3293:2009-12-06
3231:Stay Tuned
3224:2010-05-28
3191:2010-01-18
3169:0521289033
3122:1922013846
3082:2009-12-07
3032:2009-12-05
2984:Radio News
2979:Radio News
2973:Radio News
2880:Radio News
2784:2010-01-19
2654:Strasbourg
2519:2022-02-20
2463:, Klase's
2351:2010-01-19
2271:2010-03-14
2205:2010-01-19
1924:References
1686:transistor
1641:modulation
1633:rectifiers
1390:rectifying
1358:modulation
1323:modulation
1163:resistance
1016:inductance
953:inductance
861:bedsprings
830:wavelength
750:microwatts
675:modulation
565:Boy Scouts
484:signal of
428:zinc oxide
416:Oleg Losev
406:Crystodyne
380:Pittsburgh
340:demodulate
321:30, 1906,
316:physicist
306:, such as
259:industry.
245:Morse code
166:Boy Scouts
118:rectifying
53:1970s-era
5971:Americas
5960:Locations
5931:Internet2
5692:Bandwidth
5396:Vint Cerf
5293:streaming
5271:Telephone
5211:Semaphore
5102:streaming
2719:In 1907,
2708:In 1906,
2459:Al Klase
1577:impedance
1519:Earphones
1513:I-V curve
1408:called a
1406:capacitor
1222:resonated
1214:secondary
1148:bandwidth
1143:frequency
1105:impedance
1059:resonance
1039:reactance
984:π
934:impedance
930:resonator
926:capacitor
842:long wire
758:picowatts
754:nanowatts
722:capacitor
648:capacitor
636:frequency
619:in which
577:hobbyists
281:spark gap
251:by early
189:shortwave
106:amplifier
94:earphones
6039:Category
5926:Internet
5916:CYCLADES
5833:Ethernet
5783:Concepts
5707:terminal
5658:wireless
5481:Bob Kahn
5324:Pioneers
5149:Internet
5040:Cable TV
4891:Archived
4538:"Diodes"
4458:44288637
4306:, p. 282
4144:, p. 318
3877:(2001).
3405:Skywaves
3309:, p. 144
2731:bornite.
2491:Archived
2481:Archived
2465:SkyWaves
2346:51644366
2266:44288637
2109:(1988).
1871:See also
1596:ear buds
1351:detector
1234:coupling
1152:Q factor
706:earphone
663:detector
661:crystal
646:) and a
644:inductor
585:contests
504:folklore
382:station
304:minerals
134:detector
6059:Commons
6049:Outline
6002:Oceania
5921:FidoNet
5906:ARPANET
5719:circuit
5288:digital
5017:History
4362:10 July
4015:, p. 94
3795:website
3782:: 61–64
3719:398–399
3233:website
2866:, p. 15
2757:Bibcode
2178:Bibcode
1898:Coherer
1693:Gallery
1474:Perikon
1464:(ZnO-Cu
1462:bornite
1458:zincite
1442:silicon
1210:primary
1120:(in an
800:Antenna
766:hearing
617:antenna
424:zincite
314:Bengali
297:coherer
203:History
122:mineral
110:battery
102:passive
39:Radiola
5997:Europe
5967:Africa
5951:Usenet
5911:BITNET
5848:Mobile
5724:packet
5233:MOSFET
5228:device
5025:Beacon
4942:Diodes
4753:
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4285:
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2055:
2023:
1987:
1955:
1757:SCR-54
1605:filter
1560:magnet
1430:Galena
1423:buzzer
1317:. The
885:ground
875:Ground
867:, and
838:metres
820:to an
788:Design
691:galena
493:and a
474:Allied
420:biases
412:Russia
335:pyrite
331:galena
308:galena
295:. The
124:and a
79:galena
5980:South
5975:North
5936:JANET
5873:Telex
5863:Radio
5702:Nodes
5697:Links
5618:media
5196:Radio
5181:Pager
5109:Drums
5075:video
5070:image
5060:audio
4925:(PDF)
4784:(PDF)
4745:[
4482:(PDF)
4454:S2CID
4260:1 May
4035:–281.
3813:: 196
3750:(PDF)
3678:–45.
3541:–131.
3507:(PDF)
3072:(PDF)
2656:used
2342:S2CID
2262:S2CID
1861:(top)
1791:(top)
1635:. As
1374:diode
1360:(the
1150:(low
665:that
573:craze
472:When
126:metal
83:diode
55:Arrow
5992:Asia
5878:UUCP
5838:ISDN
4751:ISBN
4691:: 45
4364:2018
4283:ISBN
4262:2018
4059:ISBN
3940:ISBN
3912:ISBN
3885:ISBN
3723:ISBN
3680:ISBN
3622:ISBN
3436:–18.
3363:ISBN
3262:ISBN
3220:: 42
3164:ISBN
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3056:–94.
2860:ISBN
2773:ISBN
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2080:ISBN
2053:ISBN
2021:ISBN
1985:ISBN
1953:ISBN
1480:and
1448:(MoS
1392:the
1306:The
1249:rack
1110:ohms
920:The
384:KDKA
349:and
283:and
116:The
90:coil
5883:WAN
5853:NGN
5843:LAN
5124:Fax
5065:DCT
4789:QST
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4444:hdl
4436:doi
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