949:"Curtain Burner" sets were common in the early 1930s "midget" sets. The name is an indication of the problem—the line cord contained resistors to drop the voltage and dissipated substantial power in the cord itself. When operating properly and the line cord was stretched to full length, the cord got "warm" and was safe enough (until the heat made the rubber insulation crack). When the cord was coiled up or otherwise insulated (like from a curtain resting on it) it could get very hot, and frequently caused a fire. Resistance line cords are no longer available and the vintage cords are no longer serviceable, so the radio must be partially redesigned with either a dropping capacitor, dropping resistor, or some other workaround for safe operation.
469:, and were merely several stages (typically three) of tuned RF amplifiers in series feeding a detector tube which extracted the audio intelligence from the RF signal. TRF sets, depending on the number of stages they employed, could have poor-to-superb sensitivity (ability of the set to pick up faint signals) and corresponding selectivity (ability to parse adjacent stations from one another). Audio reproduction quality of TRF sets was limited by the available loudspeakers. "High Fidelity" was not to become a radio marketing concept until the mid-1930s and was not realized until the advent of
531:(superhet). RCA had exclusive rights to the superheterodyne circuit patents and extracted high licensing fees from other companies who sought to build superhet sets. RCA also vigorously prosecuted patent infringers. This situation helped propel RCA to the forefront of radio manufacturers in the 1920s due to the higher efficiency of the superhet circuit- a situation which lasted until the patents expired in the early 1930s, at which time a flood of low-cost superheterodyne receivers hit the market. Early (RCA-patent-era) superhets were often used with the relatively expensive
960:
voltage can be connected directly to all the metal parts of the radio any time it is plugged in, regardless of whether it is powered on or not. Proper repair or refurbishment requires an isolation transformer to remove the live connection, and care should be taken to never touch any metal part of the radio (chassis mounting screws, bare control shafts, etc.) when the radio is plugged in. Many radios with a hot chassis use interlocks on the back to ensure that the line is disconnected before the rear can be accessed for tube replacement.
307:
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243:
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66:
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168:
25:
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877:, the earlier ones suitable for audio frequencies only, car radios were valve sets with a transistor output stage; makers promoted them as transistor sets. Some historic car radios badged as transistorised are in reality of this type. All-transistor sets eventually replaced sets with vacuum tube after transistor technology improved and prices fell significantly.
745:, which is the phenolic resin component of bakelite, with no organic filler added, but nearly all historic bakelite radios are the standard black-brown bakelite color. Bakelite as used for radio cabinets was traditionally brown, and this color came from the ground walnut shell flour added to the thermosetting phenolic resin as an extender and strengthening agent.
955:
to manufacture. They are much less common in areas with 240 mains power, as there were few common tubes built to operate at the high voltages required. BC (medium wave/"AM") only radios like the "All
American 5" design, and later AM/FM radios with more tubes, and even televisions were built using the same idea, because of the simplicity and low cost possible.
937:
capacitors are electrically "leaky" and that the electrolytic capacitors in the power supply have either lost capacity (leading to excess "hum") or shorted (potentially causing a damaging or fire-inducing short-circuit). In their original state, they complied only with the limited safety standards of the time, and almost none used fuses.
623:, from a bank of lead-acid storage batteries charged from a gas powered generator or a wind-charger. The 32-volt system could also power other specially made appliances as well as electric lights around the farm. Other farm radios, especially from the late 1930s to the 1950s, reverted to using a large "A-B" dry cell that provided both
792:. They were convenient, though the prices were initially high and the sound quality of early models was not nearly as good as tube radios. Later models equalled or surpassed tube models in audio quality. Transistors also made it possible to manufacture portable FM radios, which was impractical using tubes.
954:
AC/DC sets lacking resistance line cords instead used tube filaments in series that added up to the line voltage, effectively moving the resistance into the radio. They use conventional line cords. These are the most common vintage radio in the US after about 1940 or so, as they were very inexpensive
959:
Either type of AC/DC radio can present the "hot" line of the line voltage on the chassis of the radio ("hot chassis") or isolated from the chassis by a single capacitor ("warm chassis"). This presents a safety problem, as depending on the direction of the non-polarized plug, the hot side of the line
651:
radio receiver cobbled together from whatever parts one could make (which were very few indeed) or scrounged from junked equipment. Such a set typically used salvaged domestic wiring for an antenna, a double-edged safety-razor blade and pencil lead (or bent safety-pin) for a detector, and a tin can,
944:
AC/DC sets using a no power transformer may be either "curtain burners" using a resistance cord to drop the line voltage, or warm/hot chassis radios using a series-string filament circuit where the voltages add up to the line voltage. They were named "AC/DC" because they operated on either AC or DC
963:
Later transistor-based AC table radios typically used power transformers and operate safely, but with likely hum from failed electrolytic capacitors in the power supply, and likely low volume from other failed electrolytic coupling capacitors. There were a few early transistor table radios using
884:
announced an all-transistor car radio in the April 28, 1955, edition of the Wall Street
Journal. This Philco car radio model was the first tubeless auto set in history to be developed and produced. It was a $ 150 option for 1956 Chrysler and Imperial cars and hit the showroom floor on October 21,
606:
of 1936, the vast majority of rural farms in
America did not have electricity. Many rural areas of the Midwest and South did not receive commercial power until the 1960s. Until that point, special radios were made to run on DC power. The earliest so-called "farm radios" used the "A", "B", and "C"
498:
Early TRF sets had typically two or three tuning knobs and tube filament voltage-control rheostats, all of which had to be set correctly to receive a station. Later (late 1920s) TRF sets had ganged tuning (one knob was used to control all stage tuning capacitors simultaneously), AC house current
936:
Using vintage radios generally requires inspection and repair or refurbishment before they can be safely operated. In most cases, at least the power supply section of line-operated radios must be refurbished to prevent damage to other components, but it can be assumed that most of the vintage
664:. Tending to be a major acquisition for a middle-class family, these large radios were usually placed in living rooms. Most early console radios were tall and narrow, but as the years went on they got shorter and wider in accordance with the Art Deco design precepts which had become popular
1216:
were mostly of sufficient quality that the radio's characteristics become significant. Transformer coupled sets suffered loss of bass & reduced treble, grid leak sets where rf and af were amplified by the same valve gave some nonlinearity, and output stages always provided a little more
487:. This approach provided high performance with a minimum number of expensive vacuum tubes, but these receivers tended to radiate RF interference in their immediate vicinity. Consequently, there was a significant amount of hostility by neighbors of "regen" set users over maladjusted
325:
in
Detroit. More stations opened in cities across North America in the following years and radio ownership steadily gained in popularity. Radio sets from before 1920 are rarities, and are probably military artifacts. Sets made prior to approximately 1924 were usually made on wooden
439:, despite the expense. The sound quality produced from "moving-iron" speakers used on such sets is sometimes described as torturous, although by the late 1920s the Kellogg-Rice dynamic (moving-coil) speaker had begun to find favor due to its superior sound-reproduction ability.
499:
operation, and eliminated the filament voltage adjustments. All of these changes greatly simplified operation and made radio a household appliance that even a small child could operate, instead of the highly skilled hobbyists of the brief preceding generation.
733:
allowed designers much more creativity in cabinet styling, and significantly reduced costs. However, Bakelite is a very brittle plastic, and dropping a radio could easily crack or break the case. Bakelite is a brown-black mouldable
330:, in small cupboard style cabinets, or sometimes on an open sheet metal chassis. Homemade sets remained a strong sector of radio production until the early 1930s. Until then there were more homemade sets in use than commercial sets.
866:. Vibrators are relatively unreliable as electromechanical components of limited life, buzz audibly, and produce radio interference. A few radios used a bulkier and more expensive motor-generator or motor-alternator set called a "
618:
to create a pulsating DC current that could be stepped up through a transformer to create the high voltage needed for the plates of the tubes- exactly as contemporary car radios did. Other farm radios were designed to run on
940:
AC-operated radios using power transformers require repair and refurbishment of the power supply section before operation, as any failures are likely to stress or damage the power transformer, necessitating a costly repair.
1125:, usually horn or cone loaded, and occasionally disc loaded. The sound quality of such radios is generally unimportant, since almost any defect in the audio signal will be masked by the butchery visited upon it by the
818:
Today's radios are usually uneconomical to repair because mass production and technological improvements in numerous areas have made them so inexpensive to buy, while the cost of human labor and workshop
1184:
student, on hearing some of the specs of these devices, to conclude that they could not have been capable of reproducing speech. Yet they do, and with a sound that can not be mistaken for anything else.
979:
However other not all-in-one types of pre-Depression-era radio are more demanding to put into service, being a long way from plug & play. Setting up such radios requires a bit of electronics skill.
652:
magnet and some wire for an earpiece. Razor blades of the era were chemically coated ("blued") and this coating could function as a diode, in the same way that a galena cat's whisker detector operates.
1291:
808:
There was something of a marketing war over the number of transistors sets contained, with many models named after this number. Some sets even had non-functional reject transistors soldered to the
660:
The console radio was the center piece of household entertainment in the era of radio. They were big and expensive, costing hundreds of dollars in the late 1930s and were often coupled with a
389:. They would receive only very strong signals from a local station. They were popular among the less wealthy due to their low build cost and zero run cost. Crystal sets had minimal ability to
1075:
The sound quality of antique radios depends on the technologies used in the set. The type of speaker is the main differentiator, with mains or battery also making a significant difference.
870:" that spun a high-voltage generator or alternator using a 6- or 12-volt DC motor. Filaments were powered using 6- and later 12-volt DC power from the vehicle's electrical system directly.
720:"Table top" are rectangular, with width being the larger dimension. Table top radios are usually placed in the kitchen, living room, or bedroom, and sometimes used out on the porch.
815:
Vacuum tube radios and early transistor radios were hand assembled. Today radios are designed with the assistance of computers and manufactured with much greater use of machinery.
1367:
594:
In general the technical and manufacturing advantages of the superhet ensured that the TRF set became quickly obsolete once the patent restrictions on superhets were eliminated.
805:
Transistor radios appeared on the market in 1954, but at a high price. By the 1960s, reduced prices and an increase in desire for portability made them very popular.
972:
The minority of all-in-one commercial ac mains sets that appeared in the 1930s are plug & play. Such sets should be checked for the possible existence of live
897:
sets needed a few seconds for the valves to heat up, though there were exceptions. Warm-up times changed as valves went through several generations of design.
1205:, and provided a relatively pleasant listening experience. The main defect of ID speakers was poor treble response, giving them a characteristic dull drone.
1715:
1082:
sets produce 2nd harmonic distortion, which is fairly euphonic. Some also produce significant 3rd harmonic distortion, which is less pleasant to the ear.
843:
The earliest car radios appeared not long after commercial radio broadcasts commenced, but were experimental only. They were expensive, required a large
317:
The idea of radio as entertainment took off in 1920, with the opening of the first stations established specifically for broadcast to the public such as
607:
batteries typical of 1920s radio sets; these farm radios were identical to those used in cities. Somewhat later, farm radios were made to be run on
492:
1173:
They were far from faithful in their reproduction of audio, and their technical specifications were poorly controlled. An example of this is their
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produced, but these issues seem to be secondary in practice to the ones discussed in this article, and are already well covered in other articles.
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1415:
542:
Most post-1932 commercial radios were superhets, and this technology is still in widespread use in radio receivers today, implemented with
1129:. The question of sound quality is heavily dominated by the speaker in these cases. Moving iron speakers suffer the following defects:
1059:
The user should realise that permitting historic reaction sets to oscillate causes them to transmit interference, which is illegal.
676:
904:
Direct dull emitters typical of the late '20s and 1930s came on in around a second. This type of valve continued to be popular in
802:
containing a large number of transistors has surpassed the use of singly packed transistors for the majority of radio circuitry.
2417:
2412:
2402:
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2184:
798:
were available in many sizes from console to table-top to matchbox. Transistors are still used in today's radios, though the
130:
393:, and where more than one high power station was present, inability to receive one without the other was a common problem.
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Tendency of the moving iron to stick to the pole piece, resulting in a 'whack' sound followed by very little sound output.
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circuit patents and it was more profitable for companies to jump into radio manufacturing TRF sets. These used several
359:
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Some premium makers such as E. H. Scott and Silver-Marshall started around $ 500–$ 800 range in the 1930s and 1940s.
229:
211:
149:
109:
52:
1042:
Some means to keep fingers away from the exposed live connections on the rear is wise, and often legally obligatory.
193:
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1606:
1408:
1198:
901:
Bright emitter valves universal in the early 1920s came on in a small fraction of a second, effectively instantly.
400:
or a mechanical turntable amplifier to give enough output to operate a speaker. Some even used a flame amplifier.
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788:
made it possible to produce very small portable radios that did not need a warm-up time, and ran on much smaller
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38:
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675:, General Electric, Montgomery Ward (under the Airline brand name), Sears (under the Silvertone brand name),
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Ease of designing the set for multiple-band operation, enabling reception of foreign broadcasts ("Shortwave")
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Indirect emitters used in more or less all mains valve radios from the late 1930s onward were slow to reach
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With 1920s and earlier sets using bright emitter valves, the end user should understand the use of the
1005:
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accessible to the user, and a general safety check is advisable. Many will need a repair of some sort.
1066:
sets should have their ground capacitor bypassed to convert them from live chassis to earthed chassis.
2500:
2085:
2046:
1891:
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1720:
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in the 1950s made brighter designs practical. Some of these thermoplastics are slightly translucent.
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1986:
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847:, reception was inconsistent, and they required adjustment in use, which was not very practical.
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1991:
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812:, doing absolutely nothing, so the sales pitch could advertise a higher number of transistors.
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The first radio receivers used a coherer and sounding board, and were only able to receive
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made a few high priced models ("Stratosphere") mainly produced moderately priced radios
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and a select number of competing "prestige" radio manufacturers could afford to build a
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1946:
1921:
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Some of these sets never worked very well and may benefit from some skilled debugging
480:
435:, but by the mid-1920s it was more common to use additional amplification to power a
1966:
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became possible, although Morse code transmission continued in use until the 1990s.
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Need for specialized test equipment to perform conversion-stage filter alignments.
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Failed components are to be expected, and these must be fault-found then repaired
851:
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717:"Tombstone style" are rectangular boxes that are tall and narrow like a tombstone
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420:
280:
272:
1390:- Website dedicated to collecting radios and perpetuating the love of the hobby.
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290:
All the following sections concern speech-capable radio, or wireless telephony.
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2001:
1976:
1936:
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1956:
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for the tube filaments, as did most tube-based portable radios of that era.
2156:
1996:
1941:
1871:
1836:
1771:
1670:
1660:
1512:
702:
1221:
equipped set can be pleasant, and mistakable for a modern portable radio.
1015:
A little detective work is needed to find out what PSU voltages are needed
858:
to step up the low voltage to high voltage ("B+" voltage of anywhere from
242:
2356:
2006:
1916:
1901:
1861:
1821:
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1218:
1213:
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863:
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424:
298:
1260:"Chrysler Promises Car Radio With Transistors Instead of Tubes in '56".
1177:, which varied across the audio spectrum by a ratio of more than 100:1.
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639:
World War 2 created widespread urgent need for radio communication, and
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2068:
1766:
1675:
1631:
1601:
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The sound of moving iron speakers has a strong unmistakable character.
1105:
874:
785:
661:
432:
386:
327:
276:
1025:
Fitting a local ground (earth) is frequently necessary, and quite easy
2346:
1811:
1626:
1393:
1101:
1097:
973:
867:
820:
428:
318:
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avoids the uncontrolled tone variations of TRF sets, and gives good
196:. Statements consisting only of original research should be removed.
65:
2341:
2331:
2248:
2073:
1896:
1063:
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945:
line voltage, which was not possible with a transformer-based set.
919:
761:
730:
573:
508:
322:
643:
were built by people without access to traditional radio parts. A
2336:
2321:
1539:
1090:
922:. These tiny devices reached emission temperature fairly quickly.
850:
By the early 1930s most car radios, no longer experimental, were
742:
258:
receiving set that is collectible because of its age and rarity.
1388:
WhiteRadios.com - Antique Radio
Gallery, History, and Appraisals
714:"Cathedral style", an upright rectangular box with a rounded top
2366:
2326:
1648:
1376:
1086:
881:
672:
2351:
2288:
1596:
1145:
Strong undamped resonance in the middle of the audio spectrum
488:
412:
385:, had no amplification and could operate only high-impedance
255:
915:
temperature, with wait times routinely exceeding 10 seconds.
2293:
996:
3 power supplies are needed to replace the originally used
753:
610:
515:, and again settings had to be right to achieve reception.
1318:"Mopar 914-HR Ch= C-5690HR Car Radio Philco, Philadelphia"
427:(tubes) to provide RF amplification, detection, and audio
1193:
These enjoyed brief success but were quickly eclipsed by
668:
524:
1383:
Timo's
Radiopages - Antique Radio Collection in Finland
1148:
Noisy chattering when presented with a loud bass note
964:"hot chassis" principles, but these are very rare.
729:
The availability of the first mass-produced plastic
333:Early sets used any of the following technologies:
90:. Unsourced material may be challenged and removed.
1085:Discussion is often heard about the distortion of
706:Wood-look Bakelite Tabletop set from the late '40s
535:, which offer a quality of sound unavailable from
1292:"1955: Chrysler's All-Transistor Mopar Car Radio"
830:Typical insides of an antique radio, showing the
741:In the 1930s some radios were manufactured using
2487:
1121:Homemade pre-war sets usually used some form of
931:
772:The affordability of more modern light coloured
479:, also known as regenerative receivers, rely on
411:(TRF sets) were the most popular class of early
967:
689:
679:, Motorola, Zenith and others. Brands such as
1409:
1342:http://wpchryslermuseum.org/page.aspx?pid=436
990:Repair of parts is practical, but not trivial
403:
738:, and is still used in some products today.
518:
2424:Global telecommunications regulation bodies
1275:"Chrysler Announces New Transistor Radio".
1188:
491:transmitting squealing noises and blocking
53:Learn how and when to remove these messages
2460:
1416:
1402:
779:
583:The disadvantages before about 1932 were:
1243: – List of specific models of radios
456:tin can, magnet & wire based speakers
261:
230:Learn how and when to remove this message
212:Learn how and when to remove this message
150:Learn how and when to remove this message
1366:) is being considered for deletion. See
1217:non-linearity. However the quality of a
926:
825:
760:
752:
701:
693:
614:from a car or tractor battery, using an
305:
297:
241:
16:Vintage telecommunication audio receiver
1163:Horn speakers were strongly directional
293:
2488:
1423:
1208:
1116:
823:have increased greatly in comparison.
1397:
1289:
1201:solved the worst problems of earlier
710:Table top radios came in many forms:
667:Consumer console radios were made by
557:Excellent sensitivity and selectivity
2470:
1111:
983:There are several issues with them:
285:transmission and reception of speech
246:DIORA AGA RSZ-50 ca.1947 from Poland
161:
88:adding citations to reliable sources
59:
18:
345:with carbon or mechanical amplifier
13:
1166:Cone speakers were readily damaged
1008:(unless self-biasing is used) (or
918:The last generation of valves was
655:
266:
14:
2517:
1370:to help reach a consensus. ›
1349:
634:
553:The advantages of superhets are:
302:Homemade two tube radio from 1958
275:(CW) transmissions, encoded with
34:This article has multiple issues.
2469:
2459:
2450:
2449:
2438:
2059:Free-space optical communication
1290:Hirsh, Rick (16 November 2020).
1136:Heavy intermodulation distortion
1070:
523:In the era of early radio, only
350:Tuned Radio Frequency (TRF) Sets
166:
64:
23:
888:
757:Early '50s AC/DC tabletop radio
431:. Early TRF sets only operated
396:Some crystal set users added a
370:
75:needs additional citations for
42:or discuss these issues on the
1335:
1310:
1283:
1268:
1253:
908:sets for several decades more.
748:
597:
310:1930s style homemade one-tube
1:
1355:
1247:
932:Line-operated commercial sets
838:
2445:Telecommunication portal
2226:Telecommunications equipment
1264:. April 28, 1955. p. 1.
1104:, which affect the types of
587:High patent-licensing costs.
419:(RCA) had a monopoly on the
417:Radio Corporation of America
7:
1962:Alexander Stepanovich Popov
1279:. May 8, 1955. p. A20.
1224:
968:Early battery-operated sets
724:
698:Wood tabletop set from 1941
690:Table-top wood-cased radios
381:These basic radios used no
360:Super-Regenerative Receiver
192:the claims made and adding
10:
2522:
1666:Telecommunications history
616:electromechanical vibrator
409:Tuned radio frequency sets
404:Tuned radio frequency sets
374:
2433:
2375:
2312:
2274:Public Switched Telephone
2234:
2198:
2155:
2096:
2086:telecommunication circuit
2047:Fiber-optic communication
2030:
1792:Francis Blake (telephone)
1739:
1587:Optical telecommunication
1431:
1180:It is not unusual for an
873:With the introduction of
604:Rural Electrification Act
519:Superheterodyne receivers
2185:Orbital angular-momentum
1622:Satellite communications
1461:Communications satellite
1368:templates for discussion
1199:Inductor Dynamic Speaker
1189:Inductor dynamic speaker
1160:Prone to demagnetisation
1154:Gross impedance mismatch
627:for the tube plates and
529:superheterodyne receiver
442:Speakers widely used on
415:, primarily because the
365:Superheterodyne Receiver
2064:Molecular communication
1887:Gardiner Greene Hubbard
1716:Undersea telegraph line
1451:Cable protection system
1022:will need to be erected
780:Early transistor radios
2206:Communication protocol
1992:Charles Sumner Tainter
1807:Walter Houser Brattain
1752:Edwin Howard Armstrong
1560:Information revolution
835:
769:
758:
707:
699:
495:on nearby properties.
314:
303:
262:Types of antique radio
247:
2180:Polarization-division
1912:Narinder Singh Kapany
1877:Erna Schneider Hoover
1797:Jagadish Chandra Bose
1777:Alexander Graham Bell
1508:online video platform
1231:Vintage amateur radio
927:Use of vintage radios
856:vibrator power supply
829:
784:The invention of the
764:
756:
736:thermosetting plastic
705:
697:
309:
301:
245:
2022:Vladimir K. Zworykin
1982:Almon Brown Strowger
1952:Charles Grafton Page
1607:Prepaid mobile phone
1535:Electrical telegraph
1195:moving coil speakers
1175:electrical impedance
1142:Poor treble response
1139:Little bass response
537:moving iron speakers
533:moving coil speakers
483:to achieve adequate
294:Early home-made sets
84:improve this article
1972:Johann Philipp Reis
1731:Wireless revolution
1693:The Telephone Cases
1550:Hydraulic telegraph
1262:Wall Street Journal
1209:Moving coil speaker
1157:Need for adjustment
1133:Gross non-linearity
1123:moving iron speaker
1117:Moving iron speaker
548:integrated circuits
460:moving coil speaker
451:Moving iron speaker
281:wireless telegraphy
2170:Frequency-division
2147:Telephone exchange
2017:Charles Wheatstone
1947:Jun-ichi Nishizawa
1922:Innocenzo Manzetti
1857:Reginald Fessenden
1592:Optical telegraphy
1425:Telecommunications
836:
800:integrated circuit
770:
759:
708:
700:
321:in Pittsburgh and
315:
312:regenerative radio
304:
248:
177:possibly contains
2506:Radio electronics
2483:
2482:
2221:Store and forward
2216:Data transmission
2130:Network switching
2081:Transmission line
1927:Guglielmo Marconi
1892:Internet pioneers
1757:Mohamed M. Atalla
1726:Whistled language
1277:Los Angeles Times
1203:moving iron types
1112:Loudspeaker types
796:Transistor radios
481:positive feedback
465:TRF sets used no
391:separate stations
240:
239:
232:
222:
221:
214:
179:original research
160:
159:
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57:
2513:
2501:History of radio
2473:
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2441:
2314:Notable networks
2304:Wireless network
2244:Cellular network
2236:Types of network
2211:Computer network
2098:Network topology
2012:Thomas A. Watson
1867:Oliver Heaviside
1852:Philo Farnsworth
1827:Daniel Davis Jr.
1802:Charles Bourseul
1762:John Logie Baird
1471:Data compression
1466:Computer network
1418:
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1236:History of radio
1062:Negative supply
861:
860:90 to 250 V
852:superheterodynes
767:transistor radio
630:
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613:
566:Well controlled
398:carbon amplifier
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1735:
1555:Information Age
1427:
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1322:Radiomuseum.org
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970:
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751:
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692:
658:
656:Wooden consoles
637:
628:
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572:Well shaped RF
521:
471:FM broadcasting
446:sets included:
421:superheterodyne
406:
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296:
273:continuous wave
269:
267:Morse receivers
264:
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99:"Antique radio"
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2165:Space-division
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2019:
2014:
2009:
2004:
2002:Camille Tissot
1999:
1994:
1989:
1984:
1979:
1977:Claude Shannon
1974:
1969:
1967:Tivadar Puskás
1964:
1959:
1954:
1949:
1944:
1939:
1937:Antonio Meucci
1934:
1929:
1924:
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1914:
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1907:Charles K. Kao
1904:
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1882:Harold Hopkins
1879:
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1782:Emile Berliner
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1721:Videotelephony
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1350:External links
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1241:List of radios
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1214:These speakers
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635:Foxhole radios
633:
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563:High stability
561:
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453:(horn or cone)
405:
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375:Main article:
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2190:Code-division
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2175:Time-division
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2101:and switching
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2052:optical fiber
2050:
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2042:Coaxial cable
2040:
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1957:Radia Perlman
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1847:Lee de Forest
1845:
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1842:Thomas Edison
1840:
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1832:Donald Davies
1830:
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1817:Claude Chappe
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1071:Sound quality
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880:Chrysler and
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645:foxhole radio
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605:
602:Prior to the
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503:also had the
502:
501:Reaction sets
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477:Reaction sets
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429:amplification
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378:
377:Crystal radio
366:
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355:Reaction Sets
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252:antique radio
244:
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205:
202:December 2019
195:
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181:
180:
175:This article
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104:
101: –
100:
96:
95:Find sources:
89:
85:
79:
78:
73:This article
71:
67:
62:
61:
56:
54:
47:
46:
41:
40:
35:
30:
21:
20:
2157:Multiplexing
2032:Transmission
1997:Nikola Tesla
1987:Henry Sutton
1942:Samuel Morse
1872:Robert Hooke
1837:Amos Dolbear
1772:John Bardeen
1691:
1671:Telautograph
1575:Mobile phone
1530:Edholm's law
1513:social media
1446:Broadcasting
1361:
1337:
1325:. Retrieved
1321:
1312:
1300:. Retrieved
1295:
1285:
1276:
1270:
1261:
1255:
1212:
1192:
1179:
1172:
1169:
1120:
1098:single ended
1084:
1077:
1074:
1018:A long wire
982:
978:
971:
962:
958:
943:
939:
935:
892:
889:Warm-up time
879:
872:
864:vacuum tubes
849:
842:
832:vacuum tubes
817:
814:
807:
804:
794:
783:
771:
740:
728:
709:
685:
677:Westinghouse
666:
659:
649:crystal sets
647:is a simple
641:foxhole sets
638:
621:32 V DC
601:
593:
582:
552:
541:
522:
497:
475:
467:regeneration
464:
441:
407:
395:
380:
371:Crystal sets
332:
316:
289:
270:
251:
249:
226:
208:
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176:
146:
137:
127:
120:
113:
106:
94:
82:Please help
77:verification
74:
50:
43:
37:
36:Please help
33:
2357:NPL network
2069:Radio waves
2007:Alfred Vail
1917:Hedy Lamarr
1902:Dawon Kahng
1862:Elisha Gray
1822:Yogen Dalal
1747:Nasir Ahmed
1681:Teleprinter
1545:Heliographs
1356:‹ The
1219:moving coil
1182:electronics
1127:loudspeaker
1039:) is needed
1037:transformer
1006:C batteries
875:transistors
854:and used a
749:Plastic era
598:Farm radios
578:selectivity
544:transistors
507:adjustment
437:loudspeaker
343:Crystal set
338:Crystal set
328:breadboards
2490:Categories
2403:Antarctica
2362:Toasternet
2284:Television
1767:Paul Baran
1699:Television
1683:(teletype)
1676:Telegraphy
1654:transistor
1632:Phryctoria
1602:Photophone
1580:Smartphone
1570:Mass media
1296:allpar.com
1248:References
1106:distortion
862:) for the
839:Car radios
786:transistor
662:phonograph
629:1.5 V
433:headphones
387:headphones
277:Morse code
186:improve it
140:March 2008
110:newspapers
39:improve it
2387:Americas
2376:Locations
2347:Internet2
2108:Bandwidth
1812:Vint Cerf
1709:streaming
1687:Telephone
1627:Semaphore
1518:streaming
1102:push pull
1050:rheostats
1030:impedance
974:metalwork
920:nuvistors
868:dynamotor
821:overheads
790:batteries
625:90 V
568:bandwidth
511:for each
509:rheostats
493:reception
283:). Later
190:verifying
45:talk page
2496:Antiques
2455:Category
2342:Internet
2332:CYCLADES
2249:Ethernet
2199:Concepts
2123:terminal
2074:wireless
1897:Bob Kahn
1740:Pioneers
1565:Internet
1456:Cable TV
1358:template
1327:30 March
1225:See also
1064:DC mains
1056:failure.
1047:filament
1010:DC mains
913:emission
731:Bakelite
725:Bakelite
574:passband
505:filament
2475:Commons
2465:Outline
2418:Oceania
2337:FidoNet
2322:ARPANET
2135:circuit
1704:digital
1433:History
1360:below (
1302:14 June
1298:(Forum)
1100:versus
1091:pentode
1089:versus
1033:speaker
1028:A high
1020:antenna
906:battery
743:Catalin
609:6
383:battery
184:Please
124:scholar
2413:Europe
2383:Africa
2367:Usenet
2327:BITNET
2264:Mobile
2140:packet
1649:MOSFET
1644:device
1441:Beacon
1377:Curlie
1363:Curlie
1197:. The
1096:, and
1094:valves
1087:triode
885:1955.
882:Philco
845:aerial
681:Zenith
673:Philco
489:radios
425:valves
348:Basic
126:
119:
112:
105:
97:
2396:South
2391:North
2352:JANET
2289:Telex
2279:Radio
2118:Nodes
2113:Links
2034:media
1612:Radio
1597:Pager
1525:Drums
1491:video
1486:image
1476:audio
1080:valve
1054:valve
895:valve
893:Most
765:'50s
513:valve
413:radio
256:radio
254:is a
131:JSTOR
117:books
2408:Asia
2294:UUCP
2254:ISDN
1329:2013
1304:2024
1078:All
1035:(or
1004:and
485:gain
319:KDKA
103:news
2299:WAN
2269:NGN
2259:LAN
1540:Fax
1481:DCT
1375:at
669:RCA
546:or
525:RCA
444:TRF
323:WWJ
250:An
188:by
86:by
2492::
1320:.
1294:.
1012:).
1000:,
671:,
550:.
539:.
473:.
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2426:)
2422:(
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1410:t
1403:v
1379:.
1331:.
1306:.
1002:B
998:A
834:.
611:V
279:(
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227:(
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209:(
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200:(
182:.
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147:(
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138:(
128:·
121:·
114:·
107:·
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55:)
51:(
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