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1071:. At the receiver, these pulses were sometimes directly recorded on paper tapes, but more common was audible reception. The pulses were audible as beeps in the receiver's earphones, which were translated back to text by an operator who knew Morse code. These spark-gap transmitters were used during the first three decades of radio (1887–1917), called the
1441:
1413:
1425:
1350:
1308:
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914:
to get a signal at the desired frequency. Modern designs more commonly use an oscillator at the operating frequency which is stabilized by phase locking to a very stable lower frequency reference, usually a crystal oscillator.
571:
lines. The antenna in the center is two vertical metal rods, with an alternating current applied at its center from a radio transmitter (not shown). The voltage charges the two sides of the antenna alternately positive
1366:
1419:
One of the BBC's first broadcast transmitters, early 1920s, London. The 4 triode tubes, connected in parallel to form an oscillator, each produced around 4 kilowatts with 12 thousand volts on their anodes.
356:, which radiates the energy as radio waves. The antenna may be enclosed inside the case or attached to the outside of the transmitter, as in portable devices such as cell phones, walkie-talkies, and
923:
Two radio transmitters in the same area that attempt to transmit on the same frequency will interfere with each other, causing garbled reception, so neither transmission may be received clearly.
934:
For this reason, in most countries, use of transmitters is strictly controlled by law. Transmitters must be licensed by governments, under a variety of license classes depending on use such as
966:
consisting of a string of letters and numbers which must be used as an identifier in transmissions. The operator of the transmitter usually must hold a government license, such as a
843:
than AM or FM. In OFDM multiple radio carrier waves closely spaced in frequency are transmitted within the radio channel, with each carrier modulated with bits from the incoming
1055:
developed the first practical radio communication systems using these transmitters, and radio began to be used commercially around 1900. Spark transmitters could not transmit
1360:
transmitter which generated continuous waves using an electric arc in a magnetic field, a technology used for a brief period from 1903 until vacuum tubes took over in the 20s
643:
range above about 20 kHz, the oscillating coupled electric and magnetic fields will radiate away from the antenna into space as an electromagnetic wave, a radio wave.
927:
with radio transmissions can not only have a large economic cost, it can be life-threatening (for example, in the case of interference with emergency communications or
658:
alternating current to apply to the antenna, and the antenna radiates the energy from this current as radio waves. The transmitter also encodes information such as an
1334:
305:
of information over a distance. The information is provided to the transmitter in the form of an electronic signal called the modulation signal, such as an
1992:
851:
are being sent simultaneously, in parallel. At the receiver the carriers are demodulated and the bits are combined in the proper order into one bitstream.
910:
range, free running oscillators are unstable at the output frequency. Older designs used an oscillator at a lower frequency, which was multiplied by
631:
around the conductor. The alternating voltage will also charge the ends of the conductor alternately positive and negative, creating an oscillating
670:, the waves excite similar (but less powerful) radio frequency currents in it. The radio receiver extracts the information from the received waves.
1533:
1563:
360:. In more powerful transmitters, the antenna may be located on top of a building or on a separate tower, and connected to the transmitter by a
736:. This is done by varying some aspect of the carrier wave. The information is provided to the transmitter as an electronic signal called the
1161:
in 1933, who showed that it was less vulnerable to noise and static than AM. The first FM radio station was licensed in 1937. Experimental
2700:
2672:
2667:
1692:
898:, in which the power is reflected back from the antenna toward the transmitter, wasting power and sometimes overheating the transmitter.
808:
399:
35 kW, Continental 816R-5B FM transmitter, belonging to
American FM radio station KWNR broadcasting on 95.5 MHz in Las Vegas
800:) transmitter, which transmits digital data, the frequency of the carrier is shifted between two frequencies which represent the two
967:
973:
Exceptions to the above regulations allow the unlicensed use of low-power short-range transmitters in consumer products such as
894:
to the antenna), to transfer power efficiently to the antenna. If these impedances are not equal, it causes a condition called
2694:
418:, the ICOM IC-746PRO. It can transmit on the amateur bands from 1.8 MHz to 144 MHz with an output power of 100 W
493:
control contains a low-power 2.4 GHz transmitter that sends coded commands to the garage door mechanism to open or close.
2777:
2689:
2679:
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1067:
which turned the transmitter on-and-off to produce radio wave pulses spelling out text messages in telegraphic code, usually
951:
514:
1826:
2751:
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because it produces the radio waves which "carry" the information through space. In most modern transmitters, this is a
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1573:
1543:
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2550:
1604:
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1090:
Two short-lived competing transmitter technologies came into use after the turn of the century, which were the first
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79:
57:
970:, which is obtained by passing a test demonstrating adequate technical and legal knowledge of safe radio operation.
50:
2335:
1883:
1685:
333:. The information can be added to the carrier in several different ways, in different types of transmitters. In an
261:. This usage typically includes both the transmitter proper, the antenna, and often the building it is housed in.
2772:
2446:
1114:
517:, automated microwave transmitters and receivers operating on 2.4 GHz which exchange data packets with the
2441:
2466:
1376:, a huge rotating machine used as a radio transmitter at very low frequency from about 1910 until World War 2
1284:
1590:
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2502:
2399:
1942:
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1709:
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in 1887 during his pioneering investigations of radio waves. These generated radio waves by a high voltage
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1087:
which interfered with other transmitters. Damped wave emissions were banned by international law in 1934.
1013:(FCC) regulations. Although they can be operated without a license, these devices still generally must be
2731:
2238:
1678:
1661:
Major UK television transmitters including change of group information, see
Transmitter Planning section.
862:
are also used. In large transmitters the oscillator and modulator together are often referred to as the
1435:, New York City, used for secret tests 1934–1935. It transmitted on 41 MHz at a power of 2 kW.
2590:
2512:
2451:
2158:
1481:
828:
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into the radio frequency current to be carried by the radio waves. When they strike the antenna of a
461:
A cellphone has several transmitters: a duplex cell transceiver, a Wi-Fi modem, and a
Bluetooth modem.
2362:
2323:
2168:
2068:
1997:
1930:
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and navigational transmitters. Generators of radio waves for heating or industrial purposes, such as
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172:
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1963:
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513:(background) which connects it to the Internet, creating a home Wi-Fi network. Both have Wi-Fi
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2083:
2028:
2023:
1836:
1801:
1512:
797:
258:
61:
1035:
Hertz discovering radio waves in 1887 with his first primitive radio transmitter (background).
242:
equipment, are not usually called transmitters, even though they often have similar circuits.
2384:
2188:
2153:
2073:
2053:
1975:
1863:
1784:
1432:
1318:
1079:, spark transmitters were electrically "noisy". Their energy was spread over a broad band of
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transmitting on 27 MHz with a power of 4 W, that can be operated without a license
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Transmitters are necessary component parts of all electronic devices that communicate by
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1236:) in portable devices operate automatically, in the background, to exchange data with
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transmission had been conducted by radio stations since the late 1920s, but practical
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circuit to add the information to be transmitted to the carrier wave produced by the
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earbud with microphone. It has a
Bluetooth modem to exchange audio with a cell phone
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584:. Loops of electric field (black lines) leave the antenna and travel away at the
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to various classes of users. In some classes, each transmitter is given a unique
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contain low power 2.4 GHz radio transmitters to communicate with each other.
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782:(strength) of the carrier wave is varied in proportion to the modulation signal.
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588:; these are the radio waves. This animation shows the action slowed enormously
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and are restricted to certain frequencies and power levels. A body called the
875:
to increase the power of the signal, to increase the range of the radio waves.
337:(AM) transmitter, the information is added to the radio signal by varying its
325:
signal which when applied to the antenna produces the radio waves, called the
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allowed the development in the 1960s of small portable transmitters such as
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329:. It combines the carrier with the modulation signal, a process called
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1431:
Armstrong's first experimental FM broadcast transmitter W2XDG, in the
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in which the frequency is precisely controlled by the vibrations of a
678:
A practical radio transmitter mainly consists of the following parts:
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1903:
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A transmitter can be a separate piece of electronic equipment, or an
239:
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105:
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algorithms. Other advantages of digital transmission are increased
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of the carrier wave is considered the frequency of the transmitter.
616:
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109:
1232:
networks, in which integrated digital transmitters and receivers (
2613:
2598:
1816:
1006:
943:
890:
of the transmitter to match the impedance of the antenna (or the
687:
405:
101:
1247:
is driving the development of new types of transmitters such as
1137:
in 1906. Vacuum tube transmitters were inexpensive and produced
627:
flowing back and forth in an antenna will create an oscillating
285:) to transport information (in this case sound) over a distance.
2643:
2603:
1925:
1404:
1400:
1130:
1126:
840:
222:
is usually limited to equipment that generates radio waves for
1177:
motivated the evolution of high frequency transmitters in the
686:
circuit to transform the input electrical power to the higher
104:, Wayne State University, Detroit, US. It broadcasts at 101.9
2628:
2565:
1873:
1451:
1321:, with which he performed the first experiments in practical
1243:
The need to conserve bandwidth in the increasingly congested
1229:
1220:(IC) in the 1970s made possible the current proliferation of
1170:
990:
816:
752:
which represents moving images, or for data in the form of a
745:
623:
which are changing their velocity and thus accelerating. An
231:
215:
345:(FM) transmitter, it is added by varying the radio signal's
2570:
815:
methods very widely used in high bandwidth systems such as
245:
The term is popularly used more specifically to refer to a
387:
Elcom Bauer model 701B 1100 watt AM broadcast transmitter
352:
The radio signal from the transmitter is applied to the
349:
slightly. Many other types of modulation are also used.
171:. When excited by this alternating current, the antenna
293:
within another electronic device. A transmitter and a
1532:
Serway, Raymond; Faughn, Jerry; Vuille, Chris (2008).
1259:. A related trend has been an ongoing transition from
1169:
didn't begin until the late 1930s. The development of
654:
from a power source, a battery or mains power, into a
1447:
Transmitter assembly of a 20 kW, 9.375 GHz
1531:
1295:, and greater flexibility and processing power of
1279:; that is it can often transmit more information (
831:(DAB) to transmit digital data using a minimum of
793:of the carrier is varied by the modulation signal.
1462:produces microwaves which pass from the aperture
767:. Different types of transmitters use different
2764:
1651:Jim Hawkins' Radio and Broadcast Technology Page
1153:possible, which began in about 1920. Practical
1059:(sound) and instead transmitted information by
1039:The first primitive radio transmitters (called
1568:. Cambridge University Press. pp. 16–17.
1109:All these early technologies were replaced by
1686:
1666:Details of UK digital television transmitters
1185:ranges, using new active devices such as the
1106:around 1910, which were used into the 1920s.
321:from a computer. The transmitter generates a
1613:
690:needed to produce the required power output.
619:flowing through a metal conductor called an
2701:Global telecommunications regulation bodies
1592:Antenna theory: Analysis and Design, 3rd Ed
1557:
1555:
1051:between two conductors. Beginning in 1895,
639:of the oscillations is high enough, in the
448:Consumer products that contain transmitters
2737:
1693:
1679:
1470:which conducts them to the dish antenna.
1113:transmitters in the 1920s, which used the
809:orthogonal frequency-division multiplexing
1561:
1489: – List of specific models of radios
902:In higher frequency transmitters, in the
273:A radio transmitter is usually part of a
80:Learn how and when to remove this message
1552:
1030:
554:
268:
218:sets and navigational beacons. The term
91:
43:This article includes a list of general
19:For broader coverage of this topic, see
16:Electronic device that emits radio waves
1656:WCOV-TV's Transmitter Technical Website
1588:
1075:or "spark" era. Because they generated
968:general radiotelephone operator license
313:(TV) signal from a video camera, or in
301:. The purpose of most transmitters is
2765:
1700:
1582:
1674:
1646:International Telecommunication Union
1619:
1525:
1344:transmitter in Australia around 1910.
952:International Telecommunication Union
160:. The transmitter itself generates a
2747:
309:(sound) signal from a microphone, a
29:
740:. The modulation signal may be an
473:Both the handset and the base of a
13:
1157:(FM) transmission was invented by
886:) circuit to transform the output
607:, electromagnetic waves of radio
49:it lacks sufficient corresponding
14:
2794:
1639:
1538:. Cengage Learning. p. 714.
1458:tube mounted between two magnets
1043:) were built by German physicist
1011:Federal Communications Commission
771:methods to transmit information:
701:signal. This usually generates a
297:combined in one unit is called a
2746:
2736:
2727:
2726:
2715:
2336:Free-space optical communication
1595:. John Wiley and Sons. pp.
1589:Balanis, Constantine A. (2005).
1440:
1424:
1412:
1381:
1365:
1349:
1333:
1307:
1145:to transmit audio (sound) using
611:, are generated by time-varying
526:
498:
482:
466:
454:
423:
404:
392:
380:
214:in aircraft, ships, spacecraft,
34:
759:which represents a sequence of
1620:Brain, Marshall (2000-12-07).
1005:. In the US, these fall under
682:In high power transmitters, a
635:around the conductor. If the
264:
140:in technical documents) is an
1:
1562:Ellingson, Steven W. (2016).
1518:
1395:radio transmitters, built by
918:
811:) is a family of complicated
673:
100:transmitter at radio station
2778:Telecommunications equipment
2722:Telecommunication portal
2503:Telecommunications equipment
1267:radio transmission methods.
835:bandwidth. OFDM has higher
544:
108:with a radiated power of 48
7:
2239:Alexander Stepanovich Popov
1475:
1407:) tube is visible at right.
1063:: the operator tapped on a
10:
2799:
1943:Telecommunications history
1482:List of transmission sites
1328:communication in 1895–1897
1133:) vacuum tube invented by
1125:around 1912, based on the
1024:
1020:
829:digital audio broadcasting
646:A radio transmitter is an
548:
434:transceiver in a truck, a
200:wireless computer networks
167:, which is applied to the
18:
2710:
2652:
2589:
2551:Public Switched Telephone
2511:
2475:
2432:
2373:
2363:telecommunication circuit
2324:Fiber-optic communication
2307:
2069:Francis Blake (telephone)
2016:
1864:Optical telecommunication
1708:
1565:Radio Systems Engineering
1297:digital signal processing
1216:. The development of the
519:internet service provider
2462:Orbital angular-momentum
1899:Satellite communications
1738:Communications satellite
1493:Radio transmitter design
697:circuit to generate the
551:Radio transmitter design
249:, a transmitter used in
2341:Molecular communication
2164:Gardiner Greene Hubbard
1993:Undersea telegraph line
1728:Cable protection system
1535:College Physics, 8th Ed
1374:Alexanderson alternator
1167:television broadcasting
1104:Alexanderson alternator
871:A radio frequency (RF)
839:and more resistance to
188:television broadcasting
64:more precise citations.
2773:Broadcast transmitters
2483:Communication protocol
2269:Charles Sumner Tainter
2084:Walter Houser Brattain
2029:Edwin Howard Armstrong
1837:Information revolution
1513:Television transmitter
1141:, and could be easily
1041:spark gap transmitters
1036:
798:frequency-shift keying
589:
286:
259:television transmitter
132:(often abbreviated as
113:
2457:Polarization-division
2189:Narinder Singh Kapany
2154:Erna Schneider Hoover
2074:Jagadish Chandra Bose
2054:Alexander Graham Bell
1785:online video platform
1433:Empire State Building
1340:High power spark gap
1319:spark gap transmitter
1253:trunked radio systems
1200:The invention of the
1034:
912:frequency multipliers
695:electronic oscillator
593:Electromagnetic waves
563:antenna transmitting
558:
279:electromagnetic waves
272:
247:broadcast transmitter
95:
2299:Vladimir K. Zworykin
2259:Almon Brown Strowger
2229:Charles Grafton Page
1884:Prepaid mobile phone
1812:Electrical telegraph
1206:wireless microphones
1155:frequency modulation
1147:amplitude modulation
983:wireless microphones
954:(ITU) allocates the
858:Many other types of
787:frequency modulation
776:amplitude modulation
343:frequency modulation
335:amplitude modulation
255:FM radio transmitter
152:with the purpose of
23:. For the band, see
2249:Johann Philipp Reis
2008:Wireless revolution
1970:The Telephone Cases
1827:Hydraulic telegraph
1624:. HowStuffWorks.com
1503:Transmitter station
1449:air traffic control
1399:in 1914. The early
1300:integrated circuits
1287:than analog, using
1273:spectral efficiency
1210:garage door openers
1195:traveling wave tube
1149:(AM). This made AM
1115:feedback oscillator
1073:wireless telegraphy
999:garage door openers
979:cordless telephones
929:air traffic control
837:spectral efficiency
744:, which represents
625:alternating current
358:garage door openers
315:wireless networking
303:radio communication
275:radio communication
208:garage door openers
165:alternating current
154:signal transmission
21:Signal transmission
2447:Frequency-division
2424:Telephone exchange
2294:Charles Wheatstone
2224:Jun-ichi Nishizawa
2199:Innocenzo Manzetti
2134:Reginald Fessenden
1869:Optical telegraphy
1702:Telecommunications
1269:Digital modulation
1218:integrated circuit
1151:radio broadcasting
1123:Alexander Meissner
1102:) in 1904 and the
1094:transmitters: the
1037:
880:impedance matching
827:broadcasting, and
825:digital television
813:digital modulation
789:) transmitter the
778:) transmitter the
715:crystal oscillator
648:electronic circuit
590:
491:garage door opener
374:Radio transmitters
291:electrical circuit
287:
277:system which uses
122:telecommunications
114:
2760:
2759:
2498:Store and forward
2493:Data transmission
2407:Network switching
2358:Transmission line
2204:Guglielmo Marconi
2169:Internet pioneers
2034:Mohamed M. Atalla
2003:Whistled language
1622:"How Radio Works"
1388:One of the first
1315:Guglielmo Marconi
1277:analog modulation
1271:can have greater
1238:wireless networks
1053:Guglielmo Marconi
892:transmission line
738:modulation signal
650:which transforms
613:electric currents
366:transmission line
206:enabled devices,
142:electronic device
126:radio transmitter
90:
89:
82:
2790:
2750:
2749:
2740:
2739:
2730:
2729:
2720:
2719:
2718:
2591:Notable networks
2581:Wireless network
2521:Cellular network
2513:Types of network
2488:Computer network
2375:Network topology
2289:Thomas A. Watson
2144:Oliver Heaviside
2129:Philo Farnsworth
2104:Daniel Davis Jr.
2079:Charles Bourseul
2039:John Logie Baird
1748:Data compression
1743:Computer network
1695:
1688:
1681:
1672:
1671:
1633:
1632:
1630:
1629:
1617:
1611:
1610:
1586:
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1579:
1559:
1550:
1549:
1529:
1444:
1428:
1416:
1385:
1369:
1353:
1337:
1311:
1289:data compression
1222:wireless devices
1139:continuous waves
1027:History of radio
615:, consisting of
597:electric charges
595:are radiated by
582:
576:
561:half-wave dipole
530:
502:
486:
470:
458:
427:
408:
396:
384:
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25:The Transmitters
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2064:Tim Berners-Lee
2012:
1832:Information Age
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1342:radiotelegraphy
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1326:radiotelegraphy
1312:
1257:cognitive radio
1249:spread spectrum
1234:wireless modems
1159:Edwin Armstrong
1119:Edwin Armstrong
1092:continuous wave
1061:radiotelegraphy
1029:
1023:
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699:radio frequency
676:
656:radio frequency
641:radio frequency
580:
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559:Animation of a
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323:radio frequency
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236:microwave ovens
162:radio frequency
144:which produces
98:FM broadcasting
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56:Please help to
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2279:Camille Tissot
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2254:Claude Shannon
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2244:Tivadar Puskás
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2214:Antonio Meucci
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2184:Charles K. Kao
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1640:External links
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1545:978-0495386933
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1487:List of radios
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1293:noise immunity
1245:radio spectrum
1214:walkie-talkies
1045:Heinrich Hertz
1025:Main article:
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987:walkie-talkies
960:radio spectrum
920:
917:
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896:standing waves
876:
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833:radio spectrum
805:
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757:digital signal
726:
719:quartz crystal
691:
675:
672:
668:radio receiver
652:electric power
633:electric field
629:magnetic field
599:when they are
586:speed of light
578:and negative
569:electric field
567:, showing the
549:Main article:
546:
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327:carrier signal
319:digital signal
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212:two-way radios
196:walkie-talkies
158:radio receiver
88:
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2124:Lee de Forest
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2119:Thomas Edison
2117:
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2110:
2109:Donald Davies
2107:
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1397:Lee De Forest
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1356:1 MW US Navy
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1135:Lee De Forest
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1097:
1096:arc converter
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1065:telegraph key
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1018:
1017:before sale.
1016:
1015:type-approved
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1003:baby monitors
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884:antenna tuner
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802:binary digits
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709:, called the
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436:two way radio
433:
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413:amateur radio
407:
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228:radiolocation
226:purposes; or
225:
224:communication
221:
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175:radio waves.
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32:
31:
26:
22:
2434:Multiplexing
2309:Transmission
2274:Nikola Tesla
2264:Henry Sutton
2219:Samuel Morse
2149:Robert Hooke
2114:Amos Dolbear
2049:John Bardeen
1968:
1948:Telautograph
1852:Mobile phone
1807:Edholm's law
1790:social media
1723:Broadcasting
1626:. Retrieved
1615:
1591:
1584:
1564:
1534:
1527:
1463:
1459:
1242:
1199:
1175:World War II
1117:invented by
1108:
1089:
1077:damped waves
1038:
972:
940:marine radio
933:
925:Interference
922:
901:
863:
847:so multiple
750:video signal
742:audio signal
711:carrier wave
705:of constant
684:power supply
677:
664:video signal
645:
591:
579:
573:
364:, that is a
351:
288:
254:
251:broadcasting
244:
219:
186:(audio) and
177:
137:
133:
129:
125:
115:
76:
70:October 2022
67:
48:
2634:NPL network
2346:Radio waves
2284:Alfred Vail
2194:Hedy Lamarr
2179:Dawon Kahng
2139:Elisha Gray
2099:Yogen Dalal
2024:Nasir Ahmed
1958:Teleprinter
1822:Heliographs
1390:vacuum tube
1358:Poulsen arc
1226:cell phones
1111:vacuum tube
1100:Poulsen arc
1085:radio noise
1083:, creating
1081:frequencies
975:cell phones
796:In an FSK (
605:Radio waves
601:accelerated
565:radio waves
416:transceiver
317:devices, a
299:transceiver
283:radio waves
265:Description
220:transmitter
192:cell phones
146:radio waves
130:transmitter
118:electronics
96:Commercial
62:introducing
2767:Categories
2680:Antarctica
2639:Toasternet
2561:Television
2044:Paul Baran
1976:Television
1960:(teletype)
1953:Telegraphy
1931:transistor
1909:Phryctoria
1879:Photophone
1857:Smartphone
1847:Mass media
1628:2009-09-11
1519:References
1508:Transposer
1323:Morse code
1224:, such as
1202:transistor
1163:television
1069:Morse code
919:Regulation
860:modulation
821:cellphones
819:networks,
804:, 0 and 1.
785:In an FM (
774:In an AM (
769:modulation
734:oscillator
674:Components
331:modulation
230:, such as
190:stations,
182:, such as
45:references
2664:Americas
2653:Locations
2624:Internet2
2385:Bandwidth
2089:Vint Cerf
1986:streaming
1964:Telephone
1904:Semaphore
1795:streaming
1468:waveguide
1456:magnetron
1285:bandwidth
1281:data rate
1187:magnetron
1183:microwave
1143:modulated
997:devices,
995:Bluetooth
964:call sign
956:frequency
936:broadcast
908:microwave
888:impedance
873:amplifier
845:bitstream
791:frequency
780:amplitude
765:bitstream
730:modulator
723:frequency
707:amplitude
703:sine wave
637:frequency
617:electrons
609:frequency
545:Operation
535:Bluetooth
509:and home
362:feed line
347:frequency
339:amplitude
240:diathermy
204:Bluetooth
2732:Category
2619:Internet
2609:CYCLADES
2526:Ethernet
2476:Concepts
2400:terminal
2351:wireless
2174:Bob Kahn
2017:Pioneers
1842:Internet
1733:Cable TV
1498:Repeater
1476:See also
1191:klystron
688:voltages
432:CB radio
295:receiver
253:, as in
173:radiates
156:up to a
148:with an
128:or just
2752:Commons
2742:Outline
2695:Oceania
2614:FidoNet
2599:ARPANET
2412:circuit
1981:digital
1710:History
1466:into a
1460:(right)
1265:digital
1173:during
1021:History
1009:of the
1007:Part 15
948:Amateur
944:Airband
864:exciter
721:. The
621:antenna
411:Modern
354:antenna
341:. In a
169:antenna
150:antenna
102:WDET-FM
58:improve
2690:Europe
2660:Africa
2644:Usenet
2604:BITNET
2541:Mobile
2417:packet
1926:MOSFET
1921:device
1718:Beacon
1603:
1572:
1542:
1464:(left)
1405:triode
1401:Audion
1261:analog
1193:, and
1131:triode
1127:Audion
1001:, and
841:fading
807:OFDM (
754:binary
521:(ISP).
515:modems
47:, but
2783:Radar
2673:South
2668:North
2629:JANET
2566:Telex
2556:Radio
2395:Nodes
2390:Links
2311:media
1889:Radio
1874:Pager
1802:Drums
1768:video
1763:image
1753:audio
1452:radar
1275:than
1230:Wi-Fi
1171:radar
1057:audio
1049:spark
991:Wi-Fi
817:Wi-Fi
746:sound
660:audio
311:video
307:audio
232:radar
216:radar
184:radio
180:radio
2685:Asia
2571:UUCP
2531:ISDN
1601:ISBN
1570:ISBN
1540:ISBN
1255:and
1228:and
1212:and
1181:and
1121:and
993:and
906:and
849:bits
763:, a
761:bits
748:, a
134:XMTR
124:, a
120:and
2576:WAN
2546:NGN
2536:LAN
1817:Fax
1758:DCT
1372:An
1317:'s
1263:to
1179:UHF
931:).
904:UHF
878:An
693:An
662:or
581:(−)
575:(+)
257:or
238:or
136:or
116:In
106:MHz
2769::
1599:.
1597:10
1554:^
1393:AM
1302:.
1251:,
1240:.
1208:,
1197:.
1189:,
989:,
985:,
981:,
977:,
946:,
942:,
938:,
823:,
728:A
603:.
533:A
505:A
489:A
430:A
368:.
210:,
202:,
198:,
194:,
138:TX
110:kW
2703:)
2699:(
1694:e
1687:t
1680:v
1631:.
1609:.
1578:.
1548:.
1403:(
1129:(
1098:(
882:(
866:.
281:(
112:.
83:)
77:(
72:)
68:(
54:.
27:.
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