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1829:
699:
619:
410:
20:
99:(APRS). If the APRS packet is received by an "i-gate" station, position reports and other messages can be routed to an internet server, and made accessible on a public web page. This allows amateur radio operators to track the locations of vehicles, hikers, high-altitude balloons, etc., along with telemetry and other messages around the world.
825:
Custom modems have been developed which allow throughput rates of 19.2 kbit/s, 56 kbit/s, and even 1.2 Mbit/s over amateur radio links on FCC permitted frequencies of 440 MHz and above. However, special radio equipment is needed to carry data at these speeds. The interface between
765:
Due to historical reasons, all commonly used modulations are based on an idea of minimal modification to the radio itself, usually just connecting the computer's audio output directly to the transmitter's microphone input and receiver's audio output directly to the computer's microphone input. Upon
512:
One of the first challenges faced by amateurs implementing packet radio is that almost all amateur radio equipment (and most surplus commercial/military equipment) has historically been designed to transmit voice, not data. Like any other digital communications system that uses analog media, packet
545:
serial ports for data communications between the computer and devices such as modems. The RS-232 standard specifies an asynchronous, start-stop mode of data transmission where data is sent in groups (characters) of 7 or 8 bits. Unfortunately, the simple AFSK modems typically used provide no timing
837:
The 2.4 GHz "Wi-Fi" band partially overlaps an amateur radio band, so commercial Wi-Fi hardware can be adapted and used by licensed amateur radio operators at higher power levels, although restrictions on amateur radio limit the appeal of using packet radio to connect to the internet. US FCC
79:
protocol and adapted for amateur radio use. Every AX.25 packet includes the sender's amateur radio callsign, which satisfies the US FCC requirements for amateur radio station identification. AX.25 allows other stations to automatically repeat packets to extend the range of transmissions. It is
898:
Many commercial operations, particularly those that make use of vehicle dispatch (e.g. taxis, tow trucks, police) were quick to note the value of packet radio systems to provide simple mobile data systems. This led to the rapid development of a number of commercial packet radio systems:
1154:
Security & Data
Integrity On A Modern Amateur Radio Network – By: Paul J. Toth – NA4AR "HSMM and Information Security," by K8OCL CQ-VHF Fall 2004 – preview via CQ-VHF website "Data Encryption is Legal," N2IRZ, CQ Magazine Aug 2006 – preview from the Summer 2006 TAPR PSR
817:
1,200 bit/s AFSK node controllers on 2 meters (144–148 MHz) are the most commonly found packet radio. For 1,200/2,400 bit/s UHF/VHF packet radio, amateurs use commonly available narrow band FM voice radios. For HF packet, 300 bit/s data is used over single sideband
600:
of a computer or terminal with no other equipment required. The computer is responsible for managing network connections, formatting data as AX.25 packets, and controlling the radio channel. Frequently it provides other functionality as well, such as a simple
529:
characteristics of the audio channel provided by voice radios are often quite different from those of telephone audio channels. This led to the need in some cases to enable or disable pre-emphasis or de-emphasis circuits in the radios and/or modems.
319:(FCC) granted authorization for United States amateurs to transmit ASCII codes via amateur radio. Repeaters may be designed for amateur packet radio, these are dubbed "digipeaters". The first known amateur packet radio activity in the US occurred in
283:
operators began experimenting with packet radio in 1978, when—after obtaining authorization from the
Canadian government—Robert Rouleau, VE2PY; Bram Frank, VE2BFH; Norm Pearl, VE2BQS; and Jacques Orsali, VE2EHP of the Montreal Amateur Radio Club
833:
In many commercial data radio applications, audio baseband modulation is not used. Data is transmitted by altering the transmitter output frequency between two distinct frequencies (in the case of FSK modulation, other alternates exist).
266:(a satellite packet radio network) networks. Throughout the 1970s and 1980s, DARPA operated a number of terrestrial and satellite packet radio networks connected to the ARPANET at various military and government installations.
863:
protocol suite and intended specifically for amateur radio use. Despite its name, AX.25 defines both the physical and data link layers of the OSI model. (It also defines a network layer protocol, though this is seldom used.)
737:
Modems used for packet radio vary in throughput and modulation technique, and are normally selected to match the capabilities of the radio equipment in use. Most commonly used method is one using audio frequency-shift keying
717:
2099:
778:
modulation became standard way to send the packet radio data over the radio as two distinct tones. The tones are 1,200 Hz for Mark and 2,200 Hz for space (1,000 Hz shift). In the case of
715:
811:
258:) techniques to provide 100 kbit/s and 400 kbit/s data channels. These experiments were generally considered to be successful, and also marked the first demonstration of
716:
883:), several network layer protocols have been developed for use with AX.25. Most prominent among these network layer protocols are NET/ROM & TheNET, ROSE, FlexNet and TexNet.
814:(G1NTX) and Jerry Sandys (G8DXZ) in the 1980s. Other systems which involved small modification of the radio were developed by James Miller (G3RUH) and operated at 9,600 bit/s.
554:. The receiver looks for the "frame boundary octet," then begins decoding the packet data that follows it. Another frame boundary octet marks the end of the packet frame.
331:
KA6M, and the
Pacific Packet Radio Society (PPRS). In keeping with the dominance of DARPA and ARPANET at the time, the nascent amateur packet radio network was dubbed the
185:
and performed a number of experiments beginning in the 1970s to develop methods to arbitrate access to a shared radio channel by network nodes. This system operated on
872:
Packet radio has most often been used for direct, keyboard-to-keyboard connections between stations, either between two live operators or between an operator and a
596:. Alternatively, multiple manufacturers (including Kenwood and Alinco) now market handheld or mobile radios with built-in TNCs, allowing connection directly to the
684:
1145:
Karn, P. Price H. Diersing, R. (May 1985). "Packet Radio in the
Amateur Service", pp. 431–439, "IEEE Journal on Selected Areas in Communications". ISSN 0733-8716.
538:
359:
Many groups of amateur radio operators interested in packet radio soon formed throughout the country including the
Pacific Packet Radio Society (PPRS) in
481:
A transmitted message may be broken into a sequence of packets before transmission, which are then re-assembled into the original message upon reception
2104:
794:, include using telephone modem chips via the microphone and audio out connectors. This has been proven to work at speeds up to 4,800 bit/s using fax
169:
simultaneously), one of the first technical challenges faced in the implementation of packet radio networks was a means to control access to a shared
521:
standard). While this approach worked, it was not optimal, because it used a 25 kHz FM channel to transmit at 1,200 baud. When using a direct
300:
amateur radio frequencies using homebuilt equipment. In 1980, Doug
Lockhart VE7APU, and the Vancouver Area Digital Communications Group (VADCG) in
102:
Some packet radio implementations also use dedicated point-to-point links such as TARPN. In cases such as this, new protocols have emerged such as
1290:
830:
part of the radio as opposed to the audio section used for 1,200 bit/s operation. The adoption of these high-speed links has been limited.
1770:
513:
radio systems require a modem. Since the radio equipment to be used with the modem was intended for voice, early amateur packet systems used
550:. That led to the need for a mechanism to enable the receiver to know when to start assembling each packet frame. The method used is called
1044:
396:
For an objective description of early developments in amateur packet radio, refer to the article "Packet Radio in the
Amateur Service".
250:) over packet radio links between mobile and fixed network nodes. This system was quite advanced, as it made use of direct sequence
1512:
742:) within the radio equipment's existing speech bandwidth. The first amateur packet radio stations were constructed using surplus
393:, in August, 1986. Volunteers linked several key sites to pass text traffic via packet radio which kept voice frequencies clear.
364:
1798:
1356:
754:
operation in most areas. More recently, 9,600 bit/s has become a popular, although more technically demanding, alternative. At
315:
Not long after this activity began in Canada, amateurs in the US became interested in packet radio. In 1980, the United States
1909:
1868:
838:
regulations do not allow amateur radio communications to be encrypted or private, in addition to other content restrictions.
708:
1083:
525:
modulation like G3RUH's packet radio modem, a 9,600 baud transmission is easily made in the same channel. In addition, the
377:
By 1983, TAPR was offering the first TNC available in kit form. Packet radio started becoming more and more popular across
1914:
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1763:
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pattern, where a data zero bit is encoded by a change in tones and a data one bit is encoded by no change in tones.
439:
1624:
1614:
2064:
1972:
1793:
1727:
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958:
1305:"Packet Radio Physical Layer" Useful notes taken by N1VG during the development of the OpenTracker TNC/APRS node
478:
Transmitted data is broken into packets, each of which contains a destination (and typically the source) address
2139:
2134:
2059:
1474:
640:
435:
822:) modulation. For high speed packet (9,600 bit/s upwards), special radios or modified FM radios must be used.
806:, but at faster speeds such as 9,600 bit/s, signal levels become critical and they are extremely sensitive to
1924:
1919:
1853:
1756:
1629:
636:
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are taking over the functions of the TNC, with the modem either a standalone unit or implemented entirely in
431:
205:
2024:
1479:
925:
1505:
1171:
1128:
American Radio Relay League (2008). "ARRL's VHF Digital
Handbook", pp. 1–2, American Radio Relay League.
963:
842:
1967:
1349:
819:
485:
166:
1225:
The
Internet Revolution: The Not-for-Dummies Guide to the History, Technology, and Use of the Internet
994:
The
Internet Revolution: The Not-for-Dummies Guide to the History, Technology, and Use of the Internet
1712:
492:
151:
103:
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305:
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multiple access protocol was derived. Subsequent enhancements in channel access techniques made by
155:
107:
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243:
1182:
DeRose, James F. (1999). "The Wireless Data Handbook", pp.3–7. Wiley-Interscience; 4th edition.
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A number of data "conversations" are possible on a single radio channel over a finite period.
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2003:
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308:) in quantity for use in amateur packet radio networks. In 2003, Rouleau was inducted into
178:
8:
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modems, and despite its low data rate, Bell 202 modulation has remained the standard for
2084:
1998:
1929:
1644:
799:
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A packet may be stored and subsequently forwarded towards its destination by a network
212:
58:
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began to appear. Packet radio proved its value for emergency operations following the
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To provide automated routing of data between stations (important for the delivery of
876:. No network services above the data link layer are required for these applications.
585:
499:
247:
231:
227:
194:
162:
51:
47:
1982:
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modulation, a 200 Hz shift is used. The data is differentially encoded with a
471:
372:
309:
158:
95:. Some mobile packet radio stations transmit their location periodically using the
40:
36:
1314:
1157:
http://www.arrl.org/files/file/About%20ARRL/Committee%20Reports/2004/July/HSMM.pdf
1013:
I wrote the code for the demo on May 31st 1978 at the M.A.R.C. meeting in Montreal
484:
Packets for multiple destinations can be transmitted on the same radio link in an
2180:
2094:
2019:
1707:
1309:
880:
856:
680:
505:
This is very similar to how packets of data are transferred between nodes on the
491:
A packet may be addressed to all possible recipients rather than a specific one (
259:
251:
201:
174:
76:
1087:
551:
1571:
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In principle, any network layer protocol may be used, including the ubiquitous
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85:
1490:
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2159:
2144:
2089:
2054:
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1702:
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1116:
581:
378:
328:
320:
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119:
65:
28:
1422:
774:. Due to this simplicity, and just having suitable microchips at hand, the
262:, as in these experiments data was routed between the ARPANET, PRNET, and
88:. This makes packet radio especially useful for emergency communications.
1858:
1604:
1399:
807:
597:
569:
135:
131:
1883:
1803:
1557:
1443:
1167:
795:
729:
643: in this section. Unsourced material may be challenged and removed.
547:
360:
340:
336:
323:
during December 1980, when a packet repeater was put into operation on
312:
magazine's hall of fame for his work on the Montreal Protocol in 1978.
127:
123:
81:
576:. Traditionally, the computer and modem are combined in one unit, the
371:
and the Amateur Radio Research and Development Corporation (AMRAD) in
1609:
1453:
672:
541:
data transfer. At the time, most personal computers had asynchronous
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1957:
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1379:
1304:
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16:
Form of amateur radio data communications using the AX25 protocol
1748:
39:
techniques to digital radio communications. Packet radio uses a
2185:
2079:
2039:
2034:
1878:
1737:
1662:
1552:
1334:
1261:
Don Rotolo, N2IRZ (July 2015). "Packet Networking and TARPNs".
953:
791:
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289:
263:
1324:
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output signal ("PTT") for transmitter control, one has made a
2029:
1808:
1672:
1657:
1652:
1547:
1543:
1389:
1384:
1119:, "A Short History – How it all began". Retrieved 2009-08-09.
853:
747:
709:
Example of packet radio transmission in 1,200 bits per second
565:
533:
Another problem faced by early "packeteers" was the issue of
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223:
219:
69:
55:
470:
Packet radio can be differentiated from other digital radio
1680:
1448:
931:
921:
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784:
739:
514:
304:, British Columbia began producing standardized equipment (
73:
1084:"Amateur Packet – A Brief Chronology: Phase 1 (1970–1986)"
2049:
1634:
935:
751:
675:, packet radio networks can be described in terms of the
297:
186:
139:
269:
517:
modems that followed telephone standards (notably the
208:(CSMA) protocols in the design of the now commonplace
23:
Terminal Node Controller 2400 baud packet radio modem
1329:
1241:
1168:
AX.25 Link Access Protocol for Amateur Packet Radio
181:led development of a packet radio network known as
84:, linking distant stations with each other through
1260:
2203:
1204:Lynch, Clifford A.; Brownrigg, Edwin B. (1987).
588:) used to input and display data. Increasingly,
254:(DSSS) modulation and forward error correction (
230:area and conducted a series of experiments with
1520:
605:to accept messages while the operator is away.
1203:
810:in the radio. These systems were pioneered by
189:frequencies at 9,600 baud. From this work the
1764:
1506:
1350:
798:modems in half-duplex mode. These modems use
72:(Amateur X.25) protocol was derived from the
934:is the packet data facility provided by the
762:modulation is used, at a rate of 300 bit/s.
80:possible for any packet station to act as a
1289:: CS1 maint: numeric names: authors list (
560:A basic packet radio station consists of a
438:. Unsourced material may be challenged and
1771:
1757:
1513:
1499:
1357:
1343:
173:to avoid collisions of signals. Professor
1022:Rouleau, Robert and Hodgson, Ian (1981).
790:Ways to achieve higher speeds than 1,200
659:Learn how and when to remove this message
546:signal to indicate the start of a packet
458:Learn how and when to remove this message
54:protocols to transmit digital data via a
1723:Frequency-hopping Spread Spectrum (FHSS)
292:, began experimenting with transmitting
18:
1117:"Introduction to Packet Radio – Part 1"
1077:
1075:
924:allowed packet data to be carried over
365:Tucson Amateur Packet Radio Corporation
2204:
1728:Direct Sequence Spread Spectrum (DSSS)
1597:Multiple frequency-shift keying (MFSK)
1242:Rouleau, Robert; Hodgson, Ian (1981).
1081:
826:the "modem" and the "radio" is at the
222:created a packet radio network called
1910:International Telecommunication Union
1752:
1494:
1338:
474:schemes by the following attributes:
1222:
1072:
1026:. Tab Books, Blue Ridge Summit, PA.
641:adding citations to reliable sources
612:
436:adding citations to reliable sources
403:
270:Amateur Packet Radio and the AMPRNet
1170:: the official specification, from
1045:"The CQ Amateur Radio Hall of Fame"
381:and by 1984 the first packet-based
64:Packet radio is frequently used by
13:
1197:
928:analog cellular telephone networks
893:
852:Packet radio networks rely on the
802:which works fine when there is no
697:
335:in DARPA style. Magnuski obtained
145:
14:
2223:
1905:International Amateur Radio Union
1778:
1298:
949:Automatic Packet Reporting System
356:for amateur radio use worldwide.
317:Federal Communications Commission
110:for noisy and weak signal links.
97:Automatic Packet Reporting System
1827:
1586:
1364:
728:Problems playing this file? See
713:
617:
408:
1176:
1161:
959:Spartan Packet Radio Experiment
628:needs additional citations for
1920:ITU prefixes for amateur radio
1148:
1139:
1122:
1109:
1037:
1016:
1007:
986:
389:airliner in a neighborhood in
1:
1691:Non-traditional digital modes
979:
206:carrier-sense multiple access
1531:Frequency-shift keying (FSK)
1480:Encoder receiver transmitter
847:
91:Packet radio can be used in
7:
1172:Tucson Amateur Packet Radio
1054:. June 2007. Archived from
964:Tucson Amateur Packet Radio
942:
859:protocol, derived from the
843:High-speed multimedia radio
690:
399:
10:
2228:
938:cellular telephone network
867:
840:
273:
122:communications modes were
113:
2173:
2122:
2012:
1991:
1945:
1938:
1897:
1836:
1825:
1786:
1713:Modulated continuous wave
1698:Hellschreiber (Feld-Hell)
1690:
1671:
1643:
1595:
1584:
1529:
1462:
1431:
1408:
1372:
996:, p.81. Ironbound Press.
608:
306:Terminal Node Controllers
104:Improved Layer 2 Protocol
1799:Emergency communications
1645:Phase-shift keying (PSK)
1395:Terminal node controller
578:terminal node controller
244:communications protocols
108:forward error correction
1869:International operation
974:Wireless ad hoc network
768:turn the transmitter on
685:network layer protocols
2191:Amateur radio in India
2135:Amateur radio software
1939:Modes of communication
1849:Amateur radio operator
828:intermediate frequency
804:amplitude-shift keying
702:
387:crash of an Aeromexico
383:bulletin board systems
35:is the application of
24:
2130:Amateur radio station
1915:Frequency allocations
1889:Vintage amateur radio
1814:High-speed telegraphy
1310:Packet radio software
1206:Packet radio networks
874:bulletin board system
701:
603:bulletin board system
234:to verify the use of
171:communication channel
165:are connected to the
154:inherently possess a
93:mobile communications
22:
1105:Making Modifications
687:on which they rely.
637:improve this article
564:or dumb terminal, a
552:asynchronous framing
432:improve this section
391:Cerritos, California
238:(a precursor to the
179:University of Hawaii
1432:TCP/IP packet radio
1315:Fast Packet Systems
1227:. Ironbound Press.
1223:Okin, J.R. (2005).
992:Okin, J.R. (2005).
339:allocations in the
200:in 1975 would lead
161:(i.e., many or all
1208:. Pergamon Press.
1082:Mendelsohn, Alex.
800:phase-shift keying
703:
590:personal computers
296:encoded data over
215:(LAN) technology.
213:local area network
106:(IL2P) supporting
59:communication link
25:
2199:
2198:
2118:
2117:
1746:
1745:
1488:
1487:
1101:FCC Gives The Nod
888:Internet Protocol
718:
669:
668:
661:
586:terminal emulator
468:
467:
460:
228:San Francisco Bay
195:Leonard Kleinrock
52:message switching
48:circuit switching
2219:
1943:
1942:
1831:
1809:DX communication
1773:
1766:
1759:
1750:
1749:
1718:Pulse modulation
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1501:
1492:
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1335:
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1264:CQ Amateur Radio
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1137:
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1098:
1096:
1095:
1086:. Archived from
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1070:
1069:
1067:
1066:
1060:
1052:CQ Amateur Radio
1049:
1041:
1035:
1020:
1014:
1011:
1005:
990:
720:
719:
700:
664:
657:
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613:
463:
456:
452:
449:
443:
412:
404:
373:Washington, D.C.
352:
351:
348:
345:
310:CQ Amateur Radio
246:(later known as
159:network topology
41:packet switching
37:packet switching
2227:
2226:
2222:
2221:
2220:
2218:
2217:
2216:
2202:
2201:
2200:
2195:
2181:Shortwave radio
2169:
2114:
2095:Spread spectrum
2008:
1987:
1934:
1925:Maritime mobile
1893:
1832:
1823:
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1742:
1708:Continuous wave
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1198:Further reading
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1021:
1017:
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987:
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896:
894:Implementations
881:electronic mail
870:
857:data link layer
850:
845:
735:
734:
726:
724:
723:
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447:
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429:
413:
402:
349:
346:
343:
342:
278:
272:
260:Internetworking
252:spread spectrum
202:Robert Metcalfe
175:Norman Abramson
148:
146:Aloha and PRNET
116:
86:ad hoc networks
77:data link layer
68:operators. The
17:
12:
11:
5:
2225:
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1940:
1936:
1935:
1933:
1932:
1927:
1922:
1917:
1912:
1907:
1901:
1899:
1895:
1894:
1892:
1891:
1886:
1881:
1876:
1871:
1866:
1861:
1856:
1851:
1846:
1840:
1838:
1834:
1833:
1826:
1824:
1822:
1821:
1816:
1811:
1806:
1801:
1796:
1790:
1788:
1784:
1783:
1776:
1775:
1768:
1761:
1753:
1744:
1743:
1741:
1740:
1735:
1730:
1725:
1720:
1715:
1710:
1705:
1700:
1694:
1692:
1688:
1687:
1685:
1684:
1683:(based on PSK)
1677:
1675:
1669:
1668:
1666:
1665:
1660:
1655:
1649:
1647:
1641:
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1518:
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1435:
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1426:
1425:
1420:
1414:
1412:
1406:
1405:
1403:
1402:
1397:
1392:
1387:
1382:
1376:
1374:
1370:
1369:
1362:
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1354:
1347:
1339:
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1327:
1322:
1317:
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1300:
1299:External links
1297:
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1121:
1115:Kenney, Larry
1108:
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978:
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725:
712:
707:
706:
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696:
695:
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671:Following the
667:
666:
625:
623:
616:
610:
607:
580:(TNC), with a
503:
502:
496:
489:
482:
479:
466:
465:
416:
414:
407:
401:
398:
274:Main article:
271:
268:
218:Over 1973–76,
147:
144:
115:
112:
46:as opposed to
15:
9:
6:
4:
3:
2:
2224:
2213:
2210:
2209:
2207:
2192:
2189:
2187:
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2160:Two-way radio
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2063:
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2058:
2056:
2055:Hellschreiber
2053:
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2048:
2046:
2043:
2041:
2038:
2036:
2033:
2031:
2028:
2026:
2023:
2021:
2018:
2017:
2015:
2011:
2005:
2002:
2000:
1997:
1996:
1994:
1990:
1984:
1981:
1979:
1976:
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1971:
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1966:
1964:
1961:
1959:
1956:
1954:
1951:
1950:
1948:
1944:
1941:
1937:
1931:
1928:
1926:
1923:
1921:
1918:
1916:
1913:
1911:
1908:
1906:
1903:
1902:
1900:
1896:
1890:
1887:
1885:
1882:
1880:
1877:
1875:
1872:
1870:
1867:
1865:
1862:
1860:
1857:
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1850:
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1810:
1807:
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1800:
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1791:
1789:
1785:
1781:
1780:Amateur radio
1774:
1769:
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1762:
1760:
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1754:
1751:
1739:
1736:
1734:
1731:
1729:
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1716:
1714:
1711:
1709:
1706:
1704:
1703:On-off keying
1701:
1699:
1696:
1695:
1693:
1689:
1682:
1679:
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1674:
1670:
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1642:
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1633:
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1628:
1626:
1623:
1621:
1618:
1616:
1613:
1611:
1608:
1606:
1603:
1602:
1600:
1598:
1594:
1579:
1576:
1573:
1570:
1568:
1564:
1561:
1559:
1556:
1554:
1551:
1549:
1545:
1542:
1540:
1537:
1536:
1534:
1532:
1528:
1524:digital modes
1523:
1522:Amateur radio
1516:
1511:
1509:
1504:
1502:
1497:
1496:
1493:
1481:
1478:
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1473:
1471:
1468:
1467:
1465:
1461:
1455:
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1371:
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1326:
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1321:
1318:
1316:
1313:
1311:
1308:
1306:
1303:
1302:
1292:
1286:
1278:
1274:
1270:
1266:
1265:
1259:
1255:
1253:0-8306-1345-5
1249:
1246:. TAB Books.
1245:
1240:
1236:
1234:0-9763857-6-7
1230:
1226:
1221:
1217:
1215:0-08-035913-2
1211:
1207:
1202:
1201:
1189:
1188:0-471-31651-2
1185:
1179:
1173:
1169:
1164:
1158:
1151:
1142:
1135:
1134:0-87259-122-0
1131:
1125:
1118:
1112:
1106:
1102:
1090:on 2001-01-29
1089:
1085:
1078:
1076:
1061:on 2008-12-03
1057:
1053:
1046:
1040:
1033:
1032:0-8306-9628-8
1029:
1025:
1019:
1010:
1003:
1002:0-9763857-6-7
999:
995:
989:
985:
975:
972:
970:
967:
965:
962:
960:
957:
955:
952:
950:
947:
946:
937:
933:
930:
927:
923:
920:
917:
914:
911:
908:
905:
902:
901:
900:
891:
889:
884:
882:
877:
875:
865:
862:
858:
855:
844:
839:
835:
831:
829:
823:
821:
815:
813:
809:
805:
801:
797:
793:
788:
786:
782:
777:
773:
769:
763:
761:
758:frequencies,
757:
753:
749:
745:
741:
733:
731:
710:
688:
686:
682:
678:
674:
663:
660:
652:
642:
638:
632:
631:
626:This section
624:
620:
615:
614:
606:
604:
599:
595:
591:
587:
583:
582:dumb terminal
579:
575:
571:
567:
563:
558:
555:
553:
549:
544:
540:
536:
531:
528:
524:
520:
516:
510:
508:
501:
497:
494:
490:
487:
483:
480:
477:
476:
475:
473:
462:
459:
451:
448:February 2016
441:
437:
433:
427:
426:
422:
417:This section
415:
411:
406:
405:
397:
394:
392:
388:
384:
380:
379:North America
375:
374:
370:
366:
362:
357:
355:
353:
338:
334:
330:
329:Hank Magnuski
326:
322:
321:San Francisco
318:
313:
311:
307:
303:
299:
295:
291:
287:
282:
281:Amateur radio
277:
267:
265:
261:
257:
253:
249:
245:
241:
237:
233:
229:
225:
221:
216:
214:
211:
207:
203:
199:
196:
192:
188:
184:
180:
176:
172:
168:
164:
160:
157:
153:
143:
141:
137:
133:
129:
125:
121:
120:digital radio
111:
109:
105:
100:
98:
94:
89:
87:
83:
78:
75:
71:
67:
66:amateur radio
62:
60:
57:
53:
49:
45:
42:
38:
34:
30:
29:digital radio
21:
2212:Packet radio
2165:Transceivers
2123:Technologies
2070:Packet radio
2069:
2013:Data/Digital
1563:Packet radio
1562:
1423:APRS Calling
1366:Packet radio
1365:
1285:cite journal
1271:(7): 82–84.
1268:
1262:
1244:Packet Radio
1243:
1224:
1205:
1178:
1163:
1150:
1141:
1124:
1111:
1104:
1100:
1092:. Retrieved
1088:the original
1063:. Retrieved
1056:the original
1039:
1024:Packet Radio
1023:
1018:
1009:
993:
988:
918:ARDIS (1990)
897:
885:
878:
871:
851:
836:
832:
827:
824:
816:
812:Simon Taylor
789:
780:
775:
771:
767:
764:
736:
727:
670:
655:
646:
635:Please help
630:verification
627:
559:
556:
535:asynchronous
532:
511:
504:
486:asynchronous
469:
454:
445:
430:Please help
418:
395:
376:
358:
341:
314:
279:
217:
197:
150:Since radio
149:
117:
101:
90:
63:
33:packet radio
32:
26:
1859:DX-pedition
1819:Homebrewing
1605:Olivia MFSK
1463:Specialized
1400:FBB (F6FBB)
1373:Traditional
808:group delay
772:radio modem
598:serial port
570:transceiver
539:synchronous
136:Baudot code
132:teleprinter
1992:Television
1898:Governance
1884:Radiosport
1804:Contesting
1787:Activities
1558:CLOVER2000
1444:KISS (TNC)
1094:2009-08-09
1065:2009-05-02
980:References
909:DRN (1986)
906:DCS (1984)
903:MDI (1979)
841:See also:
730:media help
649:April 2024
367:(TAPR) in
361:California
337:IP address
128:Morse code
124:telegraphy
82:digipeater
2155:Satellite
1930:Licensing
1610:Contestia
1475:FX.25 FEC
1454:Phil Karn
1277:0007-893X
848:Data link
766:adding a
681:data link
673:OSI model
493:broadcast
472:switching
419:does not
302:Vancouver
156:broadcast
140:facsimile
2206:Category
2045:EchoLink
1874:QSL card
1572:Bell 202
1567:Bell 103
1380:ALOHAnet
1320:44.0.0.0
943:See also
781:Bell 103
776:Bell 202
760:Bell 103
744:Bell 202
691:Physical
677:physical
594:software
572:with an
568:, and a
562:computer
527:baseband
519:Bell 202
507:Internet
400:Concepts
344:44.0.0.0
325:2 meters
286:Montreal
240:Internet
210:Ethernet
183:ALOHAnet
152:circuits
118:Earlier
44:protocol
2174:Related
2105:WIRES-X
1864:Hamfest
1844:History
1837:Culture
1733:AMPRNet
1470:Spartan
1439:AMPRNet
969:Winlink
913:Mobitex
868:Network
574:antenna
537:versus
488:fashion
440:removed
425:sources
369:Arizona
354:network
333:AMPRNet
276:AMPRNet
236:ARPANET
226:in the
204:to use
177:of the
167:network
134:(using
126:(using
114:History
2186:Q code
2080:PACTOR
2040:DAPNET
2035:D-STAR
1958:DSB-SC
1879:Q code
1854:Awards
1738:DAPNET
1663:Q15X25
1620:FSK441
1553:PACTOR
1275:
1250:
1231:
1212:
1186:
1132:
1030:
1000:
954:D-STAR
915:(1986)
792:bits/s
746:1,200
683:, and
609:Layers
543:RS-232
363:, the
290:Quebec
264:SATNET
198:et al.
138:) and
2030:AMTOR
1946:Voice
1673:COFDM
1658:PSK63
1653:PSK31
1548:SITOR
1544:AMTOR
1390:AX.25
1385:PRNET
1330:TARPN
1325:AMRAD
1059:(PDF)
1048:(PDF)
854:AX.25
748:bit/s
566:modem
548:frame
294:ASCII
224:PRNET
220:DARPA
191:Aloha
163:nodes
70:AX.25
56:radio
2140:IRLP
2100:C4FM
2090:RTTY
2074:APRS
2065:MFSK
2004:SSTV
1794:ARDF
1681:MT63
1630:WSPR
1625:JT6M
1615:JT65
1539:RTTY
1449:KA9Q
1418:APRS
1410:APRS
1291:link
1273:ISSN
1248:ISBN
1229:ISBN
1210:ISBN
1184:ISBN
1130:ISBN
1103:and
1099:See
1028:ISBN
998:ISBN
932:GPRS
926:AMPS
922:CDPD
861:X.25
796:V.27
785:NRZI
740:AFSK
584:(or
515:AFSK
500:node
423:any
421:cite
74:X.25
2150:SDR
2145:QRP
2110:DMR
2085:PSK
2060:DMT
2050:FT8
2025:ALE
1999:ATV
1973:AME
1968:SSB
1963:ISB
1635:FT8
1578:M17
936:GSM
820:SSB
752:VHF
639:by
523:FSK
434:by
327:by
298:VHF
256:FEC
232:SRI
187:UHF
130:),
50:or
27:In
2208::
2020:CW
1983:PM
1978:FM
1953:AM
1546:/
1287:}}
1283:{{
1269:71
1267:.
1074:^
1050:.
890:.
756:HF
679:,
509:.
288:,
248:IP
242:)
142:.
61:.
31:,
2076:)
2072:(
1772:e
1765:t
1758:v
1574:)
1565:(
1514:e
1507:t
1500:v
1358:e
1351:t
1344:v
1293:)
1279:.
1256:.
1237:.
1218:.
1190:.
1136:.
1097:.
1068:.
1034:.
1004:.
818:(
738:(
732:.
662:)
656:(
651:)
647:(
633:.
495:)
461:)
455:(
450:)
446:(
442:.
428:.
350:8
347:/
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
