1599:
1840:
710:
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421:
31:
110:(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.
836:
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
776:
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
523:
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
556:
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
848:
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
90:
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
909:
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:
1165:
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
828:
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
611:
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
540:
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.
330:(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
294:
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
844:
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).
277:(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.
874:
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.)
748:
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
728:
2110:
789:
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
726:
822:
269:) 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
727:
894:), 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.
825:(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.
565:. 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.
342:
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
196:
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
883:
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
607:. Alternatively, multiple manufacturers (including Kenwood and Alinco) now market handheld or mobile radios with built-in TNCs, allowing connection directly to the
695:
1156:
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.
549:
370:
Many groups of amateur radio operators interested in packet radio soon formed throughout the country including the
Pacific Packet Radio Society (PPRS) in
492:
A transmitted message may be broken into a sequence of packets before transmission, which are then re-assembled into the original message upon reception
2115:
805:, 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
180:
simultaneously), one of the first technical challenges faced in the implementation of packet radio networks was a means to control access to a shared
532:
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
311:
amateur radio frequencies using homebuilt equipment. In 1980, Doug
Lockhart VE7APU, and the Vancouver Area Digital Communications Group (VADCG) in
113:
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
1301:
841:
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.
1781:
524:
radio systems require a modem. Since the radio equipment to be used with the modem was intended for voice, early amateur packet systems used
561:. 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
1055:
407:
For an objective description of early developments in amateur packet radio, refer to the article "Packet Radio in the
Amateur Service".
261:) over packet radio links between mobile and fixed network nodes. This system was quite advanced, as it made use of direct sequence
1523:
753:) within the radio equipment's existing speech bandwidth. The first amateur packet radio stations were constructed using surplus
404:, in August, 1986. Volunteers linked several key sites to pass text traffic via packet radio which kept voice frequencies clear.
375:
1809:
1367:
765:
operation in most areas. More recently, 9,600 bit/s has become a popular, although more technically demanding, alternative. At
326:
Not long after this activity began in Canada, amateurs in the US became interested in packet radio. In 1980, the United States
1920:
1879:
849:
regulations do not allow amateur radio communications to be encrypted or private, in addition to other content restrictions.
719:
1094:
536:
modulation like G3RUH's packet radio modem, a 9,600 baud transmission is easily made in the same channel. In addition, the
388:
By 1983, TAPR was offering the first TNC available in kit form. Packet radio started becoming more and more popular across
1925:
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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.
450:
1635:
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1983:
1804:
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1607:
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969:
1316:"Packet Radio Physical Layer" Useful notes taken by N1VG during the development of the OpenTracker TNC/APRS node
489:
Transmitted data is broken into packets, each of which contains a destination (and typically the source) address
2150:
2145:
2070:
1485:
651:
446:
833:) modulation. For high speed packet (9,600 bit/s upwards), special radios or modified FM radios must be used.
817:, but at faster speeds such as 9,600 bit/s, signal levels become critical and they are extremely sensitive to
1935:
1930:
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are taking over the functions of the TNC, with the modem either a standalone unit or implemented entirely in
442:
216:
2035:
1490:
936:
17:
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1182:
1139:
American Radio Relay League (2008). "ARRL's VHF Digital
Handbook", pp. 1–2, American Radio Relay League.
974:
853:
1978:
1360:
830:
496:
177:
1236:
The
Internet Revolution: The Not-for-Dummies Guide to the History, Technology, and Use of the Internet
1005:
The
Internet Revolution: The Not-for-Dummies Guide to the History, Technology, and Use of the Internet
1723:
503:
162:
114:
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431:
316:
266:
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multiple access protocol was derived. Subsequent enhancements in channel access techniques made by
166:
118:
397:
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435:
254:
1193:
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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319:) in quantity for use in amateur packet radio networks. In 2003, Rouleau was inducted into
189:
8:
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modems, and despite its low data rate, Bell 202 modulation has remained the standard for
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2009:
1940:
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A packet may be stored and subsequently forwarded towards its destination by a network
223:
69:
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began to appear. Packet radio proved its value for emergency operations following the
1839:
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1008:
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To provide automated routing of data between stations (important for the delivery of
887:. No network services above the data link layer are required for these applications.
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510:
258:
242:
238:
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173:
62:
58:
1993:
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modulation, a 200 Hz shift is used. The data is differentially encoded with a
482:
383:
320:
169:
106:. Some mobile packet radio stations transmit their location periodically using the
51:
47:
1325:
1168:
http://www.arrl.org/files/file/About%20ARRL/Committee%20Reports/2004/July/HSMM.pdf
1024:
I wrote the code for the demo on May 31st 1978 at the M.A.R.C. meeting in Montreal
495:
Packets for multiple destinations can be transmitted on the same radio link in an
2191:
2105:
2030:
1718:
1320:
891:
867:
691:
516:
This is very similar to how packets of data are transferred between nodes on the
502:
A packet may be addressed to all possible recipients rather than a specific one (
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262:
212:
185:
87:
1098:
562:
1582:
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In principle, any network layer protocol may be used, including the ubiquitous
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201:
96:
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2155:
2100:
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339:
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130:
76:
39:
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785:. Due to this simplicity, and just having suitable microchips at hand, the
273:, as in these experiments data was routed between the ARPANET, PRNET, and
99:. This makes packet radio especially useful for emergency communications.
1869:
1615:
1410:
818:
608:
580:
146:
142:
1894:
1814:
1568:
1454:
1178:
806:
740:
654: in this section. Unsourced material may be challenged and removed.
558:
371:
351:
347:
334:
during December 1980, when a packet repeater was put into operation on
323:
magazine's hall of fame for his work on the Montreal Protocol in 1978.
138:
134:
92:
587:. Traditionally, the computer and modem are combined in one unit, the
382:
and the Amateur Radio Research and Development Corporation (AMRAD) in
1620:
1464:
683:
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data transfer. At the time, most personal computers had asynchronous
312:
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1968:
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Form of amateur radio data communications using the AX25 protocol
1759:
50:
techniques to digital radio communications. Packet radio uses a
2196:
2090:
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2045:
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1748:
1673:
1563:
1345:
1272:
Don Rotolo, N2IRZ (July 2015). "Packet Networking and TARPNs".
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802:
553:
300:
274:
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output signal ("PTT") for transmitter control, one has made a
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1819:
1683:
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1663:
1558:
1554:
1400:
1395:
1130:, "A Short History – How it all began". Retrieved 2009-08-09.
864:
758:
720:
Example of packet radio transmission in 1,200 bits per second
576:
544:
Another problem faced by early "packeteers" was the issue of
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234:
230:
80:
66:
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Packet radio can be differentiated from other digital radio
1691:
1459:
942:
932:
871:
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315:, British Columbia began producing standardized equipment (
84:
1095:"Amateur Packet – A Brief Chronology: Phase 1 (1970–1986)"
2060:
1645:
946:
762:
686:, packet radio networks can be described in terms of the
308:
197:
150:
280:
528:
modems that followed telephone standards (notably the
219:(CSMA) protocols in the design of the now commonplace
34:
Terminal Node Controller 2400 baud packet radio modem
1340:
1252:
1179:
AX.25 Link Access Protocol for Amateur Packet Radio
192:led development of a packet radio network known as
95:, linking distant stations with each other through
1271:
2214:
1215:Lynch, Clifford A.; Brownrigg, Edwin B. (1987).
599:) used to input and display data. Increasingly,
265:(DSSS) modulation and forward error correction (
241:area and conducted a series of experiments with
1531:
616:to accept messages while the operator is away.
1214:
821:in the radio. These systems were pioneered by
200:frequencies at 9,600 baud. From this work the
1775:
1517:
1361:
809:modems in half-duplex mode. These modems use
83:(Amateur X.25) protocol was derived from the
945:is the packet data facility provided by the
773:modulation is used, at a rate of 300 bit/s.
91:possible for any packet station to act as a
1300:: CS1 maint: numeric names: authors list (
571:A basic packet radio station consists of a
449:. Unsourced material may be challenged and
1782:
1768:
1524:
1510:
1368:
1354:
184:to avoid collisions of signals. Professor
1033:Rouleau, Robert and Hodgson, Ian (1981).
801:Ways to achieve higher speeds than 1,200
670:Learn how and when to remove this message
557:signal to indicate the start of a packet
469:Learn how and when to remove this message
65:protocols to transmit digital data via a
1734:Frequency-hopping Spread Spectrum (FHSS)
303:, began experimenting with transmitting
29:
1128:"Introduction to Packet Radio – Part 1"
1088:
1086:
935:allowed packet data to be carried over
376:Tucson Amateur Packet Radio Corporation
14:
2215:
1739:Direct Sequence Spread Spectrum (DSSS)
1608:Multiple frequency-shift keying (MFSK)
1253:Rouleau, Robert; Hodgson, Ian (1981).
1092:
837:the "modem" and the "radio" is at the
233:created a packet radio network called
1921:International Telecommunication Union
1763:
1505:
1349:
485:schemes by the following attributes:
1233:
1083:
1037:. Tab Books, Blue Ridge Summit, PA.
652:adding citations to reliable sources
623:
447:adding citations to reliable sources
414:
281:Amateur Packet Radio and the AMPRNet
1181:: the official specification, from
1056:"The CQ Amateur Radio Hall of Fame"
392:and by 1984 the first packet-based
75:Packet radio is frequently used by
24:
1208:
939:analog cellular telephone networks
904:
863:Packet radio networks rely on the
813:which works fine when there is no
708:
346:in DARPA style. Magnuski obtained
156:
25:
2234:
1916:International Amateur Radio Union
1789:
1309:
960:Automatic Packet Reporting System
367:for amateur radio use worldwide.
328:Federal Communications Commission
121:for noisy and weak signal links.
108:Automatic Packet Reporting System
1838:
1597:
1375:
739:Problems playing this file? See
724:
628:
419:
1187:
1172:
970:Spartan Packet Radio Experiment
639:needs additional citations for
1931:ITU prefixes for amateur radio
1159:
1150:
1133:
1120:
1048:
1027:
1018:
997:
400:airliner in a neighborhood in
13:
1:
1702:Non-traditional digital modes
990:
217:carrier-sense multiple access
1542:Frequency-shift keying (FSK)
1491:Encoder receiver transmitter
858:
102:Packet radio can be used in
7:
1183:Tucson Amateur Packet Radio
1065:. June 2007. Archived from
975:Tucson Amateur Packet Radio
953:
870:protocol, derived from the
854:High-speed multimedia radio
701:
410:
10:
2239:
949:cellular telephone network
878:
851:
284:
133:communications modes were
124:
2184:
2133:
2023:
2002:
1956:
1949:
1908:
1847:
1836:
1797:
1724:Modulated continuous wave
1709:Hellschreiber (Feld-Hell)
1701:
1682:
1654:
1606:
1595:
1540:
1473:
1442:
1419:
1383:
1007:, p.81. Ironbound Press.
619:
317:Terminal Node Controllers
115:Improved Layer 2 Protocol
1810:Emergency communications
1656:Phase-shift keying (PSK)
1406:Terminal node controller
589:terminal node controller
255:communications protocols
119:forward error correction
1880:International operation
985:Wireless ad hoc network
779:turn the transmitter on
696:network layer protocols
2202:Amateur radio in India
2146:Amateur radio software
1950:Modes of communication
1860:Amateur radio operator
839:intermediate frequency
815:amplitude-shift keying
713:
398:crash of an Aeromexico
394:bulletin board systems
46:is the application of
35:
2141:Amateur radio station
1926:Frequency allocations
1900:Vintage amateur radio
1825:High-speed telegraphy
1321:Packet radio software
1217:Packet radio networks
885:bulletin board system
712:
614:bulletin board system
245:to verify the use of
182:communication channel
176:are connected to the
165:inherently possess a
104:mobile communications
33:
1116:Making Modifications
698:on which they rely.
648:improve this article
575:or dumb terminal, a
563:asynchronous framing
443:improve this section
402:Cerritos, California
249:(a precursor to the
190:University of Hawaii
1443:TCP/IP packet radio
1326:Fast Packet Systems
1238:. Ironbound Press.
1234:Okin, J.R. (2005).
1003:Okin, J.R. (2005).
350:allocations in the
211:in 1975 would lead
172:(i.e., many or all
1219:. Pergamon Press.
1093:Mendelsohn, Alex.
811:phase-shift keying
714:
601:personal computers
307:encoded data over
226:(LAN) technology.
224:local area network
117:(IL2P) supporting
70:communication link
36:
2210:
2209:
2129:
2128:
1757:
1756:
1499:
1498:
1112:FCC Gives The Nod
899:Internet Protocol
729:
680:
679:
672:
597:terminal emulator
479:
478:
471:
239:San Francisco Bay
206:Leonard Kleinrock
63:message switching
59:circuit switching
16:(Redirected from
2230:
1954:
1953:
1842:
1820:DX communication
1784:
1777:
1770:
1761:
1760:
1729:Pulse modulation
1601:
1600:
1526:
1519:
1512:
1503:
1502:
1370:
1363:
1356:
1347:
1346:
1305:
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1291:
1275:CQ Amateur Radio
1268:
1249:
1230:
1202:
1191:
1185:
1176:
1170:
1163:
1157:
1154:
1148:
1137:
1131:
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1118:
1109:
1107:
1106:
1097:. Archived from
1090:
1081:
1080:
1078:
1077:
1071:
1063:CQ Amateur Radio
1060:
1052:
1046:
1031:
1025:
1022:
1016:
1001:
731:
730:
711:
675:
668:
664:
661:
655:
632:
624:
474:
467:
463:
460:
454:
423:
415:
384:Washington, D.C.
363:
362:
359:
356:
321:CQ Amateur Radio
257:(later known as
170:network topology
52:packet switching
48:packet switching
21:
2238:
2237:
2233:
2232:
2231:
2229:
2228:
2227:
2213:
2212:
2211:
2206:
2192:Shortwave radio
2180:
2125:
2106:Spread spectrum
2019:
1998:
1945:
1936:Maritime mobile
1904:
1843:
1834:
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1758:
1753:
1719:Continuous wave
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1209:Further reading
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1019:
1002:
998:
993:
956:
907:
905:Implementations
892:electronic mail
881:
868:data link layer
861:
856:
746:
745:
737:
735:
734:
733:
732:
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709:
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464:
458:
455:
440:
424:
413:
360:
357:
354:
353:
289:
283:
271:Internetworking
263:spread spectrum
213:Robert Metcalfe
186:Norman Abramson
159:
157:Aloha and PRNET
127:
97:ad hoc networks
88:data link layer
79:operators. The
28:
23:
22:
15:
12:
11:
5:
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1997:
1996:
1991:
1986:
1981:
1976:
1971:
1966:
1960:
1958:
1951:
1947:
1946:
1944:
1943:
1938:
1933:
1928:
1923:
1918:
1912:
1910:
1906:
1905:
1903:
1902:
1897:
1892:
1887:
1882:
1877:
1872:
1867:
1862:
1857:
1851:
1849:
1845:
1844:
1837:
1835:
1833:
1832:
1827:
1822:
1817:
1812:
1807:
1801:
1799:
1795:
1794:
1787:
1786:
1779:
1772:
1764:
1755:
1754:
1752:
1751:
1746:
1741:
1736:
1731:
1726:
1721:
1716:
1711:
1705:
1703:
1699:
1698:
1696:
1695:
1694:(based on PSK)
1688:
1686:
1680:
1679:
1677:
1676:
1671:
1666:
1660:
1658:
1652:
1651:
1649:
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1643:
1638:
1633:
1628:
1623:
1618:
1612:
1610:
1604:
1603:
1596:
1594:
1592:
1591:
1586:
1580:
1571:
1566:
1561:
1552:
1546:
1544:
1538:
1537:
1529:
1528:
1521:
1514:
1506:
1497:
1496:
1494:
1493:
1488:
1483:
1477:
1475:
1471:
1470:
1468:
1467:
1462:
1457:
1452:
1446:
1444:
1440:
1439:
1437:
1436:
1431:
1425:
1423:
1417:
1416:
1414:
1413:
1408:
1403:
1398:
1393:
1387:
1385:
1381:
1380:
1373:
1372:
1365:
1358:
1350:
1344:
1343:
1338:
1333:
1328:
1323:
1318:
1311:
1310:External links
1308:
1307:
1306:
1269:
1263:
1250:
1244:
1231:
1225:
1210:
1207:
1204:
1203:
1186:
1171:
1158:
1149:
1132:
1126:Kenney, Larry
1119:
1082:
1047:
1026:
1017:
995:
994:
992:
989:
988:
987:
982:
977:
972:
967:
962:
955:
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951:
950:
940:
930:
927:
921:
918:
915:
906:
903:
880:
877:
860:
857:
736:
723:
718:
717:
716:
707:
706:
705:
703:
700:
682:Following the
678:
677:
636:
634:
627:
621:
618:
591:(TNC), with a
514:
513:
507:
500:
493:
490:
477:
476:
427:
425:
418:
412:
409:
285:Main article:
282:
279:
229:Over 1973–76,
158:
155:
126:
123:
57:as opposed to
26:
9:
6:
4:
3:
2:
2235:
2224:
2221:
2220:
2218:
2203:
2200:
2198:
2195:
2193:
2190:
2189:
2187:
2183:
2177:
2174:
2172:
2171:Two-way radio
2169:
2167:
2164:
2162:
2159:
2157:
2154:
2152:
2149:
2147:
2144:
2142:
2139:
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2136:
2132:
2122:
2119:
2117:
2114:
2112:
2109:
2107:
2104:
2102:
2099:
2097:
2094:
2092:
2089:
2086:
2082:
2079:
2077:
2074:
2072:
2069:
2067:
2066:Hellschreiber
2064:
2062:
2059:
2057:
2054:
2052:
2049:
2047:
2044:
2042:
2039:
2037:
2034:
2032:
2029:
2028:
2026:
2022:
2016:
2013:
2011:
2008:
2007:
2005:
2001:
1995:
1992:
1990:
1987:
1985:
1982:
1980:
1977:
1975:
1972:
1970:
1967:
1965:
1962:
1961:
1959:
1955:
1952:
1948:
1942:
1939:
1937:
1934:
1932:
1929:
1927:
1924:
1922:
1919:
1917:
1914:
1913:
1911:
1907:
1901:
1898:
1896:
1893:
1891:
1888:
1886:
1883:
1881:
1878:
1876:
1873:
1871:
1868:
1866:
1863:
1861:
1858:
1856:
1853:
1852:
1850:
1846:
1841:
1831:
1828:
1826:
1823:
1821:
1818:
1816:
1813:
1811:
1808:
1806:
1803:
1802:
1800:
1796:
1792:
1791:Amateur radio
1785:
1780:
1778:
1773:
1771:
1766:
1765:
1762:
1750:
1747:
1745:
1742:
1740:
1737:
1735:
1732:
1730:
1727:
1725:
1722:
1720:
1717:
1715:
1714:On-off keying
1712:
1710:
1707:
1706:
1704:
1700:
1693:
1690:
1689:
1687:
1685:
1681:
1675:
1672:
1670:
1667:
1665:
1662:
1661:
1659:
1657:
1653:
1647:
1644:
1642:
1639:
1637:
1634:
1632:
1629:
1627:
1624:
1622:
1619:
1617:
1614:
1613:
1611:
1609:
1605:
1590:
1587:
1584:
1581:
1579:
1575:
1572:
1570:
1567:
1565:
1562:
1560:
1556:
1553:
1551:
1548:
1547:
1545:
1543:
1539:
1535:digital modes
1534:
1533:Amateur radio
1527:
1522:
1520:
1515:
1513:
1508:
1507:
1504:
1492:
1489:
1487:
1484:
1482:
1479:
1478:
1476:
1472:
1466:
1463:
1461:
1458:
1456:
1453:
1451:
1448:
1447:
1445:
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1435:
1432:
1430:
1427:
1426:
1424:
1422:
1418:
1412:
1409:
1407:
1404:
1402:
1399:
1397:
1394:
1392:
1389:
1388:
1386:
1382:
1378:
1371:
1366:
1364:
1359:
1357:
1352:
1351:
1348:
1342:
1339:
1337:
1334:
1332:
1329:
1327:
1324:
1322:
1319:
1317:
1314:
1313:
1303:
1297:
1289:
1285:
1281:
1277:
1276:
1270:
1266:
1264:0-8306-1345-5
1260:
1257:. TAB Books.
1256:
1251:
1247:
1245:0-9763857-6-7
1241:
1237:
1232:
1228:
1226:0-08-035913-2
1222:
1218:
1213:
1212:
1200:
1199:0-471-31651-2
1196:
1190:
1184:
1180:
1175:
1169:
1162:
1153:
1146:
1145:0-87259-122-0
1142:
1136:
1129:
1123:
1117:
1113:
1101:on 2001-01-29
1100:
1096:
1089:
1087:
1072:on 2008-12-03
1068:
1064:
1057:
1051:
1044:
1043:0-8306-9628-8
1040:
1036:
1030:
1021:
1014:
1013:0-9763857-6-7
1010:
1006:
1000:
996:
986:
983:
981:
978:
976:
973:
971:
968:
966:
963:
961:
958:
957:
948:
944:
941:
938:
934:
931:
928:
925:
922:
919:
916:
913:
912:
911:
902:
900:
895:
893:
888:
886:
876:
873:
869:
866:
855:
850:
846:
842:
840:
834:
832:
826:
824:
820:
816:
812:
808:
804:
799:
797:
793:
788:
784:
780:
774:
772:
769:frequencies,
768:
764:
760:
756:
752:
744:
742:
721:
699:
697:
693:
689:
685:
674:
671:
663:
653:
649:
643:
642:
637:This section
635:
631:
626:
625:
617:
615:
610:
606:
602:
598:
594:
593:dumb terminal
590:
586:
582:
578:
574:
569:
566:
564:
560:
555:
551:
547:
542:
539:
535:
531:
527:
521:
519:
512:
508:
505:
501:
498:
494:
491:
488:
487:
486:
484:
473:
470:
462:
459:February 2016
452:
448:
444:
438:
437:
433:
428:This section
426:
422:
417:
416:
408:
405:
403:
399:
395:
391:
390:North America
386:
385:
381:
377:
373:
368:
366:
364:
349:
345:
341:
340:Hank Magnuski
337:
333:
332:San Francisco
329:
324:
322:
318:
314:
310:
306:
302:
298:
293:
292:Amateur radio
288:
278:
276:
272:
268:
264:
260:
256:
252:
248:
244:
240:
236:
232:
227:
225:
222:
218:
214:
210:
207:
203:
199:
195:
191:
187:
183:
179:
175:
171:
168:
164:
154:
152:
148:
144:
140:
136:
132:
131:digital radio
122:
120:
116:
111:
109:
105:
100:
98:
94:
89:
86:
82:
78:
77:amateur radio
73:
71:
68:
64:
60:
56:
53:
49:
45:
41:
40:digital radio
32:
19:
2223:Packet radio
2176:Transceivers
2134:Technologies
2081:Packet radio
2080:
2024:Data/Digital
1574:Packet radio
1573:
1434:APRS Calling
1377:Packet radio
1376:
1296:cite journal
1282:(7): 82–84.
1279:
1273:
1255:Packet Radio
1254:
1235:
1216:
1189:
1174:
1161:
1152:
1135:
1122:
1115:
1111:
1103:. Retrieved
1099:the original
1074:. Retrieved
1067:the original
1050:
1035:Packet Radio
1034:
1029:
1020:
1004:
999:
929:ARDIS (1990)
908:
896:
889:
882:
862:
847:
843:
838:
835:
827:
823:Simon Taylor
800:
791:
786:
782:
778:
775:
747:
738:
681:
666:
657:
646:Please help
641:verification
638:
570:
567:
546:asynchronous
543:
522:
515:
497:asynchronous
480:
465:
456:
441:Please help
429:
406:
387:
369:
352:
325:
290:
228:
208:
161:Since radio
160:
128:
112:
101:
74:
44:packet radio
43:
37:
18:Packet Radio
1870:DX-pedition
1830:Homebrewing
1616:Olivia MFSK
1474:Specialized
1411:FBB (F6FBB)
1384:Traditional
819:group delay
783:radio modem
609:serial port
581:transceiver
550:synchronous
147:Baudot code
143:teleprinter
2003:Television
1909:Governance
1895:Radiosport
1815:Contesting
1798:Activities
1569:CLOVER2000
1455:KISS (TNC)
1105:2009-08-09
1076:2009-05-02
991:References
920:DRN (1986)
917:DCS (1984)
914:MDI (1979)
852:See also:
741:media help
660:April 2024
378:(TAPR) in
372:California
348:IP address
139:Morse code
135:telegraphy
93:digipeater
2166:Satellite
1941:Licensing
1621:Contestia
1486:FX.25 FEC
1465:Phil Karn
1288:0007-893X
859:Data link
777:adding a
692:data link
684:OSI model
504:broadcast
483:switching
430:does not
313:Vancouver
167:broadcast
151:facsimile
2217:Category
2056:EchoLink
1885:QSL card
1583:Bell 202
1578:Bell 103
1391:ALOHAnet
1331:44.0.0.0
954:See also
792:Bell 103
787:Bell 202
771:Bell 103
755:Bell 202
702:Physical
688:physical
605:software
583:with an
579:, and a
573:computer
538:baseband
530:Bell 202
518:Internet
411:Concepts
355:44.0.0.0
336:2 meters
297:Montreal
251:Internet
221:Ethernet
194:ALOHAnet
163:circuits
129:Earlier
55:protocol
2185:Related
2116:WIRES-X
1875:Hamfest
1855:History
1848:Culture
1744:AMPRNet
1481:Spartan
1450:AMPRNet
980:Winlink
924:Mobitex
879:Network
585:antenna
548:versus
499:fashion
451:removed
436:sources
380:Arizona
365:network
344:AMPRNet
287:AMPRNet
247:ARPANET
237:in the
215:to use
188:of the
178:network
145:(using
137:(using
125:History
2197:Q code
2091:PACTOR
2051:DAPNET
2046:D-STAR
1969:DSB-SC
1890:Q code
1865:Awards
1749:DAPNET
1674:Q15X25
1631:FSK441
1564:PACTOR
1286:
1261:
1242:
1223:
1197:
1143:
1041:
1011:
965:D-STAR
926:(1986)
803:bits/s
757:1,200
694:, and
620:Layers
554:RS-232
374:, the
301:Quebec
275:SATNET
209:et al.
149:) and
2041:AMTOR
1957:Voice
1684:COFDM
1669:PSK63
1664:PSK31
1559:SITOR
1555:AMTOR
1401:AX.25
1396:PRNET
1341:TARPN
1336:AMRAD
1070:(PDF)
1059:(PDF)
865:AX.25
759:bit/s
577:modem
559:frame
305:ASCII
235:PRNET
231:DARPA
202:Aloha
174:nodes
81:AX.25
67:radio
2151:IRLP
2111:C4FM
2101:RTTY
2085:APRS
2076:MFSK
2015:SSTV
1805:ARDF
1692:MT63
1641:WSPR
1636:JT6M
1626:JT65
1550:RTTY
1460:KA9Q
1429:APRS
1421:APRS
1302:link
1284:ISSN
1259:ISBN
1240:ISBN
1221:ISBN
1195:ISBN
1141:ISBN
1114:and
1110:See
1039:ISBN
1009:ISBN
943:GPRS
937:AMPS
933:CDPD
872:X.25
807:V.27
796:NRZI
751:AFSK
595:(or
526:AFSK
511:node
434:any
432:cite
85:X.25
2161:SDR
2156:QRP
2121:DMR
2096:PSK
2071:DMT
2061:FT8
2036:ALE
2010:ATV
1984:AME
1979:SSB
1974:ISB
1646:FT8
1589:M17
947:GSM
831:SSB
763:VHF
650:by
534:FSK
445:by
338:by
309:VHF
267:FEC
243:SRI
198:UHF
141:),
61:or
38:In
2219::
2031:CW
1994:PM
1989:FM
1964:AM
1557:/
1298:}}
1294:{{
1280:71
1278:.
1085:^
1061:.
901:.
767:HF
690:,
520:.
299:,
259:IP
253:)
153:.
72:.
42:,
2087:)
2083:(
1783:e
1776:t
1769:v
1585:)
1576:(
1525:e
1518:t
1511:v
1369:e
1362:t
1355:v
1304:)
1290:.
1267:.
1248:.
1229:.
1201:.
1147:.
1108:.
1079:.
1045:.
1015:.
829:(
749:(
743:.
673:)
667:(
662:)
658:(
644:.
506:)
472:)
466:(
461:)
457:(
453:.
439:.
361:8
358:/
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
