1703:
152:
983:
621:
313:
38:
1567:
1123:
The previous vacuum distance analysis does not consider the effect of atmosphere on the propagation path of RF signals. In fact, RF signals do not propagate in straight lines: Because of the refractive effects of atmospheric layers, the propagation paths are somewhat curved. Thus, the maximum service
134:
that the eye may sense. Therefore, since the ability to visually see a transmitting antenna (disregarding the limitations of the eye's resolution) roughly corresponds to the ability to receive a radio signal from it, the propagation characteristic at these frequencies is called "line-of-sight". The
308:
is composed of a conductor that completely surrounds an area on all sides, top, and bottom. Electromagnetic radiation is blocked where the wavelength is longer than any gaps. For example, mobile telephone signals are blocked in windowless metal enclosures that approximate a
Faraday cage, such as
605:
on radio propagation. It is a consequence of a circular segment of earth profile that blocks off long-distance communications. Since the vacuum line of sight passes at varying heights over the Earth, the propagating radio wave encounters slightly different propagation conditions over the path.
275:
coverage, the station may use as few as 3 (rural areas with few customers) or as many as 32 separate antennas, each covering a portion of the circular coverage. This allows the base station to use a directional antenna that is pointing at the user, which improves the
580:
468:
167:
transmitters can be foiled by tree branches, or even heavy rain or snow. The presence of objects not in the direct line-of-sight can cause diffraction effects that disrupt radio transmissions. For the best propagation, a volume known as the first
138:
In practice, the propagation characteristics of these radio waves vary substantially depending on the exact frequency and the strength of the transmitted signal (a function of both the transmitter and the antenna characteristics). Broadcast
1571:
1074:
1374:
759:
1177:
877:
193:
It is important to take into account the curvature of the Earth for calculation of line-of-sight paths from maps, when a direct visual fix cannot be made. Designs for microwave formerly used
1293:
1243:
977:
927:
179:
can also either cancel out or enhance the direct signal. This effect can be reduced by raising either or both antennas further from the ground: The reduction in loss achieved is known as
476:
370:
829:
1648:
2161:
797:
585:
The simple formulas give a best-case approximation of the maximum propagation distance, but are not sufficient to estimate the quality of service at any location.
1324:
For example, in normal weather conditions, the service range of a station at an altitude of 1500 m with respect to receivers at sea level can be found as,
1018:
122:
and higher) and in lower levels of the atmosphere, neither of these effects are significant. Thus, any obstruction between the transmitting antenna (
364:, and the presence of obstructions, for example mountains or trees. Simple formulas that include the effect of the atmosphere give the range as:
280:. If the user moves (perhaps by walking or driving) from one antenna sector to another, the base station automatically selects the proper antenna.
1641:
215:(cell phones) are in the line-of-sight range, they still function in cities. This is made possible by a combination of the following effects:
309:
elevator cabins, and parts of trains, cars, and ships. The same problem can affect signals in buildings with extensive steel reinforcement.
2247:
2154:
1436:
1390:
1330:
1634:
57:
354:
The radio horizon of the transmitting and receiving antennas can be added together to increase the effective communication range.
668:
1582:
1556:
This analysis is for high altitude to sea level reception. In microwave radio link chains, both stations are at high altitudes.
1134:
1576:
2147:
1531:
291:
56:
which means waves can only travel in a direct visual path from the source to the receiver without obstacles. Electromagnetic
31:
143:
radio, at comparatively low frequencies of around 100 MHz, are less affected by the presence of buildings and forests.
2187:
1405:
187:
1321:
can be less than 1.) That is equivalent to a hypothetical decrease in Earth radius and an increase of Earth bulge.
840:
2197:
1749:
1090:
268:(usually called "cell sites"). A phone can typically see at least three, and usually as many as six at any given time.
1262:
1212:
946:
896:
1744:
575:{\displaystyle \mathrm {horizon} _{\mathrm {km} }\approx 3.57\cdot {\sqrt {\mathrm {height} _{\mathrm {metres} }}}}
1621:
463:{\displaystyle \mathrm {horizon} _{\mathrm {mi} }\approx 1.23\cdot {\sqrt {\mathrm {height} _{\mathrm {feet} }}}}
49:
2044:
1657:
245:
reflection, diffraction, and attenuated passage through internal walls, floors and ceilings within the building
72:, reflected, or absorbed by the atmosphere and obstructions with material and generally cannot travel over the
1616:
2094:
272:
1410:
1084:
1005:
In the case, when there are two stations involve, e.g. a transmit station on ground with a station height
361:
347:
are tangential to the surface of the Earth. If the Earth were a perfect sphere without an atmosphere, the
69:
639:
Assuming a perfect sphere with no terrain irregularity, the distance to the horizon from a high altitude
249:
The combination of all these effects makes the mobile phone propagation environment highly complex, with
1385:
344:
277:
2252:
2219:
2214:
2054:
2049:
802:
602:
140:
159:
can disturb line of sight propagation even if they do not block the geometric line between antennas.
2225:
2089:
2084:
2059:
2039:
1790:
1185: > 1 means geometrically reduced bulge and a longer service range. On the other hand,
659:
640:
340:
2079:
1927:
1900:
1810:
1795:
115:
or "skip" propagation, thus giving radio transmissions in this range a potentially global reach.
2171:
1935:
1931:
1912:
1908:
1904:
1527:
1395:
594:
357:
2209:
2069:
1840:
1815:
1683:
615:
250:
236:
127:
53:
1702:
775:
2118:
2031:
1873:
1805:
1606:
1400:
1124:
range of the station is not equal to the line of sight vacuum distance. Usually, a factor
254:
1611:
2064:
1848:
1415:
317:
151:
297:
sufficient operation of mobile phone in tunnels when supported by split cable antennas
2241:
2074:
2011:
1992:
1896:
1830:
1825:
1820:
1420:
330:
316:
Two stations not in line-of-sight may be able to communicate through an intermediate
107:
bands between approximately 1 and 30 MHz, can be refracted back to Earth by the
80:
61:
242:
diffraction through windows, and attenuated passage through walls, into the building
1950:
1586:
1486:
1441:
305:
265:
212:
176:
169:
156:
2123:
1800:
1782:
1678:
1592:
1426:
1069:{\displaystyle d\thickapprox {\sqrt {2R}}\,\left({\sqrt {h}}+{\sqrt {H}}\right)}
982:
620:
123:
96:
88:
65:
2192:
2104:
1772:
1767:
1721:
1698:
1431:
1094:
312:
135:
farthest possible point of propagation is referred to as the "radio horizon".
108:
92:
37:
2139:
2113:
1960:
1736:
1714:
1693:
1668:
1314:
164:
104:
1626:
654:
be the altitude of a telecommunication station. The line of sight distance
17:
1499:"P.834 : Effects of tropospheric refraction on radiowave propagation"
1089:
The usual effect of the declining pressure of the atmosphere with height (
103:
stations to transmit beyond the horizon. Additionally, frequencies in the
2128:
1945:
1923:
1918:
1888:
1688:
1498:
100:
1097:) radio waves down towards the surface of the Earth. This results in an
271:"sectorized" antennas at the base stations. Instead of one antenna with
1997:
1983:
1547:. Technical Monograph 3108-1967. Brussels: European Broadcasting Union.
284:
112:
73:
1622:
Approximating 2-Ray Model by using
Binomial series by Matthew Bazajian
2202:
2021:
2016:
2006:
1978:
1973:
1968:
1939:
1868:
1462:
1206:. That means that the maximum service range increases by 15%.
290:
the radio link used by the phones is a digital link with extensive
1863:
1759:
1673:
1369:{\displaystyle d\approx 4.12\cdot {\sqrt {1500}}=160{\mbox{ km.}}}
348:
311:
150:
131:
84:
36:
1858:
1853:
1115:-factor can change from its average value depending on weather.
2143:
1630:
257:. For mobile phone services, these problems are tackled using:
1878:
119:
1701:
1612:
Article on the importance of Line Of Sight for UHF reception
1485:
Mean radius of the Earth is ≈ 6.37×10 metres = 6370 km. See
1013:, the line of sight distance can be calculated as follows:
754:{\displaystyle d^{2}=(R+h)^{2}-R^{2}=2\cdot R\cdot h+h^{2}}
1172:{\displaystyle d\approx {\sqrt {2\cdot k\cdot R\cdot h}}}
203: Earth radius to compute clearances along the path.
1607:
http://web.telia.com/~u85920178/data/pathlos.htm#bulges
1009:
and a receive station in the air with a station height
1360:
99:, which follow the contour of the Earth. This enables
1526:, pp 119–120. Cambridge University Press.
1333:
1265:
1215:
1137:
1021:
949:
899:
843:
805:
778:
671:
479:
373:
300:
local repeaters inside complex vehicles or buildings
2103:
2030:
1959:
1887:
1839:
1781:
1758:
1735:
1368:
1287:
1237:
1171:
1068:
971:
921:
872:{\displaystyle d\approx {\sqrt {2\cdot R\cdot h}}}
871:
823:
791:
753:
574:
462:
1189: < 1 means a shorter service range.
643:(i.e., line of sight) can readily be calculated.
631:is the height of the transmitter (exaggerated),
1545:High Altitude VHF and UHF Broadcasting Stations
1423:, stochastic model of line-of-sight propagation
261:rooftop or hilltop positioning of base stations
177:surface of the surrounding ground or salt water
41:Line of sight (LoS) propagation from an antenna
1288:{\displaystyle d\approx 1.41\cdot {\sqrt {h}}}
1238:{\displaystyle d\approx 4.12\cdot {\sqrt {h}}}
1128:is used in the equation above, modified to be
972:{\displaystyle d\approx 1.23\cdot {\sqrt {h}}}
922:{\displaystyle d\approx 3.57\cdot {\sqrt {h}}}
2155:
1642:
768:is much smaller than the radius of the Earth
79:In contrast to line-of-sight propagation, at
8:
118:However, at frequencies above 30 MHz (
27:Characteristic of electromagnetic radiation
2162:
2148:
2140:
1718:
1649:
1635:
1627:
233:diffraction into the "street canyon" below
1359:
1346:
1332:
1278:
1264:
1228:
1214:
1144:
1136:
1054:
1044:
1038:
1028:
1020:
962:
948:
912:
898:
850:
842:
804:
783:
777:
745:
714:
701:
676:
670:
548:
547:
527:
524:
505:
504:
481:
478:
442:
441:
421:
418:
399:
398:
375:
372:
981:
619:
190:for more on impairments in propagation.
147:Impairments to line-of-sight propagation
60:includes light emissions traveling in a
1454:
1025:
360:is affected by atmospheric conditions,
343:of points at which direct rays from an
130:) will block the signal, just like the
230:propagation over the rooftop landscape
993:is the height of the ground station,
7:
1524:Essentials of radio wave propagation
1391:Dipole field strength in free space
1317:in transmission. (In extreme cases
936:is given in feet, and the distance
564:
561:
558:
555:
552:
549:
543:
540:
537:
534:
531:
528:
509:
506:
500:
497:
494:
491:
488:
485:
482:
452:
449:
446:
443:
437:
434:
431:
428:
425:
422:
403:
400:
394:
391:
388:
385:
382:
379:
376:
25:
1192:Under normal weather conditions,
997:is the height of the air station
886:is given in metres, and distance
211:Although the frequencies used by
1617:Attenuation Levels Through Roofs
1570: This article incorporates
1565:
1434:
658:of this station is given by the
172:should be free of obstructions.
1583:General Services Administration
1101:, increased by a factor around
824:{\displaystyle 2\cdot R\cdot h}
799:can be neglected compared with
650:be the radius of the Earth and
287:between base stations (roaming)
698:
685:
292:error correction and detection
32:Line-of-sight (disambiguation)
1:
1522:Christopher Haslett. (2008).
1406:Non-line-of-sight propagation
1119:Refracted distance to horizon
1001:is the line of sight distance
635:is the line of sight distance
188:Non-line-of-sight propagation
175:Reflected radiation from the
126:) and the receiving antenna (
2220:Earth–Moon–Earth
989:is the radius of the Earth,
764:The altitude of the station
627:is the radius of the Earth,
83:(below approximately 3
2248:Radio frequency propagation
1750:Ultra-high-energy gamma ray
1463:"Line-of-sight propagation"
1091:vertical pressure variation
351:horizon would be a circle.
239:reflection along the street
64:. The rays or waves may be
2269:
1745:Very-high-energy gamma ray
1082:
613:
610:Vacuum distance to horizon
328:
29:
2178:
1664:
1467:IEEE Technology Navigator
50:electromagnetic radiation
46:Line-of-sight propagation
1658:Electromagnetic spectrum
1196:is usually chosen to be
601:refers to the effect of
1309:But in stormy weather,
294:in the digital protocol
48:is a characteristic of
1706:
1578:Federal Standard 1037C
1572:public domain material
1411:Over-the-horizon radar
1370:
1313:may decrease to cause
1289:
1239:
1173:
1099:effective Earth radius
1085:Atmospheric refraction
1079:Atmospheric refraction
1070:
1002:
973:
923:
873:
825:
793:
755:
636:
576:
464:
362:ionospheric absorption
358:Radio wave propagation
321:
253:effects and extensive
160:
42:
1705:
1591: (in support of
1386:Anomalous propagation
1371:
1290:
1240:
1174:
1071:
985:
974:
924:
874:
826:
794:
792:{\displaystyle h^{2}}
756:
623:
577:
465:
315:
278:signal-to-noise ratio
154:
76:or behind obstacles.
40:
2215:Tropospheric scatter
1331:
1263:
1213:
1135:
1019:
947:
897:
841:
803:
776:
669:
477:
371:
30:For other uses, see
2226:Interstellar Medium
1791:Extreme ultraviolet
660:Pythagorean theorem
155:Objects within the
1796:Vacuum ultraviolet
1707:
1366:
1364:
1285:
1256:in kilometres; or
1235:
1169:
1066:
1003:
969:
940:in statute miles,
919:
869:
821:
789:
751:
637:
595:telecommunications
572:
460:
322:
161:
43:
2235:
2234:
2188:Non-line-of-sight
2172:radio propagation
2137:
2136:
1841:Visible (optical)
1543:Busi, R. (1967).
1396:Knife-edge effect
1363:
1351:
1283:
1233:
1167:
1059:
1049:
1036:
967:
917:
867:
603:earth's curvature
570:
458:
207:Mobile telephones
16:(Redirected from
2260:
2210:Airplane scatter
2164:
2157:
2150:
2141:
1728:
1726:
1719:
1712:
1651:
1644:
1637:
1628:
1596:
1590:
1585:. Archived from
1569:
1568:
1557:
1554:
1548:
1541:
1535:
1520:
1514:
1513:
1511:
1510:
1495:
1489:
1483:
1477:
1476:
1474:
1473:
1459:
1444:
1439:
1438:
1437:
1375:
1373:
1372:
1367:
1365:
1361:
1352:
1347:
1294:
1292:
1291:
1286:
1284:
1279:
1244:
1242:
1241:
1236:
1234:
1229:
1205:
1204:
1200:
1178:
1176:
1175:
1170:
1168:
1145:
1110:
1109:
1105:
1075:
1073:
1072:
1067:
1065:
1061:
1060:
1055:
1050:
1045:
1037:
1029:
978:
976:
975:
970:
968:
963:
928:
926:
925:
920:
918:
913:
878:
876:
875:
870:
868:
851:
830:
828:
827:
822:
798:
796:
795:
790:
788:
787:
760:
758:
757:
752:
750:
749:
719:
718:
706:
705:
681:
680:
616:Horizon distance
581:
579:
578:
573:
571:
569:
568:
567:
546:
525:
514:
513:
512:
503:
469:
467:
466:
461:
459:
457:
456:
455:
440:
419:
408:
407:
406:
397:
229:
228:
222:
202:
201:
197:
54:wave propagation
21:
2268:
2267:
2263:
2262:
2261:
2259:
2258:
2257:
2238:
2237:
2236:
2231:
2174:
2168:
2138:
2133:
2099:
2026:
2001:
1987:
1955:
1883:
1835:
1777:
1754:
1731:
1724:
1717:
1710:
1708:
1660:
1655:
1603:
1575:
1566:
1564:
1561:
1560:
1555:
1551:
1542:
1538:
1521:
1517:
1508:
1506:
1497:
1496:
1492:
1484:
1480:
1471:
1469:
1461:
1460:
1456:
1451:
1440:
1435:
1433:
1401:Multilateration
1382:
1329:
1328:
1261:
1260:
1211:
1210:
1202:
1198:
1197:
1133:
1132:
1121:
1107:
1103:
1102:
1087:
1081:
1076:
1043:
1039:
1017:
1016:
945:
944:
895:
894:
890:in kilometres,
839:
838:
801:
800:
779:
774:
773:
741:
710:
697:
672:
667:
666:
618:
612:
591:
526:
480:
475:
474:
420:
374:
369:
368:
333:
327:
273:omnidirectional
255:Rayleigh fading
224:
220:
219:
209:
199:
195:
194:
149:
35:
28:
23:
22:
15:
12:
11:
5:
2266:
2264:
2256:
2255:
2250:
2240:
2239:
2233:
2232:
2230:
2229:
2223:
2217:
2212:
2207:
2206:
2205:
2200:
2190:
2185:
2179:
2176:
2175:
2169:
2167:
2166:
2159:
2152:
2144:
2135:
2134:
2132:
2131:
2126:
2121:
2116:
2110:
2108:
2101:
2100:
2098:
2097:
2092:
2087:
2082:
2077:
2072:
2067:
2062:
2057:
2052:
2047:
2042:
2036:
2034:
2028:
2027:
2025:
2024:
2019:
2014:
2009:
2004:
1999:
1995:
1990:
1985:
1981:
1976:
1971:
1965:
1963:
1957:
1956:
1954:
1953:
1948:
1943:
1921:
1916:
1893:
1891:
1885:
1884:
1882:
1881:
1876:
1871:
1866:
1861:
1856:
1851:
1845:
1843:
1837:
1836:
1834:
1833:
1828:
1823:
1818:
1813:
1808:
1803:
1798:
1793:
1787:
1785:
1779:
1778:
1776:
1775:
1770:
1764:
1762:
1756:
1755:
1753:
1752:
1747:
1741:
1739:
1733:
1732:
1730:
1729:
1696:
1691:
1686:
1681:
1676:
1671:
1665:
1662:
1661:
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1619:
1614:
1609:
1602:
1601:External links
1599:
1598:
1597:
1589:on 2022-01-22.
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1252:in metres and
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1218:
1180:
1179:
1166:
1163:
1160:
1157:
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1117:
1093:) is to bend (
1083:Main article:
1080:
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1042:
1035:
1032:
1027:
1024:
1015:
980:
979:
966:
961:
958:
955:
952:
932:If the height
930:
929:
916:
911:
908:
905:
902:
882:If the height
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318:radio repeater
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240:
234:
231:
208:
205:
148:
145:
95:can travel as
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
2265:
2254:
2251:
2249:
2246:
2245:
2243:
2227:
2224:
2221:
2218:
2216:
2213:
2211:
2208:
2204:
2201:
2199:
2196:
2195:
2194:
2191:
2189:
2186:
2184:
2183:Line-of-sight
2181:
2180:
2177:
2173:
2165:
2160:
2158:
2153:
2151:
2146:
2145:
2142:
2130:
2127:
2125:
2122:
2120:
2117:
2115:
2112:
2111:
2109:
2106:
2102:
2096:
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2091:
2088:
2086:
2083:
2081:
2078:
2076:
2073:
2071:
2068:
2066:
2063:
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2058:
2056:
2053:
2051:
2048:
2046:
2043:
2041:
2038:
2037:
2035:
2033:
2029:
2023:
2020:
2018:
2015:
2013:
2010:
2008:
2005:
2003:
1996:
1994:
1991:
1989:
1982:
1980:
1977:
1975:
1972:
1970:
1967:
1966:
1964:
1962:
1958:
1952:
1949:
1947:
1944:
1941:
1937:
1933:
1929:
1925:
1922:
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1914:
1910:
1906:
1902:
1898:
1895:
1894:
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1890:
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1880:
1877:
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1857:
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1809:
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1594:
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1573:
1563:
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1546:
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1500:
1494:
1491:
1488:
1482:
1479:
1468:
1464:
1458:
1455:
1448:
1443:
1432:
1428:
1425:
1422:
1421:Rician fading
1419:
1417:
1414:
1412:
1409:
1407:
1404:
1402:
1399:
1397:
1394:
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1356:
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1301:
1280:
1275:
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1255:
1251:
1230:
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1216:
1209:
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1207:
1195:
1190:
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1155:
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1130:
1129:
1127:
1118:
1116:
1114:
1100:
1096:
1092:
1086:
1078:
1062:
1056:
1051:
1046:
1040:
1033:
1030:
1022:
1014:
1012:
1008:
1000:
996:
992:
988:
984:
964:
959:
956:
953:
950:
943:
942:
941:
939:
935:
914:
909:
906:
903:
900:
893:
892:
891:
889:
885:
864:
861:
858:
855:
852:
847:
844:
837:
836:
835:
832:
818:
815:
812:
809:
806:
784:
780:
771:
767:
746:
742:
738:
735:
732:
729:
726:
723:
720:
715:
711:
707:
702:
694:
691:
688:
682:
677:
673:
665:
664:
663:
661:
657:
653:
649:
644:
642:
634:
630:
626:
622:
617:
609:
607:
604:
600:
596:
588:
586:
521:
518:
515:
473:
472:
415:
412:
409:
367:
366:
365:
363:
359:
355:
352:
350:
346:
342:
338:
337:radio horizon
332:
331:Radar horizon
325:Radio horizon
324:
319:
314:
310:
307:
299:
296:
293:
289:
286:
282:
279:
274:
270:
267:
266:base stations
263:
260:
259:
258:
256:
252:
244:
241:
238:
235:
232:
227:
218:
217:
216:
214:
213:mobile phones
206:
204:
191:
189:
184:
182:
178:
173:
171:
166:
158:
153:
146:
144:
142:
136:
133:
129:
125:
121:
116:
114:
110:
106:
102:
98:
94:
90:
86:
82:
81:low frequency
77:
75:
71:
67:
63:
62:straight line
59:
55:
51:
47:
39:
33:
19:
2198:Meteor burst
2182:
1709:
1587:the original
1577:
1552:
1544:
1539:
1523:
1518:
1507:. Retrieved
1505:. 2021-03-05
1502:
1493:
1487:Earth radius
1481:
1470:. Retrieved
1466:
1457:
1442:Radio portal
1323:
1318:
1310:
1308:
1303:
1302:in feet and
1299:
1297:
1253:
1249:
1247:
1193:
1191:
1186:
1182:
1181:
1125:
1122:
1112:
1098:
1088:
1010:
1006:
1004:
998:
994:
990:
986:
937:
933:
931:
887:
883:
881:
833:
769:
765:
763:
655:
651:
647:
645:
638:
632:
628:
624:
598:
592:
584:
356:
353:
336:
334:
306:Faraday cage
303:
248:
225:
210:
192:
185:
180:
174:
170:Fresnel zone
163:Low-powered
162:
157:Fresnel zone
137:
117:
97:ground waves
78:
58:transmission
52:or acoustic
45:
44:
2253:IEEE 802.11
2193:Ionospheric
2124:Medium wave
1801:Lyman-alpha
1783:Ultraviolet
1722:wavelengths
1715:frequencies
1679:Ultraviolet
1593:MIL-STD-188
1427:Slant range
772:Therefore,
641:transmitter
599:Earth bulge
589:Earth bulge
181:height gain
124:transmitter
93:radio waves
89:diffraction
18:Earth bulge
2242:Categories
2203:Sporadic E
2105:Wavelength
1961:Microwaves
1773:Hard X-ray
1768:Soft X-ray
1737:Gamma rays
1669:Gamma rays
1532:052187565X
1509:2021-11-17
1472:2023-05-10
1449:References
1306:in miles.
329:See also:
109:ionosphere
66:diffracted
2170:Modes of
2119:Shortwave
2114:Microwave
1694:Microwave
1362: km.
1344:⋅
1338:≈
1276:⋅
1270:≈
1226:⋅
1220:≈
1162:⋅
1156:⋅
1150:⋅
1142:≈
1026:≈
960:⋅
954:≈
910:⋅
904:≈
862:⋅
856:⋅
848:≈
816:⋅
810:⋅
733:⋅
727:⋅
708:−
522:⋅
516:≈
416:⋅
410:≈
251:multipath
237:multipath
186:See also
165:microwave
111:, called
105:shortwave
87:) due to
70:refracted
2129:Longwave
1889:Infrared
1689:Infrared
1380:See also
320:station.
128:receiver
101:AM radio
1720:longer
1713:higher
1684:Visible
1201:⁄
1111:. This
1106:⁄
1095:refract
345:antenna
339:is the
285:handoff
223:⁄
198:⁄
113:skywave
74:horizon
2022:L band
2017:S band
2012:C band
2007:X band
1993:K band
1979:Q band
1974:V band
1969:W band
1874:Orange
1869:Yellow
1849:Violet
1760:X-rays
1674:X-rays
1530:
1315:fading
834:Thus:
283:rapid
2228:(ISM)
2222:(EME)
2107:types
2032:Radio
1928:Bands
1901:Bands
1864:Green
1699:Radio
1574:from
349:radio
341:locus
264:many
132:light
2002:band
1988:band
1946:LWIR
1924:MWIR
1919:SWIR
1859:Cyan
1854:Blue
1528:ISBN
1349:1500
1341:4.12
1298:for
1273:1.41
1248:for
1223:4.12
957:1.23
907:3.57
646:Let
519:3.57
413:1.23
335:The
2095:ELF
2090:SLF
2085:ULF
2080:VLF
2060:VHF
2055:UHF
2050:SHF
2045:EHF
2040:THF
1951:FIR
1897:NIR
1879:Red
1831:UVA
1826:UVB
1821:UVC
1816:NUV
1811:MUV
1806:FUV
1503:ITU
1357:160
831:.
593:In
120:VHF
85:MHz
2244::
2075:LF
2070:MF
2065:HF
1938:,
1934:,
1930::
1911:,
1907:,
1903::
1595:).
1581:.
1501:.
1465:.
770:R.
662:;
597:,
304:A
183:.
141:FM
91:,
68:,
2163:e
2156:t
2149:v
2000:u
1998:K
1986:a
1984:K
1942:)
1940:N
1936:M
1932:L
1926:(
1915:)
1913:H
1909:K
1905:J
1899:(
1725:→
1711:←
1650:e
1643:t
1636:v
1534:.
1512:.
1475:.
1354:=
1335:d
1319:k
1311:k
1304:d
1300:h
1281:h
1267:d
1254:d
1250:h
1231:h
1217:d
1203:3
1199:4
1194:k
1187:k
1183:k
1165:h
1159:R
1153:k
1147:2
1139:d
1126:k
1113:k
1108:3
1104:4
1063:)
1057:H
1052:+
1047:h
1041:(
1034:R
1031:2
1023:d
1011:H
1007:h
999:d
995:H
991:h
987:R
965:h
951:d
938:d
934:h
915:h
901:d
888:d
884:h
865:h
859:R
853:2
845:d
819:h
813:R
807:2
785:2
781:h
766:h
747:2
743:h
739:+
736:h
730:R
724:2
721:=
716:2
712:R
703:2
699:)
695:h
692:+
689:R
686:(
683:=
678:2
674:d
656:d
652:h
648:R
633:d
629:h
625:R
565:s
562:e
559:r
556:t
553:e
550:m
544:t
541:h
538:g
535:i
532:e
529:h
510:m
507:k
501:n
498:o
495:z
492:i
489:r
486:o
483:h
453:t
450:e
447:e
444:f
438:t
435:h
432:g
429:i
426:e
423:h
404:i
401:m
395:n
392:o
389:z
386:i
383:r
380:o
377:h
226:r
221:1
200:3
196:4
34:.
20:)
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