58:
1497:
3280:
2034:
Because each individual telecommunication link has to encounter different terrain, path, obstructions, atmospheric conditions and other phenomena, it is intractable to formulate the exact loss for all telecommunication systems in a single mathematical equation. As a result, different models exist for
1365:
At typical communication distances from a transmitter, the transmitting antenna usually can be approximated by a point source. Doubling the distance of a receiver from a transmitter means that the power density of the radiated wave at that new location is reduced to one-quarter of its previous value.
1735:
The influence of a visual obstruction on a NLOS link may be anything from negligible to complete suppression. An example might apply to a LOS path between a television broadcast antenna and a roof mounted receiving antenna. If a cloud passed between the antennas the link could actually become NLOS
1398:
refers to radio waves which travel directly in a line from the transmitting antenna to the receiving antenna, often also called direct-wave. It does not necessarily require a cleared sight path; at lower frequencies radio waves can pass through buildings, foliage and other obstructions. This is the
2042:
Radio propagation models are empirical in nature, which means, they are developed based on large collections of data collected for the specific scenario. For any model, the collection of data has to be sufficiently large to provide enough likeliness (or enough scope) to all kind of situations that
1780:
provides maps with real time propagation conditions between a network of transmitters and receivers. Even without special beacons the realtime propagation conditions can be measured: A worldwide network of receivers decodes morse code signals on amateur radio frequencies in realtime and provides
2030:
As the path loss encountered along any radio link serves as the dominant factor for characterization of propagation for the link, radio propagation models typically focus on realization of the path loss with the auxiliary task of predicting the area of coverage for a transmitter or modeling the
2011:
and other conditions. A single model is usually developed to predict the behavior of propagation for all similar links under similar constraints. Created with the goal of formalizing the way radio waves are propagated from one place to another, such models typically predict the
1519:
In this mode the radio wave propagates by interacting with the conductive surface of the Earth. The wave "clings" to the surface and thus follows the curvature of the Earth, so ground waves can travel over mountains and beyond the horizon. Ground waves propagate in
1663:
How to achieve effective NLOS networking has become one of the major questions of modern computer networking. Currently, the most common method for dealing with NLOS conditions on wireless computer networks is simply to circumvent the NLOS condition and place
1369:
The power density per surface unit is proportional to the product of the electric and magnetic field strengths. Thus, doubling the propagation path distance from the transmitter reduces each of these received field strengths over a free-space path by one-half.
1738:
Beyond line-of-sight (BLOS) is a related term often used in the military to describe radio communications capabilities that link personnel or systems too distant or too fully obscured by terrain for LOS communications. These radios utilize active
1843:, but also causes a slight "drag" on the bottom of the radio waves, bending the signals down such that they can follow the Earth's curvature over the normal radio horizon. The result is typically several stations being heard from another
2043:
can happen in that specific scenario. Like all empirical models, radio propagation models do not point out the exact behavior of a link, rather, they predict the most likely behavior the link may exhibit under the specified conditions.
1641:
lines. Some of these obstructions reflect certain radio frequencies, while some simply absorb or garble the signals; but, in either case, they limit the use of many types of radio transmissions, especially when low on power budget.
754:) high in the atmosphere. This means that medium and short radio waves transmitted at an angle into the sky can be refracted back to Earth at great distances beyond the horizon – even transcontinental distances. This is called
667:). Line-of-sight transmission on the surface of the Earth is limited to the distance to the visual horizon, which depends on the height of transmitting and receiving antennas. It is the only propagation method possible at
1831:. These changes are most obvious during temperature inversions, such as in the late-night and early-morning hours when it is clear, allowing the ground and the air near it to cool more rapidly. This not only causes
719:(ELF) ground waves can be used to communicate worldwide. VLF to ELF waves can penetrate significant distances through water and earth, and these frequencies are used for mine communication and military
1660:
NLOS lowers the effective received power. Near Line Of Sight can usually be dealt with using better antennas, but Non Line Of Sight usually requires alternative paths or multipath propagation methods.
1468:
effects are an important factor in VHF line-of-sight propagation. The interference between the direct beam line-of-sight and the ground reflected beam often leads to an effective inverse-fourth-power
1855:
stations. In late spring and early summer, a combination of other atmospheric factors can occasionally cause skips that duct high-power signals to places well over 1000 km (600 miles) away.
1360:
631:
means radio waves which travel in a straight line from the transmitting antenna to the receiving antenna. Line of sight transmission is used for medium-distance radio transmission, such as
1736:
but the quality of the radio channel could be virtually unaffected. If, instead, a large building was constructed in the path making it NLOS, the channel may be impossible to receive.
1645:
Lower power levels at a receiver reduce the chance of successfully receiving a transmission. Low levels can be caused by at least three basic reasons: low transmit level, for example
1377:. The Earth's atmosphere is thin enough that radio waves in the atmosphere travel very close to the speed of light, but variations in density and temperature can cause some slight
3189:
2149:
4515:
1286:
2046:
Different models have been developed to meet the needs of realizing the propagation behavior in different conditions. Types of models for radio propagation include:
2027:, before 1900 formulated the first crude empirical rule of radio propagation: the maximum transmission distance varied as the square of the height of the antenna.
3738:
1307:
2179:
1532:
as they follow the Earth's surface. Attenuation is proportional to frequency, so ground waves are the main mode of propagation at lower frequencies, in the
1808:
patterns to cope with skywave propagation at night. Very few stations are allowed to run without modifications during dark hours, typically only those on
1728:
because the capability of such links to provide a reasonable level of NLOS coverage greatly improves their marketability and versatility in the typical
3225:
1668:
at additional locations, sending the content of the radio transmission around the obstructions. Some more advanced NLOS transmission schemes now use
1851:
are also the result of inversions, but these normally cause more scattered omnidirection propagation, resulting mainly in interference, often among
1709:
As a virtual LOS i.e., as a straight line through visually obstructing material, thus leaving sufficient transmission for radio waves to be detected
4508:
2877:
4417:
2881:
1862:
are in the UHF band, ranging from 700 to over 2600 MHz, a range which makes them even more prone to weather-induced propagation changes. In
2398:
Cellular networks function even without a single clear line-of-sight by relaying signals along multiple line-of-sight paths through cell towers.
690:
allows radio waves to bend over hills and other obstacles, and travel beyond the horizon, following the contour of the Earth. These are called
2538:
1586:
bands and relied exclusively on ground-wave propagation. Frequencies above 3 MHz were regarded as useless and were given to hobbyists (
1575:. They can also penetrate to a significant depth into seawater, and so are used for one-way military communication to submerged submarines.
3731:
4501:
2339:
2946:
599:. Understanding the effects of varying conditions on radio propagation has many practical applications, from choosing frequencies for
4165:
2974:
2771:
3724:
2639:
1529:
4085:
1890:
areas, these cells are larger and so more likely to cause interference over longer distances when propagation conditions allow.
3218:
1827:), weather is the primary cause for changes in VHF propagation, along with some diurnal changes when the sky is mostly without
588:
274:
4195:
2898:
2848:
2582:
1703:
Either as a straight line free of any form of visual obstruction, even if it is actually too distant to see with the unaided
280:
1637:
Obstacles that commonly cause NLOS propagation include buildings, trees, hills, mountains, and, in some cases, high voltage
4740:
766:
477:
269:
4616:
4550:
4410:
2162:
2060:
292:
1630:. Near-line-of-sight (also NLOS) conditions refer to partial obstruction by a physical object present in the innermost
3750:
2643:
1657:
more than 31 miles (50 km) away; and obstruction between the transmitter and the receiver, leaving no clear path.
1319:
539:
1941:, and cool water temperatures also cause inversions in surface air, this "fringe roaming" sometimes occurs across the
3211:
2829:
2810:
2682:
2516:
2462:
2429:
17:
1732:
environments where they are most frequently used. However NLOS contains many other subsets of radio communications.
4675:
2129:
4583:
4080:
3933:
3929:
2095:
1930:
1918:
1075:
layer ionospheric refraction during high sunspot activity up to 50 MHz and rarely to 80 MHz. Sometimes
786:
4403:
4244:
2489:
2386:
2931:
4443:
4215:
4044:
2598:
1777:
1619:
1612:
1602:
frequencies useful for long-distance communication and they were allocated to commercial and military users.
720:
707:
and amateur radio stations use ground waves to cover their listening areas. As the frequency gets lower, the
403:
155:
2533:
2381:. Long distance shortwave transmission is most reliable at night and during the winter. Since the advent of
4680:
4287:
3988:
3758:
2967:
2239:
2134:
140:
4611:
4545:
4453:
4185:
3326:
3165:
2674:
2065:
1721:
1717:
and therefore the quality of operation of a radio channel, if it is possible at all, over an NLOS path.
1183:
1080:
393:
31:
4023:
3811:
3801:
3796:
3791:
3781:
3776:
3771:
3766:
3321:
2385:
in the 1960s, many long range communication needs that previously used skywaves now use satellites and
2199:
1568:
230:
798:
At different frequencies, radio waves travel through the atmosphere by different mechanisms or modes:
4438:
3998:
2284:
2209:
1748:
1685:
1623:
1395:
1390:
1235:
1204:
1175:
1142:
1109:
1058:
627:
572:
383:
2839:
Pocock, Emil (2010). "Propagation of Radio
Signals". In Silver, H. Ward and Wilson, Mark J. (eds.).
1654:
4712:
3621:
3234:
3150:
2324:
2319:
1875:
1801:
1452:
1154:
2647:
4524:
4317:
4190:
3671:
3000:
2960:
2382:
2234:
1765:
1752:
1572:
1564:
1451:
receive signals from communication satellites 22,000 miles (35,000 km) above the Earth, and
1444:
1436:
821:
774:
716:
660:
652:
1407:
frequencies and above. On the surface of the Earth, line of sight propagation is limited by the
4718:
4706:
4601:
4578:
4458:
4239:
4205:
4200:
4160:
4013:
3953:
2871:
2204:
2090:
2000:
1902:
1744:
1672:
signal propagation, bouncing the radio signal off other nearby objects to get to the receiver.
1064:
532:
494:
240:
2574:
1796:, the dramatic ionospheric changes that occur overnight in the mediumwave band drive a unique
4374:
4111:
2506:
2289:
2254:
2169:
1847:– usually a neighboring one, but sometimes ones from a few hundred kilometers (miles) away.
1809:
1669:
1505:
1428:
1270:
428:
285:
2566:
2479:
4540:
4475:
4470:
4353:
4338:
4249:
4101:
4075:
3983:
3631:
3626:
3135:
3120:
2055:
1962:
1789:
The average person can notice the effects of changes in radio propagation in several ways.
1521:
1465:
1260:
1250:
1121:
1113:
1088:
1076:
664:
592:
576:
413:
1713:
There are many electrical characteristics of the transmission media that affect the radio
8:
4481:
4292:
4254:
4155:
4115:
3666:
3661:
3636:
3616:
3367:
3105:
3030:
3015:
1909:
may occur despite not having left the country at all. This often occurs between southern
1859:
1805:
1579:
1528:) are required. Since the ground is not a perfect electrical conductor, ground waves are
1291:
1037:
873:
847:
625:
Several different types of propagation are used in practical radio transmission systems.
3716:
1961:, among others. While unintended cross-border roaming is often automatically removed by
1288:
of an electromagnetic wave is proportional to the inverse of the square of the distance
4180:
4130:
3656:
3504:
3477:
3387:
3372:
3045:
2749:
2299:
2269:
2259:
2184:
2036:
1950:
1871:
1571:
mechanism allows even longer range transmission. These frequencies are used for secure
1560:
1545:
1541:
1264:
901:
712:
683:
373:
333:
175:
100:
3861:
4568:
4493:
4307:
4125:
4120:
3747:
3512:
3508:
3489:
3485:
3481:
2894:
2844:
2825:
2806:
2678:
2578:
2567:
2512:
2485:
2458:
2435:
2425:
2264:
2080:
2024:
1797:
1773:
1627:
790:(NVIS) which are used when HF communications are desired within a few hundred miles.
525:
433:
408:
378:
313:
130:
41:
2750:
Why AM stations must reduce power, change operations, or cease broadcasting at night
4465:
4234:
4175:
4018:
3968:
3646:
3417:
3392:
3260:
3075:
2616:
2607:
2189:
1926:
1894:
1714:
1696:
1553:
1533:
1525:
1424:
1223:
1192:
965:
780:
747:
735:
675:
644:
615:
560:
220:
165:
160:
90:
2039:
for a link under a certain probability that the considered conditions will occur.
1755:
to extend communication ranges from a few kilometers to a few thousand kilometers.
4644:
4606:
4333:
4225:
4150:
4106:
3973:
3695:
3608:
3450:
3382:
2294:
2274:
2115:
1883:
1820:
1793:
1692:
1432:
772:
In addition, there are several less common radio propagation mechanisms, such as
704:
499:
225:
170:
80:
57:
49:
2921:
1886:
and user capacity. However, since this would not be very cost-effective in more
1781:
sophisticated search functions and propagation maps for every station received.
4700:
4659:
4654:
4312:
4140:
4054:
3943:
3641:
3425:
3090:
2983:
2249:
2214:
1958:
1816:. Many stations have no authorization to run at all outside of daylight hours.
1638:
1448:
1416:
1374:
1072:
1028:
999:
739:
636:
423:
388:
343:
95:
75:
2843:(88th ed.). Newington, CT: American Radio Relay League. Chapter 19.
2035:
different types of radio links under different conditions. The models rely on
4734:
4634:
4395:
4028:
3978:
3857:
3847:
3843:
3839:
3835:
3831:
3827:
3823:
3819:
3815:
3805:
3785:
3651:
3588:
3569:
3473:
3407:
3402:
3397:
3060:
2279:
2174:
2105:
1938:
1934:
1852:
1680:
1587:
1537:
1420:
935:
762:
679:
640:
600:
453:
215:
185:
135:
67:
3279:
2936:
4379:
4170:
4059:
3993:
3963:
3888:
3527:
3522:
3500:
3495:
3203:
3193:
2389:, to avoid dependence on the erratic performance of skywave communications.
2329:
2304:
2229:
2154:
1989:
1844:
1631:
1509:
1462:
1310:
1212:
692:
611:
607:
398:
323:
210:
145:
105:
85:
2918:
Propagation widget based on NOAA data. Also available as WordPress plugin.
2508:
Principles of
Terahertz Time-Domain Spectroscopy: An introductory textbook
4649:
4348:
4343:
4282:
4008:
3948:
3938:
3700:
3377:
3359:
3255:
2244:
2194:
2017:
1992:
1954:
1942:
1828:
1689:
1665:
1595:
1549:
1496:
1491:
984:
956:
926:
727:
708:
698:
687:
584:
463:
368:
318:
180:
2698:
4639:
4626:
4573:
4532:
4448:
4277:
4210:
4145:
3958:
3681:
3349:
3344:
3298:
3275:
2952:
2378:
2224:
2110:
2085:
1996:
1893:
While this is generally transparent to the user thanks to the way that
1863:
1824:
1729:
1599:
1456:
1412:
1378:
1256:
921:
893:
865:
743:
632:
596:
580:
568:
556:
468:
363:
4384:
4369:
4302:
4297:
4272:
3690:
3537:
3313:
3291:
3270:
3245:
2942:
Online
Propagation Tools, HF Solar Data, and HF Propagation Tutorials
2621:
2602:
2365:
2309:
2013:
2004:
1986:
1946:
1910:
1879:
1874:, this is partly offset by the use of smaller cells, which use lower
1848:
1704:
1404:
1163:
1130:
1097:
1046:
1012:
1005:
974:
944:
910:
882:
765:
operators to communicate with operators in distant countries, and by
731:
668:
604:
458:
338:
328:
190:
150:
4135:
4003:
3853:
3705:
3465:
3265:
2941:
2377:
Skywave communication is variable: It depends on conditions in the
2008:
1740:
1583:
648:
250:
2752:(Report). U.S. Federal Communications Commission. 11 December 2015
2603:"Short electromagnetic waves of wave-length up to 82 Microns"
993:
ionospheric refraction at night, when D layer absorption weakens.
4593:
4560:
3908:
3574:
3560:
2859:
2505:
Coutaz, Jean-Louis; Garet, Frederic; Wallace, Vincent P. (2018).
2314:
1922:
1914:
1906:
1898:
1591:
1408:
1022:
990:
839:
756:
575:, like light waves, radio waves are affected by the phenomena of
2915:
2724:
2439:
1178:, limited by atmospheric absorption to a few kilometers (miles)
4696:
3883:
3598:
3593:
3583:
3555:
3550:
3545:
3516:
3445:
2344:
2334:
2219:
1867:
1769:
564:
1590:). The discovery around 1920 of the ionospheric reflection or
4049:
3913:
3903:
3898:
3440:
3336:
3250:
1887:
1836:
1813:
1725:
1676:
1646:
1440:
856:
830:
656:
619:
508:
245:
235:
125:
2889:
Ghasemi, Adbollah; Abedi, Ali; and
Ghasemi, Farshid (2016).
1238:, mostly limited by atmospheric absorption to a few meters.
3878:
3435:
3430:
2925:
1905:
signals are involved, unexpected charges for international
1720:
The acronym NLOS has become more popular in the context of
1411:
to about 40 miles (64 km). This is the method used by
486:
3893:
3746:
3455:
1840:
1832:
1400:
751:
1965:
billing systems, inter-island roaming is typically not.
1724:(WLANs) and wireless metropolitan area networks such as
802:
Radio frequencies and their primary mode of propagation
2932:
HF Radio and
Ionospheric Prediction Service - Australia
2671:
200 meters & Down - The Story of
Amateur Radio
1650:
1626:(LOS) between the transmitter and receiver, such as in
1622:(NLOS) radio propagation occurs outside of the typical
4523:
2364:
At microwave frequencies, moisture in the atmosphere (
2347:– Free professional HF propagation prediction software
2180:
Computation of radiowave attenuation in the atmosphere
1679:
to describe a radio channel or link where there is no
2725:"Network of CW signal decoders for realtime analysis"
1800:
scheme in the United States, with entirely different
1322:
1294:
1273:
1207:, limited by atmospheric absorption to a few meters.
2144:
2888:
2642:. Caltech Infrared Processing and Analysis Center.
2597:
1582:) before the mid-1920s used low frequencies in the
1512:following the contour of the Earth; this is called
2504:
1447:uses longer line-of-sight paths; for example home
1354:
1301:
1280:
2891:Propagation Engineering in Wireless Communication
2453:Paris, Demetrius T. and Hurd, F. Kenneth (1969).
2016:along a link or the effective coverage area of a
1764:HF propagation conditions can be simulated using
1675:Non-Line-of-Sight (NLOS) is a term often used in
1355:{\displaystyle \rho \propto {\frac {1}{r^{2}}}~.}
4732:
2860:"Electromagnetic wave propagation by conduction"
2031:distribution of signals over different regions.
1957:and vice versa, or between the U.S. and British
1504:Lower frequency (between 30 and 3,000 kHz)
1933:. Since signals can travel unobstructed over a
1882:to reduce interference, and therefore increase
1384:
4425:
2858:Blanarovich, Yuri (VE3BMV, K3BU) (June 1980).
2415:
2413:
1772:, and realtime measurements can be done using
1770:the Voice of America Coverage Analysis Program
4509:
4411:
3732:
3219:
2968:
2539:National Aeronautics and Space Administration
2457:. New York, NY: McGraw Hill. Chapter 8.
1485:
954:Guided between the Earth and the ionosphere.
533:
3233:
2876:: CS1 maint: multiple names: authors list (
2569:Unexploded Ordnance Detection and Mitigation
1649:power levels; far-away transmitter, such as
2857:
2410:
2340:Vertical and horizontal (radio propagation)
1759:
4579:Longley–Rice Irregular Terrain Model (ITM)
4516:
4502:
4418:
4404:
3739:
3725:
3295:
3226:
3212:
2975:
2961:
2880:) CS1 maint: numeric names: authors list (
2841:The ARRL Handbook for Radio Communications
2805:. New York, NY: McGraw-Hill Book Company.
2634:
2632:
2091:Longley–Rice irregular terrain model (ITM)
1605:
1229: 20,000,000,000,000 Hz)
540:
526:
2620:
2511:. Boca Raton, FL: CRC Press. p. 18.
2452:
2424:(Fifth ed.). Howard W. Sams and Co.
2420:Westman, H.P.; et al., eds. (1968).
1858:Non-broadcast signals are also affected.
1578:Early long-distance radio communication (
1548:stations in the MF and LF bands, and for
1403:and above, and the only possible mode at
1298:
1277:
1244:
1198: 3,000,000,000,000 Hz)
742:bands), radio waves can refract from the
4166:Output power of an analog TV transmitter
2982:
2800:
2591:
2560:
2558:
1653:more than 5 miles (8.0 km) away or
1495:
1482:law for ground-plane limited radiation.
2629:
2477:
2419:
1169: 300,000,000,000 Hz)
793:
721:communication with submerged submarines
14:
4733:
2838:
2668:
2564:
2531:
2484:. John Wiley and Sons. pp. 3–10.
2471:
1263:(radio, light, X-rays, etc.) obey the
1136: 30,000,000,000 Hz)
275:Wireless electronic devices and health
4497:
4399:
4196:Direct-broadcast satellite television
3720:
3207:
2956:
2819:
2555:
2534:"Studying the Energy of the Universe"
2525:
2498:
2023:The inventor of radio communication,
1103: 3,000,000,000 Hz)
487:Multiple-input multiple-output (MIMO)
281:International Telecommunication Union
2824:. Dordrecht, NL: Kluwer Acad. Publ.
1784:
1373:Radio waves in vacuum travel at the
1267:which states that the power density
1146:
306:Radiation sources / regions
270:Wireless device radiation and health
4617:Single vegetative obstruction model
4551:Dipole field strength in free space
4086:Vestigial sideband modulation (VSB)
2163:Index of radio propagation articles
2061:Dipole field strength in free space
1968:
1381:(bending) of waves over distances.
1052: 300,000,000 Hz)
293:World Radiocommunication Conference
27:Behaviour of travelling radio waves
24:
4525:Radio frequency propagation models
3278:
2822:Wave Propagation in the Ionosphere
2793:
2644:California Institute of Technology
2422:Reference Data for Radio Engineers
1559:At even lower frequencies, in the
25:
4752:
2909:
2050:Models for free space attenuation
1983:radio frequency propagation model
920:Guided between the Earth and the
892:Guided between the Earth and the
864:Guided between the Earth and the
838:Guided between the Earth and the
784:(ducting) at VHF frequencies and
4676:ITU model for indoor attenuation
3187:
2937:NASA Space Weather Action Center
2778:. Radio Society of Great Britain
2147:
2130:ITU model for indoor attenuation
1823:(and the few remaining low-band
1611:This section is an excerpt from
1544:bands. Ground waves are used by
1399:most common propagation mode at
56:
4584:Two-ray ground-reflection model
4081:Quadrature amplitude modulation
2764:
2742:
2717:
2691:
2662:
2392:
2096:Two-ray ground-reflection model
1699:. In this context LOS is taken
1016:(3,000,000–30,000,000 Hz)
787:near vertical incidence skywave
567:, or into various parts of the
563:, from one point to another in
4245:Television channel frequencies
2481:Introduction to RF Propagation
2446:
2371:
2358:
2072:Models for outdoor attenuation
2037:computing the median path loss
1459:billions of miles from Earth.
1031:layer ionospheric refraction.
603:communications, international
13:
1:
4216:Digital television transition
4045:Multichannel television sound
2699:"WSPR propagation conditions"
2404:
2124:Models for indoor attenuation
1945:, and between islands in the
1613:Non-line-of-sight propagation
769:to transmit internationally.
156:Low-noise block downconverter
4681:Log-distance path loss model
4476:Earth–Moon–Earth
4288:Field strength in free space
3989:Horizontal blanking interval
2640:"Near, mid and far-infrared"
2455:Basic Electromagnetic Theory
2352:
2135:Log-distance path loss model
1995:for the characterization of
1979:radio wave propagation model
1949:. Signals can skip from the
1722:wireless local area networks
1385:Direct modes (line-of-sight)
1188:Tremendously High frequency
978:(300,000–3,000,000 Hz)
767:shortwave broadcast stations
711:with distance decreases, so
674:At lower frequencies in the
141:Counterpoise (ground system)
7:
4741:Radio frequency propagation
4612:One woodland terminal model
4546:Friis transmission equation
4186:Superheterodyne transmitter
3327:Ultra-high-energy gamma ray
2926:American Radio Relay League
2675:American Radio Relay League
2669:DeSoto, Clinton B. (1936).
2368:) can degrade transmission.
2140:
2066:Friis transmission equation
394:Friis transmission equation
32:Radio Propagation (journal)
10:
4757:
4024:Vertical blanking interval
3322:Very-high-energy gamma ray
2947:HF ionospheric propagation
2928:page on radio propagation.
2200:Earth-ionosphere waveguide
2160:
1917:at the western end of the
1749:tropospheric scatter links
1610:
1569:Earth-ionosphere waveguide
1508:radio waves can travel as
1489:
1486:Surface modes (groundwave)
1388:
1248:
231:Municipal wireless network
29:
4689:
4668:
4625:
4592:
4559:
4531:
4434:
4362:
4326:
4263:
4224:
4094:
4068:
4037:
3999:Nominal analogue blanking
3922:
3871:
3757:
3680:
3607:
3536:
3464:
3416:
3358:
3335:
3312:
3241:
3183:
2991:
2801:Boithais, Lucien (1987).
2478:Seybold, John S. (2005).
2285:Radio resource management
2210:Electromagnetic radiation
1776:. For radio amateurs the
1391:Line-of-sight propagation
1236:Line-of-sight propagation
1205:Line-of-sight propagation
1176:Line-of-sight propagation
1159:Extremely High Frequency
1143:Line-of-sight propagation
1110:Line-of-sight propagation
1059:Line-of-sight propagation
948:(30,000–300,000 Hz)
806:
628:Line-of-sight propagation
573:electromagnetic radiation
478:Bell Laboratories Layered
4713:Point-to-point Lee model
3235:Electromagnetic spectrum
2383:communication satellites
2325:Tropospheric propagation
2320:Traffic generation model
2240:Kennelly–Heaviside layer
1876:effective radiated power
1802:transmitter power output
1766:radio propagation models
1760:Measuring HF propagation
1025:ionospheric refraction.
826:Extremely Low Frequency
610:, to designing reliable
4318:Television interference
4191:Television receive-only
2599:Glagoleva-Arkadiewa, A.
2235:Inversion (meteorology)
1975:radio propagation model
1753:ionospheric propagation
1606:Non-line-of-sight modes
1573:military communications
1500:Ground wave propagation
1445:Satellite communication
1437:television broadcasting
1281:{\displaystyle \rho \,}
914:(3,000–30,000 Hz)
835:100,000–10,000 km
775:tropospheric scattering
717:extremely low frequency
671:frequencies and above.
661:satellite communication
653:television broadcasting
559:as they travel, or are
511:Multiple Access (WSDMA)
509:Wideband Space Division
4707:Area-to-area Lee model
4240:Microwave transmission
4206:Terrestrial television
4201:Television transmitter
4161:Intermediate frequency
3954:Chrominance subcarrier
3283:
2803:Radio Wave Propagation
2729:Reverse Beacon Network
2565:Byrnes, James (2009).
2532:Siegel, Peter (2002).
2205:Effective Earth radius
1921:, and between eastern
1745:groundwave propagation
1524:so vertical antennas (
1501:
1356:
1303:
1282:
1245:Free space propagation
241:Radio masts and towers
4112:Broadcast transmitter
3282:
2922:ARRL Propagation Page
2772:"VHF/UHF Propagation"
2673:. Newington, CT: The
2573:. Springer. pp.
2543:. Education materials
2290:Ray tracing (physics)
2170:Anomalous propagation
1953:to a mountainside in
1522:vertical polarization
1499:
1455:can communicate with
1429:microwave radio relay
1357:
1304:
1283:
1261:electromagnetic waves
1249:Further information:
1126:Super High Frequency
1093:Ultra High Frequency
861:10,000–1,000 km
429:Signal-to-noise ratio
264:Safety and regulation
30:For the journal, see
4541:Free-space path loss
4471:Tropospheric scatter
4354:Zero reference pulse
4339:Field strength meter
4076:Frequency modulation
3984:Horizontal scan rate
2820:Rawer, Karl (1993).
2677:. pp. 132–146.
2056:Free-space path loss
1977:, also known as the
1963:mobile phone company
1937:far larger than the
1897:handle cell-to-cell
1870:) areas with a high
1866:(and to some extent
1860:Mobile phone signals
1677:radio communications
1506:vertically polarized
1320:
1292:
1271:
1251:Free-space path loss
1114:tropospheric ducting
1077:tropospheric ducting
1042:Very High Frequency
886:(300–3,000 Hz)
878:Ultra Low Frequency
852:Super Low Frequency
794:Frequency dependence
781:tropospheric ducting
665:satellite television
414:Radiation resistance
4602:Weissberger's model
4482:Interstellar Medium
4293:Noise (electronics)
4156:Intercarrier method
4116:Transmitter station
3751:broadcasting topics
3368:Extreme ultraviolet
1806:directional antenna
1594:mechanism made the
1580:wireless telegraphy
1302:{\displaystyle r\,}
906:Very Low Frequency
842:of the ionosphere.
803:
555:is the behavior of
4719:Longley–Rice model
4181:Split sound system
4131:Differential phase
3373:Vacuum ultraviolet
3284:
2300:Schumann resonance
2270:Radio atmospherics
2260:Near and far field
2185:Critical frequency
1951:Dominican Republic
1931:U.S./Canada border
1919:U.S./Mexico border
1872:population density
1774:chirp transmitters
1688:(LOS) between the
1628:ground reflections
1546:radio broadcasting
1502:
1352:
1299:
1278:
1265:inverse-square law
1232:1,000–150 μm
1217:Far infrared light
889:1,000–100 km
801:
713:very low frequency
618:, to operation of
480:Space-Time (BLAST)
334:Near and far field
4728:
4727:
4721:(20 MHz - 20 GHz)
4569:ITU terrain model
4491:
4490:
4444:Non-line-of-sight
4428:radio propagation
4393:
4392:
4308:Radiation pattern
4126:Differential gain
3748:Analog television
3714:
3713:
3418:Visible (optical)
3201:
3200:
3178:
3177:
2900:978-3-319-32783-9
2850:978-0-87259-095-3
2584:978-1-4020-9252-7
2265:Propagation graph
2081:ITU terrain model
2025:Guglielmo Marconi
1999:propagation as a
1895:cellular networks
1798:broadcast license
1785:Practical effects
1697:receiving antenna
1620:Non-line-of-sight
1427:, point-to-point
1425:wireless networks
1348:
1344:
1242:
1241:
1227:(300,000,000,000–
1219:(overlaps radio)
1196:(300,000,000,000–
970:Medium Frequency
748:charged particles
645:wireless networks
553:Radio propagation
550:
549:
434:Spurious emission
419:Radio propagation
409:Radiation pattern
384:Equivalent radius
379:Electrical length
286:Radio Regulations
131:Block upconverter
18:Radio Propagation
16:(Redirected from
4748:
4518:
4511:
4504:
4495:
4494:
4466:Airplane scatter
4420:
4413:
4406:
4397:
4396:
4235:Frequency offset
4176:Residual carrier
4121:Cavity amplifier
4019:Television lines
3741:
3734:
3727:
3718:
3717:
3305:
3303:
3296:
3289:
3228:
3221:
3214:
3205:
3204:
3194:Radio portal
3192:
3191:
3190:
2994:
2993:
2977:
2970:
2963:
2954:
2953:
2904:
2893:(2nd ed.).
2885:
2875:
2867:
2854:
2835:
2816:
2788:
2787:
2785:
2783:
2768:
2762:
2761:
2759:
2757:
2746:
2740:
2739:
2737:
2735:
2721:
2715:
2714:
2712:
2710:
2695:
2689:
2688:
2666:
2660:
2659:
2657:
2655:
2646:. Archived from
2636:
2627:
2626:
2624:
2622:10.1038/113640a0
2595:
2589:
2588:
2572:
2562:
2553:
2552:
2550:
2548:
2529:
2523:
2522:
2502:
2496:
2495:
2475:
2469:
2468:
2450:
2444:
2443:
2417:
2399:
2396:
2390:
2387:submerged cables
2375:
2369:
2362:
2190:Diversity scheme
2157:
2152:
2151:
2150:
1969:Empirical models
1715:wave propagation
1554:radio navigation
1481:
1479:
1478:
1474:
1449:satellite dishes
1361:
1359:
1358:
1353:
1346:
1345:
1343:
1342:
1330:
1308:
1306:
1305:
1300:
1287:
1285:
1284:
1279:
1167:(30,000,000,000–
1065:E ionospheric (E
1004:High Frequency (
981:1000–100 m
816:Propagation via
804:
800:
778:(troposcatter),
761:. It is used by
616:radio navigation
612:mobile telephone
542:
535:
528:
307:
221:Cellular network
161:Passive radiator
60:
37:
36:
21:
4756:
4755:
4751:
4750:
4749:
4747:
4746:
4745:
4731:
4730:
4729:
4724:
4685:
4664:
4645:COST Hata model
4621:
4607:Early ITU model
4588:
4555:
4527:
4522:
4492:
4487:
4430:
4424:
4394:
4389:
4358:
4334:Distortionmeter
4322:
4259:
4220:
4151:Frequency mixer
4107:Antenna (radio)
4090:
4064:
4033:
3974:Composite video
3918:
3867:
3753:
3745:
3715:
3710:
3676:
3603:
3578:
3564:
3532:
3460:
3412:
3354:
3331:
3308:
3301:
3294:
3287:
3285:
3237:
3232:
3202:
3197:
3188:
3186:
3179:
3174:
3171:
3170:300 GHz/1 mm
3169:
3159:
3156:
3154:
3144:
3141:
3139:
3129:
3126:
3125:300 MHz/1 m
3124:
3114:
3111:
3109:
3099:
3096:
3094:
3084:
3081:
3080:300 kHz/1 km
3079:
3069:
3066:
3064:
3054:
3051:
3049:
3039:
3036:
3035:300 Hz/1 Mm
3034:
3024:
3021:
3019:
3009:
3006:
3004:
2987:
2981:
2912:
2907:
2901:
2869:
2868:
2851:
2832:
2813:
2796:
2794:Further reading
2791:
2781:
2779:
2770:
2769:
2765:
2755:
2753:
2748:
2747:
2743:
2733:
2731:
2723:
2722:
2718:
2708:
2706:
2697:
2696:
2692:
2685:
2667:
2663:
2653:
2651:
2638:
2637:
2630:
2596:
2592:
2585:
2563:
2556:
2546:
2544:
2530:
2526:
2519:
2503:
2499:
2492:
2476:
2472:
2465:
2451:
2447:
2432:
2418:
2411:
2407:
2402:
2397:
2393:
2376:
2372:
2363:
2359:
2355:
2350:
2295:Rayleigh fading
2275:Radio frequency
2255:Nakagami fading
2165:
2153:
2148:
2146:
2143:
2116:COST Hata model
2077:Terrain models
1971:
1884:frequency reuse
1821:FM broadcasting
1794:AM broadcasting
1787:
1762:
1757:
1756:
1616:
1608:
1494:
1488:
1476:
1472:
1471:
1469:
1453:ground stations
1417:cordless phones
1393:
1387:
1338:
1334:
1329:
1321:
1318:
1317:
1293:
1290:
1289:
1272:
1269:
1268:
1253:
1247:
1228:
1226:
1218:
1197:
1195:
1168:
1166:
1135:
1134:(3,000,000,000–
1133:
1106:100–10 cm
1102:
1100:
1096:300–3,000
1068:
1051:
1049:
1015:
977:
973:300–3,000
947:
917:100–10 km
913:
885:
796:
637:cordless phones
571:. As a form of
546:
517:
516:
513:
510:
504:
500:Spread spectrum
495:Reconfiguration
482:
479:
473:
448:
440:
439:
438:
358:
357:Characteristics
350:
349:
348:
308:
305:
298:
297:
289:
283:
265:
257:
256:
255:
205:
197:
196:
195:
120:
112:
111:
110:
70:
35:
28:
23:
22:
15:
12:
11:
5:
4754:
4744:
4743:
4726:
4725:
4723:
4722:
4716:
4710:
4704:
4693:
4691:
4687:
4686:
4684:
4683:
4678:
4672:
4670:
4666:
4665:
4663:
4662:
4660:Ten-rays model
4657:
4655:Six-rays model
4652:
4647:
4642:
4637:
4631:
4629:
4623:
4622:
4620:
4619:
4614:
4609:
4604:
4598:
4596:
4590:
4589:
4587:
4586:
4581:
4576:
4571:
4565:
4563:
4557:
4556:
4554:
4553:
4548:
4543:
4537:
4535:
4529:
4528:
4521:
4520:
4513:
4506:
4498:
4489:
4488:
4486:
4485:
4479:
4473:
4468:
4463:
4462:
4461:
4456:
4446:
4441:
4435:
4432:
4431:
4423:
4422:
4415:
4408:
4400:
4391:
4390:
4388:
4387:
4382:
4377:
4372:
4366:
4364:
4360:
4359:
4357:
4356:
4351:
4346:
4341:
4336:
4330:
4328:
4324:
4323:
4321:
4320:
4315:
4310:
4305:
4300:
4295:
4290:
4285:
4280:
4275:
4269:
4267:
4261:
4260:
4258:
4257:
4252:
4247:
4242:
4237:
4231:
4229:
4222:
4221:
4219:
4218:
4213:
4208:
4203:
4198:
4193:
4188:
4183:
4178:
4173:
4168:
4163:
4158:
4153:
4148:
4143:
4141:Dipole antenna
4138:
4133:
4128:
4123:
4118:
4109:
4104:
4098:
4096:
4092:
4091:
4089:
4088:
4083:
4078:
4072:
4070:
4066:
4065:
4063:
4062:
4057:
4055:Sound-in-Syncs
4052:
4047:
4041:
4039:
4035:
4034:
4032:
4031:
4026:
4021:
4016:
4011:
4006:
4001:
3996:
3991:
3986:
3981:
3976:
3971:
3966:
3961:
3956:
3951:
3946:
3944:Blanking level
3941:
3936:
3926:
3924:
3920:
3919:
3917:
3916:
3911:
3906:
3901:
3896:
3891:
3886:
3881:
3875:
3873:
3869:
3868:
3866:
3865:
3851:
3809:
3799:
3794:
3789:
3779:
3774:
3769:
3763:
3761:
3755:
3754:
3744:
3743:
3736:
3729:
3721:
3712:
3711:
3709:
3708:
3703:
3698:
3693:
3687:
3685:
3678:
3677:
3675:
3674:
3669:
3664:
3659:
3654:
3649:
3644:
3639:
3634:
3629:
3624:
3619:
3613:
3611:
3605:
3604:
3602:
3601:
3596:
3591:
3586:
3581:
3576:
3572:
3567:
3562:
3558:
3553:
3548:
3542:
3540:
3534:
3533:
3531:
3530:
3525:
3520:
3498:
3493:
3470:
3468:
3462:
3461:
3459:
3458:
3453:
3448:
3443:
3438:
3433:
3428:
3422:
3420:
3414:
3413:
3411:
3410:
3405:
3400:
3395:
3390:
3385:
3380:
3375:
3370:
3364:
3362:
3356:
3355:
3353:
3352:
3347:
3341:
3339:
3333:
3332:
3330:
3329:
3324:
3318:
3316:
3310:
3309:
3307:
3306:
3273:
3268:
3263:
3258:
3253:
3248:
3242:
3239:
3238:
3231:
3230:
3223:
3216:
3208:
3199:
3198:
3184:
3181:
3180:
3176:
3175:
3162:
3160:
3155:30 GHz/10 mm
3147:
3145:
3132:
3130:
3117:
3115:
3110:30 MHz/10 m
3102:
3100:
3087:
3085:
3072:
3070:
3065:30 kHz/10 km
3057:
3055:
3042:
3040:
3027:
3025:
3020:30 Hz/10 Mm
3012:
3010:
2997:
2992:
2989:
2988:
2984:Radio spectrum
2980:
2979:
2972:
2965:
2957:
2951:
2950:
2944:
2939:
2934:
2929:
2919:
2911:
2910:External links
2908:
2906:
2905:
2899:
2886:
2855:
2849:
2836:
2830:
2817:
2811:
2797:
2795:
2792:
2790:
2789:
2763:
2741:
2716:
2690:
2683:
2661:
2650:on 29 May 2012
2628:
2590:
2583:
2554:
2524:
2517:
2497:
2490:
2470:
2463:
2445:
2430:
2408:
2406:
2403:
2401:
2400:
2391:
2370:
2356:
2354:
2351:
2349:
2348:
2342:
2337:
2332:
2327:
2322:
2317:
2312:
2307:
2302:
2297:
2292:
2287:
2282:
2277:
2272:
2267:
2262:
2257:
2252:
2250:Mobility model
2247:
2242:
2237:
2232:
2227:
2222:
2217:
2215:F2 propagation
2212:
2207:
2202:
2197:
2192:
2187:
2182:
2177:
2172:
2166:
2161:Main article:
2159:
2158:
2142:
2139:
2138:
2137:
2132:
2126:
2125:
2121:
2120:
2119:
2118:
2113:
2108:
2100:
2099:
2098:
2093:
2088:
2083:
2074:
2073:
2069:
2068:
2063:
2058:
2052:
2051:
1970:
1967:
1959:Virgin Islands
1810:clear channels
1786:
1783:
1761:
1758:
1711:
1710:
1707:
1639:electric power
1617:
1609:
1607:
1604:
1588:radio amateurs
1516:propagation.
1490:Main article:
1487:
1484:
1421:walkie-talkies
1409:visual horizon
1389:Main article:
1386:
1383:
1375:speed of light
1363:
1362:
1351:
1341:
1337:
1333:
1328:
1325:
1297:
1276:
1246:
1243:
1240:
1239:
1233:
1230:
1220:
1215:
1209:
1208:
1202:
1201:1–0.1 mm
1199:
1189:
1186:
1180:
1179:
1173:
1170:
1160:
1157:
1151:
1150:
1140:
1137:
1127:
1124:
1118:
1117:
1107:
1104:
1094:
1091:
1085:
1084:
1081:meteor scatter
1066:
1056:
1053:
1043:
1040:
1034:
1033:
1020:
1019:100–10 m
1017:
1009:
1002:
996:
995:
982:
979:
971:
968:
962:
961:
952:
949:
941:
940:Low Frequency
938:
932:
931:
918:
915:
907:
904:
898:
897:
890:
887:
879:
876:
870:
869:
862:
859:
853:
850:
844:
843:
836:
833:
827:
824:
818:
817:
814:
811:
808:
795:
792:
641:walkie-talkies
548:
547:
545:
544:
537:
530:
522:
519:
518:
515:
514:
507:
503:
502:
497:
491:
490:
489:
483:
476:
472:
471:
466:
461:
456:
450:
449:
446:
445:
442:
441:
437:
436:
431:
426:
424:Radio spectrum
421:
416:
411:
406:
401:
396:
391:
386:
381:
376:
371:
366:
360:
359:
356:
355:
352:
351:
347:
346:
344:Vertical plane
341:
336:
331:
326:
321:
316:
310:
309:
304:
303:
300:
299:
296:
295:
290:
279:
277:
272:
266:
263:
262:
259:
258:
254:
253:
248:
243:
238:
233:
228:
223:
218:
213:
207:
206:
203:
202:
199:
198:
194:
193:
188:
183:
178:
173:
168:
163:
158:
153:
148:
143:
138:
133:
128:
122:
121:
118:
117:
114:
113:
109:
108:
103:
98:
96:Satellite dish
93:
88:
83:
78:
72:
71:
66:
65:
62:
61:
53:
52:
46:
45:
26:
9:
6:
4:
3:
2:
4753:
4742:
4739:
4738:
4736:
4720:
4717:
4714:
4711:
4708:
4705:
4702:
4698:
4695:
4694:
4692:
4688:
4682:
4679:
4677:
4674:
4673:
4671:
4667:
4661:
4658:
4656:
4653:
4651:
4648:
4646:
4643:
4641:
4638:
4636:
4635:Okumura model
4633:
4632:
4630:
4628:
4624:
4618:
4615:
4613:
4610:
4608:
4605:
4603:
4600:
4599:
4597:
4595:
4591:
4585:
4582:
4580:
4577:
4575:
4572:
4570:
4567:
4566:
4564:
4562:
4558:
4552:
4549:
4547:
4544:
4542:
4539:
4538:
4536:
4534:
4530:
4526:
4519:
4514:
4512:
4507:
4505:
4500:
4499:
4496:
4483:
4480:
4477:
4474:
4472:
4469:
4467:
4464:
4460:
4457:
4455:
4452:
4451:
4450:
4447:
4445:
4442:
4440:
4439:Line-of-sight
4437:
4436:
4433:
4429:
4421:
4416:
4414:
4409:
4407:
4402:
4401:
4398:
4386:
4383:
4381:
4378:
4376:
4373:
4371:
4368:
4367:
4365:
4361:
4355:
4352:
4350:
4347:
4345:
4342:
4340:
4337:
4335:
4332:
4331:
4329:
4325:
4319:
4316:
4314:
4311:
4309:
4306:
4304:
4301:
4299:
4296:
4294:
4291:
4289:
4286:
4284:
4281:
4279:
4276:
4274:
4271:
4270:
4268:
4266:
4262:
4256:
4253:
4251:
4248:
4246:
4243:
4241:
4238:
4236:
4233:
4232:
4230:
4227:
4223:
4217:
4214:
4212:
4209:
4207:
4204:
4202:
4199:
4197:
4194:
4192:
4189:
4187:
4184:
4182:
4179:
4177:
4174:
4172:
4169:
4167:
4164:
4162:
4159:
4157:
4154:
4152:
4149:
4147:
4144:
4142:
4139:
4137:
4134:
4132:
4129:
4127:
4124:
4122:
4119:
4117:
4113:
4110:
4108:
4105:
4103:
4100:
4099:
4097:
4093:
4087:
4084:
4082:
4079:
4077:
4074:
4073:
4071:
4067:
4061:
4058:
4056:
4053:
4051:
4048:
4046:
4043:
4042:
4040:
4036:
4030:
4029:White clipper
4027:
4025:
4022:
4020:
4017:
4015:
4012:
4010:
4007:
4005:
4002:
4000:
3997:
3995:
3992:
3990:
3987:
3985:
3982:
3980:
3979:Frame (video)
3977:
3975:
3972:
3970:
3967:
3965:
3962:
3960:
3957:
3955:
3952:
3950:
3947:
3945:
3942:
3940:
3937:
3935:
3931:
3928:
3927:
3925:
3921:
3915:
3912:
3910:
3907:
3905:
3902:
3900:
3897:
3895:
3892:
3890:
3887:
3885:
3882:
3880:
3877:
3876:
3874:
3872:Color systems
3870:
3863:
3859:
3855:
3852:
3849:
3845:
3841:
3837:
3833:
3829:
3825:
3821:
3817:
3813:
3810:
3807:
3803:
3800:
3798:
3795:
3793:
3790:
3787:
3783:
3780:
3778:
3775:
3773:
3770:
3768:
3765:
3764:
3762:
3760:
3756:
3752:
3749:
3742:
3737:
3735:
3730:
3728:
3723:
3722:
3719:
3707:
3704:
3702:
3699:
3697:
3694:
3692:
3689:
3688:
3686:
3683:
3679:
3673:
3670:
3668:
3665:
3663:
3660:
3658:
3655:
3653:
3650:
3648:
3645:
3643:
3640:
3638:
3635:
3633:
3630:
3628:
3625:
3623:
3620:
3618:
3615:
3614:
3612:
3610:
3606:
3600:
3597:
3595:
3592:
3590:
3587:
3585:
3582:
3580:
3573:
3571:
3568:
3566:
3559:
3557:
3554:
3552:
3549:
3547:
3544:
3543:
3541:
3539:
3535:
3529:
3526:
3524:
3521:
3518:
3514:
3510:
3506:
3502:
3499:
3497:
3494:
3491:
3487:
3483:
3479:
3475:
3472:
3471:
3469:
3467:
3463:
3457:
3454:
3452:
3449:
3447:
3444:
3442:
3439:
3437:
3434:
3432:
3429:
3427:
3424:
3423:
3421:
3419:
3415:
3409:
3406:
3404:
3401:
3399:
3396:
3394:
3391:
3389:
3386:
3384:
3381:
3379:
3376:
3374:
3371:
3369:
3366:
3365:
3363:
3361:
3357:
3351:
3348:
3346:
3343:
3342:
3340:
3338:
3334:
3328:
3325:
3323:
3320:
3319:
3317:
3315:
3311:
3304:
3300:
3293:
3281:
3277:
3274:
3272:
3269:
3267:
3264:
3262:
3259:
3257:
3254:
3252:
3249:
3247:
3244:
3243:
3240:
3236:
3229:
3224:
3222:
3217:
3215:
3210:
3209:
3206:
3196:
3195:
3182:
3173:
3172:3 THz/0.1 mm
3168:
3167:
3161:
3158:
3157:300 GHz/1 mm
3153:
3152:
3146:
3143:
3142:30 GHz/10 mm
3140:3 GHz/100 mm
3138:
3137:
3131:
3128:
3127:3 GHz/100 mm
3123:
3122:
3116:
3113:
3108:
3107:
3101:
3098:
3095:3 MHz/100 m
3093:
3092:
3086:
3083:
3078:
3077:
3071:
3068:
3067:300 kHz/1 km
3063:
3062:
3056:
3053:
3052:30 kHz/10 km
3050:3 kHz/100 km
3048:
3047:
3041:
3038:
3037:3 kHz/100 km
3033:
3032:
3026:
3023:
3018:
3017:
3011:
3008:
3005:3 Hz/100 Mm
3003:
3002:
2996:
2995:
2990:
2985:
2978:
2973:
2971:
2966:
2964:
2959:
2958:
2955:
2949:several pages
2948:
2945:
2943:
2940:
2938:
2935:
2933:
2930:
2927:
2923:
2920:
2917:
2914:
2913:
2902:
2896:
2892:
2887:
2883:
2879:
2873:
2872:cite magazine
2866:. p. 44.
2865:
2861:
2856:
2852:
2846:
2842:
2837:
2833:
2831:0-7923-0775-5
2827:
2823:
2818:
2814:
2812:0-07-006433-4
2808:
2804:
2799:
2798:
2777:
2773:
2767:
2751:
2745:
2730:
2726:
2720:
2704:
2700:
2694:
2686:
2684:0-87259-001-1
2680:
2676:
2672:
2665:
2649:
2645:
2641:
2635:
2633:
2623:
2618:
2614:
2610:
2609:
2604:
2600:
2594:
2586:
2580:
2576:
2571:
2570:
2561:
2559:
2542:
2540:
2535:
2528:
2520:
2518:9781351356367
2514:
2510:
2509:
2501:
2493:
2487:
2483:
2482:
2474:
2466:
2464:0-07-048470-8
2460:
2456:
2449:
2441:
2437:
2433:
2431:0-672-20678-1
2427:
2423:
2416:
2414:
2409:
2395:
2388:
2384:
2380:
2374:
2367:
2361:
2357:
2346:
2343:
2341:
2338:
2336:
2333:
2331:
2328:
2326:
2323:
2321:
2318:
2316:
2313:
2311:
2308:
2306:
2303:
2301:
2298:
2296:
2293:
2291:
2288:
2286:
2283:
2281:
2280:Radio horizon
2278:
2276:
2273:
2271:
2268:
2266:
2263:
2261:
2258:
2256:
2253:
2251:
2248:
2246:
2243:
2241:
2238:
2236:
2233:
2231:
2228:
2226:
2223:
2221:
2218:
2216:
2213:
2211:
2208:
2206:
2203:
2201:
2198:
2196:
2193:
2191:
2188:
2186:
2183:
2181:
2178:
2176:
2175:Channel model
2173:
2171:
2168:
2167:
2164:
2156:
2145:
2136:
2133:
2131:
2128:
2127:
2123:
2122:
2117:
2114:
2112:
2109:
2107:
2106:Okumura model
2104:
2103:
2101:
2097:
2094:
2092:
2089:
2087:
2084:
2082:
2079:
2078:
2076:
2075:
2071:
2070:
2067:
2064:
2062:
2059:
2057:
2054:
2053:
2049:
2048:
2047:
2044:
2040:
2038:
2032:
2028:
2026:
2021:
2019:
2015:
2010:
2006:
2002:
1998:
1994:
1991:
1988:
1984:
1980:
1976:
1966:
1964:
1960:
1956:
1952:
1948:
1944:
1940:
1939:Detroit River
1936:
1935:body of water
1932:
1928:
1925:and western
1924:
1920:
1916:
1913:and northern
1912:
1908:
1904:
1900:
1896:
1891:
1889:
1885:
1881:
1877:
1873:
1869:
1865:
1861:
1856:
1854:
1853:weather radio
1850:
1846:
1842:
1838:
1834:
1830:
1826:
1822:
1817:
1815:
1814:North America
1811:
1807:
1803:
1799:
1795:
1790:
1782:
1779:
1775:
1771:
1767:
1754:
1750:
1746:
1742:
1737:
1733:
1731:
1727:
1723:
1718:
1716:
1708:
1706:
1702:
1701:
1700:
1698:
1694:
1691:
1687:
1686:line of sight
1684:
1683:
1678:
1673:
1671:
1667:
1661:
1658:
1656:
1652:
1648:
1643:
1640:
1635:
1633:
1629:
1625:
1624:line-of-sight
1621:
1614:
1603:
1601:
1597:
1593:
1589:
1585:
1581:
1576:
1574:
1570:
1566:
1562:
1557:
1555:
1551:
1547:
1543:
1539:
1535:
1531:
1527:
1523:
1517:
1515:
1511:
1510:surface waves
1507:
1498:
1493:
1483:
1467:
1464:
1460:
1458:
1454:
1450:
1446:
1442:
1438:
1434:
1430:
1426:
1422:
1418:
1414:
1410:
1406:
1402:
1397:
1396:Line-of-sight
1392:
1382:
1380:
1376:
1371:
1367:
1349:
1339:
1335:
1331:
1326:
1323:
1316:
1315:
1314:
1312:
1295:
1274:
1266:
1262:
1258:
1252:
1237:
1234:
1231:
1225:
1221:
1216:
1214:
1211:
1210:
1206:
1203:
1200:
1194:
1190:
1187:
1185:
1182:
1181:
1177:
1174:
1172:10–1 mm
1171:
1165:
1161:
1158:
1156:
1153:
1152:
1148:
1144:
1141:
1139:10–1 cm
1138:
1132:
1128:
1125:
1123:
1120:
1119:
1115:
1111:
1108:
1105:
1101:(300,000,000–
1099:
1095:
1092:
1090:
1087:
1086:
1083:
1082:
1078:
1074:
1071:. Uncommonly
1070:
1060:
1057:
1054:
1048:
1044:
1041:
1039:
1036:
1035:
1032:
1030:
1024:
1021:
1018:
1014:
1010:
1007:
1003:
1001:
998:
997:
994:
992:
986:
983:
980:
976:
972:
969:
967:
964:
963:
960:
958:
953:
951:10–1 km
950:
946:
942:
939:
937:
934:
933:
930:
928:
923:
919:
916:
912:
908:
905:
903:
900:
899:
895:
891:
888:
884:
880:
877:
875:
872:
871:
867:
863:
860:
858:
854:
851:
849:
846:
845:
841:
837:
834:
832:
828:
825:
823:
820:
819:
815:
812:
809:
805:
799:
791:
789:
788:
783:
782:
777:
776:
770:
768:
764:
763:amateur radio
760:
758:
753:
749:
746:, a layer of
745:
741:
737:
734:frequencies (
733:
729:
724:
722:
718:
714:
710:
706:
702:
700:
695:
694:
693:surface waves
689:
685:
681:
677:
672:
670:
666:
662:
658:
654:
650:
646:
642:
638:
634:
630:
629:
623:
621:
617:
613:
609:
606:
602:
601:amateur radio
598:
594:
590:
586:
582:
578:
574:
570:
566:
562:
558:
554:
543:
538:
536:
531:
529:
524:
523:
521:
520:
512:
506:
505:
501:
498:
496:
493:
492:
488:
484:
481:
475:
474:
470:
467:
465:
462:
460:
457:
455:
454:Beam steering
452:
451:
444:
443:
435:
432:
430:
427:
425:
422:
420:
417:
415:
412:
410:
407:
405:
402:
400:
397:
395:
392:
390:
387:
385:
382:
380:
377:
375:
372:
370:
367:
365:
362:
361:
354:
353:
345:
342:
340:
337:
335:
332:
330:
327:
325:
322:
320:
317:
315:
312:
311:
302:
301:
294:
291:
287:
282:
278:
276:
273:
271:
268:
267:
261:
260:
252:
249:
247:
244:
242:
239:
237:
234:
232:
229:
227:
224:
222:
219:
217:
216:Amateur radio
214:
212:
209:
208:
201:
200:
192:
189:
187:
184:
182:
179:
177:
174:
172:
169:
167:
164:
162:
159:
157:
154:
152:
149:
147:
144:
142:
139:
137:
136:Coaxial cable
134:
132:
129:
127:
124:
123:
116:
115:
107:
104:
102:
99:
97:
94:
92:
89:
87:
84:
82:
79:
77:
74:
73:
69:
64:
63:
59:
55:
54:
51:
48:
47:
43:
39:
38:
33:
19:
4454:Meteor burst
4427:
4380:Hanover bars
4264:
4171:Pre-emphasis
4095:Transmission
4060:Zweikanalton
3964:Color killer
3889:Clear-Vision
3286:
3185:
3164:
3163:
3149:
3148:
3134:
3133:
3119:
3118:
3112:300 MHz/1 m
3104:
3103:
3097:30 MHz/10 m
3089:
3088:
3082:3 MHz/100 m
3074:
3073:
3059:
3058:
3044:
3043:
3029:
3028:
3022:300 Hz/1 Mm
3014:
3013:
3007:30 Hz/10 Mm
2999:
2998:
2916:Solar widget
2890:
2863:
2840:
2821:
2802:
2780:. Retrieved
2775:
2766:
2754:. Retrieved
2744:
2732:. Retrieved
2728:
2719:
2707:. Retrieved
2702:
2693:
2670:
2664:
2652:. Retrieved
2648:the original
2612:
2606:
2593:
2568:
2545:. Retrieved
2537:
2527:
2507:
2500:
2480:
2473:
2454:
2448:
2421:
2394:
2373:
2360:
2330:TV and FM DX
2305:Skip (radio)
2230:Fresnel zone
2155:Radio portal
2102:City models
2045:
2041:
2033:
2029:
2022:
1990:mathematical
1982:
1978:
1974:
1972:
1903:cross-border
1892:
1857:
1845:media market
1818:
1791:
1788:
1763:
1734:
1719:
1712:
1690:transmitting
1681:
1674:
1662:
1659:
1644:
1636:
1632:Fresnel zone
1618:
1577:
1558:
1550:time signals
1518:
1513:
1503:
1463:Ground plane
1461:
1394:
1372:
1368:
1364:
1311:point source
1254:
1222:0.3–20
1162:30–300
1147:rain scatter
1145:. Sometimes
1112:. Sometimes
1069:) refraction
1062:
1050:(30,000,000–
1045:30–300
1026:
988:
985:Ground waves
957:Ground waves
955:
943:30–300
927:Ground waves
925:
797:
785:
779:
773:
771:
755:
725:
705:AM broadcast
697:
691:
673:
626:
624:
614:systems, to
608:broadcasters
593:polarization
552:
551:
418:
324:Ground plane
211:Antenna farm
68:Common types
4650:Young model
4449:Ionospheric
4349:VIT signals
4344:Vectorscope
4283:Earth bulge
4265:Propagation
4228:& bands
4226:Frequencies
4009:Raster scan
3949:Chrominance
3939:Black level
3934:front porch
3701:Medium wave
3378:Lyman-alpha
3360:Ultraviolet
3299:wavelengths
3292:frequencies
3256:Ultraviolet
2864:CQ Magazine
2782:11 February
2756:11 February
2703:wsprnet.org
2245:Link budget
2195:Earth bulge
2018:transmitter
1993:formulation
1955:Puerto Rico
1943:Great Lakes
1829:cloud cover
1825:TV stations
1804:levels and
1596:medium wave
1514:ground wave
1492:Ground wave
1413:cell phones
1191:0.3–3
1063:Infrequent
881:0.3–3
813:Wavelength
759:propagation
728:medium wave
709:attenuation
701:propagation
699:ground wave
688:diffraction
633:cell phones
585:diffraction
557:radio waves
464:Beamforming
369:Directivity
319:Focal cloud
181:Transmitter
4640:Hata model
4574:Egli model
4533:Free space
4459:Sporadic E
4278:Distortion
4211:Transposer
4146:Dummy load
4102:Amplifiers
4069:Modulation
3959:Colorburst
3930:Back porch
3682:Wavelength
3538:Microwaves
3350:Hard X-ray
3345:Soft X-ray
3314:Gamma rays
3246:Gamma rays
2734:4 December
2709:4 December
2654:28 January
2541:(nasa.gov)
2491:0471743682
2405:References
2379:ionosphere
2225:Free space
2111:Hata model
2086:Egli model
1997:radio wave
1929:along the
1849:Ice storms
1768:, such as
1600:short wave
1567:bands, an
1530:attenuated
1466:reflection
1457:spacecraft
1379:refraction
1257:free space
1011:3–30
1006:Short Wave
922:ionosphere
909:3–30
894:ionosphere
866:ionosphere
810:Frequency
744:ionosphere
597:scattering
589:absorption
581:refraction
577:reflection
569:atmosphere
561:propagated
469:Small cell
447:Techniques
374:Efficiency
364:Array gain
119:Components
101:Television
4715:(900 MHz)
4709:(900 MHz)
4426:Modes of
4385:Sparklies
4370:Dot crawl
4363:Artifacts
4303:Path loss
4298:Null fill
4273:Beam tilt
4014:Safe area
3696:Shortwave
3691:Microwave
3271:Microwave
2366:rain fade
2353:Footnotes
2310:Skip zone
2014:path loss
2005:frequency
1987:empirical
1947:Caribbean
1911:San Diego
1880:beam tilt
1778:WSPR mode
1741:repeaters
1705:human eye
1670:multipath
1556:systems.
1526:monopoles
1405:microwave
1327:∝
1324:ρ
1275:ρ
732:shortwave
715:(VLF) to
669:microwave
663:(such as
622:systems.
605:shortwave
459:Beam tilt
339:Side lobe
329:Main lobe
314:Boresight
191:Twin-lead
151:Feed line
4735:Category
4375:Ghosting
4136:Diplexer
4004:Overscan
3969:Color TV
3862:System F
3858:System E
3854:819-line
3848:System N
3844:System L
3840:System K
3836:System I
3832:System H
3828:System G
3824:System D
3820:System C
3816:System B
3812:625-line
3806:System M
3802:525-line
3797:455-line
3792:441-line
3786:System A
3782:405-line
3777:375-line
3772:343-line
3767:180-line
3706:Longwave
3466:Infrared
3266:Infrared
2776:rsgb.org
2601:(1924).
2440:43-14665
2141:See also
2009:distance
2001:function
1985:, is an
1899:handoffs
1868:suburban
1695:and the
1584:longwave
1477:distance
649:FM radio
485:Massive
251:Wireless
166:Receiver
91:Monopole
50:Antennas
42:a series
40:Part of
4594:Foliage
4561:Terrain
4327:Testing
3909:PALplus
3759:Systems
3297:longer
3290:higher
3261:Visible
2615:(113).
2315:Skywave
1981:or the
1927:Windsor
1923:Detroit
1915:Tijuana
1907:roaming
1901:, when
1693:antenna
1592:skywave
1475:⁄
1431:links,
1309:from a
1055:10–1 m
1023:E layer
991:F layer
855:30–300
840:D layer
757:skywave
686:bands,
226:Hotspot
204:Systems
171:Rotator
81:Fractal
4697:VOACAP
4669:Indoor
3884:NTSC-J
3599:L band
3594:S band
3589:C band
3584:X band
3570:K band
3556:Q band
3551:V band
3546:W band
3451:Orange
3446:Yellow
3426:Violet
3337:X-rays
3251:X-rays
2897:
2847:
2828:
2809:
2681:
2608:Nature
2581:
2547:19 May
2515:
2488:
2461:
2438:
2428:
2345:VOACAP
2335:Upfade
2220:Fading
1751:, and
1682:visual
1666:relays
1347:
1259:, all
682:, and
659:, and
595:, and
565:vacuum
404:Height
389:Factor
76:Dipole
4690:Other
4627:Urban
4484:(ISM)
4478:(EME)
4050:NICAM
4038:Sound
3923:Video
3914:SECAM
3904:PAL-S
3899:PAL-M
3684:types
3609:Radio
3505:Bands
3478:Bands
3441:Green
3276:Radio
2986:(ITU)
2705:(map)
2577:–22.
1888:rural
1864:urban
1839:, or
1837:frost
1730:urban
1726:WiMAX
1647:Wi-Fi
1441:radar
1129:3–30
829:3–30
807:Band
657:radar
620:radar
246:Wi-Fi
236:Radio
186:Tuner
126:Balun
4313:Skew
3994:Luma
3932:and
3879:NTSC
3579:band
3565:band
3523:LWIR
3501:MWIR
3496:SWIR
3436:Cyan
3431:Blue
2924:The
2895:ISBN
2882:link
2878:link
2845:ISBN
2826:ISBN
2807:ISBN
2784:2017
2758:2017
2736:2020
2711:2020
2679:ISBN
2656:2013
2613:2844
2579:ISBN
2549:2021
2513:ISBN
2486:ISBN
2459:ISBN
2436:LCCN
2426:ISBN
1878:and
1819:For
1598:and
1552:and
1540:and
1439:and
1435:and
1313:or:
1027:F1,
752:ions
738:and
730:and
399:Gain
176:Stub
146:Feed
106:Whip
86:Loop
4255:VHF
4250:UHF
3894:PAL
3672:ELF
3667:SLF
3662:ULF
3657:VLF
3637:VHF
3632:UHF
3627:SHF
3622:EHF
3617:THF
3528:FIR
3474:NIR
3456:Red
3408:UVA
3403:UVB
3398:UVC
3393:NUV
3388:MUV
3383:FUV
3166:THF
3151:EHF
3136:SHF
3121:UHF
3106:VHF
3046:VLF
3031:ULF
3016:SLF
3001:ELF
2617:doi
2003:of
1841:fog
1833:dew
1812:in
1792:In
1565:ELF
1563:to
1561:VLF
1542:VLF
1401:VHF
1255:In
1224:THz
1213:FIR
1193:THz
1184:THF
1164:GHz
1155:EHF
1131:GHz
1122:SHF
1098:MHz
1089:UHF
1079:or
1047:MHz
1038:VHF
1013:MHz
989:E,
975:kHz
945:kHz
911:kHz
902:VLF
883:kHz
874:ULF
848:SLF
822:ELF
726:At
696:or
684:VLF
4737::
4701:HF
3860:,
3846:,
3842:,
3838:,
3834:,
3830:,
3826:,
3822:,
3818:,
3652:LF
3647:MF
3642:HF
3515:,
3511:,
3507::
3488:,
3484:,
3480::
3091:HF
3076:MF
3061:LF
2874:}}
2870:{{
2862:.
2774:.
2727:.
2701:.
2631:^
2611:.
2605:.
2575:21
2557:^
2536:.
2434:.
2412:^
2020:.
2007:,
1973:A
1835:,
1747:,
1743:,
1655:TV
1651:3G
1634:.
1538:LF
1536:,
1534:MF
1443:.
1433:FM
1423:,
1419:,
1415:,
1149:.
1116:.
1073:F2
1061:.
1029:F2
1008:)
1000:HF
987:.
966:MF
959:.
936:LF
929:.
924:.
896:.
868:.
857:Hz
831:Hz
740:HF
736:MF
723:.
703:.
680:LF
678:,
676:MF
655:,
651:,
647:,
643:,
639:,
635:,
591:,
587:,
583:,
579:,
44:on
4703:)
4699:(
4517:e
4510:t
4503:v
4419:e
4412:t
4405:v
4114:/
3864:)
3856:(
3850:)
3814:(
3808:)
3804:(
3788:)
3784:(
3740:e
3733:t
3726:v
3577:u
3575:K
3563:a
3561:K
3519:)
3517:N
3513:M
3509:L
3503:(
3492:)
3490:H
3486:K
3482:J
3476:(
3302:→
3288:←
3227:e
3220:t
3213:v
2976:e
2969:t
2962:v
2903:.
2884:)
2853:.
2834:.
2815:.
2786:.
2760:.
2738:.
2713:.
2687:.
2658:.
2625:.
2619::
2587:.
2551:.
2521:.
2494:.
2467:.
2442:.
1615:.
1480:)
1473:1
1470:(
1350:.
1340:2
1336:r
1332:1
1296:r
1067:s
750:(
541:e
534:t
527:v
288:)
284:(
34:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
