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76-690: Starfish Prime was a high-altitude nuclear test conducted by the United States, a joint effort of the Atomic Energy Commission (AEC) and the Defense Atomic Support Agency . It was launched from Johnston Atoll on July 9, 1962, and was the largest nuclear test conducted in outer space , and one of five conducted by the US in space. A Thor rocket carrying a W49 thermonuclear warhead (designed at Los Alamos Scientific Laboratory ) and

152-492: A Mk. 2 reentry vehicle was launched from Johnston Atoll in the Pacific Ocean, about 900 miles (1,450 km) west-southwest of Hawaii. The explosion took place at an altitude of 250 miles (400 km), above a point 19 miles (31 km) southwest of Johnston Atoll. It had a yield of 1.4  Mt (5.9  PJ ). The explosion was about 10° above the horizon as seen from Hawaii, at 11 pm Hawaii time. The Starfish test

228-419: A beam of radio waves in the microwave frequency range to transmit video , audio , or data between two locations, which can be from just a few feet or meters to several miles or kilometers apart. Microwave links are commonly used by television broadcasters to transmit programmes across a country, for instance, or from an outside broadcast back to a studio. Mobile units can be camera mounted, allowing cameras

304-528: A connection between New York City and Murray Hill, the location of Bell Laboratories in 1946. The TDX system was set up between New York and Boston in 1947. The TDX was upgraded to the TD2 system, which used [the Morton tube, 416B and later 416C, manufactured by Western Electric] in the transmitters, and then later to TD3 that used solid-state electronics . Remarkable were the microwave relay links to West Berlin during

380-419: A diameter of up to 4 m (13 ft). Highly directive antennas permit an economical use of the available frequency spectrum, despite long transmission distances. Because of the high frequencies used, a line-of-sight path between the stations is required. Additionally, in order to avoid attenuation of the beam, an area around the beam called the first Fresnel zone must be free from obstacles. Obstacles in

456-413: A distance of 56 km (35 miles), was followed in 1935 by a 300 MHz telecommunication link, the first commercial microwave relay system. The development of radar during World War II provided much of the microwave technology which made practical microwave communication links possible, particularly the klystron oscillator and techniques of designing parabolic antennas. Though not commonly known,

532-488: A few kilometers, not enough for long-distance communication. The electronic technologies needed in the millimeter wave band are also in an earlier state of development than those of the microwave band. More recently, microwaves have been used for wireless power transmission . Microwave radio relay is a technology widely used in the 1950s and 1960s for transmitting information, such as long-distance telephone calls and television programs between two terrestrial points on

608-621: A few more decades. The Starfish bomb contained Cd as a tracer, which helped work out the seasonal mixing rate of polar and tropical air masses. High altitude nuclear explosion The Partial Test Ban Treaty was passed in October 1963, ending atmospheric and exoatmospheric nuclear tests. The Outer Space Treaty of 1967 banned the stationing of nuclear weapons in space, in addition to other weapons of mass destruction . The Comprehensive Nuclear-Test-Ban Treaty of 1996 prohibits all nuclear testing; whether over- or underground, underwater or in

684-507: A fire that burned down the Karaganda power plant, and shut down 1,000 kilometres (620 mi) of shallow-buried power cables between Tselinograd and Alma-Ata . US Government Films: Microwave radio relay#Microwave radio relay Microwave transmission is the transmission of information by electromagnetic waves with wavelengths in the microwave frequency range of 300 MHz to 300 GHz (1 m - 1 mm wavelength) of

760-456: A form of saber rattling. The worst effects of a Soviet high-altitude test occurred on 22 October 1962, in the Soviet Project K nuclear tests (ABM System A proof tests) when a 300 kt missile-warhead detonated near Dzhezkazgan at 290-kilometre (180 mi) altitude. The EMP fused 570 kilometres (350 mi) of overhead telephone line with a measured current of 2,500  A , started

836-530: A line of sight limits the separation between stations to the visual horizon, about 30 to 50 miles (48 to 80 km). For longer distances, the receiving station could function as a relay, retransmitting the received information to another station along its journey. Chains of microwave relay stations were used to transmit telecommunication signals over transcontinental distances. Microwave relay stations were often located on tall buildings and mountaintops, with their antennas on towers to get maximum range. Beginning in

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912-524: A lower cost per bit. During the Cold War, the US intelligence agencies, such as the National Security Agency (NSA), were reportedly able to intercept Soviet microwave traffic using satellites such as Rhyolite/Aquacade . Much of the beam of a microwave link passes the receiving antenna and radiates toward the horizon, into space. By positioning a geosynchronous satellite in the path of the beam,

988-487: A narrow beam of microwaves. In microwave radio relay, a microwave transmitter and directional antenna transmits a narrow beam of microwaves carrying many channels of information on a line of sight path to another relay station where it is received by a directional antenna and receiver, forming a fixed radio connection between the two points. The link was often bidirectional, using a transmitter and receiver at each end to transmit data in both directions. The requirement of

1064-528: A spherical 'cloud' until distorted by Earth's magnetic field . The charged particles resulting from the blast are accelerated along the Earth's magnetic field lines to create an auroral display at the conjugate point , which has led documentary maker Peter Kuran to characterize these detonations as 'the rainbow bombs'. The visual effects of a high-altitude or space-based explosion may last longer than atmospheric tests, sometimes in excess of 30 minutes. Heat from

1140-428: A state of frozen stillness. All this occurred, I would judge, within 45 seconds. As the purplish light turned to magenta and began to fade at the point of burst, a bright red glow began to develop on the horizon at a direction 50 degrees north of east and simultaneously 50 degrees south of east expanding inward and upward until the whole eastern sky was a dull burning red semicircle 100 degrees north to south and halfway to

1216-464: Is a strong need, not only for better instrumentation, but for further tests covering a range of altitudes and yields. The Starfish test was originally planned as the second in the Fishbowl series, but the first launch ( Bluegill ) was lost by the radar tracking equipment and had to be destroyed in flight. The initial Starfish launch attempt on June 20 was also aborted in flight, this time due to failure of

1292-408: Is regulated by International Telecommunication Union ( ITU-R ) and local regulations ( ETSI , FCC ). In the last decade the dedicated spectrum for each microwave band has become extremely crowded, motivating the use of techniques to increase transmission capacity such as frequency reuse, polarization-division multiplexing , XPIC , MIMO . The history of radio relay communication began in 1898 with

1368-627: The Bluegill Triple Prime shot, at an altitude of 50 kilometers (31 miles), was felt by personnel on the ground at Johnston Atoll , and this test caused retina burns to two personnel at ground zero who were not wearing their safety goggles. The Soviets detonated four high-altitude tests in 1961 and three in 1962. During the Cuban Missile Crisis in October 1962, both the US and the USSR detonated several high-altitude nuclear explosions as

1444-554: The Cold War , which had to be built and operated due to the large distance between West Germany and Berlin at the edge of the technical feasibility. In addition to the telephone network, also microwave relay links for the distribution of TV and radio broadcasts. This included connections from the studios to the broadcasting systems distributed across the country, as well as between the radio stations, for example for program exchange. Military microwave relay systems continued to be used into

1520-483: The English Channel using 10-foot (3 m) dishes. Telephony, telegraph, and facsimile data was transmitted over the bidirectional 1.7 GHz beams 40 miles (64 km) between Dover , UK, and Calais , France. The radiated power, produced by a miniature Barkhausen–Kurz tube located at the dish's focus, was one-half watt. A 1933 military microwave link between airports at St. Inglevert, France, and Lympne, UK,

1596-750: The English Channel was demonstrated in 1931, the development of radar in World War II provided the technology for practical exploitation of microwave communication. During the war, the British Army introduced the Wireless Set No. 10, which used microwave relays to multiplex eight telephone channels over long distances. A link across the English Channel allowed General Bernard Montgomery to remain in continual contact with his group headquarters in London. In

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1672-498: The Thor launch vehicle. The Thor missile flew a normal trajectory for 59 seconds; then the rocket engine stopped, and the missile began to break apart. The range safety officer ordered the destruction of the missile and warhead. The missile was between 30,000 and 35,000 feet (9,100 and 10,700 m) in altitude when it was destroyed. Parts of the missile and some radioactive contamination fell upon Johnston Atoll , nearby Sand Island, and

1748-483: The electromagnetic spectrum . Microwave signals are normally limited to the line of sight , so long-distance transmission using these signals requires a series of repeaters forming a microwave relay network. It is possible to use microwave signals in over-the-horizon communications using tropospheric scatter , but such systems are expensive and generally used only in specialist roles. Although an experimental 40-mile (64 km) microwave telecommunication link across

1824-403: The zenith obliterating some of the lesser stars. This condition, interspersed with tremendous white rainbows, persisted no less than ninety minutes. At zero time at Johnston, a white flash occurred, but as soon as one could remove his goggles, no intense light was present. A second after shot time a mottled red disc was observed directly overhead and covered the sky down to about 45 degrees from

1900-400: The 1950s a unit of the US telephone carrier, AT&T Long Lines , built a transcontinental system of microwave relay links across the US which grew to carry the majority of US long distance telephone traffic, as well as television network signals. The main motivation in 1946 to use microwave radio instead of cable was that a large capacity could be installed quickly and at less cost. It

1976-611: The 1950s, networks of microwave relay links, such as the AT&;T Long Lines system in the U.S., carried long-distance telephone calls and television programs between cities. The first system, dubbed TDX and built by AT&T, connected New York and Boston in 1947 with a series of eight radio relay stations. Through the 1950s, they deployed a network of a slightly improved version across the U.S., known as TD2 . These included long daisy-chained links that traversed mountain ranges and spanned continents. The launch of communication satellites in

2052-485: The 1960s, when many of these systems were supplanted with tropospheric scatter or communication satellite systems. When the NATO military arm was formed, much of this existing equipment was transferred to communications groups. The typical communications systems used by NATO during that time period consisted of the technologies which had been developed for use by the telephone carrier entities in host countries. One example from

2128-824: The 1970s and 80s, and the introduction of long-distance fibre optic systems in the 1980s and especially 90s led to the rapid rundown of the relay networks, most of which are abandoned. In recent years, there has been an explosive increase in use of the microwave spectrum by new telecommunication technologies such as wireless networks , and direct-broadcast satellites which broadcast television and radio directly into consumers' homes. Larger line-of-sight links are once again popular for handing connections between mobile telephone towers, although these are generally not organized into long relay chains. Microwaves are widely used for point-to-point communications because their small wavelength allows conveniently-sized antennas to direct them in narrow beams, which can be pointed directly at

2204-411: The 1970s provided a cheaper alternative. Much of the transcontinental traffic is now carried by satellites and optical fibers , but microwave relay remains important for shorter distances. Because in microwave transmission the waves travel in narrow beams confined to a line-of-sight path from one antenna to the other, they do not interfere with other microwave equipment, so nearby microwave links can use

2280-406: The 1990s. Frequency bands below 10 GHz, and above all, the information to be transmitted, were a stream containing a fixed capacity block. The target was to supply the requested availability for the whole block ( Plesiochronous digital hierarchy , PDH, or synchronous digital hierarchy , SDH). Fading and/or multipath affecting the link for short time period during the day had to be counteracted by

2356-524: The British Army used the Wireless Set Number 10 in this role during World War II. The need for radio relay did not really begin until the 1940s exploitation of microwaves , which traveled by line of sight and so were limited to a propagation distance of about 40 miles (64 km) by the visual horizon. After the war, telephone companies used this technology to build large microwave radio relay networks to carry long-distance telephone calls. During

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2432-743: The Earth's surface. The potential as an anti-satellite weapon became apparent in August 1958 during Hardtack Teak . The EMP observed at the Apia Observatory at Samoa was four times more powerful than any created by solar storms , while in July 1962 the Starfish Prime test damaged electronics in Honolulu and New Zealand (approximately 1,300 kilometres (810 mi) away), fused 300 street lights on Oahu (Hawaii), set off about 100 burglar alarms , and caused

2508-453: The Earth. The added electrons increased the intensity of electrons within the natural inner Van Allen radiation belt by several orders of magnitude. There was much uncertainty and debate about the composition, magnitude and potential adverse effects from the trapped radiation after the detonation. The weaponeers became quite worried when three satellites in low Earth orbit were disabled. These included TRAAC and Transit 4B . The half-life of

2584-638: The South Pacific Ocean near the Samoan Islands . This location was at the southern end of the magnetic field line of the Earth's magnetic field from the position of the nuclear detonation, an area known as the "southern conjugate region" for the test. An uninvited scientific expeditionary ship from the Soviet Union was stationed near Johnston Atoll for the test, and another Soviet scientific expeditionary ship

2660-578: The Starfish Prime detonation. In addition, a large number of rocket-borne instruments were launched from Barking Sands , Kauai, in the Hawaiian Islands. A large number of United States military ships and aircraft were operating in support of Starfish Prime in the Johnston Atoll area and across the nearby North Pacific region. A few military ships and aircraft were also positioned in the region of

2736-451: The U.S. Government Project Officer's Interim Report on the Starfish Prime project: Previous high-altitude nuclear tests: YUCCA , TEAK , and ORANGE , plus the three ARGUS shots were poorly instrumented and hastily executed. Despite thorough studies of the meager data, present models of these bursts are sketchy and tentative. These models are too uncertain to permit extrapolation to other altitudes and yields with any confidence. Thus there

2812-531: The USA is the RCA CW-20A 1–2 GHz microwave relay system which utilized flexible UHF cable rather than the rigid waveguide required by higher frequency systems, making it ideal for tactical applications. The typical microwave relay installation or portable van had two radio systems (plus backup) connecting two line of sight sites. These radios would often carry 24 telephone channels frequency-division multiplexed on

2888-659: The United Kingdom's first satellite, Ariel 1 . Detectors on Telstar, TRAAC, Injun , and Ariel 1 were used to measure distribution of the radiation produced by the tests. In 1963, it was reported that Starfish Prime had created a belt of MeV electrons. In 1968, it was reported that some Starfish electrons had remained in the atmosphere for 5 years. A year later, the US and USSR signed the Partial Nuclear Test Ban Treaty , which banned all above-ground nuclear testing. France and China continued above-ground tests for

2964-400: The area and reception issues arising from the use of nearby land (such as in manufacturing and forestry) are important issues to consider when planning radio links. In the planning process, it is essential that "path profiles" are produced, which provide information about the terrain and Fresnel zones affecting the transmission path. The presence of a water surface, such as a lake or river, along

3040-482: The artificial aurora was unexpected. "A 'Quick Look' at the Technical Results of Starfish Prime" (August 1962) states: At Kwajalein , 1,400 [nautical] miles [2,600 km; 1,600 mi] to the west, a dense overcast extended the length of the eastern horizon to a height of 5 or 8 degrees. At 0900 GMT a brilliant white flash burned through the clouds rapidly changing to an expanding green ball of irradiance extending into

3116-405: The artificial radiation belt. These measurements describe the explosion from 0.1 milliseconds to 16 minutes after the detonation. The explosion released roughly 10 electrons into the Earth's magnetosphere . While some of the energetic beta particles followed the Earth's magnetic field and illuminated the sky, other high-energy electrons became trapped and formed radiation belts around

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3192-518: The atmosphere and collide with air molecules, depositing their energy to produce huge quantities of positive ions and recoil electrons (also known as Compton electrons ). These MeV-energy Compton electrons then accelerate and spiral along the Earth's magnetic field lines. The resulting transient electric fields and currents generate electromagnetic emissions in the radio frequency range of 15 MHz to 250 MHz . This high-altitude EMP occurs between 30 and 50 kilometers (19 and 31 miles) above

3268-474: The atmosphere, but hasn't entered into force yet as it hasn't been ratified by some of the states party to the Treaty. The strong electromagnetic pulse (EMP) that results has several components. In the first few tenths of nanoseconds, about a tenth of a percent of the weapon yield appears as powerful gamma rays with energies of one to three mega-electron volts ( MeV , a unit of energy). The gamma rays penetrate

3344-664: The atmosphere. An interesting side effect was that the Royal New Zealand Air Force was aided in anti-submarine maneuvers by the light from the bomb. These auroral effects were partially anticipated by Nicholas Christofilos , a scientist who had earlier worked on the Operation Argus high-altitude nuclear shots. According to U.S. atomic veteran Cecil R. Coale, some hotels in Hawaii offered "rainbow bomb" parties on their roofs for Starfish Prime, contradicting some reports that

3420-458: The clear sky above the overcast. From its surface extruded great white fingers, resembling cirro-stratus clouds, which rose to 40 degrees above the horizon in sweeping arcs turning downward toward the poles and disappearing in seconds to be replaced by spectacular concentric cirrus like rings moving out from the blast at tremendous initial velocity, finally stopping when the outermost ring was 50 degrees overhead. They did not disappear but persisted in

3496-586: The design yield, which various sources have set at different values in the range of 1.4 to 1.45  Mt (5.9 to 6.1  PJ ). The nuclear warhead detonated 13 minutes 41 seconds after liftoff of the Thor missile from Johnston Atoll. Starfish Prime caused an electromagnetic pulse (EMP) that was far larger than expected, so much larger that it drove much of the instrumentation off scale, causing great difficulty in getting accurate measurements. The Starfish Prime electromagnetic pulse also made those effects known to

3572-860: The detrimental factors mentioned in this section, collectively known as path loss , make it necessary to compute suitable power margins, in order to maintain the link operative for a high percentage of time, like the standard 99.99% or 99.999% used in 'carrier class' services of most telecommunication operators. The longest known microwave radio relay crosses the Red Sea with a 360 km (220 mi) hop between Jebel Erba (2,170 m (7,120 ft) a.s.l., 20°44′46.17″N 36°50′24.65″E  /  20.7461583°N 36.8401806°E  / 20.7461583; 36.8401806 , Sudan) and Jebel Dakka (2,572 m (8,438 ft) a.s.l., 21°5′36.89″N 40°17′29.80″E  /  21.0935806°N 40.2916111°E  / 21.0935806; 40.2916111 , Saudi Arabia). The link

3648-542: The diversity architecture. During 1990s microwave radio links begun widely to be used for urban links in cellular network . Requirements regarding link distance changed to shorter hops (less than 10 km (6.2 mi), typically 3 to 5 km (1.9 to 3.1 mi)), and frequency increased to bands between 11 and 43 GHz and more recently, up to 86 GHz (E-band). Furthermore, link planning deals more with intense rainfall and less with multipath, so diversity schemes became less used. Another big change that occurred during

3724-452: The energetic electrons was only a few days. At the time it was not known that solar and cosmic particle fluxes varied by a factor of 10, and energies could exceed 1  MeV (0.16  pJ ). In the months that followed, these man-made radiation belts eventually caused six or more satellites to fail, as radiation damaged their solar arrays or electronics, including the first commercial relay communication satellite , Telstar 1 , as well as

3800-584: The failure of a microwave repeating station on Kauai , which cut off the sturdy telephone system from the other Hawaiian islands. The radius for an effective satellite kill for the Compton radiation produced by such a nuclear weapon in space was determined to be roughly 80 kilometres (50 mi). Further testing to this end was carried out, and embodied in a Department of Defense program, Program 437 . . There are problems with nuclear weapons carried over to testing and deployment scenarios, however. Because of

3876-414: The freedom to move around without trailing cables. These are often seen on the touchlines of sports fields on Steadicam systems. Terrestrial microwave relay links are limited in distance to the visual horizon, a few tens of miles or kilometers depending on tower height. Tropospheric scatter ("troposcatter" or "scatter") was a technology developed in the 1950s to allow microwave communication links beyond

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3952-443: The horizon to the north and grew to the south and at about 2 minutes the white-yellow bands were still about 10 degrees wide and extended mainly from near zenith to the south. By about two minutes, the red disc region had completed disappearance in the west and was rapidly fading on the eastern portion of the overhead disc. At 400 seconds essentially all major visible phenomena had disappeared except for possibly some faint red glow along

4028-453: The horizon, to a range of several hundred kilometers. The transmitter radiates a beam of microwaves into the sky, at a shallow angle above the horizon toward the receiver. As the beam passes through the troposphere a small fraction of the microwave energy is scattered back toward the ground by water vapor and dust in the air. A sensitive receiver beyond the horizon picks up this reflected signal. Signal clarity obtained by this method depends on

4104-420: The last decade was an evolution toward packet radio transmission. Therefore, new countermeasures, such as adaptive modulation , have been adopted. The emitted power is regulated for cellular and microwave systems. These microwave transmissions use emitted power typically from 0.03 to 0.30 W, radiated by a parabolic antenna on a narrow beam diverging by a few degrees (1 to 3-4). The microwave channel arrangement

4180-466: The microwave band has a bandwidth 30 times that of all the rest of the radio spectrum below it. A disadvantage is that microwaves are limited to line of sight propagation; they cannot pass around hills or mountains as lower frequency radio waves can. Microwave radio transmission is commonly used in point-to-point communication systems on the surface of the Earth, in satellite communications , and in deep space radio communications . Other parts of

4256-409: The microwave beam can be received. At the turn of the century, microwave radio relay systems were used increasingly in portable radio applications. The technology is particularly suited to this application because of lower operating costs, a more efficient infrastructure , and provision of direct hardware access to the portable radio operator. A microwave link is a communications system that uses

4332-438: The microwave carrier (i.e. Lenkurt 33C FDM). Any channel could be designated to carry up to 18 teletype communications instead. Similar systems from Germany and other member nations were also in use. Long-distance microwave relay networks were built in many countries until the 1980s, when the technology lost its share of fixed operation to newer technologies such as fiber-optic cable and communication satellites , which offer

4408-458: The microwave radio band are used for radars , radio navigation systems, sensor systems, and radio astronomy . The next higher frequency band of the radio spectrum , between 30 GHz and 300 GHz, are called " millimeter waves " because their wavelengths range from 10 mm to 1 mm. Radio waves in the millimeter wave band are strongly attenuated by the gases of the atmosphere , which limits their practical transmission distance to

4484-458: The north-south line and on the horizon to the north. No sounds were heard at Johnston Atoll that could be definitely attributed to the detonation. Strong electromagnetic signals were observed from the burst, as were significant magnetic field disturbances and earth currents. A 2006 report described the particle and field measurements of the Starfish diamagnetic cavity and the injected beta flux into

4560-416: The path also must be taken into consideration since it can reflect the beam, and the direct and reflected beam can interfere with each other at the receiving antenna, causing multipath fading. Multipath fades are usually deep only in a small spot and a narrow frequency band, so space and/or frequency diversity schemes can be applied to mitigate these effects. The effects of atmospheric stratification cause

4636-487: The post-war era, the development of microwave technology was rapid, which led to the construction of several transcontinental microwave relay systems in North America and Europe. In addition to carrying thousands of telephone calls at a time, these networks were also used to send television signals for cross-country broadcast, and later, computer data. Communication satellites took over the television broadcast market during

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4712-445: The public by causing electrical damage in Hawaii, about 900 miles (1,450 km) away from the detonation point, knocking out about 300 streetlights, setting off numerous burglar alarms, and damaging a telephone company microwave link . The EMP damage to the microwave link shut down telephone calls from Kauai to the other Hawaiian Islands . A total of 27 small rockets were launched from Johnston Atoll to obtain experimental data from

4788-648: The publication by Johann Mattausch in the Austrian journal, Zeitschrift für Elektrotechnik. But his proposal was primitive and not suitable for practical use. The first experiments with radio repeater stations to relay radio signals were done in 1899 by Emile Guarini-Foresio. However the low frequency and medium frequency radio waves used during the first 40 years of radio proved to be able to travel long distances by ground wave and skywave propagation. In 1931, an Anglo-French consortium headed by Andre C. Clavier demonstrated an experimental microwave relay link across

4864-556: The radio path to bend downward in a typical situation so a major distance is possible as the earth equivalent curvature increases from 6,370 km (3,960 mi) to about 8,500 km (5,300 mi) (a 4/3 equivalent radius effect). Rare events of temperature, humidity and pressure profile versus height, may produce large deviations and distortion of the propagation and affect transmission quality. High-intensity rain and snow making rain fade must also be considered as an impairment factor, especially at frequencies above 10 GHz. All of

4940-408: The receiving antenna. This use of tightly-focused direct beams allows microwave transmitters in the same area to use the same frequencies, without interfering with each other as lower frequency radio waves would. This frequency reuse conserves scarce radio spectrum bandwidth. Another advantage is that the high frequency of microwaves gives the microwave band a very large information-carrying capacity;

5016-407: The same frequencies. The antennas must therefore be highly directional (high gain ), and are installed in elevated locations such as large radio towers in order to be able to avoid the obstructions closer to the ground and transmit across long distances. Typical types of antenna used in radio relay link installations are parabolic antennas , dielectric lens, and horn-reflector antennas , which have

5092-403: The signal field cause unwanted attenuation . High mountain peaks or ridges are often ideal positions for the antennas. In addition to the use of conventional repeaters with back-to-back radios transmitting on different frequencies, obstructions in microwave paths can also be dealt with by using Passive repeater or on-frequency repeaters. Obstacles, the curvature of the Earth, the geography of

5168-403: The surrounding ocean. On July 9, 1962, at 09:00:09 Coordinated Universal Time (11:00:09 pm on July 8, 1962, Honolulu time), the Starfish Prime test was detonated at an altitude of 250 miles (400 km). The coordinates of the detonation were 16°28′N 169°38′W  /  16.467°N 169.633°W  / 16.467; -169.633 . The actual weapon yield came very close to

5244-508: The very large radius associated with nuclear events, it was nearly impossible to prevent indiscriminate damage to other satellites, including one's own satellites. Starfish Prime produced an artificial radiation belt in space that soon destroyed three satellites ( Ariel , TRAAC , and Transit 4B all failed after traversing the radiation belt, while Cosmos V , Injun I and Telstar 1 suffered minor degradation, due to some radiation damage to solar cells , etc.). The radiation dose rate

5320-486: The zenith. Generally, the red mottled region was more intense on the eastern portions. Along the magnetic north-south line through the burst, a white-yellow streak extended and grew to the north from near zenith. The width of the white streaked region grew from a few degrees at a few seconds to about 5–10 degrees in 30 seconds. Growth of the auroral region to the north was by addition of new lines developing from west to east. The white-yellow auroral streamers receded upward from

5396-462: Was at least 0.6 Gy /day at four months after Starfish for a well-shielded satellite or crewed capsule in a polar circular earth orbit , which caused NASA concern with regard to its crewed space exploration programs. In general, nuclear effects in space (or very high altitudes) have a qualitatively different display. While an atmospheric nuclear explosion has a characteristic mushroom-shaped cloud , high-altitude and space explosions tend to manifest

5472-445: Was built in 1979 by Telettra to transmit 300 telephone channels and one TV signal, in the 2 GHz frequency band. (Hop distance is the distance between two microwave stations). Previous considerations represent typical problems characterizing terrestrial radio links using microwaves for the so-called backbone networks: hop lengths of a few tens of kilometers (typically 10 to 60 km (6.2 to 37.3 mi)) were largely used until

5548-413: Was expected at that time that the annual operating costs for microwave radio would be greater than for cable. There were two main reasons that a large capacity had to be introduced suddenly: Pent-up demand for long-distance telephone service, because of the hiatus during the war years, and the new medium of television, which needed more bandwidth than radio. The prototype was called TDX and was tested with

5624-402: Was illuminated by the auroral phenomena, from far south of the south magnetic conjugate area ( Tongatapu ) through the burst area to far north of the north conjugate area ( French Frigate Shoals )... At twilight after the burst, resonant scattering of light from lithium and other debris was observed at Johnston and French Frigate Shoals for many days confirming the long time presence of debris in

5700-516: Was in the southern conjugate region near the Samoan Islands. After the Starfish Prime detonation, bright auroras were observed in the detonation area, as well as in the southern conjugate region on the other side of the equator from the detonation. According to one of the first technical reports: The visible phenomena due to the burst were widespread and quite intense; a very large area of the Pacific

5776-468: Was one of five high-altitude tests grouped together as Operation Fishbowl within the larger Operation Dominic , a series of tests in 1962 begun in response to the Soviet announcement on August 30, 1961, that they would end a three-year moratorium on testing. In 1958, the United States had completed six high-altitude nuclear tests that produced many unexpected results and raised many new questions. According to

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