Category:Near Vertical Incidence Skywave
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English: Near Vertical Incidence Skywave, or NVIS, is a radio-wave propagation method that provides usable signals in the range between groundwave and skywave distances (usually 30 to 150 miles, or 50 to 240 km). It is used mainly for military and paramilitary communications and by radio amateurs. The radio waves travel upwards into the ionosphere, where they are refracted back down and can be received within a circular region up to 300 km from the transmitter. If the frequency is too high, refraction fails to occur and if it is too low absorption reduces the signal strength.
The usable frequencies for NVIS communications are between 1.8 MHz and 12 MHz.
Français : Le N.V.I.S. (Near Vertical Incidence Skywave), en Français: onde radio ionosphèrique à incidence quasi verticale, est un mode de propagation utilisé pour des radiocommunications locales et régionale dans la bande des moyennes fréquences et hautes fréquences (1,6 à 12 MHz) à l’intérieur d’une zone arbitraire de 240 km autour de l'émetteur.
Ce mode de propagation des ondes radios nécessite une antenne NVIS dont le lobe de rayonnement principal est en direction du ciel.
Media in category "Near Vertical Incidence Skywave"
The following 27 files are in this category, out of 27 total.
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82d Airborne Division paratroopers wearing their maroon beret-1983.jpg 899 × 664; 214 KB
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82d Airborne jeep Urgent Fury 1983.JPEG 2,800 × 1,820; 1.21 MB
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Antenne a fil.jpg 1,704 × 1,744; 1.74 MB
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Bundesarchiv Bild 101I-769-0229-12A, Frankreich, Guderian, "Enigma".jpg 511 × 799; 222 KB
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Bundesarchiv Bild 146 Reichswehr Nachrichtenwagen-colorized.jpg 1,280 × 860; 204 KB
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Bundesarchiv Bild 146-2006-0199, Reichswehr, Nachrichtenwagen.jpg 792 × 532; 51 KB
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Commandeered British Land Rover Pyongyang.jpg 550 × 392; 64 KB
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CriticalFrequency-NPS.png 400 × 200; 12 KB
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Ionogramme.png 327 × 259; 4 KB
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Namibienun.jpg 1,015 × 689; 76 KB
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NVIS Radiation Pattern.svg 4,834 × 2,649; 185 KB
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NVIS.svg 1,029 × 543; 24 KB
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Peugeot 203 Break Gendarmerie Française antenna NVIS.jpg 768 × 919; 286 KB
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Radiostacja R-118K-colorized.jpg 1,280 × 1,137; 274 KB
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Radiostacja R-118K.jpg 536 × 476; 45 KB
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SafirVehicle4.jpg 900 × 683; 177 KB
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SafirVehicle5.jpg 900 × 670; 166 KB
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Super Constellation HB-RSC 02.jpg 2,154 × 1,437; 649 KB
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Super Constellation HB-RSC 03.jpg 2,128 × 1,266; 445 KB
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Super Constellation HB-RSC 04 NVIS.jpg 2,272 × 1,704; 612 KB
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Super Constellation HB-RSC 04.jpg 2,160 × 1,506; 267 KB
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Vedette plaisance.jpg 1,443 × 709; 717 KB
