Near Vertical Incidence Skywave (NVIS) propagation can be used for radio communication in a large area (200 km radius) without any intermediate man-made infrastructure. It is therefore especially suited for disaster relief communication, communication in developing regions and applications where independence of local infrastructure is desired, such as military applications. NVIS communication uses frequencies between approximately 3 and 10 MHz. A comprehensive overview of NVIS research is given, covering propagation, antennas, diversity, modulation and coding. Both the bigger picture and the important details are given, as well as the relation between them.
The Normandy Invasion communications were NVIS, designed to cover from the
center of Britain, across the Channel, to the landing area in France, and to
be effective from ships, shore stations and man-pack radios. The principal
problem concerned advance lookouts directing bombing runs, which were
initiated from airfields in England. Ground wave was too short and skywave
reflection was not dependable. Dr. H. H. Beverage redesigned the
communications shortly before the landing