Radio atmospheric In the case of the ionospheric D-layer, it depends, in addition, on time of day, season, latitude, and the geomagnetic field in a complicated manner. VLF propagation within the Earth–ionosphere waveguide can be described by ray theory and by wave theory. When distances are less than about 500 km (depending on frequency), then ray theory is appropriate. The ground wave and the first hop (or sky) wave reflected at the ionospheric D layer interfere with each other. At distances greater than about 500 km, sky waves reflected several times at the ionosphere must be added. Therefore, mode theory is here
The Tidal Waves The Tidal Waves The Tidal Waves were an American garage rock band formed in Roseville, Michigan, in 1964. Despite the young ages of the group members, the Tidal Waves were one of the more accomplished musical acts in the bustling Michigan garage band scene. They are best remembered for their regional hit, a cover version of "Farmer John", which managed to reach the Top 10 of several radio station charts around Detroit. Inspired by the Beatles' momentous appearance on "The Ed Sullivan Show" in February 1964, high school students Tom Wearing (drums, vocals), Mark Karpinski (lead guitar, vocals), and Vic