I will pay for the following article Radio Wave Propagation. The work is to be 6 pages with three to five sources, with in-text citations and a reference page. Radio waves are transmitted from a point source in straight lines filling a sphere. Wave propagation occurs by the inverse square law: signal strength is proportional to 1/x2, where x = distance from the source. So, the waves lose strength rapidly.

Radio waves travel very fast but only in a straight line. Thus, the curvature of the earth should limit the distance between transmitter and receiver, a distance of about 60 miles (100 km). However, the earth’s atmosphere has properties that allow enhanced propagation. The atmosphere is layered, and these layers have important effects on waves that are propagated on the earth’s surface. The layer called the troposphere is a heavy, oxygen-filled layer that extends from the surface to about 30 miles (50 km) altitude. From 30m (50 km) to 260m (416 km) is a highly charged layer called the ionosphere. The ionosphere affects radio signals in different ways depending on their frequencies.

The frequencies used for radio propagation range from 30 kHz to 3 GHz. Frequencies are continuous but defined in bands according to their properties and uses. Higher frequencies have shorter wavelengths and more energy.

LF waves are propagated as ground waves which, as the name implies, travel along the ground. Because the ground and its terrain interfere with ground waves, transmission requires lots of power. LF waves are used mainly in maritime communications over the sea and the navigational system called LORAN. Sometimes ground waves suffer from a reflecting wave off the ionosphere that can return to the earth out of phase near the receiver and interfere with the direct reception.

MF wave frequencies are used for AM radio broadcasting. They are also ground waves, and during the daylight hours are limited to a range of about 60 miles (100 km). But radio waves can be bent or refracted by changes in the earth’s atmosphere, particularly by weather patterns and by the ionosphere.

The Ionosphere consists of the “D”, “E”, F1, and the F2 layers. At night, the “E” layer disappears, and the F1 and F2 layers combine to form the “F” layer. Since the “E” layer disappears at night, the lower frequency Sky Waves (MF) travel further up into the atmosphere, where they are REFRACTED by the “F” layer [up to 300m].