Radiation and Propagation of Waves

Extraterrestrial Communications

Extraterrestrial Communications: Extraterrestrial Communications : The most recent, and by far the fastest-growing, field of communications involves the use of various satellite relays, of which the first was launched in 1957,-12 years after the practicability and orbital positioning of stationary satellites were first described and calculated. The field may be subdivided into three parts, each …

Extraterrestrial Communications Read More »

Tropospheric Scatter Propagation

Tropospheric Scatter Propagation: Tropospheric Scatter Propagation is a means of beyond-the-horizon propagation for UHF signals. Tropospheric Scatter Propagation uses certain properties of the troposphere, the nearest portion of the atmosphere (within about 15 km of the ground). Properties of Tropospheric Scatter Propagation: As shown in Figure 8-20, two directional antennas are pointed so that their …

Tropospheric Scatter Propagation Read More »

Space Waves

Space Waves: Space waves generally behave with merciful simplicity. They travel in (more or less) straight lines! However, since they depend on line-of-sight conditions, space waves are limited in their propagation by the curvature of the earth, except in very unusual circumstances. Thus they propagate very much like electromagnetic waves in free space. Such a …

Space Waves Read More »

Interference of Electromagnetic Waves

Interference of Electromagnetic Waves: Interference of Electromagnetic Waves occurs when two waves that left one source and travelled by different paths arrive at a point. This happens very often in high-frequency sky-wave propagation and in microwave space-wave propagation. It occurs when a microwave antenna is located near the ground, and waves reach the receiving point …

Interference of Electromagnetic Waves Read More »