As the original signal power is spread over a constantly growing area, only a fraction of the transmitted energy reaches a receiving antenna. Beam divergence loss is caused by the geometric spreading of the electromagnetic field as it travels through space. The received SNR is degraded by a combination of two factors: beam divergence loss and atmospheric attenuation. The range of a radio communications link is defined as the farthest distance that the receiver can be from the transmitter and still maintain a sufficiently high signal-to-noise ratio (SNR) for reliable signal reception. On the other hand, unlike guided channels such as wire or optical fibre, the medium through which radio waves propagate is highly variable, being subject to diurnal, annual, and solar changes in the ionosphere, variations in the density of water droplets in the troposphere, varying moisture gradients, and diverse sources of reflection and diffraction. ![]() This makes radio ideal for mobile communications, satellite and deep-space communications, broadcast communications, and other applications in which the laying of physical connections may be impossible or very costly. Radio wave propagation is not constrained by any physical conductor or waveguide.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |