| Autor: |
Allnutt, Jeremy E. |
| Předmět: |
|
| Zdroj: |
Encyclopedia of Electrical & Electronics Engineering; 1999 1st Edition, Vol. 18, p379-388, 10p |
| Abstrakt: |
This article presents information on refraction and attenuation in the troposphere. The average refractive index of a medium is called the bulk refractive index, and it affects the average direction of the electromagnetic energy. Most media are not completely homogeneous, however: small volumes of different refractive indices will exist within the larger scale of the medium. The refractive index of a given portion of the atmosphere will therefore vary far more quickly with change in height than with change in horizontal position. Ducting is defined as occurring when a radio ray originating close to the earth's surface is sufficiently refracted that it is either bent back towards the earth's surface or travels along a path that is parallel to the earth's surface. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
