Skip distance
Encyclopedia
A skip distance is the distance a radio wave
travels, usually including a hop in the ionosphere
. A skip distance is a distance on the Earth's surface between the two points where radio waves
from a transmitter
, refracted downwards by different layers of the ionosphere
, fall. It also represents how far a radio wave
has travelled per hop on the Earth's surface, for radio waves
such as the short wave (SW) radio signals that employ continuous reflections for transmission.
Radio waves
from a particular transmitting antenna do not all get refracted by a particular layer of the ionosphere; some are absorbed, some refracted while a portion escapes to the next layer. At this higher layer, there is a possibility of this radio wave being bent downwards to earth again. This bending happens because each layer of the ionosphere has a refractive index
that varies from that of the others. Because of the differing heights of refraction, or apparent reflection, the radio waves hit the earth surface at different points hence generating the skip distance. Skip distance is greatest during the night when the ionosphere is the highest.
Radio Wave
Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...
travels, usually including a hop in the ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
. A skip distance is a distance on the Earth's surface between the two points where radio waves
Radio waves
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies from 300 GHz to as low as 3 kHz, and corresponding wavelengths from 1 millimeter to 100 kilometers. Like all other electromagnetic waves,...
from a transmitter
Transmitter
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...
, refracted downwards by different layers of the ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
, fall. It also represents how far a radio wave
Radio Wave
Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...
has travelled per hop on the Earth's surface, for radio waves
Radio waves
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies from 300 GHz to as low as 3 kHz, and corresponding wavelengths from 1 millimeter to 100 kilometers. Like all other electromagnetic waves,...
such as the short wave (SW) radio signals that employ continuous reflections for transmission.
Radio waves
Radio waves
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies from 300 GHz to as low as 3 kHz, and corresponding wavelengths from 1 millimeter to 100 kilometers. Like all other electromagnetic waves,...
from a particular transmitting antenna do not all get refracted by a particular layer of the ionosphere; some are absorbed, some refracted while a portion escapes to the next layer. At this higher layer, there is a possibility of this radio wave being bent downwards to earth again. This bending happens because each layer of the ionosphere has a refractive index
Refractive index
In optics the refractive index or index of refraction of a substance or medium is a measure of the speed of light in that medium. It is expressed as a ratio of the speed of light in vacuum relative to that in the considered medium....
that varies from that of the others. Because of the differing heights of refraction, or apparent reflection, the radio waves hit the earth surface at different points hence generating the skip distance. Skip distance is greatest during the night when the ionosphere is the highest.