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
Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz ( GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (s ...
from a
transmitter
In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the ...
, 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
Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz ( GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (s ...
such as the
short wave (SW) radio signals that employ continuous
reflections for transmission.
Propagation Path
Radio waves
Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz ( GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (s ...
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
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium.
The refractive index determines how much the path of light is bent, or ...
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.
References
External links
Principles of Radio Wave PropagationRadio Waves and Communications Distance
See also
Maximum usable frequency
In radio transmission maximum usable frequency (MUF) is the highest radio frequency that can be used for transmission between two points via reflection from the ionosphere (skywave or "skip" propagation) at a specified time, independent of transm ...
Radio
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