Ground conductivity refers to the
electrical conductivity
Electrical resistivity (also called volume resistivity or specific electrical resistance) is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. A low resistivity in ...
of the subsurface of the
earth
Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
. In the International System of Units (SI) it is measured in millisiemens per meter (mS/m).
Radio propagation
Ground conductivity is an extremely important factor in determining the field strength and propagation of
surface wave (ground wave) radio transmissions.
Low frequency (30–300 kHz) and
medium frequency (300–3000 kHz) radio transmissions are particularly reliant on good ground conductivity as their primary propagation is by surface wave. It also affects the real world radiation pattern of
high frequency
High frequency (HF) is the ITU designation for the band of radio waves with frequency between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one ...
(3-30 MHz) antennas, as the so-called "takeoff angle" is not an inherent property of the antenna but a result of a
ground reflection. For this reason ITU publishes an extensive world atlas of ground conductivities.
Other uses
Ground conductivity is sometimes used in determining the efficiency of a
septic tank
A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater (sewage) flows for basic sewage treatment. Settling and anaerobic digestion processes reduce solids and organics, but the treatment ...
, using
electromagnetic induction
Electromagnetic or magnetic induction is the production of an electromotive force, electromotive force (emf) across an electrical conductor in a changing magnetic field.
Michael Faraday is generally credited with the discovery of induction in 1 ...
, so that contaminants do not reach the surface or nearby water supplies.
References
External links
Ground conductivity maps in the United States(provided by the
Federal Communications Commission
The Federal Communications Commission (FCC) is an independent agency of the United States government that regulates communications by radio, television, wire, internet, wi-fi, satellite, and cable across the United States. The FCC maintains j ...
and includes large scale map)
Measurement of the ground conductivity and relative permittivity with high frequency using an open wire line (OWL)(Practical example with network analyzer and mathematics for the conversion)
Broadcast engineering
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