Explain in brief the ground wave propagation.

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Q. Explain in brief the ground wave propagation.

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[!TLDR]

Ground-wave propagation carries vertically polarized LF/MF waves along the earth's surface over hundreds to thousands of km.

Radio waves that are transmitted along, or reflected from, the earth's surface are called ground waves or surface waves. Key points:

The wave must be vertically polarized (electric field perpendicular to the earth) and uses the earth as a transmission line.
It is used mainly in the LF and MF bands, covering a few hundred to a few thousand kilometres.
As the wave travels, energy is absorbed by the earth, so the signal strength decreases with distance until the field $E$ is reduced to zero.
The earth's conductivity increases with wetness (water conducts better), so ground-wave propagation is well suited to marine communication (ship-to-shore and shore-to-ship).

[!ANSWER]

Ground-wave propagation is the travel of vertically polarized LF/MF radio waves guided along the earth's surface; the signal is progressively absorbed by the earth (so strength falls with distance) and it is widely used for marine communication.

Same / Similar Concept — real previous-year questions on the same or a closely similar concept, not this exact question.

CBSE 2016Set ANNUAL2 marks
$Q. Write a short note on surface wave propagation of electromagnetic waves.$
›Reveal solutionSolution

In surface-wave (ground-wave) propagation, the radio wave hugs the Earth's curved surface, diffracting around it, but loses energy to the ground as it travels.

Surface wave (ground wave) propagation: When a radio wave is radiated from a transmitting antenna close to the ground, it can travel along the surface of the Earth, guided by the boundary between the Earth (a partial conductor) and the atmosphere. This mode of propagation is called surface-wave or ground-wave propagation, and is one of the three principal modes of electromagnetic wave propagation (the others being sky wave and space wave).

The wave follows the curvature of the Earth to some extent because of diffraction — the ground effectively acts as a wave-guide. However, the conducting Earth absorbs energy from the wave as it travels (induced currents dissipate energy as heat in the ground), so the wave is progressively attenuated; the attenuation increases rapidly with frequency, which is why this mode is practical mainly at low and medium frequencies (below a few MHz, roughly up to the MF/AM broadcast band).

Ground-wave propagation is affected by the electrical conductivity of the terrain it passes over — it travels farther over highly conducting surfaces like sea water than over poorly conducting ground like dry, rocky soil. It is used mainly for local and regional AM radio broadcasting, and for maritime and navigational communication, where reliable coverage over a few hundred kilometres is needed regardless of atmospheric/ionospheric conditions.

✓Final answer
$Surface (ground) wave propagation: EM waves travel along the Earth's surface, diffracting around its curvature but being progressively attenuated by ground absorption — practical mainly for low/medium-frequency (e.g. AM radio) transmission over moderate distances.$

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Q.Explain in brief the ground wave propagation.

Concept understanding — Ground Wave Propagation

Q.Explain in brief the ground wave propagation.

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