Ground Wave Propagation

What is Radio Wave Propagation?

It is important to understand the meaning of radio wave propagation, to understand the meaning of ground wave propagation. Radio wave propagation can be explained as the radio waves which propagate from one point to another or into various parts of the atmosphere.


Depending upon the frequencies, these waves propagation can be classified as:

  1. Ground waves propagation

  2. Skywave propagation

  3. Free space propagation


Ground Wave Propagation:

Ground Wave propagation uses the area between the surface of the earth and the ionosphere for transmission, it is a method of radio wave propagation. Ground wave propagation is also called surface wave propagation. The ground wave follows the contour of earth and hence it can propagate considerable distances. Such a wave is called a direct wave. It exists below the 2 MHz frequency range. Ground wave propagation over the earth's surface can be propagated to a considerable distance by the ground wave, in the low frequency and medium frequency portion of the radio spectrum. Ground waves are mainly used for transmission between the surface of the earth and the ionosphere. These are made up of the number of constituent waves. Low frequencies of the electromagnetic spectrum were used. The collection of these radiations along the surface of the earth is known as ground wave propagation. The intensity of these radiations drops with distance due to its absorption by ground. 


It is known as a ground wave because it is the sum of the waves that are reflected by the earth’s surface or any hills. The curvature of the earth is being followed by the waves, enabling them to cover beyond the horizon. The waves get blocked beyond the horizon, by the curvature of the earth and the signals are produced by the diffracted surface wave.


(image will be uploaded soon)


(image will be uploaded soon)


Depending on the Type of Ground, the Frequency of Ground Waves:

Type of Ground

f = 1 MHz

f = 10 MHz

f = 100 MHz

Dry ground like a desert

10⁻⁴

10⁻⁴

10⁻⁴

Very moist ground like fields

10⁻²

10⁻²

2 x 10⁻²

Freshwater at 20oC

3 x 10⁻³

3 x 10⁻³

5 x 10⁻³

Seawater at 20oC

5

5

5


Advantages of Ground Wave Propagation

  1. As it uses lower frequencies, interference occurs due to atmospheric noise only. That's why the absorption of EM waves at lower frequencies is less. Hence it can cover longer distances. However, the path loss increases as the distance from the transmitter increases.

  2. These waves are more efficient and also these are not affected by the change in atmospheric conditions, due to the bending around the corners or obstructions during propagation.

  3. They are vertically polarized in order to prevent short circuits of the electric field (E) component. 


Disadvantages of Ground Wave Propagation

  1. High-frequency waves cannot be transmitted as the energy losses are more because of the absorption of energy in the earth’s atmosphere.

  2. These are used to cover short ranges and also involve attenuation of waves as they interact with the eddy currents produced by the surface of the earth.

  3. If the polarization of the ground wave is affected, E field components are short-circuited with the ground.


Applications Ground Wave Propagation

  1. To provide the local radio communications coverage, we generally use ground wave propagation, especially by radio broadcast stations that are required to cover a particular locality.

  2. Ground wave propagation can be used for one-way communication from the military to submerged submarines as they penetrate to a significant depth into seawater.

  3. AM, FM, and television broadcasting can be done with the help of ground waves.

  4. Ground wave propagation of radio signals is ideal for relatively short distance propagation on these frequencies during the daytime.


Fun Facts

  1. The signal of ground wave propagation travels over the surface of the ground, and as a result, it is used to provide regional coverage on the long and medium wavebands.

  2. To provide the local radio communications coverage, we generally use ground wave propagation, especially by radio broadcast stations that are required to cover a particular locality.

  3. Ground wave propagation of radio signals is ideal for relatively short distance propagation on these frequencies during the day time.

  4. Ground wave propagation of the wave follows the contour of the Earth. Such a wave is called a direct wave. Due to the Earth’s magnetic field, the wave bends and gets reflected to the receiver. Such a wave can be termed as a reflected wave.

  5. The wave that propagates through the Earth’s atmosphere is known as a ground wave. The signal at the receiver station is being contributed by the direct wave and reflected wave together.

FAQ (Frequently Asked Questions)

1. Where Ground Wave Propagation is Used?

Ground wave propagation is one of the types of radio propagation which is also known as a surface wave. These are made up of the number of constituent waves. These waves are propagating over the earth's surface in low and medium frequencies. The main use of ground wave propagation is the transmission between the surface of the earth and the ionosphere.

2. What is the Range of Ground Wave Propagation?

A brief review of ground wave propagation and it was developed when the work of Zenneck and Sommerfeld a century ago is presented. The interest in using ground waves for wireless communication with remote under-populated areas using the high frequency (HF) range is being increased in the current situation which extends from 3 - 30 MHz.