Why should ground waves be vertically polarized?

Why should ground waves be vertically polarized?

Medium wave broadcasting: Medium wave broadcast stations generally use vertical polarisation because ground wave propagation over the earth is considerably better using vertical polarization, whereas horizontal polarization shows a marginal improvement for long distance communications using the ionosphere.

Why horizontal polarization is avoided in ground wave propagation?

Using horizontal polarization gives addition antenna gain due to the ground reflection near the antenna. Therefore most broadcast station on long or medium wave (0.1 – 1.5 MHz) are designed for ground wave propagation, for which vertically polarized antennas work best.

Who uses ground waves?

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

Can ultrasonic waves be Polarised?

Ultrasonic waves are high-frequency sound waves. These waves are longitudinal in nature, hence it cannot be polarized. Only transverse waves can be polarised.

What are the properties of ground wave propagation?

3.1 Ground waves can be direct, be ground reflected, or follow the surface. To achieve an optimal propagating result with a surface wave, you must use vertical polarization. That is the reason why long and medium wave radio stations use self-radiating, vertical transmitting masts as their antennas.

What is the difference between vertically and horizontally polarized radio waves?

Therefore vertical polarization is used for ground-wave transmission, allowing the radio wave to travel a considerable distance along the ground surface with minimum attenuation. Horizontally polarized. Horizontally polarized antennas have their electric field parallel to the Earth’s surface.

Why are vertical polarized antennas preferred at low frequency?

You might want to adapt the antenna poalrization (antenna orientation) to the propagation. Davies, Ionospheric Radio, is a good book to start with. Low frequency means long wavelength, so using vertical antennas you can half at least the dimension of any linear antennas by using image principle wrt to the ground.

How are reflected waves polarized in the ground?

By the ground we mean the land, for example. To understand what is going on in this process, we need to first understand that reflected waves can be polarized because the initial unpolarized light has energy that is multidirectional in all angles that are perpendicular to the direction of travel.

Why are radio waves transmitted in all directions?

Signals are transmitted in all directions. Therefore vertical polarization is used for ground-wave transmission, allowing the radio wave to travel a considerable distance along the ground surface with minimum attenuation. Horizontally polarized antennas have their electric field parallel to the Earth’s surface.