Why do radio waves not follow a straight line?

Answer 1

radio waves are affected by a number of environmental conditions which cause the following:

• refraction
• reflection
• absorption
• diffraction
• scattering

Radio waves at UHF and above frequencies can be refracted around sharp edge grounded objects such as walls. The effect gets more apparent as the frequency increases.

Reflection of radio occurs if an obstruction is sufficiently dense to deflect radio waves such as aluminium and other metals.

In the case of absorption and material of high density will either block a signal or absorb it if grounded or of sufficient mass. The level of absorption is dependent of the radio frequency emitted or the density of the obstruction.

Earths atmosphere can become ionised be Solar radiation and cause radio waves of LF to HF to be reflected back to Earth. This propagation is known as "Skip". VHF UHF and Microwaves are significantly less likely to be affected by the ionisation layers.

VHF radio can have a non linear path if subjected to charged plasma such as caused by cosmic radiation such as the Northern or southern aurora borealis.

UHF and microwaves can be subject to "Ducting" where the radio signal will bounce between charged cloud layers.

All radio waves can be scattered by an object which reflects. An example of this is meteor scatter or moon bounce (Also known as EME earth moon earth).

These exotic modes of radio propogation use objects to scatter the radio signal. In this case either meteor showers lilke the Persids which occurs every year or the surface of the moon. These modes are generally only used by Amatuer radio enthusiasts.

Answer 2

I'm pretty sure that they travel in parabolas, although honestly I'm tyring to find the same out for myself. The waves themselves are sin/cosine (I always forget) curves.

ADDED.

No, like light, they travel in straight lines, though can be imagined as an infinite number of thin rays fanning out from their source. They are described for analysis as sine curves so their 0-level points start at 0 s. in time, but the cosine curve is the same shape as its companion sine curve, simply displaced by 90º forwards. (Sin 0º = 1, Sin 90º = 1; but Cos 0º = 1, Cos 90º = 0)

Answer 3

Radio waves generally do travel in a straight line, in the vacuum of space.

Here on earth, they are affected by the atmosphere and will bend towards the curvature of the earth, by refraction.

Radio is an electromagnetic waveform, the same as light.

As a radio wave travels through the atmosphere, it will be slowed down on one side causing it to curve slightly towards the earth.

The amount will be dependant on the wavelength, the same as white light splitting into the colours of the spectrum. The composition of the air and water vapour, will also affect the amount of refraction.

Answer 4

Light travels from the sun to your eyes with no wires. Heat travels from the fire to

your skin with no wires. A radio signal is exactly the same kind of thing as heat and

light. They're all called "electromagnetic radiation". Other examples of the same thing

are infrared, ultraviolet, and X-rays. The only difference between all of them is their

wavelength. They're made of electric and magnetic fields, and none of them needs

anything to carry it. They travel through empty space with no trouble at all, without

even any air in it.

Answer 5

In homogeneous media without borders. On borders usually changes its direction according with Snell law. The only one exception is when waves are perfectly perpendicular to borders.