How can radio waves be used for communication

The radio station that you plug into is one of many specific radio wave frequencies being transmitted at all hours of the day. You load up your Google docs, websites and email, all using radio waves to connect wirelessly to the internet through WiFi. You see, radios waves are used in many more things than the square boxes that we use to play music and listen to talk shows.

Modern wireless communication builds off of simple design inside the conventional radio, allowing us to connect humanity all around the world with information, video, audio, data, and a whole lot more. But for how widespread radio waves are in their use today, how exactly do they work, and what is a radio wave?

All of these waves manage to defy physical barriers, hurtling through the vacuum of space at the speed of light. The organization of this spectrum is categorized by two measurements, frequency, and wavelength.

All the waves in the electromagnetic spectrum are measured by both their frequency and wavelength. On this electromagnetic spectrum, radio waves have both the longest wavelengths and the lowest frequencies, which makes them slow and steady, the long-distance runners of the bunch. They do this by sharing specific bands in the radio wave spectrum, and these include:. The United States publishes an annual Radio Spectrum Frequency Allocation chart that shows how all of these radio services are allocated per frequency.

Now you might be wondering, how exactly do those radio waves in their particular frequencies get from place to place? The magic of being able to talk with someone on your smartphone halfway around the world boils down to some very simple principles. A transmitter, as its name implies, transmits information through the air in the form of a sine wave. This wave goes flying through the air, eventually being caught by a receiver, which decodes the information within the sine wave to extract the stuff we want, like music, a human voice, or some other bit of data.

All of the information we can decode from a radio wave is transmitted as a sine wave. This is why we need to take this sine wave and modulate it, which is the process of adding another layer of useful information. There are three methods of modulation, including:. When you combine a sine wave and modulated wave signal together, it modulates the original signal.

Modulating a sine wave with a frequency signal results in less modulation than an amplitude modulation. Once all of those modulated sine waves are sent via a transmitter and received by a receiver, the wave of information that we embedded gets extracted, allowing us to do with it as we please, like play it as audio through a speaker, or view it as video on a television screen. There are three ways this journey can happen, including:.

With this method of travel, radio waves are sent as a simple beam of light from point A to point B. This method was commonly used in old-fashioned telephone networks that had to transmit calls over a long distance between two massive communication towers.

When you do this, the radio waves will hit the ionosphere, bounce back down to earth, and bounce back up again. This is the process of mirroring a wave, bouncing it back and forth to its final destination.

At the end of the 19th century, an understanding of electromagnetism led to the mastery of electricity, which has populated our daily lives with artificial electromagnetic field sources or EMF. So today, at home, EMFs are present in light bulbs, microwave ovens, cordless phones, induction cookers and, of course, Wi-fi boxes and all devices connected to it. A band apart: radio waves While many different types of EMF are used to convey information over distance, the most common are radio waves, also called radiofrequencies.

This is a wide spectrum ranging from tens of kilohertz to gigahertz. Within this spectrum, frequency bands are allocated to each use. How do radio waves carry information?