It seemed like a simple assignment: Write an article answering the question, “What are radio waves?” After all, I work with radio all the time. I’m the guy who is usually chosen to explain technical stuff to non-technical clients. I’ve written posts and articles on how radio waves can carry information, such as this one on modulation. I’ve been “playing” with radio waves for decades. I have a mug that literally says, “I’m the Radio Guy.” This should be easy, right?

Well…

What Are Radio Waves? A Simple Explanation

I wanted to craft a simple, straightforward explanation of what a radio wave is rather than something aimed at a PhD student. I thought I would get an idea of what information is out on the Internet about the nature of radio waves. I did a quick Google search with the question, “What are radio waves?” What I got back showed me that I might be in some trouble. 

Wikipedia gave the typical response, which was more or less echoed by everyone else: “Radio waves are a type of electromagnetic radiation with the lowest frequencies and the longest wavelengths in the electromagnetic spectrum, typically with frequencies below 300 gigahertz (GHz) and wavelengths greater than 1 millimeter (3⁄64 inch), about the diameter of a grain of rice.”

This definition, while accurate, immediately raises another question: What is electromagnetic radiation?

Understanding Electromagnetic Radiation

Electromagnetic radiation includes various types of waves, such as light, infrared heat, x-rays, and gamma rays. Radio waves are just one part of this spectrum. But that doesn’t really answer the question about the fundamental nature of electromagnetic radiation. And it doesn’t give me a satisfactory answer to the question, “What are radio waves?”

In crafting this explanation, I wanted to avoid discussing quantum physics, bosuns, photons, Maxwell’s equations, and other graduate-level subjects. I tried to keep it simple, but I also didn’t want to resort to “some sort of magic happens here” either. It’s bad enough that the reality of quantum physics looks a lot like magic already. For example, radio waves are really photons, which are particles that have no mass and travel at the speed of light. Right away, I struggled with particles that have nothing there but are there and that travel at the speed of light, mainly because they ARE light. And don’t get me started about how sometimes they act like waves, and other times they act like particles. No wonder Einstein wasn’t happy about various aspects of quantum physics…

To simplify, radio waves consist of photons—particles with no mass that travel at the speed of light. If that sounds confusing, you’re not alone. As this post on frequency use explains, different frequencies of electromagnetic radiation serve different practical purposes.

Radio Waves vs. Physical Waves: Key Differences

Let’s make this relatable by comparing radio waves to physical waves, like those you see at the beach. Ocean waves rely on water to travel, while sound waves need air. Without these mediums, the waves can’t exist. Radio waves, however, are different—they travel through the vacuum of space without needing a medium. Let’s dive in…

Go to the beach, and you will see a constant stream of waves coming ashore. These waves are carried by the water, and without the water, there would be no waves. Energy is produced by storms, wind, and other natural forces (sometimes by earthquakes, in which case the waves might be disastrously huge). That energy pushes the water into “lumps,” which are the high points on the waves. The difference between the high and low points is called the amplitude of the waves. The higher the amplitude, the more the energy.

Sound is also a wave. In the case of sound, the wave is carried by varying pressure in the air. No air, no wave. As they say, in space (where there is no air), no one can hear you scream.

But with radio waves, things are different. You might not hear me screaming in my spacesuit, but assuming I’m not in darkness, you could certainly see me screaming. Why? Because light, like radio waves, does not need water or air to carry the wave. Instead, radio waves consist of photons, acting like waves, carrying themselves across the universe.

Wait, what? Ocean waves need water, sound waves need air, but radio waves need… Nothing? Yep, that’s right! 

How Do Radio Waves Travel?

While ocean waves and sound waves can travel only as fast as the movement of water or air allows them to, radio waves are incredibly speedy, traveling at 186,000 miles per second. In a sense, they carry themselves from one place to another, and they do it quite quickly.

Nonetheless, they do have a speed limit. 186,000 miles per second. It’s not just a good idea; it’s the law (for those of you who are old enough, you’ll remember that bumper sticker). At times (for example, in air and, even more so, in cables), radio waves move more slowly, but this finite speed of radio waves is what makes things like radar work. The time it takes for a radio wave to travel to a target and bounce back tells us how far away it is. On the other hand, it makes for slow conversations with places that are far away, like Mars, where it can take up to 21 minutes for the signal to get there.

Why Radio Waves Don’t Need a Medium

Unlike ocean and sound waves, radio waves are self-sustaining. This property makes them invaluable for communication and other technologies. Over the years, our retro technology products have demonstrated the practical uses of this unique characteristic.

Applications of Radio Waves in Everyday Life

From AM/FM radio to GPS and Wi-Fi, radio waves are everywhere. They’re even used in scientific research, such as radio astronomy, and in medical imaging, like MRI scans. For a deeper dive into how radio wave properties like gain and noise affect their performance, check out this guide.

How Environmental Factors Affect Radio Waves

Radio waves can be reflected, refracted, or absorbed depending on their surroundings. For example, weather and solar activity can interfere with communication. This post on solar interference explores how such natural phenomena impact radio waves.

The Challenge of Explaining Radio Waves

Defining radio waves is deceptively complex, as it touches on both the practical and theoretical aspects of physics. While I work with them daily, I don’t often think about their fundamental nature. And that’s okay—sometimes, it’s enough to understand their practical applications and leave the deep physics to the experts.

Radio waves are like ocean and sound waves—except they’re not. They’re unique, mysterious, and endlessly fascinating, making them a vital part of our technological world.

This post aims to simplify the science behind radio waves while providing useful resources for readers who want to dive deeper. Have any lingering questions? Feel free to ask—after all, I’m the Radio Guy!