How Radio Waves Really Travel

Eric Marquette

Alright, so let’s start with a term you’re gonna hear a lot about in radio communication: ‘line of sight.’ And at first, that might sound pretty self-explanatory, right? Like, you probably think, “Oh, so the two points need to see each other,” and yeah, that’s basically the gist of it. But trust me, there’s a lot more to it than just that.

Eric Marquette

When we’re talking about radio waves and line of sight, we mean the idea that signals—radio signals—travel in straight lines, kinda like light. They don’t bend around the Earth—not naturally, at least. So in an ideal situation, the transmitter and the receiver… they’d be able to ‘see’ each other directly without anything getting in the way.

Eric Marquette

Let me give you an example. I remember the first time I got my hands on a walkie-talkie. I must’ve been—I don’t know—10, maybe 11? My friend and I were on the school field testing how far we could go, and I was so excited because, in my head, it was like, these things could work anywhere. But then boom, he walked behind the school building, and the signal just died. Like, completely gone. And I just stood there, you know, staring at this walkie-talkie like it had betrayed me or something. But, looking back, that was my first lesson in how objects can block the 'line of sight' for radio waves.

Eric Marquette

And this line-of-sight idea, it’s not just for walkie-talkies. It’s crucial for understanding why some ham radio signals work great in one spot but not in another. It’s why, if you’re trying to make contact with someone across a hill, you might struggle or, honestly, just not get through at all. It’s all about what’s literally in the way of the waves.

Eric Marquette

So yeah, think of radio waves sorta like rays of light. If there’s something blocking them—like, say, a tall building or a mountain—they’re not going to pass right through. Well, not most of the time, anyway. But hang on, there’s actually more to this. Radio waves do have some interesting tricks up their sleeve.

Eric Marquette

So let’s talk about reflections for a minute—because, honestly, this is where things start getting really, really interesting. Like we said before, radio waves generally travel in straight lines, right? But here’s the kicker: they can also bounce off stuff. Imagine shining a flashlight against a mirror—it’s kinda like that. The waves hit a surface, and they just… bounce off in a different direction.

Eric Marquette

Now, these surfaces? Oh, they can be almost anything solid—like, think buildings, mountains, even big metal structures. Ever been in a city with a ton of skyscrapers? That’s probably one of the best places to see this in action. You might think your radio connection is blocked by a building, but somehow, the signal still reaches you. And why? Because it’s bouncing off one surface, then another, and finding its way to your receiver. It’s almost like the signal is playing a game of pinball. Pretty wild, isn’t it?

Eric Marquette

Here’s a cool example for you. Amateur radio operators—ham radio folks—have been known to use reflections to talk to people in totally unexpected places. Like, imagine someone in a crowded city, completely surrounded by tall buildings. With the right angle and enough reflective surfaces, they can make connections way beyond what you’d expect. It’s not magic, it’s just physics. Well, physics and a little bit of luck, I guess.

Eric Marquette

But here’s the thing—it’s not always easy to predict how these reflections will work. Like, okay, let’s say there’s a building in the way of your direct signal. How do you know where or how the waves will reflect? Can you actually use those reflections to your advantage? That’s where the real challenge—and I guess the fun—comes in.

Eric Marquette

The key is to pay attention to your environment. Look for large surfaces that could act as mirrors for your signal. Experiment, you know? Because sometimes, when the direct path is blocked, those reflections might be the only way you’re gonna make that connection.

Eric Marquette

Alright, now here’s where radio waves really show off their smarts—diffraction. It’s this neat ability they have to bend around corners or squeeze through gaps. Think of it like this—where reflection is the signal bouncing off a surface, diffraction is more like the signal flexing and bending to get around whatever’s in its way.

Eric Marquette

This is the reason you can sometimes communicate through tunnels or even behind hills. It’s why, when you’re on your ham radio, you don’t always need a perfectly clear line of sight to make a connection. The waves? They’re bending, essentially wrapping themselves around whatever’s standing between your transmitter and the receiver.

Eric Marquette

Let me give you a quick story to paint the picture. A friend of mine, also into ham radio, once had this really annoying setup—his antenna was on one side of a tall wooden fence, while the person he was trying to connect with was on the other side. Now, line of sight was out of the question, reflection wasn’t much help either, since there weren’t any big surfaces nearby to bounce the signal. But you know what pulled it off? Diffraction. The waves bent right over that fence and made the contact happen. I mean, yeah, it wasn’t the strongest signal, but it worked. And that’s the beauty of diffraction—it finds a way.

Eric Marquette

So whether it’s getting past buildings, hills, or even trees, diffraction can be a ham radio operator’s best friend. But keep in mind, the effect isn’t infinite. The sharper the corner or the smaller the gap, the harder it’ll be for those waves to bend effectively. Still, with a little patience and the right frequency, it’s amazing what you can accomplish.

Eric Marquette

And that wraps up today’s exploration of radio wave behavior. We covered line of sight, reflections, and now diffraction—all critical pieces of the puzzle when it comes to understanding how signals travel and how you, as a ham radio operator, can make the most of them. On that note, thanks for joining me on this journey through the fascinating world of radio communication. I’m Eric Marquette, signing off for now. Catch you next time, and happy transmitting!