Longwave facts for kids

Diagram showing amplitude (a) and wavelength (b).

In the world of radio, longwave refers to a special part of the radio spectrum. This part has very long wavelengths. Imagine waves that are a kilometer or even longer!

The name "longwave" is quite old. It comes from the early 20th century. Back then, people divided the radio spectrum into long, medium, and short waves. Today, most radio devices use much shorter waves. These would have been called 'ultra-short' waves in the past.

For radio broadcasting, longwave usually means the radio band between 30 kHz and 299 kHz.

Why Longwaves Travel Far

One cool thing about longwaves is how far they can travel. This is thanks to something called diffraction. Diffraction helps these waves bend around obstacles like hills or even the curve of the Earth. This means they can reach places that shorter waves might miss.

Imagine a wave hitting a building. Shorter waves might just bounce off or get blocked. But longwaves can actually bend around the building, almost like water flowing around a rock. This makes them great for sending signals over long distances, especially across oceans or large land areas.

What is the Radio Spectrum?

The radio spectrum is like a giant highway for all kinds of wireless signals. It's a range of electromagnetic radiation frequencies. Think of it as different lanes on a highway. Each lane is used for different things. Some lanes are for radio, some for TV, some for Wi-Fi, and so on.

Radio waves are a type of energy that travels in waves. These waves have different lengths and frequencies. Longwaves are just one small part of this huge spectrum. Understanding the spectrum helps us use radio waves for many purposes.

How Longwaves Were Used

In the past, longwaves were very important. They were used for early radio broadcasts. They also helped ships communicate across the ocean. Because they travel so far, they were perfect for these long-distance connections.

Even today, longwaves are still used for some special purposes. They might be used for navigation signals or for broadcasting in certain parts of the world. Their ability to travel far makes them unique and useful.

Images for kids

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  Tuning dial on 1946 Dynatron Merlin T.69 console radio receiver, showing LW wavelengths between 800 and 2000 metres (375–150 kHz)