Marconi's successful transmission of radio waves across the Atlantic Ocean was made possible despite the curvature of the Earth. The curvature of the Earth does not pose a fundamental obstacle to long-distance radio communication. Here's how it works:
Line of sight: In short-range communication, such as within a city or between nearby locations, obstacles and the Earth's curvature can obstruct the direct line of sight between transmitter and receiver. However, for long-range communication like Marconi's transatlantic transmission, the use of high-frequency radio waves and the Earth's atmosphere allow the signals to propagate over longer distances without being significantly blocked by the Earth's curvature.
Ionosphere and reflection: The Earth's atmosphere contains a layer known as the ionosphere, which extends from approximately 50 to 600 kilometers above the Earth's surface. This region consists of electrically charged particles that can reflect radio waves back to the Earth's surface. By directing the radio waves at an appropriate angle toward the ionosphere, Marconi was able to achieve "skywave" propagation, where the waves are reflected and refracted back to Earth, allowing them to travel beyond the horizon.
Bending of radio waves: Radio waves can also experience a phenomenon called "refraction" in the Earth's atmosphere, where they bend due to changes in the density of the atmosphere. This bending can enable radio waves to follow the curvature of the Earth and reach distant locations, even if they are not within the direct line of sight.
By leveraging these mechanisms, Marconi and his team were able to establish transatlantic radio communication. They used powerful transmitters and sensitive receivers to overcome attenuation (weakening) of the signals over long distances. The successful transmission of radio waves across the Atlantic Ocean demonstrated the potential of wireless communication on a global scale, laying the foundation for further advancements in long-distance radio communication.