Radio waves can bounce off the edge of space to travel a thousand kilometers
Longwave radio signals can bypass the horizon by bouncing off the upper atmosphere, allowing a single transmitter to broadcast music across entire continents through a phenomenon known as skywave propagation.
While standard FM radio signals travel in straight lines and vanish after 100 kilometers, longwave transmissions at 198 kHz exploit the physics of the ionosphere to travel much further. During the day, the atmosphere's D-layer absorbs these waves, but after sunset, this layer vanishes. This allows 400-kilowatt transmitters to bounce signals off the edge of space, reaching listeners over 1,000 kilometers away.
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