The horizon distance estimation relies on which formula components?

• A. The square roots of vessel antenna height and receiver antenna height
• B. The square root of the sea distance and the square root of the transmitter height
• C. The square root of the wind speed and humidity
• D. The sum of transmitter power and receiver sensitivity

Answer: (A)

Horizon distance is set by the geometry of the line of sight over a curved Earth. For a radio link, how far you can see depends on how high each end’s antenna sits above sea level. The distance to the horizon from a height grows roughly with the square root of that height, so the maximum line-of-sight distance is proportional to the sum of the square roots of the vessel antenna height and the receiver antenna height. That’s why the components are the square roots of those heights. Other factors like wind speed, humidity, sea distance, or transmit power and receiver sensitivity affect signal strength and reliability, but they don’t determine the geometric horizon limit.