What is the formula for calculating VHF range in aviation?

The formula for calculating VHF range in aviation is indeed based on the heights of the antennas involved. The correct formula, which is used to determine the line-of-sight distance (d) between two points, takes into account the effective heights (h1 and h2) of the transmitting and receiving antennas.

Using the formula d = 1.23 * (√h1 + √h2), the constant (1.23) is derived from the Earth’s geometry, where height is measured in feet and distance is reported in nautical miles. The square root of the heights (√h1 and √h2) reflects how the signal propagation can vary with height. Essentially, increasing the height of either antenna increases the range of VHF communication, and taking the square root helps to establish a diminishing return beyond a certain height.

This formula helps pilots and air traffic controllers understand the limits of VHF radio communication and ensures effective transmission and reception of radio signals, which is vital for safety and operational efficiency in aviation. The mention of heights indicates that the elevation of the transmitting and receiving points significantly impacts radio range, as signals can travel further line-of-sight when elevated.

In contrast, other options differ in either the constant multiplier or the mathematical