Determine the distance between the origination point of the wave and a secondary point at the end of the wave's reach in meters. Once you have the distance in meters, divide this number by the wave's distance in mega hertz (MHz). This number will be placed into the formula in the space of "I" in the equation. The distance in meters is represented by the symbol "R" in the equation.
Enter the "I" information into the formula used to calculate a radio's line of sight. The overall formula for the calculation is as follows: FSL (dB) = 20*LOG ( l /4 p *R). FSL, or free space loss, is the calculation for the radio's line of sight and is defined as the amount that a signal strength has decreased as a result of the distance between the wave's transmitter and its receiver.
Enter the distance in meters (R) into the equation. Once you have entered all the numbers, use a scientific calculator to determine the line of sight calculation for the wave in question. The answer will come out in decibels (dB's). Decibels are units used to measure the difference in intensity between the two signals. The final answer is the radio's line of sight in relation to the two points being measured.