I am trying to find out the formula to calculate how high antennas need to be for Line of Sight (LoS) propagation.
I found:
d = 3.57sqrt(h)
also
d = 3.57sqrt(Kh)
d can also be worked out using
d = 3.57( sqrt(K[h1]) + sqrt(K[h2]) )
Where d is the distance between an antenna and the horizon (or between two antennas) in kilometres, h is the height of the antenna(s) in meters, and K is used to account for the curvature of the earth (which is usually 4/3).
The problem with this equation is it is making the antennas ridiculously high for the distance I am trying to calculate. The question I am trying to answer is: “Two antennae are used for line of sight propagation. The antennae are spaced 150km apart. Determine the required antennae heights.”
My calculations:
d=3.57sqrt(4/3)(h)
d=3.57(sqrt[4/3])(sqrt[h])
d=3.57(1.1547)(sqrt[h])
150=(4.1223)sqrt(h)
150/4.1223=sqrt(h)
sqr(36.3875)=sqr(sqrt(h))
1324.05=h 1324meters = h1 + h2 -> each antenna needs to be 762meters high
Is this the correct method? Or have I chose the wrong equation totally?