Hi I'm new here so I don't know if I posted in right place but here is the problem. I don't know if you are familiar with antenna theory but I need to calculate radius of 1. Fresnel ellipsoid. It's easy when two antennas are on same altitude but if they aren't there is a problem. If you look the picture in attachment you will see that I need to calculate height h. I won't give you and numbers because I need calculation for various cases but here are known variables: ht - height of first antenna hr - height of second antenna Dtr - distance between antennas D - distance between first antenna and point where h needs to be calculated r - radius of 1. Fresnel ellipsoid on distance D r=sqrt((λ*d1*d2)/(d1+d2)) λ=f/c f - frequency c - speed of light These are all known numbers for various cases and for each of them I need to calculate h Thank you very much.