We plan to take a shot at making a link of 400km or more
What we need! is a someone who can tell us, or give as a link to, a calculator that can work with links over 160km. We specifically need to know what elevation we will need at either end in order to make the link work (theoretically). I imagine that at 400km the curvature of the earth is quite a consideration more than anything else.
It is our intention for the vast majority of the link to be over water as well. What should we know that we dont already?
One end is likely to me 2000m above sealevel, and the other end anywhere from 400m -> 800m (is the highest point we have available).
**edit** I should probably mention we do have a fair amount of experience with shorter links (60 - 100km), and this 400km link is purely a test & a shot at the record