While in the U.S., I am researching various hardware and software options for this project, and also building a mini prototype of the network. As part of this research, I wanted to set up a three-node network which includes a very long distance point-to-point link (over 100 km) to determine the feasibility of using long overland links rather than satellite to connect rural areas with urban centers. This research and testing is much more easily done in the U.S. because of the readily available tools, equipment, Internet access, and transportation.
I spent a good bit of time setting up and learning Radio Mobile -- a wonderful piece of software for this sort of work. It uses freely-available USGS altitude data to determine line of sight and predict signal strength. It can even display all of the areas which have line of sight from a given point.
I spent a while searching for a suitable 100 km link, one end of which had line of sight to a location with Internet access which we were allowed to use. In the end, I actually found two options. I called the site with an existing Internet connection node 10. Node 10 has line of sight to node 12 and node 13. Both node 12 and node 13 also had line of sight to node 14, and both of these links were over 100 km.
I had a choice between the potential locations for node 12 or node 13. Node 13 has better line of sight for both links, but it was a longer drive, so I decided to try node 12.