In a little experiment with a 100 meters high node last week, SF7 packets were received almost 50 km away in line-of-sight.
I was expecting that to happen for SF12 packets (which were even received 73 km away). No problem for SF12: if capacity needs to be increased, more near-by gateways can be deployed and the network servers can use adaptive data rate to tell the nodes to use more efficient spreading factors, and hence limit their reach. Or, so I thought.
But now, seeing long distances happen for SF7 as well, I wonder if a 100 meters high gateway might receive too many packets from (far-away) nodes that happen to have (near) line-of-sight, eating its capacity and causing collisions for nodes that rely on that gateway? Even when using directional antennas, a 50+ km long area would still be huge.
So: could 100 meters be too high if the number of nodes increases...?
(Note that I am not an expert at all!)