Oddbean new post about login | logout Line of sight is a nice to have, not a necessity. The best mitigation is having a higher density of nodes to relay messages. They're so inexpensive, it's quite feasible and there may be a decent network around you already!
If the map I saw the other day shows actual nodes, there is only ONE other node in the whole city of Barcelona. I am more than willing to buy and set up a few to distribute them around my friends, but realistically will I get them to work without line of sight? I would need them to reach 10-15 km through all this concrete and steel. https://meshtastic.liamcottle.net/?lat=41.343824581185686&lng=362.1670532226563&zoom=10