Useful info on post-collapse communications in books like this:
"How to Survive the End of the World As We Know It Tactics, Techniques, and Technologies for Uncertain Times" by James Wesley Rawles
btdb.to/torrent/rBo7xJrzgAij2GllbnP0t8YnJr38GKT6rBV.html
And on his website: survivalblog.com/category/communications-receivers/