It seems to me that if cell towers are down, radio towers are down and electrical grid towers are down too. DMR would be useless without towers, repeaters and computers. Simplex will work until batteries die. Then you will need solar chargers. I am talking about a REAL emergency like earth quake, hurricane, tornado or major fire (as in Calinfornia). Not a minor emergency like a thunderstorm. Coordinating life saving medical supplies, potable water and food... among the MAJOR reasons for being able to communicate with someone counties or states away. But, again I say; DMR will be of no use if electric, internet, towers and repeaters are down. The Native Americans used smoke signals because they could not depend on DMR.