Despite what you may be reading about on Facebook, Zello is not an app that magically turns your cell phone into a device that can communicate worldwide when cell towers and electricity go out.
Spreading this false information is doing a disservice to your friends and family. You need to understand how a cell phone works. A cell phone works on a radio frequency designed to connect to powerful cell towers. It also likely has two other very weak radio transmitters in it — Bluetooth and WiFi. These radios have a range of 15-30 feet at best.
Without a connection to data, be it cellular or wifi internet access, Zello will be useless as a communication app on your device. According to Zello’s own website, the app will not work without internet access.
If cell towers are down, then power is likely out. If power is out, then you don’t have wifi. If you have no data access, the only person you’ll be talking to with Zello is yourself.
Telling people it is a good emergency communication option is not helping people. If you want good emergency communication, get real walkie talkies, a satellite phone, or VHF radio (get all three if you can).
I’m not saying that Zello isn’t a cool app or that it doesn’t have a use, but, your cell phone will not turn into a magical worldwide communication device that doesn’t need an internet connection with Zello. If it could, then all cell carriers would be out of business by now. Think about that for a sec.