Meshtastic is an interesting project turning cheap IoT devices into emergency communications devices.  

Using the impressively long range available over LoRa, every device becomes part of an encrypted private network.  Pairable with a mobile device over Bluetooth you can share your GPS coordinates and text messages without ever touching a tower.

Interesting stuff.  Great project, check it out:

What is Meshtastic?
An opensource hiking, pilot, skiing, secure GPS mesh communicator