Offline networking
Introduction
Offline and off-grid networking broadly refers to the practice of sharing information between devices without use of the global Internet. The advantage of this in a disaster scenario is to provide a fallback for access to critical information and communication services in cases where reaching the Internet is not possible. This can be done with a device acting as a WiFi access point and router, LoRaWAN devices sharing information over long distances using the LoRa radio specification, or with a digital radio service known as packet radio. Each of these will be covered here.
Linkdump
(to be expanded out into text)
https://learn.adafruit.com/lora-and-lorawan-radio-for-raspberry-pi/overview