Would you add another radio to your smartphone? No, not another WiFi or cellular radio; a smartphone already has that. I’m talking about something that provides connectivity through ISM bands, either 433 or 915 MHz. This can be used where you don’t have cell phone coverage, and it has a longer range than WiFi. This is the idea behind the LoRa Sleeve, a messaging system that allows you to send off-the-grid messages.