Direbox is a wireless modem that turns your radio into an off-grid messaging powerhouse! It enables you to send messages, beacon locations, check weather data, and more, all without the Internet:

https://direbox.net/docs

All you need is a Direbox, a soundcard interface like Digirig, and a radio. The Direbox software comes with a fully responsive and modern front-end for both desktop and mobile. It even has PWA support!

Direbox operates using the time-tested APRS network. Licensed amateur radio operators can use Direbox on their regional 2 meter band allocation, but since Direbox is frequency-agnostic, it can be used on any band, including license-free frequencies.

It also comes with a full end-to-end encryption suite built in (but disabled by default) for Part 90 operators.

The Direbox software is licensed under GPLv2. The hardware is quite simple - just a Raspberry Pi Zero 2W, an OLED display, a charge controller, 3000mAh battery, and two tact switches.