Frequency Range: 134~174MHz
Tx/Rx frequency independent
Channel space: 12.5/25KHz
CTCSS / CDCSS codes
UART interface
3.3~4.5V

Atmega328p based 1200 Baud AFSK radio modem.

An electronics project for patching together a small APRS transmitter module. The project is largely obsolete and unmaintained but it's good because it talks about the DRA818V radio module, which is pretty obscure.

This program aims to be a lightweight, extensible APRS client specifically written to run as a daemon for tracking and telemetry purposes.

It currently supports building APRS compressed position reports with course, speed, optional altitude, and optional timestamps from a running local gpsd instance. It can broadcast APRS packets either through the Linux AX.25 stack by calling out to the beacon program or send packets directly to an APRS-IS server. It is designed to run from systemd as a service and be part of a headless installation.

Tracksoar is one of the smallest, lightest, open source APRS trackers available. It makes tracking weather balloons, model rockets, RC aircraft, and anything else that flies simple and easy. It is able to report location, altitude, temperature pressure and humidity to the internet or direct to an amateur radio once a minute for up to twelve hours with just 2xAA batteries. Because Tracksoar is open source you can add your own modules to accommodate custom sensors, inputs or outputs to meet your specific requirements. Tracksoar can also use a range of drop in transmitters to allow for easy world wide operation. No other APRS solution offers this level of integration, compact size, and customization.

Built around an ATMEL ATMEGA 32u4 running the Arduino bootloader. It has a UBLOX MAX-M8Q GPS receiver for precise high speed location data, with a compact and lightweight chip antenna. In addition the board has a BME280 combination temperature, pressure, and humidity sensor allowing for the collection precise atmospheric data in flight.