They sell QRP kits - ham radio kits that are designed for low power transmission and reception. You can go remarkably far on just five watts. They have transceivers, balloon trackers, filters, APRS modules, and more.
This WeeWX extension allows the generation of APRS-compliant packets containing weather information collected by weewx. This extension was written for the purpose of easy integration with aprx. When this extension is enabled, weewx will generate a new APRS packet every StdArchive.archive_interval seconds.
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.
Dire Wolf is a software "soundcard" AX.25 packet modem/TNC and APRS encoder/decoder. It can be used stand-alone to observe APRS traffic, as a tracker, digipeater, APRStt gateway, or Internet Gateway (IGate).
In the early days of Amateur Packet Radio, it was necessary to use an expensive "Terminal Node Controller" (TNC) with specialized hardware. You can now get better results at lower cost by connecting your radio to the sound card of a computer and using software to decode the signals.
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.