- One goal is use a cell phone to generate beacon audio samples that can then be passed two a handy radio. This is accomplished using Termux, a rad feature packed terminal for phones. You will need to install it from F-Droid and install Termux-Api, which allows for fetching the GPS points. In termux, you can install python3, pypy3, sox, screen and any other goodies that suit your fancy.
- Modulate and play APRS becaons messages. You will need:
- Type-C to audio cable connected to the mic of your radio. I opted for one with additional power connector. In the developer settings for Android, I set screen to always be on when plugged in.
- 3.5 mm TRS to Dual 3.5 mm TSF Stereo Breakout Cable. The mic connector only uses the tip connector, the rest are grounded.
- A 3.5 mm to 2.5 mm jumper. My handy radio mic input is 2.5mm.
- For my radio, I also needed to AC couple the the mic pin TIP like so. I couldn't find any suitable cables, so got the soldering iron out! Not difficult!
To be run in Termux.
- Fetch GPS points and generate beacon APRS messages
python termux_beacon.py
- Play APRS beacon messages to radio
python termux_beacon.py | python aprs_mod.py -vox -t play -t -