I built a fox hunt transmitter from scratch as one of my first hands-on amateur radio projects. Fox hunting, also called amateur radio direction finding, is where a hidden transmitter is placed somewhere and operators use radios and antennas to track it down.

For this project, I followed a build that uses an Arduino, a relay module, and a handheld radio to automatically key up and transmit an identifier. The end result is a simple transmitter that can be hidden for a fox hunt and found using radio direction finding.

How I Built It

The build started by modifying a handheld radio speaker/mic cable. I cut the cable, identified the internal wires, and used continuity testing with a multimeter to map the correct connections. After that, I soldered on new wires and used heat shrink to make the cable cleaner and more durable.

I then programmed an Arduino with fox transmitter code. The Arduino controls a relay module, which keys the radio and allows it to transmit automatically. The code can send an identifier and control the timing between transmissions.

What I Learned

This project helped me get more comfortable with soldering, continuity testing, Arduino programming, relay wiring, and radio control. It was also a good introduction to how simple hardware can be combined with amateur radio equipment to create something useful for club activities and field exercises.