This tracker uses Quanum RC540R 5.8GHz 40CH Race Band FPV Diversity Receiver which has two video receivers with RSSI output. RSSI is measured with an Arduino's analog inputs, signal strength is compared and tracker head is turned towards stronger signal with servo.
This tracker relies solely on RSSI, no GPS or compass is involved. This means you can track any 5.8GHz signal source to which the receiver is tuned to. No pairing, no telemetry, no configuration, just tune and track.
https://www.youtube.com/watch?v=aACTKziuDVE
To install Timer library, download the ZIP file here: https://github.com/JChristensen/Timer
How to install libraries https://www.youtube.com/watch?v=Alz-rX6lkEw