Field testing the very first prototype of the microcontroller based PA8W RDF-40 Doppler Radio Direction Finder.

This setup was tested in a car, hunting a 424MHz transmitter.
The pelorus arrow gives the averaged direction, and corrupt measurements due to signal reflections are ignored to a high degree.
Using this prototype, lots of measurements and tests were done which led to greatly improved follow-up models like the RDF41, RDF42 and RDF43.

For more information on affordable Doppler Radio Direction Finders, check out https://radiodirectionfinding.nl