Currently i'm building a Arduino based stand-alone doppler finder. Using LED RGB led ring for the direction, GPS, compass to calculate the movement of the car correlate the correct direction of the object (even when driving).
If the unit is ready i will publish the schematic, source code and of course the results. The goal is to use this device in the next ballon fox hunt +/- 11 September 2017.
The old doppler finder by PA3BNX design
Make your own PCB's. I have used this doppler finder during the ballon fox hunt.
Ballon fox hunt
Some impressions of the use of the doppler direction finder.
The FT-817 as doppler receiver.
And if the doppler finder doesn't give an answer, yes do it the old style!