#Meshtastic question, or maybe just a general microwave doppler motion sensor question:

I'm using a RAK 19007/4631 and a RAK12013 radar motion board and I get a lot of false alarms. I eliminated the RF possibility from the 4631, so I'm down to reflections or something causing it. One was in the car as a test and it falsed when the sun came up, which shouldn't be a thing for this type of sensor.

Are there some accepted good practices for mounting these things that I should know about?