Thanks for the links.
I think I'm starting to understand... Could take a month or two more but it is making sense!
I like the idea of sticking the unit out of a car window.
I actually did do that once in my old windsurfing days. It was with the old style tube and disc wind meter.
It was surprisingly accurate.

I like the idea of sticking the unit out of a car window.


It was surprisingly accurate.