There are some threads on eevblog where people add a DIY horn antenna and get about a hundred feet of range for car detection. e.g. [0], video with Doppler audio [1].

[0] https://www.eevblog.com/forum/projects/playing-with-cheap-hb...

[1] https://www.youtube.com/watch?v=r2NwtRPYWK4

Noted, thanks.

"delve"