A guy on Facebook C-150/C-152 Lounge said he took one of these -- Rami AV-525 VOR antenna ($270)-- and fabricated a mount and mounted it on a C-150.
In my view, there is only one place for this design to be installed (see picture)
This location also serves an additional roll:
Kinda like curb feelers on a car, this location acts like a runway feeler. When you hear the antenna ends scraping the runway, you know the tail is just about the right height.
