I made this adapter to mount the stalink rectangular antenna to an inexpensive and super stiff M3/4'' THREADED GALVANIZED IRON PIPE
This pipe is used for gas and water and is easy to find in Italy and europe.
the iron pipe that I used is this https://www.tecnomat.it/it/tubo-ferro-zincato-3-4-20-cm-10008363/
The author marked this model as their own original creation.