This is a bracket I made on CNC plasma for a 1/2" CB antenna stud to mount the antenna on a Garvin Adventure Rack's windshield hoop. It is held on by a 5/16" U-bolt. The windshield is tilted at 25 degrees, so cutting this part and putting a 90 degree bend in it puts the antenna vertical. I cut this out of a piece of 3" x 8" x 3/16" mild steel, overkill for this application. 1/8" would be fine.