Use this sketch on the left along with the photos below. In bottom left photo you can clearly see the copper matching strip as well as the start of the helix and the mounting plate with the collar around the boom at one end and the 50 ohm co-ax going to the “N” connector at the other. I have added a small PTFE support between the copper matching strip and the plate that the “N” connector is mounted on, this takes the mechanical load off the connector centre pin, you can see it clearly in both photos.