The suggestions I took were: get a NanoVNA, eliminate the parallel feedline I had going on, and change the brackets from metal to plastic (3D printed).
Hello all, I made this antenna according to this website's plans: https://www.qsl.net/dk7zb/Duoband/4+5_2m-70cm.htm I used Dzus fasteners so it can be quickly disassembled. There is 1/4-20 mounting in the middle for a camera stand or selfie stick handle.
I am having SWR of 2.5+ on 2 m and 3.5+ on 70 cm, with SWR decreasing with frequency (suggesting elements are short). All elements are exactly to specifications (position and length), except the driven elements, which are staggered and overlap as you can see. Tip to tip matches specs. I suspect the problem has to do with the choke or the arrangement of driven elements, but I don't know what. Note that the parasitic 70 cm element also passing through the box does not actually touch the BNC jack, although it looks really close. Any ideas?