Stopping metallic construction held by a threaded rod from wobbling

I am working on a 1.5m satellite dish with a custom feed. The problem is that the feed is being very wobbly once slightly pushed, as shown here: https://www.youtube.com/watch?v=rAFGbEhhDZ8 (it swings back and forth, which would not be a good thing on a windy day).

Would adding a second thick plate to the back of the feed (where it's held on by the threaded rod (24M)) make the feed any stiffer and reduce/stop wobbliness? I had this problem with my previous thin rod (see Stopping/reducing wobbliness in threaded rod), but I fixed it by increasing the diameter of the rod. What could I do with the feed?

• How do they stabilize tall antenna masts ( towers) ? With guy-wires, right ? Mar 11 '19 at 15:55
• @WilliamHird I don't want to stabilize the antenna mast, I want to stabilize the feed. I was just told by an engineer friend that I'd weld the threaded rod (mast) with a custom-built 2mm thick washer (so it contacts the feed from the inside), and get a second washer on the out-side of the feed that is just used as a regular washer with a nut on top. So just 1 nut will be used. I hope it works. Mar 11 '19 at 17:57
• Sorry, I meant stabilize the feed The principle is the same , you can stabilize the feed with tensioned guy-wires Mar 12 '19 at 17:28
• @WilliamHird I don't want to start adding guy-wires etc. to my dish. Isn't it easier to just do this, or will it not work at all? Would adding a second thick plate to the back of the feed (where it's held on by the threaded rod (24M)) make the feed any stiffer and reduce/stop wobbliness? Mar 13 '19 at 13:34
• Depends on the degree of stability you need If you have a cantilevered structure the free end will always be subject to some motion unless it is prevented from moving by an external truss ( in this case, tensioned guy wires) Mar 13 '19 at 18:11