Ideas or suggestions for stable ground mount

Hello fellow owners!

I’ve noticed my ground mount for my Sky is a tiny bit shaky just enough to possibly give some oversensitive rain readings. I currently have a mailbox post in the ground far out in my backyard. I’ve installed a pole on this from my old Davis Pro and reused it for the Sky. Anybody have any good suggestions for keeping this post stable? It has to stay in the location it’s at unfortunately.

Thanks for brainstorming sessions!

-Matt

Guy wires would certainly to be able keep a ground mounted post stable. This kit has been suggested elsewhere: https://www.amazon.com/dp/B011AEQVNY/ref=cm_sw_r_cp_ep_dp_lrWtAb1D62DZ0