If you ever wondered why the WiFi signal is so poor in your Teclast X98 Pro then you should check if there is no cold solder joint as in my unit. To keep price so low manufacturer didn’t use proper coaxial connector (as you would find in brand name products) but chose to solder coaxial antenna cable directly to motherboard. In my tablet only cable shielding was actually soldered but the signal wire was just floating above of a big blob of the solder. I found it when I was replacing battery for 12Ah.