Total posts : 45366
“Any idea of what the case/chasis ground will actually do?”
Nothing but provide a better pathway for static and lighting since it will be outdoors.
As mentioned by others and me and also buried in the thread abyss, the TH internal ATU function will not tune to elaborate antenna systems because it is designed to see primarily a simple wire, or the whip, but with no elaborate ground system.
However throw it to external ATU mode and use the proper ATU unit with it, ground mounted about 1 meter or less over an elaborate ground system and it will perform very well.
“Will that function as a normal ground typically would? Should there be an improvement in signal with the chassis ground?”
There won’t be any signal increase as nothing is being done to the radiating output or radiator. It is only adding more pathway for lightning and static discharge in an outdoor setting.
In either case..ie for improved antenna performance and lightning protection, a nice pathway to dirt is a heck of a lot better than having that lightning coming down your thin tiny power cable and/or audio line and into your studio. Lightning can split or cook a tree, power pole, melt HV high tension lines, imagine what it would do to that thin power supply cable or audio line.