From your description of the placement of the robot radio, it needs to be relocated. You listed a lot of things it shouldn't be close to (battery, motor, I bet it's close to speed controllers too isn't it).
Before rewiring, if you can, just take it off the robot and attach an extra Ethernet cable/power cord just so you can hold it in your hand while the robot runs while up on blocks.
Watch the Charts while holding it away from the robot with the motors running, then move it closer and to various places on the robot to see how proximity to various things affects the packet loss and round-trip transit time.
We just did that with a visiting team and it was quite an eye opener for them.
Nice job with the Charts this year Greg. Kudos.
