title_body: How do I set up IRC Tramp for my HGLRC Forward VTX?
upvoted_answer: Since you confirmed that the protocol+vtx table is correct I'd focus on the physical connection. One explaination would be that the signal is disturbed and the vtx has a hard time decoding it.
  
  Try to disconnect all other components and focus just on the fc+vtx. Try to isolate the SMA connector of the vtx from any carbon parts/metal parts of the frame. Another option is to twist the cables going from the fc to the vtx. You could also add capacitors to the power supply.
  
  If nothing works I'd try a different vtx and check if the problems carry over the new vtx. Adding a phono of your wiring could also help to identify the issue.