TVG is Time Varied (or Variable) Gain. It's under MENU then SONAR SETUP then ADVANCED. Mine is at Medium. Guess it came that way. I am not sure what it does or doesn't do. Was under the impression it was only effective for really deep water, but IDK. Perhaps Machine will help us out on that.

I agree on finding so much cover that I never knew was there. Plus it is a very easy unit to work. I am more than satisfied. I found an old bp on a local lake last year that I fished when I was a teen. Not much left after another almost 60 yrs but two hollowed logs, but I found it. Nothing home tho.