Hey Texan,
I had a Groundhog 25yrs ago and it was a great machine. No bells and whistles like today's machine, but still a great machine. I found the best way to use it was to go very slow and take your time. It had very good depth, I dug pennies at 12". After awhile I learned to tell the targets by the size of the signal. Short, sharp hits were almost always coins. It was a great machine and I still regret selling mine.
Bill