I just a 6" DD HF coil for my XT-70 and took it in the back yard. Seems to be a great coil, but its going to be brutal covering any area with this. Tomorrow, I'm going to an early school yard (founded early 1900s) that is still in use. Would I be better off starting with my stock coil, then use the small coil in areas where I've found a coin or two? I'm a relic hunter, but the season hasn't really started in earnest yet and I figure coin hunting might be a good way to get familiar with the XT-70.