yep the signals sound close enough, I was kicking around the idea of getting a nel coil for my ATP. Wondering how much deeper you can get a good reliable signal with it. I've passed up some signals that were very faint with no VDI reading at all, but pick up the signal maybe once every three swings. The depth meter says 10+ inches. Maybe with the nel coil it would give some kind of VDI reading to indicate what the target might be.
I dug such a signal once and found an Indian arrow head in the hole at about 12" , but never did find the target because water started filling the hole. I might go back and re dig it this summer. It's a nice arrow head so I'm glad I dug it.