I saw this post on the TreasureNet forum and it got me thinking. I often read these discussions online about detector depth. Way back when, depth was the "next big thing" a detector could offer. The marketing started to be all about depth. Now here we are and most modern detectors
Discussions of depth are also often exaggerated, much like the proverbial "fish story," so I always take estimated depths with a grain of salt. Some claim to dig coins at 14" deep. While I think it is possible, I also think that may be the limits of the depth possible with dinner plate sized coils.
Most coins in undisturbed ground are going to be less than 7" deep. This has been my experience in all areas of Ohio I have detected. Even my two oldest coins, an 1820 large cent and 1833 dime were about that deep. Where I do run into unusually deep coins are areas near rivers that have been silted in, sites that have been backfilled, farm fields that have been tilled or sites that have had construction/destruction activity.
From what I have observed, even the entry-level Garrett Ace 250 gets excellent depth on coins. In clean ground, I think most modern quality detectors are going to give more-or-less equal depth.
So, why spend $1500 on a machine that only goes as deep as a $200 one? Aha! That gets to my point.
High priced detectors offer other enhancements and tweaks that give them an edge over the cheaper machines. More information about targets provided on grids and graphs, better coils, faster processors, automatic ground balancing, etc. And this is why I said earlier that in clean ground, I think most modern quality detectors are going to give more-or-less equal depth. Note the italics.
I have confidence that my high-end detector will find coins that a cheaper machine will not. The important factors in finding coins in hunted out or trashy locations are target ID and target masking, not just raw depth. The electronics of my machine give me good information to help me make better decisions about what to dig. If you have an entry-level machine and dig everything, you will make some great finds. But you have to dig everything! That's a lot of nails, pull-tabs and holes!
So, will your detector find coins at 11"? I bet it will. Are you going to dig a lot of coins at 11"? I doubt it. Stop worrying about the depth, the machine can take care of that. Spend time learning about interpreting the information... sounds and sights, the machine gives you.