What is the deepest coin you’ve found with the Nox and what conditions and settings were you hunting in?
Beach hunting in clean sand I’ve found coins to approximately 14” using a low recovery speed of 2-3 with sensitivity maxed out. In dirt the deepest coin I’ve found has been around 9” running park 1 with a recovery speed of 4 and sensitivity at 23.
I’m trying to find the deepest setting for coins in mineralized dirt.
How deep do you want to go? In order to give you the magic answer I am going to need to know exactly what type of coin you are after and and exactly how mineralized your soil is, how much junk is present, how much moisture is in the soil, the orientation of the coin targets you are going after, the type of coil you are using, how many power lines are present, and, for good measure, the phase of the moon on the day you expect to hunt.
Of course I am being facetious, but I am trying to make a point. You have asked a specific question (how deep was your deepest coin found and what were your settings) with non-specific conditions (a coin in mineralized conditions) and the settings answers you are going to get are going to be all over the map and probably not useful for the relatively specific situation you are thinking about.
Think about the two scenarios you mentioned. You did not mention the type of coin and you didn't mention the settings you used at the beach. Your results are pretty consistent with mine at both a salt beach and in relatively mild ground. Could I tell you exactly what settings I was using, or even the mode I was in when I found my deepest coins under similar conditions with the Nox. Probably not exactly, the reason being that I vary my settings on the fly depending on the situation at hand with the knowledge of what those settings do and how they affect both depth, separation, and ground noise. All factors that determine the general success at recovering targets at depth. BTW for the beach, it was nickels in approximately 15+ inches deep in wet sand probably in Beach 1 mode at default settings with sensitivity cranked (my typical setup at the beach) and on land my maximum recovery of a coin was probably about the same as yours, but I would be lying if I knew the exact settings and even the coin. My deepest recovery inland, in mild soil was probably closer to a foot for a quarter sized, brass button - probably using field 2, stock settings. Is any of this helpful to you? Probably not.
What modes are going to work best in mineralized ground for X composition coins (e.g., nickel, gold, copper, silver) of X denomination (the answer for a 3 cent silver trime or half reale is going to be a lot different than a even a silver dime or quarter).
Understand the tradeoffs of the settings and what targets each of the modes are optimized for and you will be able to answer your own question. Furthermore, you should know which modes might excel under mineralized conditions. Hot soil can severely limit target ID depth to around 3 to 4 inches max (sometimes even less than that) and absolute target detection (without reliable ID) down to about 6 inches. The mode you choose is dependent on the target type of interest. If you are looking for nickels or small silver coins like trimes or gold $1 gold pieces, then Park 2, Field 2, or Gold modes are your best bet because they are optimized for mid-conductive targets. If you are looking for silver, then Park 1 or Field 1 are your best bet. In heavy mineralized soil, reducing transmit power is can help, so that means there may be rare inland situations where the mineralization is so bad, that running Beach mode (Beach mode 2 cuts transmit power in half from the get go regardless of the level of mineralization present) which reduces transmit power when "black sand" mineralization is sensed might actually run well. But don't expect miracles. We are talking shades of gray here, incremental less than an inch improvement in depth.
Regarding recovery speed, it is true that lowering recovery speed improves detectability at depth somewhat, but lower it too much, besides losing separation, you will also increase ground noise (in all metal) which is counterproductive because in highly mineralized dirt, maximum recovery depth means you probably have to dig iffy ferrous signals due to the loss of reliable target ID at depth. Speaking of which, you might think that lowering iron bias is the right answer, but for iffy targets in mineralization, your best bet might be to increase iron bias to make those iffy signals definitely sound like iron which might help depth. No real right answer on that one. BTW - on that really deep nickel I found at the beach, I was using the stock beach mode recovery setting of 6, go figure. Same goes for that deep button, which was at the default recovery speed of 7, but I was trying to pick it out of a bunch of iron nails.
Sometimes, single frequency can help, too. Sometimes, not.
Proper ground balance is key in really mineralized dirt, so be sure to check that. BTW - the Equinox can only give you a relative ground reading and it is applicable to the specific mode you are in at the time. The number high or low, really doesn't definitively tell you how much mineralization is present. You need a detector with a separate mineralization meter such as a Deus/Orx, Fisher F75/T2, or a Whites that has this capability.
The best thing you can do is do some sample target experimentation at the site. Bury some desirable targets in the dirt at the site (don't worry about halos which don't apply to non-ferrous targets, pack the dirt down tight (air gaps reduce detection depth), use a baggy with a string to make your target easy to recover when you are done, and use your knowledge of of how the settings vary depth and noise to tweak and dial in your detector.
You are invariably going to get a variety of specific settings answers in this thread, hopefully, this information will help you sort through it all.
HTH and good luck.
I did move down further by the fence about the same distance and the signal died off...so Im guessing theres something there just a bit deeper...
