I believe it was freshwater. I was always under the impression that a larger coil gave more depth than a smaller coil. Am I wrong? My question is how much additional depth should I expect? Thanks!
It always, always, ALWAYS depends on your soil and site conditions.
Or beach and sand conditions, fresh or salwater.
When I hunted in Kansas with low mineralization and rich black dirt my F70 could but 10" easily, sometimes 12" with a 5" sniper.
The same detector with an 11" coil could go a few inches deeper.
I have a bigger coil too but I rarely got much further than the 11" but mostly because most of my deeper targets weren't much deeper than 8 -9" .
Where I hunt now in the mineralized SE. where good signals in good targets that make sense rarely can be seen much last 6" or so.
That is with all three coils that had no problem going much deeper than that in much better soil.
I have dug a few deeper here and there but only because I used some strange settings and learned some weird repeating indicators and language to help me notice them.
Luckily, there is a nice layer of good targets from about 6-8" still around mostly because nobody has been able to make sense of signals much past 5 -6" in the bad stuff and missed them all since detectors were invented.
Using the Nox here I have the sniper and the standard coil.
After using them awhile and digging thousands of targets they seem to hit about the same depth.
Still get to the 6" mark easily, maybe a few a little past that but that is rare unless it is something really big like horseshoes or big lantern parts and other things like that.
I doubt the 15" coil would help me much at all where I hunt, even if it was able to get a bit deeper than the standard coil I come across so few targets at those deeper depths I don't think it would be worth it to spend the money.
Also the Nox isn't the most ergonomic thing to swing...the standard coil is ok but the sniper is a breeze and much better so I assume for me the bigger, heavier coil would be more of a hassle and make it less fun to hunt...again for me.
Larger coils can usually get a bit deeper than smaller coils and also maybe give you clearer signals on some targets where the smaller coils might be a bit iffier which is something I have noticed using several sizes of coils on a few different detectors.
That is just physics and how things work using metal detectors.
However to answer your question on how much deeper YOU can get with bigger coils is something only you can answer if you try it or talk to someone that has and hunts where you hunt in YOUR dirt or beach sites.
