With the "ground compensating" technology being carried over from the E-TRAC, in GB OFF mode, the CTX 3030 handles hot rocks equally as well as the E-TRAC. With the ability to implement Ground - Coin Audio Profile and turning on the Ground Balance, it was more stable than the E-TRAC in highly mineralized sites.
Although I didn't work directly under a power substation, I did detect in both rural and urban areas without EMF problems. And in several of those sites, there were HV overhead transmission lines as well as commercial and residential service lines.
On rare occassions, it would chatter a bit. Especially if I had too quick of sweep speed. But performing another NC, and being more aware of my sweep speed, I would quickly remedied the situation.
With the additional information on the display, combined with some of the new Separation profiles, I was able to recover several nice pieces of small gold jewelry and one very fine gold chain. When I purposely go hunting for jewelry, it is typically in areas with modern trash. parks school yards, athletic fields etc. At those sites, I usually set up with the High Trash Search mode, make a separate discrimination Pattern for Pattern 2, set up my modified coin program for the "previous search mode", (along with it's own Pattern 2). Using High Trash allows me to sweep more quickly, covering more ground in a given hunt. By being able to switch to a second search mode, or implement the secondary Pattern of either mode, I can use the additional functionality to obtain more accurate information on targets that I suspect to be good.
In the places I hunted, and by comparing it "head to head" with my E-TRAC, I did find a small increase in raw depth. But probably no more than 10% max. However, as I mentioned in several other posts, the amount of information on the screen, combined with some of the new functionality, I pulled some very nice coins from places that I've been detecting for over 25 years. JMHO HH Randy