To whatever extent this is true, and to whatever extent it has any bearing on the ability of detectors (depth etc...) : It has been debated on other threads. Seems that opinion was: There could be no better/deeper , if it wasn't for the big bad govt. restrictions. I think that issue was pretty much put to rest as being baseless.
And if it was true that some output was disallowed for hobbyist machines, that's it's equally true that the same dis-allowance would be for industrial detectors too. (if you meant units available to industrial buyers). Otherwise: We'd all simply be going out and buying those industrial machines, instead of our hobby machines.
If you look hard enough, you can find almost anything online.
From what I read, power is limited more by physics, the law of diminishing returns.
First, to extend the field, the power required goes up squared. You cant ust double one milliwatt and get two feet of depth.
Second, the ground itself has magnetic/electric properties. A bigger detecting field means more noise. This easily gets louder than the small differences your detector measures from metal.
The main method used to get depths seem to be a bigger coil, as the field size is a function of coil size, and DD coils, which are said to be deeper. Their field shape also is said to enhance.
Minelabs Multi frequency may help, by giving the detector more signal difference to read. PI helps as AC helps transmit electricity. I also assume makers continue to upgrade their electronics allowing the electronics to detect and interpret ever fainter difference signals.
Also, the law has been re-written in recent years, to where it really is inapplicable to detectors. So, manufacturers are free to do as they please. You cant fry an egg on one yet, so I guess its OK.
Its odd that manufacturers never seem to discuss power, and many other tech questions. You think that one might come out and brag about power, or have a blog, or some sort of technical resource where curious hobbyists could acquire knowledge. Manufacturers are not limited on power, to a point, but power causes its own problems.
You can put TONS more power into a machine, but the same problem persists: The medium that the detectors see through is solid ground. And you can't exceed the laws of physics.
