[ivconic]

Originally Posted by WM6

Exactly. We going to find out LRLs, when the earth runs out of gold. Until then, will be available to us only inoperative LRL and tale stories connected to such creations.

Metalic item to be found at long distance, must have some unique feature that makes it much different from environment and at the same time need device capable to "recognize" that item only by that unique feature. It is hard to imagine device itself! Which technology to use? Radio? How to relate radio wave with any of metalic item features? IR? The same. NMR? Yes it could be done and already was done but with limitations and it is to expensive for our matters. EM field? Done and explored but not satisfactory, with huge limitations. Something else? Maybe.
But what is with environment? It is not empty space. It is composite substance.
How to cancel environment factor in process of LR locating/detecting?
How to acuratelly detect only "needle in hay stack" ?
Tough task.