[ivconic]

Originally Posted by WM6

The problem with these T/R searches is that you can not have anything metallic on you, otherwise you alone generate false signals. So a plastic digging tool or hunting for two.

I am awared of that.
I am interested in precise explanations of it's working principles. Not generally explained, but in exact details. For example; i would like to know how they calculated coupling relation between Al loop and small coil inside it? What relation? What is resonance of Al loop? What happening if loop was with different sizes? What are merrits and what drawbacks from such coupling. Is loop size dependable on working frequency and how? How possibly that loop can be suitable for such low frequency? Is it the coupled coil the one which solving that issue?
Working frequency in relation to all of that? Etc..etc...

Wild guess: instead Al loop, why not use another coil coupled with existing one on ferrite rod? Depths will be lower but better directional sensitivity maybe achieved? Other type of coupling? Coil?

Following simiillar logic we can come to conclusion that any other nonmotion metal detector can also be easilly adapted to work as 2 box? Right or wrong?