See how much I know about it--I rewound the loop antenna in smaller diameter, shorter, and multi-layer and the inductance was almost the same. I was expecting the inductance to be much higher. I used the same length of wire. The coil is not as powerful but it has a nice sharp focus when pointing at the target. This thing is working pretty good now but I still need to get it out in the field for some real hunting, and that's at least a couple months away.It hits a half ounce of silver at about 75 feet on the lowest power setting. The neighbors have a large brass pipe fitting and it pulls to that at first, but after a few minutes it moves to the target. So yeah, it likes big copper. I found with too much power it is hard to ignore it. So I guess I like the litz wire now.
