Magnet wire coil

[green]

Hi Green in post #28 are the toothpicks removable ?

Yes. At first they weren't. After I added the beads I can.

[green]

Making another coil. Cut 20mm off each side of the 200mm ID round form and the race track coil form that went over them. Question. What is the correct name for the two coils? Two Rx 200mm ID, Tx race track and two Rx trimmed, Tx race track. Lose some signal but they reject ground, noise and EF. The round Rx is better with target over 100mm away. The trimmed is better less than 100mm away.

Why isn't the o0o or figure 8 (what ever it's called) coil used more often since it cancels or at least reduces ground signal, noise and EF? Might still need to take a GEB and EF sample. Damaged the o0o narrow. Want to make another narrow and wide o0o coil. Need to reduce Tx resistance. Thinking of twisting 2 to 4 strands of the awg 28 and then winding the Tx coil. Charted the last o0o wide coil I made. The response at each end is is similar to a round mono coil with a sharp null in the center that looks like it could be used to pin point. I made a Heath kit probably 50 years ago. Used it to find arrows that were buried in the grass when we missed the target so I have little experience metal detecting. With help from ITMD, GEOTECH forum and Eric Fosters PI tech forum I'm learning something about PI metal detectors. The o0o coil is the same as the narrow but with round Rx coils and a wider race track coil.

[Tinkerer]

The depth is relative to the diameter of the TX coil. In the case of a narrow coil, it is the narrow width that defines the depth.
The oOo coil reduces the ground response, but is sensitive to tilt. Therefore the user needs to be careful the keep the coil parallel to ground.