Making a 15" round coil.

[Jim in Idaho]

Yup...thanks, KT. I knew that. I'm going to connect direct, but with separate coils. Might not work as well, but no way to know, but to try it, and test.
Jim

[kt315]

I'm going to convert a Whites 6000 into a two-box

there is not a coil in two-box either it is TF900 or TM-808. it is some kinda a transformer with one loop, on TX side and RX side.
TX - for translating, one loop is second output winding, RX - for receiving, one loop is first input winding.
in both uses ferrous ring. certainly, you may use winding of wires instead of the transformers.

[Jim in Idaho]

Many thanks, guys. So, no benefit to an oval, except maybe slightly wider area covered? I'm thinking I'd get at least a 36" wide swath with a 12" coil, and maybe even with a 10". Not sure about the math to determine that. With the data-logger and the TF-1200, I'm now doing swaths at about 4' centers, though I know I could do wider. I'd rather do more walking and have better resolution.
Jim

[Carl-NC]

If you take a round coil and squash it into an oval, then the inductance will decrease by the root-root of the area ratio:

[pito]

Round coils are giving maximum surface of the circle/coil with the same length of the wire, squeezing coil will reduce inductance , sensitivity of Rx coil and strength of the emitted field by Tx coil, usually squeezing is not big so decreasing is about 15%.

[Jim in Idaho]

I'm going to convert a Whites 6000 into a two-box. Going to make the coils. If I make them round, but decide to squash them into an oval, what happens to the inductance value? Is there any advantage to the oval shape, as far as depth or sensitivity? Thanks
Jim