Quick IB coil question.

[kac]

I am trying to make a 5x10 concentric coil for my Tesoro delta pin detectors. I have the Tx and Rx wound in same direction and Bx opposite outside of Rx. I have a cable with connector to the detector and coil wires clipped on other end to the cable. When I fire the machine up the scope reads 14.5khz which is correct for the Cibola but detection is off to one side and not very far (possible emi issues).
When I put it in all metal mode (pin point) I just get a steady sound and can't change volume with threshold knob.

Is the coil way out of phase?

First coil attempt here so I am sure I am doing a lot wrong.

Thanks,
Ken

[surfdetector]

Have you read the guide Building Concentric Coplaner coils
that Don Bowers wrote? I am wondering if you have the correct RX inductance and if your TX coil connections are correct.

Cheers

[Carl-NC]

Did you null the coil?

[dbanner]

Judging by the questions you've asked, I'd say you're pretty intelligent.

You'll figure it out, eventually.

[dbanner]

By the way, out of curiosity, what gauge wire did you wind the Rx coil with?

[dbanner]

I harvested some wire from an old computer monitor. It worked for me.

Nulling the coil ain't all what they said it would be.

Induction balance is so misunderstood.

[dbanner]

In all metal mode, if you are getting a constant beep, then something is wrong with your circuit.

[dbanner]

Double check the wiring to the switch.

[kac]

I do have the null wrapped around counter to the outside of the Rx.
Using 26 awg on Tx and 32 awg on the Rx.
Tx including null is 1.53mh
Rx is 21.6 mH

So stock coils work fine including all metal (pinpoint). Only time the pp sounds off steady is with the coil I am trying to make. I tested the bench with one of the stock coils and detector seems fine.

Little stumped on this, I know it's something really stupid too.