Feedback coil on Whites 6000di XMIT coil

[Jim in Idaho]

Wondered about the size, number of turns, etc. on what's shown as a feedback coil in the XMIT windings on a Whites 6.59khz coil. What's the purpose of the feedback loop in there?. I appreciate any help, or explanation.
Jim

[Carl-NC]

It's the bucking coil, used to create an induction balance. Usually wound right on top of the RX coil.

[Jim in Idaho]

Thanks, Carl. I figured it had something to with the IB between the coils. So, if I make coils, ala the TM-808, I assume I can leave it out?
Jim

[kt315]

explanation you may seek in the patent. US4293816
if you are not able to seek it on the site (this site) i will help you. anyway first do a click on the huge banner GEOTECH you see above. it is clickable.

PS. oh not... they had changed the link linked to the banner

[Gwil]

Hi Jim

If you haven't seen it I suggest you read Carl's article on Coil Basics. Go to geotech1.com, click on Metal Detectors, then Info. "Coil Basics" is there as a pdf document. Lots of helpful information.

Gwil

[Carl-NC]

Thanks, Carl. I figured it had something to with the IB between the coils. So, if I make coils, ala the TM-808, I assume I can leave it out?
Jim

Yes, orthogonal coils are balanced by their orientation.

[Jim in Idaho]

Yup...should be fairly easy. Probably won't get to it before winter, though. As always, Carl, Thank you
Jim

[Jim in Idaho]

Hi Jim

If you haven't seen it I suggest you read Carl's article on Coil Basics. Go to geotech1.com, click on Metal Detectors, then Info. "Coil Basics" is there as a pdf document. Lots of helpful information.

Gwil

Yup, I'll get to that, for sure.
Jim