Whites TDI Classroom

Hi all,

Is it possible to add a switch/toggle conversion that would make the standard Whites DF coil select either one of the coils only?

The reason being, it would be ideal to have only the small diameter innner coil option for certain junk/ or heavy iron laden areas to help fight target masking.

Terry.

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When in Doubt...dig it Out!

From what I understand, it's not (2) two coils. It's one large mono winding, split into two different sizes without breaking the connection between them. Re: 1 + & 1 - wire.

Mr. Bill

Thanks for the info Mr Bill.

Guess it's like a folded eight coil then?

Terry.

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When in Doubt...dig it Out!

No it's not. It's just like it looks, but both coils are formed from one wire. A folded 8 would look like a "8".

Bill

Thanks Mr Bill

So if both inner and outer wire can transmit by turning on and off seperately,
It would suggest one can be switched off?
Any one opened a DF coil up?
Picture would be nice
Terry.

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When in Doubt...dig it Out!

It's one continuous wire, not a inner & outer. Look at it as a one 25' long wire coiled into 2 loops.

Lets say you managed to open the coil, and clipped the wire making 2 individual coils. You have to over come the induction/capacitance/resistance change you caused, or the coil would most likely fail.

The next statement is: What is going to be the advantage of modifying the coil that way ?

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Mr. Bill

Yep, got that Mr Bill.
but that's all a folded 8 coil is.
So should we call the DF a folded OO

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When in Doubt...dig it Out!

Terry,

For your information, I designed what is called the foldback coil a few years ago. I posted how to build it on the Geotech forum and that is where certain people got the design and began building it after they got the basics on building coils from me to begin with. I am sure I can find the link to my original posting of the foldback design for those really interested.

Now, with that said, there is a significant difference between the foldback and the DF designs and they react differently. A foldback does not mimic a DF in many ways. The reason I came up with the foldback concept was to not step on the White's patent but still build a coil with enhanced small target response.

A DF coil fundamentally acts like what Mr. Bill described but physically is a little different. Hopefully, the patent application will be posted soon so people can look at the design themselves.

What you might want would have to be built and then it becomes a problem in actually wiring one using the connector on the unit. I know of a way one might be able to build one to work the way you want but I will leave the specifics to others. I have no desire for such a coil and I am not sure just how well it would work. For me it is much easier to have two different size coils already mounted on lower shafts and take a few minutes to switch them when desired.

Reg

Won't let me edit my last post.

Should have said "unfolded OO"

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When in Doubt...dig it Out!

Point taken Reg.
Thanks for the input.
Terry.

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When in Doubt...dig it Out!

Hi Terry,

A DF coil consists of a large outer coil and a small inner coil, wired in series but with split damping. As it is designed, you can't separate the coils. You could design a dual switched coil loop, but it would be a different design, and getting proper damping with an inactive coil could be a challenge.

- Carl

Hi Carl,

Thank you for the information and insight.

Terry.

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When in Doubt...dig it Out!