The Jimmy Loop for TDI [only]

[whiskey]

The Jimmy Loop is a Mono Search Coil with a White's Dual Field design. Yeah, I know, just what does that mean? According to Jimmy Sierra, "This means that it has two distinct sets of transmit and receive coils: a large outside coil maximized for larger targets and a smaller center coil to hear those tiny pieces better."

Let's think a moment here. TWO sets of COILS.

Without ripping into a TDI search coil it appears there is an outer mono coil and an inner mono coil each with its own set of TX and RX operating at the same time.

Brilliant! So, it appears that the TDI is designed to run two mono coils simultaneously as a standard search coil configuration.

My thought is it would be nice to have an eliptical design and that is just what Jimmy has to offer. An important notice goes along with the Jimmy coil and the Dual Field design: "This loop is designed for use only with the PulseScan TDI".

I'm thinking that it can't be used on any other White's detector...

Yet, can it also mean you can't use it on a MineLab? Not like anybody is crying about that. If that were true, then the TDI search coil is exculsive to the TDI only and interchanging ML coils could make the detector not function properly as designed. Now I'm over thinking here and making myself sick.

vs I own a TDI and GP 3000.

I will never use my ML coil on the TDI because from what I understand it is a DD coil. And from what I understand about the TDI...I will only consider mono coils.

Maybe best for me to save up my nickels and get a Jimmy. Until then...

What I or we need is a schematic of some sort for this dual field thingy. Anybody got any ideas?

[Reg]

Hi Whiskey,

The TDI dual field coil has two separate windings only. One is a larger winding and the other is the smaller one that sets inside the larger outer one. These two coils are connected in series and make up the transmit coil assembly.

There are no separate receive windings. Instead, the combination of the two coils operate as both the transmit and receive coils.

Now, this coil will not work on the Minelab because of the ML's design.

As for your statement about the DD coils and not using them on a TDI, that isn't necessary. A DD coil made for the ML will work just fine on the TDI as will other DD coils made for the GS 5.

I am not sure where the misconception came from that DD coil can't be used, but that is incorrect. What was probably said is the TDI works just fine in most places here in the US using a mono coil, so there is no real need for using the DD.

Usually, the DD coil is used to reduce the ground effects, thus reducing the need for any ground balance, or at least, less ground balance. PI's such as the Hammerhead operate with less ground signal when a DD coil is used.

The TDI will need less ground signal also, but will still work just fine using a DD. One advantage of a DD is this type of coil generally gives a stronger signal on real small objects such as small gold nuggets. So, a DD can be an advantage when searching for small gold when compared to a typical mono coil. On the down side because of the smaller windings inside a DD, the same size DD coil (housing size) will not go as deep as a typical mono of the same housing size. In other words, a 11" mono will go deeper than a 11" DD when searching for larger objects.

Now the dual field mono design is still a mono type coil but because of the two windings is much more sensitive to small gold, much like the DD. As a result, the dual field mono provides the benefits of a mono while adding the sensitivity to small gold closer to what can occur on a DD.

This dual field works well in many locations but it is my understanding it doesn't work that well in the extreme mineralized areas that can be found in OZ. So, there are places where the dual field may not work as expected. Fortunately, no such place has been found here in the US, so the dual field appears to work just fine here in the US about everywhere.

As for a schematic, hopefully, the patent information will provide the specific details of the dual field. Unfortunately, I have not seen a copy of that patent as of yet. In the mean time, you might search the Geotech forums for more information posted by Aziz pertaining to separating a mono into segments and dampening each segment. That is similar in concept as far as I know.

Reg