Tweet
Good day all. I hear how the TDI can use any and all SD, GP or GPX search coils available; therefore, did White's Electronics design the TDI to accept these coils or is because the connector is the same and everyone is plugging the coils up and giving them a try? Because Jeg's artwork shows different wiring at the connector for MineLabs. I copied from Reg's artwork to show the TDI's wiring and it is way different.
-
-
Despite What You See At The Connector
I contacted White's and made an inquiry about using search coils designed for MineLab on the TDI and as such perhaps White's should post compatible coils. Looking at the Goldstalker 13.5"x9" Mono Coil for MineLab can be an expensive purchase for the TDI. It appears that Minelab coils will work but there are some exceptions. As I have suspected TDI is best to use just mono coils as there is a performance hit if DD or the wrong coils are used. The information below should help with considering different coils for build or purchase.
Steve Howard was gracious enough to make an attempt at providing an accurate enough answer as possible:
Sorry it has taken so long to get back to you. I was attempting to get an accurate answer as these loops are expensive I know.
White’s is uncomfortable coming right out and mentioning or advertising coils we do not manufacture or sell, so it is highly unlikely you will ever see an official statement from White’s regarding this subject.
Please see the following explanation I received...
I don’t have anything written, but I do know it works on most all of the loops that the Minelab detector works with. Except I think the very earliest models. I have used it with both Minelab and CoilTek and Nugget-Finder coils from Australia and it works fine. I am not certain about the new 4500, but the prior more recent models like the 2500 and the 3500 etc work just fine.
The only thing is that the TDI works much better on MONO loops, so I don’t recommend using aftermarket DD loops. The DD loops apparently work better than mono loops on the Minelab units, but not on the TDI.
I have the 6x10 Joey by CoilTek loop here.
PS: One other problem. The lower rod setups are different than ours. They only use one hole for adjusting the rod and it is 90 degrees off from our 2 holes. Also, the ears are not a good fit.
Cool. Well, wherever you go...there you are and TDI can use some MineLab coils, too. Using different coils is still a buy-and-try or a-hit-and-a-miss unless someone can say for certain that a paticular coil worked better. I'm gonna stick with the standard coil for now, will consider a Jimmy Loop and will build a larger mono some day. Being that the wiring is different at the connector it would be nice to see how a TDI Dual Field search coil is assembled.
Cheers
-
Hi Whiskey,
The ability to use ML coils on the TDI actually began with the GS 5. At a point some time back, Eric Foster began using the same connector once he found a supplier of quality connectors. The purpose was to enlarge the number of coils that would be available for use on the GS 5. This also reduced the strain to develop a wide range of coils for the GS 5 and left more time for actual design of detectors.
The natural thing to do was simply to use the same connector as found on the ML PI's and use a similar wiring setup since ML was using the same inductance as the GS 5. This would result in making a whole lot of coils GS 5 compatible. Now, you will notice I said ML was using the same inductance as the GS 5 and not the other way around. The reason I said this was Eric's detectors have been using the 300 uh inductance as a base way before the ML PI even existed.
Now, Eric Foster assisted in the design of the TDI so the two detectors are really quite similar. The next logical thing for Whites to do was to use the same feature, meaning ML coils could be used on the TDI. This reduced the strain of having to try to make a wider range of coils at the onset. It also gave new owners a very large selection of coils to chose from, but better yet, if they owned a ML PI, then they probably already had extra coils, so there would not be any other expenses except for the detector.
The bottom line was Whites used the same connector as what is used on the ML PI's for the convenience of the customer.
As for DD coils, they work just fine on a TDI and there are no ill effects. The reason DD coils are generally used is to reduce the ground response, thus making it possible to hunt in areas were hunting was extremely difficult.
Now, the TDI does not have the extreme gain as some other detectors, so the TDI doesn't suffer from some of the interference problems, but more importantly, doesn't require a DD coil in most places here in the US. So, one simply doesn't have to use a DD coil to hunt certain areas. Instead, the detector will work just fine with a mono.
I suspect that any concerns about the use of a DD coil had to do with the fact a 11" DD will not go quite as deep as a 11" mono. This holds true for other sizes also. The reason isn't a rocket science but simply the fact the actual windings are smaller in the DD than in the mono. Since depth of detection is related to coil winding size when hunting larger objects, then the mono simply goes a little deeper.
Now, on the other side of the coin, testing indicates a DD actually works better than a standard mono when trying to hunt real small gold since there is some enhanced sensitivity to the small stuff.
Now, this enhanced sensitivity difference between the DD and the mono is greatly reduced when using the Whites dual field mono since there is both a smaller winding and a larger winding within the dual field search head itself. So, the dual field coils have a built in increase in small target sensitivity not found on normal mono's.
RegComment
-
Greetings, Reg.
Since the connectors are the same I can plug my ML coil in. I can easily give it a try and see what the DD does for me. While the wiring is different at the connector both do use the same 1,2 and 4,5 pins. The exception is pin 3 for TDI as it is not used at all. In constructing a coil I will jump to pin 3 so I can use it on ML as well.
In another post someone tried what I can do and later retracted his positive statement after more field testing. It would be nice if someone with aftermarket ML coils and a video camera would do some testing for everyone and put them up on YouTube...providing the same settings are always being used.
Understanding that small gold requires being closer to the coil to detect an increase in performance would be worth noting if the distance was much greater for the same size or larger of coil. The video can then only be used 'for reference only' as actual conditions may vary.
The bottom line for me is cost. No sense making a purchase for an expensive coil that can turn out to be something I have to sell, modify or worse become rubish.
Reg, you have given me great confidence in building a coil and trying borrowed coils for my TDI. Thank you!
cheers,
Comment
-
Hi Whiskey,
I wouldn't jumper pin 3 to anything. It really isn't needed as far as I can tell. I have tried various coils including a ML coil, a couple of Coiltek coils and a Nugget finder on my TDI and Gs 5 and all work fine.
Now, building a coil for the ML is a real pain, but extremely easy to build one that will work on the TDI.
Don't expect any dramatic differences when testing coils on the TDI. The design of the machine is such that you will not see much difference between similar inductance coils. This is what should happen.
Actually, I would expect the same on a Minelab if one had control over all key settings such as the delay, the setting to minimize external noise, and the ground balance setting. As it is, any of the three can cause problems for any coil, thus making one look worse than another.
Given little or no noise, the ground balance set properly and the delay the same, I would expect various ML coils to work the same also even on a ML.
RegComment
Comment