Detech 11 DD Anti Interference For Minelab Gp, Sd Or GPX Detectors..... Advice, Suggestions Etc.

[RickUK]

Looking at getting one of these coils Detech 11 DD Anti Interference for Minelab GP, SD or GPX detectors for my GPX,the stock coil that comes with it is the stock 11'' Mono which i dont particularly like as a stock coil,but this Detech 11'' AI coil is seriously grabbing my attention as a everyday use coil,it will never be used for nugget hunting predominately for coin,artefacts and hoard hunting,but will mainly use my selection of larger coils for the latter option.

Has any one on the Forum used one of these coils and if so am i going down the right route for my needs and would you recommend this coil as they are pretty tough coils and a decent price here in the UK although they are shipped from Bulgaria.

Rick

[RickUK]

Decided that was the right coil for my type of detecting and ordered it from Bulgaria,should be here in the UK within the next 7-10 days and will be the stock everyday use coil....have about 8 coils for the GPX from the 6'' Mono Coiltek upto a 18'' Detech Mono coil.

 

[PhaseTech]

Not sure about the DD part, but if they are wound like the Coiltek AI coils, you can still get Iron ID to work on them. And if you switch into the Mono position on your coil switch, then it will work like a straight mono. 

[RickUK]

2 hours ago, PhaseTech said:

Not sure about the DD part, but if they are wound like the Coiltek AI coils, you can still get Iron ID to work on them. And if you switch into the Mono position on your coil switch, then it will work like a straight mono. 

Many thanks for that very important advice,will give it a try when it arrives.

[Chase Goldman]

On 2/10/2024 at 6:57 AM, RickUK said:

Looking at getting one of these coils Detech 11 DD Anti Interference for Minelab GP, SD or GPX detectors for my GPX,the stock coil that comes with it is the stock 11'' Mono which i dont particularly like as a stock coil,but this Detech 11'' AI coil is seriously grabbing my attention as a everyday use coil,it will never be used for nugget hunting predominately for coin,artefacts and hoard hunting,but will mainly use my selection of larger coils for the latter option.

Has any one on the Forum used one of these coils and if so am i going down the right route for my needs and would you recommend this coil as they are pretty tough coils and a decent price here in the UK although they are shipped from Bulgaria.

Rick

Rick - I think you take a slight performance depth hit on the these AI coils vs. a DD with the same coil footprint.  Since you are getting one anyway, you can be the judge of that if you have any DD coils in your arsenal you might use for mineralized ground or use of the GPX ferrous blanking feature.

For relic hunting with the GPX, I have run DD coils exclusively because I primarily solely used (I have a Garrett Axiom now) the GPX in hot ground and I also utilized the ferrous blanking feature with great success.  I found the Commander Coils to be best behaved in that regard, but also had good experiences with my Detech 12.5" DD. 

Anyway, the point I wanted to make was that I have experienced detecting in situations with localized interference that could not be mitigated with a simple frequency scan to find an alternate quiet frequency.  Since I did not want to take a perpetual depth hit by running an AI coil full time, what I did was utilize Minelab's excellent "Mono-DD-Cancel" toggle on my GPX 4800 that enabled instant, on-the-fly switching of the DD coil wiring to put it in noise cancel mode.  This completely eliminated any common-mode external EMI.  As with a normal AI coil, there are no free lunches as far as doing this is concerned.  You will take a depth penalty (perhaps 10%?) and pinpointing will be offset to one side and as I recall tones switched from low-high to high-low for high conductive targets.  All that being said, I recovered one of my best and deepest relics while operating in this mode (it was a brass 1860's military bit boss that was down greater than 1 foot) - I was using the 11" DD stock Commander coil.  The best part was that when I was clear of the localized interference, I was able to switch the coil back to DD mode and restore full performance.  That would not be possible with an AI without completing switching to a different coil.  Even though you are getting an AI coil for use, in those situations were you might be encountering localized EMI while running a DD coil, you can try this approach on the fly without having to switch in your AI coil.  FWIW.

[RickUK]

@Chase Goldman,many many thanks for your reply and excuse the pun indepth opinion on a few coil,the reason i chose the AI 11' coil was that it was a decent price brand new and my GPX4500 although almost brand new only came with a 11'' Mono and a 15x12 DD ML coil,i all ready had about 7 coils which are all Mono and the reason for that i used them on my TDI Pro.

I wont be using the GPX as say a everyday out as i brought it mainly for hoard/artefact hunting here in the UK,our soil conditions are very every mild indeed with the exception of a roman trading villa site which has thrown up 1000s of roman coinage over the 15 years that we have been detecting this site.Its about 60 miles inland but about 60 acres of this site is about as bad a it gets soil wise.

But the main reason is pure depth and i do have some large Mono coils that i can use when we suspect a hoard is in that locaation,typical the weather is deep in the winter grip here at the moment so wont be getting out again for another few weeks as the older i get i am rapidly becoming a fair weather detectorist.

Once again many thanks for your information and advice,all taken onboard and will update on how i get on with the GPX and the various coils i have for the machine.

Many thanks

[phrunt]

Coiltek advertised their AI coil as having a 5% hit from the DD of the same size, although the extra gain you could run with it more than made up for that so by running the gain much higher in high EMI areas you were gaining performance not hindering it with the AI coil. 

I can run my AI coil directly under powerlines with the detector maxed out on sensitivity and it's stable. 

I never liked Cancel mode, cuts out all smaller targets, but I guess if you're hoard hunting that wouldn't be too much of an issue for you.  

It will be good to hear how the Detech AI coil goes, keep us updated.