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OK - I'm looking to buy a GP Extreme (From Chris of course), and have a question for all of you who already own and operate one. How accurately does the Extreme detect Iron? Here is the reason I ask - I was out with a friend who has a Whites Goldmaster and he hit a signal that according to the meter and sound was iron trash so he passed it up. About 10 minutes later another friend of mine hit the same signal (his detector does not have any iron discrimination) and he dug.............a 1.2 ounce nugget! My friend with the Whites that didn't dig the signal almost threw his detector off into the nearest wash!!! I'm curious how accurate the GP extreme is as far as truly detecting iron.




On another note, I just returned from 3 days prospecting/camping in Box Canyon in South Arizona (65 miles North of the Mexican border). On the second day I thought I had made a ghoulish find. While digging a signal I hit a bone. I thought, OK - There have been many battles and ambushes in this Canyon (between Mexicans, Indians, and early pioneers), so an occasional skeleton being found may not be too unusual. So do I continue digging and have to report this to the authories, or do I cover it back up and not say anything? Well I kept digging, then I found a knee joint with another bone attached - it appeared to be a leg. I was starting to wonder how much of the skeleton was still there when I uncovered.....the hoof. It was only a deer leg! WHEW!!!! The original signal only turned out to be a bullet that was just below the deer leg. :o


Keep your Coil to the Soil,

Stan THE Man

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Hi Stan,


I do not use the Discrim on my GP unless the trash is severe and I am convinced there is a chance of gold being there. The other main reason for my not using discrim is because I mainly use the monoloop coils, the discriminator on the GP does not work with monoloop coils. Keep in mind the discriminator doesn't have the same power as the detector, even though you can easily find boot tacks the discriminator won't necessarily tell you reliably if they are worth digging.


The discriminator on the GP extreme, has a blanking effect (on the signal response in your headphones) on a possible ferrous signal, if this blanking only happens intermittently or from only one direction then that would have to be considered to be a maybe and should be investigated. When you do find a potential target try whipping the coil across the target zone quickly, this helps to give a more reliable discrimination.


Jonathan Porter

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Here's my 2 cent worth Stan. I just make believe that my GP discriminator does not exist,and dig all targets. I have used the Disc. with DD coils, and am dissapointed with the GP Disc.! I also prefer using mono coils with the GP as they give a sharper target response, and sizes being equal,go deeper than a DD coil! I have yet to find a spot here in the S.W where I could not easily use a Mono coil with my GP! My favorite ones are the Coiltek 14 inch Mono, and the 5x10 Joey. Hope that this helps Stan!


Regards Bob



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Hi Stan,


As for the GP's discrimination ability, I would agree with Jonathan. It really only works for larger-sized ferrous objects like cans, big chunks of scrap metal, rusty nails, etc. In Disc mode, as the coil approaches the target there is a quick rise in pitch, then as it passes directly over the object the threshold seems to drop out causing a "blanking" in sound, finally as the coil moves away from the target you get another quick rise and then it returns to the normal "thresh" tone. Not too bad for the larger rubbish, unfortunately it is of little use for the smaller junk like boot tacks and old dry-washer staples that seem to plague the AZ goldfields.


And as JP pointed out, it can only be used effectively with the DD coils. Personally, about 99% of my hunting is done with the monoloop coils. I have only found a handful of spots here in AZ that are really suited for a DD, and even then, they can still usually be negotiated by a mono if the operator is patient and doesn't mind putting up with a bit more racket. I am using AZ as an example, but try using a mono in parts of Western Australia, Queensland and Victoria and you could easily go out of your mind, so the DD coils most definitely have there place.


My GP Extreme is almost rusted in the All Metal position. I like to use my "mental discriminator" as opposed to the one on the machine. It seems to me that an experienced hunter can usually determine more accurately if a target is going to be trash by its' volume, tone, and location. For instance, if the signal of a target breaks up or "double-hits" as the coil is passed over, it is almost always rubbish, usually wire or a nail. On the other hand, if the signal is steady, solid and gives off the same sound in both directions of the coil sweep, it is usally gold or lead. Keep in mind there are always exceptions, this is just a general rule of thumb. The only time I will use the discriminator is on known gold-bearing soil that is trashed beyond belief. In this case it is better to run the ground in Disc than not at all.


The GP is an incredible gold machine, but I believe it is even more incredible when ran in the All Metal mode :)



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