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I own a GP 3500 with the Minelab 11" DD coil. I wanted an all terrain so I have ordered a Platypus DD Pro from Rob. Now I would like to sorta round out my coil selection. Will be doing the majority of my detecting in the high mountains of Colorado looking for speciman gold and pocket gold. Will be in mostly very mineralized ground. There will be a few trips to AZ. and northern NV. Also looking at a lot of the old mine dumps in Colorado. So what do you think should be my next coil????

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Dredgebug . No question about that. A small mono coil is the cats meow for small specimen gold which often gives a weak signal on bigger coils. A 5x10 eliptical or 8 " round. For deep pockets and larger specimens , a 14" or 16" round mono. In rough or brushy terrain a bigger coil is very hard to work with and I,ve never seen any colorado gold country that wasn't rough or brushy. Swinging a 20" coil on a steep sidehill will turn a strong mans arm to jelly in minutes.----Bob

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Hi Dredgebug,

I too have GP3500, Platypus :rolleyes: great combo :rolleyes: also have 8" commander mono coil, but I'm thinking about the coiltec UFO 12x24 to look for pockets or stringers, myself... Both UFO and mini ufo are also all terrain coils, and open web design like the platypus, except coilcover. I'd use Epoxy on bottom, like Grubstake, use's on his proto-type platypus.

Take care,

Ed

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I contacted Coiltek and this is all I got back when asked about any new coils.

" Dec 26,2006 Email

Hi Iggy

There are some new coils coming but as yet we have not even tested the proto type so I cant tell you much at this stage

Thanks Andrew"

:o So we will just ahev to wait in suspense.....

Iggy

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Dear dredgebug;

I consider the Wallaby DD Pro to be an uber-coil and the Joey DD Pro is another awesome coil , however if it were me, I'd order a Platypus (which only comes wound as a DD Pro coil) and scratch the Joey DD Pro, because they are so close in performance that having both the Platy and the Joey is quite unecessary. Instead of the Joey DD Pro, I'd seriously consider a Coiltek 14" round mono coil. A CTK 14" round mono, a Wallaby DD Pro and a Platy DD Pro should be all the coils you will need for a while, IMVHO. Start off with the 14" mono and if the ground becomes too noisy, switch to the Wallaby DD Pro and for clean up work use the Platy.

Your friend;

LAMAR

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Hello Lamar,

Good to hear from you! I talked with Dredgebug last night and he placed the order for the three Coiltek Searchcoils. I told him the performance between the Joey DD and Platypus wouldn't be huge. However, the Joey is much smaller and get fit into tight areas and he liked that. He also wanted a completely waterproof searchcoil so he decided on the Platypus for that. The Wallaby DD Pro will be his patch or pocket finding searchcoil. He wanted all DD Pro Searchcoil to elliminate any ground noise on his GP3500.

I hope Dredgebug comes up with some nice gold!

Take care,

Rob Allison

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Hey Lamar: Thanks for your input on coil choices. Beleive me I seriously considered the 14" Skippy, but I chose the Joey due to its small size. Have an area above timberline in the ten mile range covered in large talus block that I want to be able to get the coil down between the blocks. Not sure yet how I will dig the targets though down in those tight areas, but I'll figure that out when I get the beeps! Needed the Platypus for all those small shallow creeks high up in Taylor park area around Tin Cup. This is all high mountain Colorado stuff................PS.............Would be very interested in any info anyone may have out there on detecting for gold in the high San Juans. Red Mountain, Silverton, Lake City, Ouray Colorado etc;......Thanks

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dredgebug

I'm glad you have it all figured out on the coils.

I'm so confused on what I need someone can sell me a coat hanger and I will probably be happy.

DD or Mono

I wish someone out there would explain the difference.

I understand the shape of the field is different. Mono is more cone shaped and the DD is basically a rectangle wall from North to South on the coil.

Correct me if I'm wrong.

The Mono will go deeper and pinpoint small nuggets. Some say it also is more sensitive

The DD is good for large nuggets deep or shallow?

I understand smaller round or elliptical and small size is good for tight places.

Here is my delema.

I use the 24k claims and presently use standard Minelab 11" round DD.

I enjoy the pushes but want to start climbing up the hill as well as the flats bown below.

I'm considering ONE of these.....

1- Coiltek Joey 5"x10" Elliptical Mono

2 - NUGGET FINDER 14 X 7 INCH ELLIPTICAL MONO

3 - Minelab 11" Round Mono

4 -Minelab 15" x 12" Semi-Elliptical Mono

What do you suggest?

Thanks,

Iggy with more questions....LOL :D

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Hello Iggy: So you say you would be happy with a coat hanger! Prehaps so, but not in noisey soil as a single coathanger would be a mono type coil, But two coat hangers wired together along there long sides I think would be better as now you have a DD....HA HA............As for going up on Rich Hill, I've been there with the 11' round and I think the Joey would be a good choice there so you could get down between the boulders.

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Dear group;

Yep, I was out in the sticks for the last month and I just returned to civilization, more or less. OK, here is my spin on the mono vs. DD debate. When we start out detecting for nuggets, one of the very first questions we all ask is "Which coil is better suited for me, the mono or the DD?" Actually, there isn't any single "one size fits all' sort of answer. Instead, we need to look at the bane of all nugget shooters, that is the prevailing ground mineralization. This one factor has a VERY decided effect on ALL coils, be they mono, DD or salt coils. Now for an explanation of how each coil type is constructed and how they work:

On the outside, all coils look like they are created equal, however it's what takes place inside of the plastic coil housing that affects a coils' performance and gives them their respective names. A mono coil is just that, a single wire is wound round and round along the inner perimeter of the coil shell until a certain impedence is met and then it is sealed up. There is much more to it than that, but for our discussion I am taking the short explanation. A DD coil is formed by 2 separate wire coils, each one shaped like a letter D, with the left hand D facing backwards. The vertical line of the 2 Ds overlap each other slightly and this is where the coil gets it's name double D, or simply DD. A salt coil can be wound as both a DD or a figure 8, however the figure 8 seems to be the most popular configuration. So, how does each type of coil affect us, and more importantly, how does each coil type affect our chances of success? The answer is below. Not below as in the "next paragraph" , but below as in beneath our feet.

A mono coil emits a cone shaped pattern, much like a snowcone shape, with the widest part of the cones' mouth being the perimeter of the coil and it extends downwards into a more or less blunt point. Theoretically, any metallic object inside of the cone will be picked up by the detector and be sent to the detectorist as a target. The truth of the matter is how far down the signal penetrates depends on a number of factors, being the size and shape of the coil, the power of the signal and lastly, but never leastly, the ground mineralization. If we were to assume that we were detecting for nuggets in completely neutral terrain, then we could use the formula that the depth of a mono coil is quite simply put, the same as it's diameter. For example, a 14 inch round mono coil would have an effective depth of 14 inches, an 18 inch round mono would have a depth of 18 inches, etc. In our fantasy world, these are great looking numbers, however our old enemy mineralization takes a machete and chops up those numbers dramatically.

This is where a DD coil comes into the picture. Remember the cone shaped pattern that the mono coil emits? This pattern is great for picking out gold nuggets but it's also great at picking out the ground mineralization too! in other words, the heavier the mineralization becomes the noisier the mono coil becomes as well. The DD coil emits a distinctly different pattern than a mono coil does, as both the left and right hand windings become charged with energy then the field to them is collapsed, and thus a signal is emitted from the coil windings, however the signal is cancelled out from the left and right windings, leaving only the narrow overlapping band which runs down the length of the coil from toe to heel. It's in this narrow 1 to 1.5" narrow that all of the action takes place. Instead of having a big cone shaped signal in which EVERYTHING inside of the cone is relayed to the operator, instead there is only a narrow band remaining, which picks up a LOT less ground mineralization.

So, a DD coil is quieter than a mono coil in heavy mineralization because it's pattern is much narrower and thus it sees less of the ground, and therefore less of the mineralization as well.. That's just great! Or is it? A DD coil has markedly less penetration than a mono coil does, in fact I've read where the depth of a DD coil is 10% less than an equal sized mono coil, however in my experiences I find the true figure to be closer to 25% less in many cases. So what's a detectorist to do? THIS is the 50 dollar question folks! In my limited experience I feel that a beginning detectorist should strap on a Wallaby DD Pro and get busy because it's a superb coil, with limited noise in the even the heaviest mineralization with good sensitivity to around the 12" depth mark. As the detectorist gains experience, then he or she can gravitate towards the mono coils with success.

There IS another factor which I will include in this discussion as well. That is, the MODEL of the detector in question also affects my coil selection choice. For instance, if I am in an area with my SD2100 then the first coil that I always use is the 14" mono, then if I can't ground balance it properly I'll go to the 11" mono, and so on, all of the way down to either my 8" ML mono or my Joey mono. I've yet to find mineralization so severe that I cannot achieve a decent GB with the CTK 11" mono. I stay away from DD coils when using my SD2100 because I feel that I cannot detect an engine block just below the surface with one, therefore my SD2100 only sees mono coils.

Now, if I am using my GP3000 then the Wallaby DD Pro is the permanent fixture on the end of it's stick. That is one SWEET coil for the GP3K! It almost always achieves a near perfect GB and it's sensitivity is quite impressive for a coil of it's size. It has very good depth and after going over a patch my GP300/Wallaby combo, there are precious few nugs remaining to be detected with either my 8" mono, Joey mono, or Joey DD Pro coils. In conclusion, I'd like to state that my SD2100 is my *mono* rig and my GP3K is my *DD Pro* rig.

And now for the standard disclaimer. I haven't been at the PI detecting game for very long so if there are any mistakes then please chalk it up to innocent ignorance on my part. Also, I've heard some vicious rumors that the new GPX-4000 is breaking all of the conventional rules pretaining to when and where to use mono coils. It's so good that I've even heard some unfounded rumors that many of the old diehard SD2100 users have let go of their precious SD series detectors and have embraced the GPX-4K. I am not one of those, in case anybody is wondering.

Your friend;

LAMAR

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LAMAR,

Thank you for Coil 101 class. As time goes on I learn more and more about my new hobby.

I have a SD2100v2 with the stock DD. I probably will be ok with it but I have had no luck yet.

I guess the bottom line is I will have to make my own decision as for my 2nd coil.

Hope you have a great 2007.

Iggy

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Dear Iggy;

You're very welcome my friend. Your decision should be based on the mineralization in the area you plan on detecting in and the average depth of the soil. As for you choices, the ML Commander is built like a main battle tank and it should be able to take a lifetime of use and abuse. The downside to the 15X12 Commander is that it's not as sensitive as a like Coiltek coil is, however the lack of sensitivity also means that it runs quieter as well. So it's a trade-off really. It's also a VERY heavy coil for it's size. The CTK Joey mono is a superb *clean up* coil and I use mine religiously when scrubbing. It has the same depth and sensitivity as my ML 8" round mono has, only it has a very narrow footprint and thus it can get into more nooks and crannies. It has become my fave clean up coil. I don't have any experience with the ML 11" round mono so I can't comment on it, however I DO have a CTK 11" round mono and it is a great *in between* coil when I am switching down from my 14" CTK round mono. I always sweep the area that I am in very well with my CTK 11" round mono before tying on my Joey mono and I've realized that by doing this, I can pretty much guarantee a success rate of close to 100%. I don't use Nugget Finder coils because I feel that they are overpriced and they rely on hype to sell their products, therefore I stay with the Coilteks as much as possible. Also, I stay away from epilleptical monos because I feel that monos perform best in the round configuration and DDs perform best in the epi configuration. The 14" round mono, the 11" round mono and the Joey mono are all great coils, just don't expect to get any extreme depth from them.

Your friend;

LAMAR

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