A New Concentric Coil Coming For The Earlier GPX 4500/5000 Series From X-coils

[10fp]

13 minutes ago, Northeast said:

You mention the GPX 4500/5000.  I assume they will also work on a 4000 or even a GP 3500 - any Minelab PI that has DD ability?  Or are they just not as useful as they are on the more recent GPX models? 

Northeast , the 18cc was the best coil ever on the GP3000  especially in Mono

[phrunt]

The Detech ones are bundle wound so hopefully the X-coil being spiral gives it a bit a boost in sensitivity.

 

[PhaseTech]

Simon, if you have bad hot rocks why not run your GPZ in Difficult instead of Normal? If you run your GPX in Normal or Sensitive extra, you will still have a problem with hot rocks. Your timings selection determines your detectability of hot rocks far more than the coil does. A concentric coil isn't going to be the magic answer of being able to run Normal or Sens Extra and kill hot rocks, especially if it's spiral wound. 

Be interesting to see how it compares to a 15" Evo, and a 15" DD, in terms of depth, ground handling, sensitivity. 

[phrunt]

48 minutes ago, PhaseTech said:

Simon, if you have bad hot rocks why not run your GPZ in Difficult instead of Normal? If you run your GPX in Normal or Sensitive extra, you will still have a problem with hot rocks. Your timings selection determines your detectability of hot rocks far more than the coil does. A concentric coil isn't going to be the magic answer of being able to run Normal or Sens Extra and kill hot rocks, especially if it's spiral wound. 

Thanks Nenad, on the GPZ I've tried various things including going into Severe to try get rid of them, coils appear to make minimal difference with these particular hot rocks, all coils I've tried respond on them very similar as you've pointed out.  I actually found General/Difficult to be the best on the 7000 with them but still not great, and the problem is they're often buried so you're digging these faint targets thinking you might be about to recover gold and it's just a little hot rock 🙂

The GPX 5000 especially in Enhance, Sensitive smooth and Fine Gold worked quite well in dealing with them, especially when using a DD coil but then my other problem is the gold is often very small, tame the detector too much and miss the gold, so that's why I gave the Equinox a good run and it paid off that day with quite a few nuggets.  I've rarely been back to the spot since other than to test coils/detectors as it's just nasty ground due to the hot rocks.

As most of our gold is solid type chunky bits although very small, I'm not overly concerned about the GPX 5000 missing too much of it due to its detection holes, so it's worth giving a Concentric a try.    I also intend to use the GPX as a black sand beach detector so the 15" CC would be great for that, better than the Coiltek 11" AI coil I have been using for the task I think as I'll run it in Concentric (DD) mode to cut down the EMI.

I've kept a little collection of the worst types of hot rock that I struggle with the most, many of these the GPX 6000 can't get rid of at all using even difficult and the DD coil.   The only painful hotrock my little collection there is missing is the green schist type rock which is always a pain on every detector however it's usually large so easy to deal with, although can sound like a nice faint target when buried even if it is big.

Here are some of my most troublesome types of hot rock, the GPZ and GPX struggle with these to varying degrees but neither can eliminate them from what I've seen so far.

This one sparkles with silver looking flecks in it when you move it around in the sun.  I'm no rock expert so have no idea what any of them are.

A little video of how they behave on a very strong hard drive magnet, one the biggest one more feels like it pushes away from the magnet than being attracted to it.  The dark colour ones are very magnetic and hard to even get off the magnet, the brown ones are very frustrating as they give a soft gold like signal when buried and often fool me, with the 6000 they're really deceiving.

The GPX 4500 and 5000 are much better with all of them, eliminating a lot of them or at least needing the coil to be very close to them to be a problem, hence why I'm thinking this Concentric maybe the ticket if it gives me good sensitivity, good EMI handling for this high EMI spot where a mono can be annoying on the older GPX and cuts down on the hot rocks GPX 5000 style.

I'll soon know 🙂 Either way, it's going to make a killer beach coil.

[Gold Catcher]

The gpz/Zsearch in general/difficult is the only remedy for me when it comes to hot rocks. It is not perfect, but better than all I have tried. The difficult timings of the 6000 don't do anything for the hot rocks that I encounter. Difficult only seems to help somewhat for mineralization, but not anywhere close to the difficult timings of the gpz. Curious to know if the cc xcoils would make an improvement with the older gpx series. I would be willing to buy any detector with any coil configuration if it would outperform the gpz on hotrocks, without loosing much sensitivity.

GC

[lostmypassworddude]

If it does better then the 15" mono evolution on small to medium size nuggets at depth I can see paying more for an x coil for the older gpx 4500 and 5000. 

[Dutchman4]

The difficult timings of the 6000 don't do anything for the hot rocks that I encounter.

GC

Same here, no help on hot rocks of any kind that I have run into. 

[Gold Catcher]

6 hours ago, Dutchman4 said:

Same here, no help on hot rocks of any kind that I have run into. 

We are dealing with the same type of hot rocks (mostly volcanic). Here is a flavor of what I am talking about. Literally every rock screams like a beer can. There is alot of gold in this ground. But good luck getting it. These rocks go all the way deep. If the old gpx with the Xcoils can work here and outperform the gpz in general/difficult, I am in! BTW, despite all that I have recovered small nuggets that were stuck to these hot rocks with the GPZ. Just to show the power of the GPZ timings. The 6000 is totally useless here, doesn't matter the configuration.

 

 

 

 

 

 

 

 

 

[phrunt]

You really need to try an older GPX on this ground, especially with a DD coil, I think you would be pleasantly surprised.  Borrow or hire one or something, there has to be a way to try before you buy.  Someone may meet up with you with one.  If the concentric deals with it in DD mode while also controlling EMI and having some decent sensitivity I will be a very happy person.

These rock formations are quite weird, I don't know if lava caused them, but they're nasty to detect and smash up to try get targets out of them.  There is no soil there, it's all rock.

[Aureous]

44 minutes ago, phrunt said:

You really need to try an older GPX on this ground, especially with a DD coil, I think you would be pleasantly surprised.  Borrow or hire one or something, there has to be a way to try before you buy.  Someone may meet up with you with one.  If the concentric deals with it in DD mode while also controlling EMI and having some decent sensitivity I will be a very happy person

Its a very exciting development, pity its through X coils though.....great product but crazy pricing. If I had a decent ABS coil shell to work with, I could build a CC coil for about $150, costs only. Plenty of old ML DD coils floating around to deconstruct & obtain the transmit and receive coil specs from. When I had my 4500 (and earlier models) I built maybe 9 coils for it. Using old Hayes USA and Bulgarian shells. Also a pity that Detech only ever made big CC coils for the legacy ML machines....the size that X coils are developing (or slightly smaller) would be killer....