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New Minelab Manticore


Sheppo

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2 hours ago, steveg said:

I'm still fuzzy about how, with a continuous transmission, a VLF-IB unit can still get some sense of decay/hysteresis -- i.e. how it can extract that information from in-ground targets since you have continuous transmisson occurring, and therefore -- I'd think -- continuous maintenance of induced current in the target, and thus no "decay" of the eddy currents over time, allowed to occur. 

First of all, I don't think its possible to get rid of the fuzziness, Steve.  Many degreed engineers don't find this stuff intuitive.  Electromagnetic Theory and time domain-to-frequency domain conversions were advanced weeding out courses/topics where I went to school :smile:  Anyway, Pimento explained the FBS specifics, but even under any conitinuous wave situation where you are utilizing the induction balance principle, if you transiently change the parameters of the CW waveform (amplitude (including temporarily driving it zero), frequency) you will induce a transient response in the target that can be measured and this information can be used by the detector signal processing to infer more about the characteristics of the target. 

 

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13 minutes ago, Daniel Tn said:

I've swung the GPX with DeTech 15" coil for 10 hrs a day, for a whole week.

Yes a CTX is less heavy than a GPX with a trashcan lid coil, no doubt.  And a GPX is lighter than an ATX.  And I've swung both for a week at a time in Culpeper and elsewhere. Which is why I am now considering an Axiom.  Again, there should be no need to sacrifice performance for weight or vice versa now that we have the likes of the GPX 6000, Axiom, and even the Deus 2.  So if the M-core can bring with it CTX-like performance or at least some of the now-few advantages that CTX brings to the table in a lighter package, not sure why people are discounting that feature.  But I get that it isn't necessarily something that is a priority over performance.  But if we are going to have to put some serious coin down for a modern detector, I see no reason for it to be heavier than it needs to be.

And there are more to ergonomics than just weight.  As pointed out previously, the CTX is a well balanced (though heavy) detector.  If ML doesn't get balance right (like they didn't on Equinox) then that negates a lot of the weight advantage.

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Very interesting discussion, I'm enjoying reading.

For the comments regarding weight vs. performance (CTX vs. Manticore), 99% of the time I hunt parks in mild Midwestern US ground for 3-4 hour stretches. People around me hate the CTX because of the weight and they think it's old tech. But there is a layer of deep coins here reserved for the CTX and 17x13" coil combo that people can't seem to touch with the Equinox/Etrac/Deus. For this very specific application, the CTX seems to still be without a peer, and the weight is nothing compared to the difference in finds. I'll be interested to see how the Manticore stacks up.

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5 hours ago, deathray said:

Mark Dayton and Ron Swenson would disagree. Both use ctx, and all our sites are loaded with iron. Now Ron did switch to Deus, but not Mark...even though he has a D1 and D2. 

I stand corrected, you're right they do, but I'd say they're more the exception then the norm.  I know they're hard core hunters,  I used to hunt with Mark when we lived in the east bay.  Most folks I hunt with or run into relic hunting the desert sites and other early relic sites (admittedly not GR sites) are Equinox, Deus, Nokta/Makro of some sort, even the occasional White's whatever, but rarely a CTX 🙂   There's still holdouts on the Explorer's too, you know who you are @TomCA 🙂

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16 hours ago, Steve Herschbach said:

Does the fact the sampling takes place when there is no reactive signal, preclude the possibility of discrimination in the GPZ based designs? In your opinion only Carl. Hard to know what the wizards down under are up to.

Yes, to a large degree. With GPX models you can use a balanced DD coil and look at the target response during the TX pulse where there is a reactive signal and do some iron discrimination. The TX transition in the GPZ is very fast and therefore creates a very large signal even in an IB coil so it's tough to look into that event and see the reactive signal. But not saying it can't be done.

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4 hours ago, steveg said:

OK -- so, then, since BOTH VLF and PI units CAN, if engineered to do so, use "processing in the time domain" to extract information, then is it correct to say that when this is being discussed and it is said that there cannot be a PI/VLF-IB "hybrid," or that a VLF does NOT use "PI" methods, what is REALLY the differentiator is that VLF constantly transmits, whereas a PI transmits, followed by a period of nothing, and then receives, and then another transmit?  In other words, the "differentiator" is continuous transmission coming from the coil, versus sequential/periodic transmission coming from the coil?

I'm still fuzzy about how, with a continuous transmission, a VLF-IB unit can still get some sense of decay/hysteresis -- i.e. how it can extract that information from in-ground targets since you have continuous transmisson occurring, and therefore -- I'd think -- continuous maintenance of induced current in the target, and thus no "decay" of the eddy currents over time, allowed to occur.  It seems that the explanation lies, Carl, in your "ramped exponential decays vs. sinusoids" statement, but this starts to become where my lack of enough EE knowledge becomes my enemy.  I think I understand that VLF-IB uses phase shifts/changes of the EM waves being transmitted.  But the "ramped exponential decays" part puzzles me, as I don't know how there can BE a "decay" if there is no "break" in the transmit EMI, and thus presumably no opportunity for "decay" in a target's EM field to occur.

With PI the induced eddy currents spike and then decay back to zero. All MF designs induce eddy currents that exponentially rise to some value before being driven in the opposite direction, also exponentially. In both case you can use time-domain sampling to look at the exponentials, and the exponential time constant is directly related to target phase. With SMF it is easier to use channel bandpass filters to separate the frequencies into respective sinusoids and use freq domain analysis. You can't do this with sequential MF (FBS) so it is left in the time domain.

IMO, yes, the differentiator is that PI looks at the RX signal during a TX dead zone. The TX current could be a sawtooth (traditional PI), a square wave (GPZ), or a half-sine (Barringer). But you can have a hybrid VLF/PI. GPX leans slightly this way when using a DD coil to look at the active TX region for iron ID. At White's I built a half-sine detector where a true VLF-like phase angle was extracted during the half-sine pulse and a PI response was extracted during the dead time.

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I guess in the end it’s all about setting how a person wants to define things. With the technology in flux, new definitions and ways of thinking about things, are the order of the day. If you want to define certain things as hybrid, then hybrid it is. The problem is see with going down that road is people equate that with meaning a detector with the full depth of a GPX 5000 with 18” mono coil, plus the discrimination of the best VLF. It’s a breeding ground for marketing BS, where people read more into the buzz words, than paying attention to reality in the field. You can bet everything is going to labeled as new whiz bang hybrid technology in the next few years. I’m just the old curmudgeon who is going to figure I’m going to be running what I call a PI for max depth, or a IB for max discrimination. I’m not going to hold my breath, or fall for anyone promising both in one detector, no matter what it’s called. Tarsacci was the best example of this. Hype galore about being a hybrid, disc to PI depths.  Sorry, not even close.

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7 hours ago, Chase Goldman said:

Simon - Beside that sentence being logically contradictory, curious as to what's the typical uninterrupted duration of a detecting session when you are using the CTX and how far from your vehicle do you typically have to travel to get there? 

I know you hit some pretty rugged sites nugget hunting, but if you are just silver slaying in a park or ball fields with the CTX, I get why weight would be down on the list.  Hiking a couple miles into a site for 8 to 10 hours relic hunting or hours of wet sand/wash beach hunting and walking 2 to 5 miles at a clip and weight goes way up on my list. I ran 1200 miles last year at 60+ years old, so they aren't exactly pushing me around in a wheelchair yet, but a 5+ lb detector is NOT what I'm interested in swinging these days regardless of performance when tech, ergonomics, and modern materials can easily be integrated to get the weight out.  Why should I demand any less regardless of my physical condition?

I guess what I was trying to say is if two detectors are sitting in my car all charged up ready to roll the one I'd pick up is the one with the best performance regardless of weight.  This is why I tend to favour the GPZ over the GPX 6000 even though it's heavier, I guess significantly heavier too but I just know I find it better to use.  But you're also right, for the long hike locations or if I'm biking into somewhere the GPZ in a backpack can be a real pain as it doesn't really fit so that's what attracted me to a smaller lighter detector like the 6000 that shrinks down.   I've been put off the super light detector idea from the GPX 6000, the cutting off weight seems to have gone too far making it flimsy and it just feels cheap although it's anything but cheap.

If I was at the shop buying a detector if one was heavier but had slightly better performance than the lighter model I'd buy the heavier model without question as weight isn't a top priority, I pick performance, features, how it feels on my arm, coils available etc long before doing weight comparisons.

When it comes to nugget hunting I mostly always use the GPZ, the heaviest of the bunch I believe and it often involves some sort of hike sometimes a very long one but I do detect from first thing in the morning when I arrive usually until it's getting dark, or I have to start my hike out so it's not too dark when I get back to the car, sometimes that hasn't worked and going back down in the dark has been necessary 😛 I say going back down as it's usually in a mountain type setting.

You're right with the CTX coin situation though it's usually a half day or rarely a full day with no hike involved, that's just how coin detecting is for me so that makes having a super light coin detector even less necessary.

I also agree it's great manufacturers are striving for lighter detectors and I like that as who wouldn't want a lighter detector, as long as you don't sacrifice build quality doing so which seems to be the case with the 6000 with the 7000 (CTX housing) being much better build quality from the coils to the rest of the unit.

The Mandible looks like it's good quality, very good in fact, and it's weight is fine.  If a new CTX comes out one day and it's in the same housing as the current CTX with the weight to go with that I won't complain as I like that housing design and find it very nice on the arm.

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Tarsacci is the deepest detector I have ever worked in iron. Beats other SMFs. Even a Deus II with reactivity set to 0 in Relic is shallower. It's a good alternative at this price. Comparing to Whites TDI it is similar. Tarsacci gives more information, the fact of discrimination is not perfect, but it can be distinguished whether it is high conductor or iron. I did not deal with the GPX, but it is a different price range. There is also Nexus MP in IB technology.

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