Gold Catcher

An interesting aspect of alluvial fans is the often observed "reverse grading". This means that the heavier rocks (and gold) can often be found on the surface of the debris flow, not at the bottom like in water-only flows, such as rivers. This has to do with the density and strength of the flow material (matrix) which creates pressure gradients by which larger (and heavier) material are moved upwards, not downwards. This is why you don't have to look for bedrock in alluvial fans (good luck...), instead the heavy materials (including coarse gold) can be on the surface and within detector reach.🤠🤑 GC "Reverse grading often forms due to sieving and density differentials during transport, which forces large clasts to the top" https://sites.google.com/site/wvugeol616advancedsed/home/alluvial-fans https://en.wikipedia.org/wiki/Graded_bedding

That's why I haven't thus far come across a "professional" detectorist here in the US who is not living full time in a tent.....unless of course you have some sort of other income, like being a detector dealer. GC

Thanks for posting. Looks like he run with 4 clicks gain. Although the button was rather large 18 inch of depth with 4 clicks is still pretty good. That combined with the higher stability and the elliptical shape makes this coil a really interesting option, also because you can get it better in deeper holes. I wonder if NF coils generally are quieter. The NF-Zsearch is also much more stable than the 14 stock. GC

I really think the global supply chain crunch, due to Covid and other related factors, is to blame. All sectors are impacted, just look at the car industry. The question is just to what extend companies, especially those with high reputation, are willing to take a gamble and risk their good name by implementing lower end backup strategies.

Fair deal!!😁

If technical issues with the 6k would indeed be a systemic and wide spread problem (note the word if) then I don't see how they could possibly release any more detector models anytime soon. Obviously, some major issues in quality control and manufacturing would need to be addressed first. Mine has no issue thus far however, but I surely acknowledge all the problems reported here. This brings back the king question to my mind.... GC

Oh no.....

Thanks, Norvic. You amaze me. And you really want to get rid of it? I always get so attached to my good old detectors with all the memories I have with them. And in your case, this would be especially emotional to part from such a beauty 🙂 GC

Very cool! I would keep it! ML should learn from you. I have hopes for a more modern SDC coming out sometime in the near future GC

Super modded lightweight SDC? mmmmm...this sounds interesting. How did you manage? The regular SDC is so clunky. But yeah, the MPF timings can come in really handy. You guys are so blessed with your mild soils over there! I have grounds here where the SDC is the only detector that is working on shallow fast gold. GC

And there is of course the easy way: if you can scrape the target off with your boots don't even bother. Simple but effective in many grounds. Relieves about 50% of the frustration. GC

The alternative would be to change the detector settings such that surface targets become less visible, and dig all the rest. Like an inverse 6000 so to speak. This would probably increase the gold/trash ratio quite significantly for areas that have a lot of surface trash (which doesn't). The settings that JR described for the 7000 seem to fit that purpose. GC

Thanks, Chet. This is the most comprehensive and best description I have seen on ZVT. I will have a few dozen reads of it to try to fully understand it 😆🙃 GC

I often think the same. Amazing what the old-timers have accomplished without any advanced machinery and in often brutal conditions. Whenever I see those hand stacked large boulder piles along the river canyons in gold country I feel embarrassed when complaining about the weight of the 7000....But I wonder if they were just in general more enduring people with more physical strength, and most of all with more will-power and determination. GC

Nice set up, Norvic! I thought of doing something similar but I am worried that if I take a dive during hiking the detector might get a brutal beating. Where I hike at times dives are not uncommon 🤪 GC

Could not agree more! Just the weight sucks.

chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.minelab.com/__files/f/254716/KBA%2024-1%20Basics%20of%20the%20GPZ%207000%20Technology%20Zero%20Voltage%20Transmission%20(ZVT).pdf Sorry, long URL....

"A more complete definition actually would be Zero Reactive Voltage Transmission. The transmit coil Reactive Voltage refers to voltage associated with the transmit coil winding that is proportional to changes in the transmitted magnetic field. Signals detected directly from the transmit coil are given the same name ‘reactive‘ because they are directly proportional to the transmit coil reactive voltage. The ZVT transmitted field is designed to be as constant (unchanging) as possible during the receive periods; this means that the transmit coil’s reactive voltage must be zero during these constant field periods, and thus too is a receive signal directly from the transmit coil’s field. Hence Zero Reactive Voltage Transmission (ZVT) refers to this ultra‑stable transmitted magnetic field period during which receiving occurs."

That would certainly be a good strategy. The question is just how good a detector really could be at this price range and whether it would truly be competitive in the gold fields. It is already so hard to find decent gold here in the US, despite using rather expensive high tech machines and despite having many years of experience. So, I am not sure if a lower end tech package in the hands of mostly less experienced operators, who quickly want to find gold, would pay off. Now, for coin and relic hunting this is a different story and lower-end detectors are certainly available in good variety. But for gold prospecting in particular we need high tech improvements that will (unfortunately) have their price. And we also need those Gerrys, Robs and JPs of this world who provide field training to make this investment worthwhile (and to really give newcomers a chance to actually find gold!). I totally understand why many dealers make such a strong sales pitch for the 6000, because it will produce gold quicker for the newcomer (hence positive feedback) than the 7000 which is much harder to learn. This will result in much better sale figures which of course is in every dealers interest. But technology wise ZVT has a bright future (perhaps the brightest?), the question is just at what price. As stated before, competition would really come in handy for better pricing/product quality. So, perhaps this could make the entire gold detecting market look more promising. However, I suspect the GPZ successor will more likely be a GPZ 12000 than a GPZ 8000 (let alone a GPZ 2500......).😔 GC

Beautiful pictures! Does the snow ever melt? GC

Many thanks, JR. Yes these settings are probably ideal when using a big CC coil. I don't have access to these coils, so I will try this with the regular DOD including the smaller NF-Zsearch. Far away from ideal (due to much smaller size and DOD configuration), but I am curious to see what difference it might make, regardless. Thanks again! GC

Very interesting, JR. I have not tried "Bogene's type" settings with Xtra Deep. What volume setting did you use (not threshold volume)? Does that really eliminate most small surface targets? Thanks, and awesome finds! GC

Conventional PIs receive in off time, the GPZ does'nt. Conventional PIs transmit with voltage, the GPZ does'nt. To me this is a very different duck. 😁 But hey, it really does'nt matter how you call it and we are probably all right, nobody is wrong. Let's just call it an awesome machine, and with a modern design and some tweaks this should be the next king (in it's own kingdom). 👍 GC

Hey Lunk, finally tried the 6k/14DD in hot rock infested grounds (volcanic tuff). It is indeed an improvement over the 11 inch coil, however, not as much as I thought (perhaps 10% better overall). However, after some experimentation I found that the 7000 in general/ difficult gives a vast improvement, 80% or better. Neither HY/ normal (worse than the 6k), HY/difficult nor general/normal worked. Only general/ difficult. I can highly recommend these settings for everyone struggeling with hot rocks and it allowed smooth detecting in the worst hot rock conditions that I have ever encountered. Despite the tamed down machine I managed to recover a few small pickers in the 0.1 g range (not worthwile showing). This is a good example of how the 7000 with its settings can save the day. Here my exact settings: NF-Zsearch, general/difficult, sens 11, smoothing off, gb semi auto, other settings are default. GC

Good discussion guys. I think there is big difference in what "pulse" means for both PI and ZVT. For regular PI machines there is an "off time" for receiving (hence the word pulse) whereas for ZVT the term "pulse" refers to just switching the pole of the magnetic field while continuously transmitting (no off-time). Hence, in my view the 7000 is not a PI machine in it's conventional definition and should not be called as such. In contrast, the 6000 is still a "conventional" PI (with off times in between pulses for receiving), so the same advantages (or shall I say differences) that ZVT has over PI will remain in effect when comparing the 7000 with the 6000. This is the reason why I don't think the king trophy discussion makes much sense, both detectors are really so different. Now, when it comes to all the other stuff (weight, ergonomics, coil variety, easiness of use for beginners, etc.) then you can call the 6000 a king. You can also call it king (or god...!) if your primary focus is super fast timing gold in shallow to medium depth ground. However, the ZVT technology will always have distinct advantages that will not be reached by any conventional PI machine and the 7000 could equally be called king, just in a different kingdom. Even with a newer GPZ version released the differences between PI and ZVT will remain fundamental, hence the 6000 will likely remain king in it's kingdom, even after the "GPZ 8000" has been released. In summary, ZVT is not an old obsolete technology and calling it outdated is simply not accurate (IMHO). Just my 2 ct. GC