Gold Catcher

1 hour ago, Rob Allison said:

I normally always run High Yield & Normal Soil.  I run my Sensitivity from 10-14, normally no higher, but keep Auto Smoothing OFF.

Thanks, Rob, my to-go settings as well unless the grounds require otherwise (like described above). I wonder if you would have picked it up with the 6000.

GC 

1 hour ago, Rob Allison said:

We were metal detecting with the Minelab GPZ 7000'

Congrats, Rob! What an awesome find. What settings are you usually using for the grounds where you hunt? I more and more use the GPZ in general/difficult (with NF12 coil) and I have to say I really like these settings, in particular for the hot rock infested grounds that I usually encounter. It even works for the notoriously difficult ultramafic serpentine schist (Motherlode), with reasonably good remaining sensitivity for shallow gold as well. No other detector works in this particular ground btw, including the 6000 which is completely useless doesn't matter what settings. The 6000 just keeps howling even at lowest gain when the coil moves over the schist due to complete saturation and overload (14DD makes no difference neither with EMI nor with salt cancel mode). In contrast, the GPZ in general/diff runs completely smooth, even when run with gain 15 and smoothing off. Just curious what your to-go settings are for the 7000 in AZ. I know you guys can have some really nasty hot ground too.

Best,

GC

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

8 hours ago, phrunt said:

I think in many places to enjoy gold hunting you've got to expect you may not make a profit and you do it for the fun of it and the thrill of the finds, Australia in some areas is likely the main exception to that rule

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

6 hours ago, phrunt said:

Nenad put up a video using the 12x7"

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.

Just now, Norvic said:

compensate us users by ditching those chips. 

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 

8 minutes ago, Norvic said:

Note my 6Ks 11" is getting a wee bump sensitive, a glued on PC skid plate seemed to stop it for a month or so but looks like my early lottery win has timed out.

Oh no.....

1 hour ago, Norvic said:

Actually not hard to do GC, hack saw, PVC pipe and ends from hardware store, the SDC CB is very easy to remove and fix, is rugged as, no soldering or alterations to stop one putting back into original case, batteries are just RC LiPo readily available. Another advantage is more stable threshold, I believe the voltage supplied is much more stable and does not depend on the tolerance of the voltage regulator to regulate, not because of lithium batteries used but because there is no longer spring loaded battery connections.

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

1 hour ago, Norvic said:

Being a mad SH Engineer as all are helped

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

2 hours ago, Norvic said:

If you want a lightweight, ergonomic, lithium powered super modded SDC23000 (probably unique as could be only one in existence)

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

4 hours ago, jrbeatty said:

Yep, Don't do it, far too risky-  🙂

I didn't say I wouldn't do it. 🙂  It's just that you would be on your own warranty wise, and for some people with existing warranties (not me) this is something to keep in mind when cutting the cable. Personally, I would most certainly consider it if I would live in Australia. The 22CC pics you show should convince anyone! Here in the US this might be less of a pressing need and I am doing just fine with my GPZ/NF12 - 6000 combo pack.

GC

4 hours ago, Rob Allison said:

Is there anymore, including X-coils Manufacture that are now including the adapter or have someone that makes them that can guarantee the adapter or warranty on the GPZ 7000?"

"does not cover damage caused by accident, misuse, negligent act or omission, fair wear and tear, 
alteration, modifications or unauthorised service by the Purchaser or any other party"

There is your answer, Rob. You will be on your own.

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

35 minutes ago, Chet said:

GPZ 7000 ZVT

The GPZ 7000 Zero Voltage Transmission (ZVT) technology provides a stable processing period throughout the entire receive period. It also provides a stable magnetic field that reduces the amount of undesirable soil that is detected. This along with better signal processing provides improved detection of small nuggets and larger deeper nuggets. 

Bipolar (positive and negative) pulses can be generated in standard Pulse Induction detectors. But between pulses the transmit energy starts at zero voltage and builds until it peaks and discharges energy then it must start at zero again in the opposite polarity. This creates current and voltage variations on the power wiring that can adversely affect the receiver and processing circuits. Thus is not as stable as the GPZ 7000.

In the attached oscilloscope GPZ 7000 Transmit Waveform displays; the zero volt level is across the vertical center of the display.  Both the positive and negative excursions of the waveform pass up and down through the zero voltage level rapidly. 

In a standard Pulse Induction detector the waveform would stop at zero volts for a short period while the receiver timings and processing completed then start recharging the transmit coil for the next cycle.

In the GPZ 7000 the receiver coil timings and signal processing does not require the transmit function to return to zero volts to recharge for a new transmit cycle. 

In the time stretched displays; the squidgy somewhat sine shaped forms at the top and bottom is time periods where the receiver timings and signal processing can be applied to the receiver coil signals to determine if a target is present.

Note; only the Transmit waveform is shown in these displays. The receiver displays are a distorted mess of EMI and ground noise. That is where good engineers really excel in signal processing to extract target information that best fits the Time Constant curves that are displayed in a previous posting.

In my opinion reference to the Bipolar power and high voltage pulse with coinciding receive operation as being similar to a VLF detector is not false but somewhat of a stretch. But maybe a good sales pitch.

Have a good day,
Chet

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

1 hour ago, phrunt said:

I couldn't survive if I was doing what they did.

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   

8 hours ago, Norvic said:

Early in the 80s too JR. Below is another reason the 6000 is King to this old fart, you need lightweight, compact gear to get into the billy goat country I prospect, you make tracks every Tom, Dick & Harry will follow, tis shanks`s pony all the way. Come on Phrunt forget choppers the old fellas didnt have them, get out of your comfort zone and live butterfly. 😉

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

10 minutes ago, PhaseTech said:

I still love the GPZ, its performance, ground balance, audio, robustness etc etc. 

Could not agree more! Just the weight sucks. 

1 minute ago, jasong said:

Not sure where that quoted paragraph came from

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."

4 hours ago, jasong said:

If they want to have any hope of keeping a good market in the US then they need their good prospecting machines at $2500 or under and they need to start putting them in the hands of younger people that will go out and use them daily and post about it. Otherwise I think the US gold-specific detector market is probably on a long, slow road to eventual death by attrition even if there were more nuggets here to find.

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

18 minutes ago, jrbeatty said:

Hi GC:

It certainly does. Bear in mind that those settings are applicable for the 22"CC. I have no idea how they would work with other coils.

Volume setting about half way but also bear in mind I use a Sennheiser RS160 cordless headphone system (with two separate volume controls in addition to the Z internal volume control) and run with the built in "Z" WM12 transmitter turned off.

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