Missing Gold In " Difficult Ground Type" GPZ

[jasong]

I posted quite a bit here on this forum about Normal vs Difficult last year, made a vid to demonstrate it on an undug nugget too.

mn90403, if you have 3 GPZ's at hand do a quick test - 1 operator, 1 target and 3 different machines with the same settings, report back. Switch to manual if you are tracking targets out.

With very tiny targets it often comes down to coil placement - height and placement of the TX windings over the target makes a big difference for the tiny or deep faint stuff and can be the difference in hearing and not hearing something. 

 

[fredmason]

Mitchel;

next time have your associates take YOUR machine and use it...sometimes the machine is the problem not the user and no one will know because they have not used the machine in question...meanwhile, you use their machine...it would not take more than 30 minutes or so for them to see any inherent problems with your detector. Like my 3500 your GPZ may have incipient problems that will not easily reveal themselves.

Of course it could be you...oh the pain of self doubt...just teasing

fred

[DDancer]

This is my opinion, however there has been some recent reporting on it, that there is one more filter that should be taken into account outside of the Mode and Ground type settings.  Its the Auto/Manual Ground balance.

GB mode does affect response to small targets.  This can be pretty pronounced during recovery if you carry a lot of metal on you.  While the Zed is pretty darn good at not tracking out targets in Auto while well away from the coil; once I move into recovery small targets tend to kind of disappear much like mn90403 describes.  This is because, and I and my partner proved it to ourselves, the Zed starts taking into account the pick, my glasses, and anything else on our person *gps, radio, pack and whatever else* and starts to dull down due to the extra "metal" its seeing.  I had to move to a smaller pick and dropping my gear off in patches with smalls *had to keep my glasses* as a result.  My partner would just drop his pick and gear *and he really killed the tiny weeny fairy farts*.  During general hunting we both carried our picks high *I'd loop mine in my harness behind my shoulder*.

The disappearing effect in Auto goes away pretty quickly once we backed off from the coil and put picks outta reach when we felt the target was out of the hole.

Its not a flaw~ just the detector doing its job.  An old suggestion is to dedicate the user button to switch between Auto and Manual for use during recovery.  I found it works well.  Especially since I wear glasses with a metal frame though it does mean I have to keep my head still and use my arms with a scoop at length.  I've also recently read how others are using manual in mild ground conditions with success.  Thing is you have to dig on "iffy" stuff often.

[mn90403]

7 hours ago, fredmason said:

Mitchel;

next time have your associates take YOUR machine and use it...sometimes the machine is the problem not the user and no one will know because they have not used the machine in question...meanwhile, you use their machine...it would not take more than 30 minutes or so for them to see any inherent problems with your detector. Like my 3500 your GPZ may have incipient problems that will not easily reveal themselves.

Of course it could be you...oh the pain of self doubt...just teasing

fred

Fred,

My machine was used by another and he got it to hear a nugget he was working on but it was sizeable.  Later I did use his and while I didn't find anything I thought I noticed a quality difference in the audio of the threshold. (my headphones, his unit and remote).  The other 7000 user does not use a remote.  He wants to be hard-wired to the transmitter.  A better test should be conducted to let them use my detector longer. 

It is probably my error but the responses here have already made me feel better.

Mitchel

[Breakofday]

Purely from a part time prospectors perspective.You can own the most sofisticated rigg in the world, but "driver" and experience is where the rubber meets the road.

My dirt digging buddy gave up the 7 and went back to a 5 with immediate results.

I would be happy with a mod'd 2000 and the elite coil series, but you couldn't pass up the ping ability of a 2300 and inline amp.⛏

[mn90403]

I need to add something ... in the last year that I have had the 7000 I have found more total nuggets than I did with 4 years plus with my 5000.  My first year with the 5000 I didn't find any gold.

I've also found many iron and chondrite meteorites with the 7000 so I know it can find ... it just seemed like an odd circumstance I described above.  Maybe a latent bug that has crept into my software.  I reset it.

The 7000 is a keeper.  I just want it and me to be in sync.

Mitchel

[hawkeye]

DDancer, your above post re the "interference" you may get from the iron you are carrying makes sense.  I carry a pick (Hermit) that has a lot of metal.  I have to carry it high over my shoulder or in behind my back tucked through the harness or I can hear the detector (7000) reacting to the pick.  So I pose this question, would the pick and other metal be affecting the effective depth and performance of the detector even when you can't actually hear the interfence?  This thought ran through my mind a number of times while detecting after I heard my pick interfering with the detector and moved it away.  

Two years ago I found a small patch of sub 0.5 gram "nuggets" with my 2300.  Last year I rechecked and expanded the patch with the 7000.  I found no nuggets in the area I found with the 2300, and none deeper than 6" in the expanded area.  Also, none of the other "stray" sub grammers I found were deeper than 6".  As I mentioned earlier in the thread I expected to find these deeper with the 7000.  Maybe I can next season when taking into consideration this discussion on settings and other suggestions.  Thanks everyone.  

 

[DDancer]

Hawkeye,

As I said its my opinion but its one as I hold fact to myself that excess metal does affect the GB of the Zed and act as a filter with some limits to performance.  My partner and I both noted the effect in small target recovery.  When I switched from my big Walco to a smaller pick my small finds increased (bird shot being the "Gold" standard).  Recovery improved by switching to manual GB as well as getting metal away from the coil.   The Zed does see all that metal, and most likely treats it as a ground effect with the result that it dumbs itself down *or whatever those clever bits do* to adjust to the conditions it perceives.  This affect also applies to PI's with Auto GB and I proved that years ago with a hand full of nickels and some tape.  However the effect was not as extreme with PI's as with the ZVT.

I know what your experiencing with the big pick :)  I did the same thing by carrying it high however that never fully got it out of the Zeds "eye" and at my settings I could still hear it as a ground noise.  Smaller picks can be carried low however I've observed that even though the Zed will eventually tune the pick out it does know its there and it, the Zed, is going to dumb down.  So I carry the small pick high to.

It, Ground Balance, is a bit off topic to Ground modes however I feel it has a significant impact on all modes and settings and thought to bring it up.

As to the 2300 and the Zed.  Well, opinion, I can use the Zed like a 2300 but the 2300 will smoke the Zed on smalls.  Watched it for a fact on a small fairly condensed patch I found.  Pulled a couple of grams out and set my mate on it as repayment for helping me pop a bit out at 1 meter thru calcrete.  He came back with a happy 4 grams from all around my dig holes.  I feel it had more to do with the fact that the Zed has a honking big coil but in another location my mate pulled over a 100 bits where my partner and I pulled almost none.  Kinda apples and oranges but an interesting observation.  Man I'd love a smaller coil for the Zed.

[PhaseTech]

Yes all the usual precautions of keeping metal away from the coil hold true, you just have to be a bit more vigilant on the Zed. I keep my keys in my left pocket or water bottle pouch, and my speaker on my left shoulder. I also tend to take advantage of the WM12 and walk around the front of the coil. This way my body is a lot further away from the coils search field. Flat wide scoops are a must. 

In response to comparing Normal and Difficult, it isn't as simple as detecting away, get a signal in Normal and switch into Difficult to compare. What about all your other settings? I find that all your audio settings can be drastically different as well as your Gold mode.

E.g. during GPZ training, I go through all the options, and then on the trainees machine we go through the process of setting it up for the conditions. I do this for Difficult and then Normal ground types and then compare the end result on test targets that we buried at the start in factory settings. The end result settings vary a little between courses, possibly due to changing EMI levels, soil moisture and different ground conditions (don't always do the training in the exact same spot). On the last course our two final settings combos were: 

In Difficult ground type: General, Sens - 17, Smoothing - High, Target Volume 13, Threshold 27 

In Normal ground type: High Yield, Sens - 6, Smoothing - Low, Target Volume 12, Threshold 26 

Both these combos gave an equal response on my 0.3g test piece, with maybe the Normal combo giving a broader response, and less sweep speed dependent, i.e. this would be the better combo for patch hunting. The Difficult combo had a better Signal:Noise ratio, i.e. the signal was slightly less positive but the detector was generally running smoother, so the signal stood out better. However, it required a slow steady sweep, mainly due to High Smoothing, so this would be the better combo for slowly gridding a known productive area. 

The GPZ definitely needs Modes, where I can bundle all these setting combos into Mode A, B C and THEN you can switch between them a lot faster, and the comparative results would be a lot more accurate. Think of the GPX series search mode switch, but I'd want to add Timings into them. The "timings" in this instance would be the Gold Mode and Ground Type options. Minelab....are you reading this? C'mon P.B. I know how much you like Modes