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Better Understanding GPZ 7000 Zero Voltage Transmission ( ZVT )


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5 hours ago, Jonathan Porter said:

Now that you've worked out the GPZ 19 coil makes less ground noise and less X signal therefore targets greater than 2 grams will actually be more obvious with the larger coil, you will then start to realise that an air test is just plain silly because like I just said it's the ground signal or lack thereof that is providing the performance gain over the smaller coil.

JP,

Does this mean that the more mild the ground is the less performance gain we can expect out of the 19" coil relative to the 14" coil then?

Since quiet ground has less saturable component, some of it like in some places up north in the US has almost no saturable component and is just mostly clay (some even completely lacks gravel completely but still has gold), it's really not much different from air. Unless it has a conductive component, in which case the bigger coil will suffer as already noted upon release.

It seemed like the results Gold Hound just got showed it actually excelled well over the 14" coil in mild soil running in normal and high gain, did you have a chance to look at his post?

*edit: another question: With ZVT can we still expect performance gains relative to the size increase/decrease of coils as we have with PI? Like, mineralization amounts aside, can we still expect a larger coil to have some scalable kind of increase in depth independent of the ground we use them in, and can we expect a smaller coil to have a similarly scalable increase in sensitivity to smaller stuff? Or is it really entirely dependent on ground as you stated?

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Many Thanks JP, the 19" is a diff beast than the 14" for me. With the 14" I just walked onto gold, (just thought I was a legend.....) no drama but the 19" is taking more to get myself up to speed. I think I`ve caused this by having my volume up to even 16, worked with the 14" but not with the 19". I can see I`ve gotta retrain myself and get a better understanding of ZVT and importantly listen to the young fella........

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14 minutes ago, jasong said:

JP,

Does this mean that the more mild the ground is the less performance gain we can expect out of the 19" coil then?

Since quiet ground has less saturable component, some of it like in some places up north in the US has almost no saturable component and is just mostly clay (some even completely lacks gravel completely but still has gold), it's really not much different from air. Unless it has a conductive component, in which case the bigger coil will suffer as already noted upon release.

It seemed like the results Gold Hound just got showed it actually excelled well over the 14" coil in mild soil running in normal and high gain, did you have a chance to look at his post?

*edit: another question: With ZVT can we still expect performance gains relative to the size increase/decrease of coils as we have with PI? Like, mineralization amounts aside, can we still expect a larger coil to have some scalable kind of increase in depth independent of the ground we use them in, and can we expect a smaller coil to have a similarly scalable increase in sensitivity to smaller stuff? Or is it really entirely dependent on ground as you stated?

The GPZ REALLY shows its potential in quiet ground, that's were it has the most performance hence Goldhounds results. The larger the coil the less the ground signal and the greater the depth as targets increase in size. High Yield Normal is the Go-To mode for Quiet ground.

JP

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Are you able to clarify just a bit more? It seems like you are saying it shines in both high and low mineralized ground then.

I'm assuming it's for different reasons? The high-min performance from the increase ground immunity and the low-min performance from the raw increase in coil size? Am I understanding that more or less correctly?

If so, I'm still having a hard time understanding why air comparisons are coming up short, that's the lowest mineralization environment we can have. Is it because the air tests were done in the air, but with the coil resting on high mineralization ground?

 

 

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Jonathan 

  Thank you for much needed information; it provides a lot to work with the next time out with the GPZ 14 coil.  I am eager to receive the GPZ 19 coil which is on order. 

A few questions:

  Is it the larger area of the 19” coil allowing it to obtain a better average measurement of the soil and mineralization to allow it to run smoother? Then does this smoothed average provide a better reference for comparison to provide a better target signal to ground noise ratio?

  In reference to; “correct range of coil motion in relation to the depth of the target”.  Does this mean use wide coil swings for deep wide target responses and shorter coil swings for sharp narrow target responses?

   You use a B&Z booster with twin speakers.  Is the B&Z booster just a better quality amplifier are is there some kind of signal altering occurring within it?  Likewise is there something special with the twin speakers?

Thank you for your assistance and have a good day,
Chet
 

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HI JP 

Maybe now might be a great time for you to do the "Secrets of the GPZ" video :wink:

From what you have said here today has shown us all that there is still so much to learn with the Z and now with the new coil to boot 

just a thought 

Marty

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54 minutes ago, Chet said:

Jonathan 

  Thank you for much needed information; it provides a lot to work with the next time out with the GPZ 14 coil.  I am eager to receive the GPZ 19 coil which is on order. 

A few questions:

  Is it the larger area of the 19” coil allowing it to obtain a better average measurement of the soil and mineralization to allow it to run smoother? Then does this smoothed average provide a better reference for comparison to provide a better target signal to ground noise ratio?

  In reference to; “correct range of coil motion in relation to the depth of the target”.  Does this mean use wide coil swings for deep wide target responses and shorter coil swings for sharp narrow target responses?

   You use a B&Z booster with twin speakers.  Is the B&Z booster just a better quality amplifier are is there some kind of signal altering occurring within it?  Likewise is there something special with the twin speakers?

Thank you for your assistance and have a good day,
Chet
 

Hi Chet, the B&Z booster just does a very good job of amplifying the audio without distortion. Larger coils run quieter because they have less windings so are therefore less sensitive to smaller targets. The advantage is the lower sensitivity also allows deep faint targets to stand out more from the reduced grounds signal. The sweep distance is determined by target size and depth, its usually a case of experimentation for each target to get the sweet spot of the coil right over the target zone.

JP

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On ‎11‎/‎25‎/‎2016 at 2:54 AM, Norvic said:

Reading through your posting, one thing has stood out your threshold settings are in the range I use,  or close to I vary between about 0-15 (audio smoothing off, varying sensitivity) most are using threshold settings in the 20`s which with audio smoothing off is way too high for me. I cannot understand how one would pick up those slight changes with such a high threshold. Works for me and obviously works for you. My volumes in the same range, is it a variance that our machines have?

Norvic,

I really don't know if its a variance of machine~ mine is a pre-production one, machine set up~ I use the stock headphones~ or our native hearing.  Then there is the good old comfort zone.  Higher thresholds do cut back signal recognition for me as well.  Note that JP refers to the ground stutter he recognizes with his set ups~ for me with smoothing on and lower thresholds I hear similar patterns.  With smoothing off its just more recognizable but harder for me to process as the noise environment increases dramatically.

11 hours ago, Jonathan Porter said:

If you are running the Volume above 8 it is akin to increasing the Sensitivity by 2 for every point you go up, so adjust your volume via another way if the threshold at 27 is too faint. You need to maintain as much volume variation between threshold and maximum volume to hear the full gamut of audio information from the detector.

JP points out the interaction between three of the 4 settings I mess with most but does not address Volume Limit.  While he is speaking of the 19 inch coil similar methodology appears to be being used for increases in target recognition I feel that occurs regardless of the coil size.  ZVT is reading a window of noise where sensitivity falls behind volume and threshold limits that improve target recognition.

Thanks JP and sorry if you or anyone else feels I'm taking you out of context.

Vanursepaul,

I'll be interested to know if your tweaking improves things for you :)

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DDancer, Further "playing" with volume, has eliminated  what I thought might be machine variance. The 19" may have illustrated a folly in the way I have used the 14", but that is easy to prove or disprove by simply going over the old ground with the 14" again with the conservative settings.

I do know that during the first few months of using the 14", I used the default settings and did well, when scanning some of those areas again with higher volume, lower threshold and no audio smoothing I only picked up small sub grammers, that would have probably been picked up with the default settings had I simply slowed down. But at this stage it does appear the 19" requires those conservative settings, even HY as JP points out is giving better recognition of deep targets than I found general did on the 14".

Basically we are just going where JP has been, but this also points out the Z certainly is a amazing machine and so much is reliant on our individual hearing as Dale of the GHs has spoken of and illustrated. That individuals hearing ability was also so for the VLFs and the PIs, no doubt ones hearing deteriorates with age which just adds to the mix. Exciting times as always.

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