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Jonathan Porter

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Jonathan Porter last won the day on July 8 2019

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About Jonathan Porter

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  • Location:
    Clermont, QLD, Australia
  • Gear Used:
    GPZ 7000, SDC 2300, GM 1000, EQX800

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  1. A few salient points based on logic and please this is not a flame post before anyone gets all bent out of shape. Firstly there are major differences between Monoloop coils and DOD coils, monos are way more sensitive to variations in ground signal, salt signal and saturation signal however in the case of the SDC the narrow band width timings it uses are specifically designed to provide max sensitivity to shallow fast time constant nuggets but at the cost of overall depth, the narrow timings design is why the SDC does so well in salty, highly variable ground types. On a direct comparison in Fine Gold on an in-situ 1/2 gram nugget at 9 inches in noisy variable ground the GPX 5000 walked all over the SDC for strength of target signal (SDC wouldn’t respond until 4 inches of packed soil was excavated), whereas on tiny little surface nuggets especially in noisy ground the SDC reigns supreme. Secondly the 8” coil on the SDC also helps it immensely in salty ground, the smaller the coil the better it works in a salty environment, a small coil also helps with EMI but as has been noted the SDC is still pretty twitchy around EMI sources. For GPZ there is a strong correlation between different coils and control box combinations, so if you swap coils and control boxes the GB and X balance will be quite a bit different from one unit to the next, however once calibrations are performed there is very little difference between units. This means that not all electronics are exactly the same nor are all coils the same, however the controlling software that drives them is assuming the coil being attached is within reasonable range of tolerances required. Not being able to correctly calibrate any of these factors is not good in my opinion. A lot of the discussions around coils for the GPZ is mainly based on size configurations, obviously a smaller coil is going to result in less EMI, less Salt signal and more sensitivity, these reductions will aid somewhat in other areas of concern with regards to X balance and explains the users who’s results reflect environments that are conducive to not needing to calibrate. My feeling is operators should look on these options as being like the old days of Normal timings on the GP series when the Smooth class of “ground noise and hot rock ignoring“ timings became available. In those days noisy ground required the use of a DD coil, quieter more homogeneous soils allowed the use of Monoloop coils, those of us who had access to quieter ground types could enjoy the benefits of what a monoloop had to offer or developed skills to be able to listen through the ground clutter for the deeper penetration abilities of a monoloop.
  2. I work under similar power lines like those being shown all the time with the GPZ14 coil, thats were the GPZ is a major improvement over previous GPX machines. I can even turn the GPZ on in our shop and detect a 0.05 gram piece during assembly and training with our customers, the key is to keep the coil as flat as possible relative to the EMI source. High Yield is less susceptible to EMI than General and Xtra Deep.
  3. Lead pellets generally will give a clean high-low non-ferrous single signal just like gold when first hit, the way to differentiate them is when you scrape off the surface layer their signal will invert more readily (before the coil gets close to the target) whereas gold targets usually won’t invert till the coil is right on them or as has been mentioned they can channel flip to and fro. Old lead tends to be a softer signal due to the oxidisation/patina, I presume the patina and round shape is what causes the initial channel flipping (From high/low to loW/high). Solid water worn little nuggets using high sensitivity levels can channel flip on each pass of the coil, the channel flipping tends to act like noise cancelling making the signal seem very faint yet you can hear the faint signal a long way from the target (careful coil control is needed).
  4. Something to consider with regards to water proofing, cutting the coil lead and adding a new connector might then allow moisture to ingress the coil via the lead (especially the leads cut before the curls), the GPZ14 coil is over moulded both ends as part of the waterproofing of the assembly, dependant on where the cut was made could be the reason for the OP’s fail. JP
  5. The science behind the GPZ requires the detector to be calibrated to the X signal, Minelab have given operators a choice, they can use Auto and let the detector control the calibration with or without the Ferrite (Recommenced if you do not want to use the Ferrite or have lost your Ferrite) or they can take control and calibrate the detector themselves or they can just go detecting and use whatever mode they prefer and forget about the Ferrite and X calibration altogether, this also includes opting out of the tech and using something else. (The last option should theoretically save some from having to post ‘late at night quips’)😜 BTW flat wound coil users on GPX, when you couple your coil to the ground, guess what that target like noise mostly is? It’s mostly X signal due to the forced early demod!
  6. High Yield Normal is the most sensitive mode on the GPZ to the Ferrite, in other words that mode will make the loudest Ferrite response over any other. In some instances if the G balance is way out it is best to pump the coil first to get the G balance correct before introducing the Ferrite, the reason you do this is to avoid the G balance trying to also balance out the Ferrite signal at the same time it has to get rid of a lot of G signal. High Yield also saturates the most (when you couple the coil to the ground and a signal is heard as you briskly pull the coil away (de-couple), High Yield is also the most sensitive mode to Salt signals (bring coil from ground height straight up to above your head and listen for a moaning sound as the coil moves through from knee height to above your waist, the stronger the signal the greater the amount of salt present). So best Ferrite balance practice using High Yield Normal is: Check for EMI and perform a Manual or Auto Tune till threshold is a smooth and stable as possible. Bring coil to ground and pump coil till the GB is Quiet (Make sure Semi-Auto Mode is selected). Place Ferrite on ground where there are no target signals, preferably non-saturable non-salty ground. With Quick-Trak depressed bring coil in over Ferrite at front of coil where the word Minelab is on Blue sticker. Move coil slightly slower than brisk left and right over Ferrite till there is no noise then release QT button. Pump coil to one side, you can also sweep the coil left and right away from the Ferrite to average the GB (I personally pump the coil up and down and occasionally combine some sideways sweep if the ground is saturable). Bring coil back in over the Ferrite and check for any residual signal, if there is repeat Quick-Trak Ferrite Balance till there is no signal with GB correct waving over the Ferrite (do not scrub the Ferrite because there will usually be a bit of residual signal left over (not loud). If this method still results in a dominant signal off the Ferrite then potentially you have a faulty coil, try using the Reset-All method holding down the Power button at switch on re-do your settings and repeat above. Re-set all is a HARD re-set and re-sets the GB and Ferrite balance and all other global settings to factory settings.
  7. Recommend not to use Quick Start, just turn on machine check for EMI with coil held flat and away from ground, change the Freq manually or do aN auto tune if required till threshold is smooth as possible then perform the Ferrite balance. The Guides in Quick Start are not actually linked to the Ferrite balance good or bad and are just there to provide a Guide and remind users to perform the process. Quick Start resets the ferrite balance and the G balance back to factory as well as the auto tune, there is no advantage in doing this other than the auto tune which can easily be done from the menu below. As I have said before the GPZ only makes a noise on the Ferrite if the electronics X calibration is OUT, if the calibration is good then no or minimal noise, however with a faulty coil the GPZ will not calibrate to the Ferrite no matter how many times you try, this is for varying reasons as has been discussed MANY times on this forum. In cold weather, especially where ambient temperatures vary greatly from first switch on to later in the day, there will always be some variation in the Ferrite calibration, to say it never varies is highly circumspect, the ground, mild or otherwise, only comes into the equation if X is present. If the unit gets into a fuddle you can try a number of things Turn OFF then ON again. Perform a reset via last menu option. Hold ON button in on start up till reset options come up, this will then trigger a HARD reset.
  8. There is no tick or any other sort of indication associated with X balance, the onscreen video when Quick-Trak is triggered is a GUIDE only. When we trigger Quick-Trak the Guide comes up while the QT button is pressed, release the button the Guide goes away, there is no time frame on this and there is no tick when X balance is completed. You can turn Guides off in the Menu. If you go into the Ground Balance menu and go from Auto to Semi-Auto a GUIDE will come up recommending a Ferrite Balance be performed, this is logical because the detector requires you to perform a Ferrite balance manually now via Quick-Trak because it is in semi-auto mode, the same goes when you go from Manual to Semi-auto, to avoid the hassle of having to back arrow out of the Guide screen or triggering the Quick-Trak button (undesirable if your X balance is already good) configure the User button to the GB menu to be able to quickly change the GB modes, no Guide is triggered when go into the Menu this way. If the Ferrite was not actually needed why then would there be so much emphasis on its use within the Menu systems of the GPZ? Not using the Ferrite is akin to digging a deep target one day and finding out it was trash so a week later in a totally different location you decide to not dig a deep target based on the previous experience. I cannot really tell if X is present other than vague impressions based on detector behaviour, however if X is present then it WILL affect performance IF the Ferrite balance isn’t correct. Lastly as I have said many times before a changing/shifting Ferrite balance has nothing to do with the ground changing except you’ll hear X if the Ferrite balance is out, then spurious depth reducing noises will intrude into the target signal of the detector. X signal only affects the audio if the balance is incorrect, X balance via the Ferrite is directly associated with the temperature of the electronics, so if you perform a Ferrite balance early on a cold morning and then the detector electronics and day warm up the Ferrite balance will then be incorrect (especially in winter) for the given temperature, as such noise will be introduced into the audio which will then compete with target signals. IMHO being blasé about X balance is not an option especially when you consider it is so easy to do. JP
  9. It’s all pure speculation on my part but seeing how this is a thread about a non-existent GPZ8000, I have a hunch discrimination isn’t even possible on ZVT. But is discrimination depth at its pinnacle? No way, there is always room for improvement. I’m all for a hunch type discrimination allowing the user to have some input, it doesn’t have to be 100% accurate, I already have a well trained ear, just need a supplement or a probability meter to use as a tool when making decisions, something that would help with making an informed decision, call it the “Informed Hunch-Ferrometer”.🤣
  10. The trade offs would be huge in noisy ground, plus nuggets are all over the place time constant wise so even more pain. What’s left is probably the CTX 3030 with a large coil. 😞
  11. I sell a lot of detectors to people with hearing loss and in most cases have found hearing aids to be ineffective for detector use unless the person is extremely deaf, they tend to lift everything especially wind noise, birds calls human voices that type of thing which tends to drown out the Threshold. The key to detecting with hearing loss is to be able to ‘hear’ the threshold pitch, if you can hear that in all conditions your fine. Most men have hearing loss in the higher frequency range so I usually suggest they use a lower threshold pitch. In my case in my younger days I used a threshold pitch of 60 but since my late 40’s have found a lower threshold pitch of 40 is better (I actually go as low as 20 in the right conditions especially when I’m chasing low/high deep nuggets at depth). Too low a threshold pitch (below 40) and I usually recommend headphones over speakers as the low frequency sounds tend to have a lot of competition in the natural environment. Just my 2cents JP
  12. If your using the GPZ in auto mode then the GB is actively trying to track X and G at the same time, in the case of the X coils that do not X balance properly the G balance will go a long way to help compensate for the inaccuracy in the X signal which is a good thing especially in the case of the 10” X. As is evidenced by jasong its the only option because the most sensitive mode to X signal on the GPZ is High Yield Normal, however due to that sensitivity the X signal is also more readily tracked by the G tracking. I don’t consider myself an ‘Xpert’ (pun intended😂), the way i run my machine is not an opinion its based around knowledge imparted to my by the designer of the detector. Running the GPZ noisy as possible is fine, I prefer moderation because in my experience the edge of detection target signals, especially the larger ones tend not to benefit from increases in Sensitivity levels but instead stability and correct tuning of the X and GB. Facts are if the detector is making a noise on the X signal that resultant noise is going to set up shop and go into competition with target signals a little like Nugget Finder getting into the GPZ coil market.😅 If the detector is making a noise on X its not the end of the earth because X is variable and thankfully blends in with regular ground noise especially for you crazy ‘Running things like Steve’ operators who like to crank things up a bit. At the end of the day a 10” coil is not really being used for super deep edge of detection subtle target signals anyway, and even then the difference between an obvious signal and a subtle signal is measured in mm not inches. JP
  13. Norvic it would be impossible to run my detector like that here in Clermont which gets back to many original comment were I said...... If you’re able to use Manual Ground Balance (gives the best outright depth) that suggests the ground type you are working is homogeneous. The other question I would have is are you using the ferrite each and every time you hit Quick-Trak? If not and your getting away with it suggests the ground you are working is also low X (lucky fellow). If your X coil makes a noise on the Ferrite anywhere near the centre of the coil, fore or aft, even after ferrite balancing then the coil does not have the mods, the noise on the ferrite will then indicate the coil will manifest a signal on any residual X signal in the ground, once again your ground seems to not have a lot of X signal (suggests homogeneous low X soils), which is what I’ve experienced up that way too, so lucky fellow again. I actually went away from our last exchange feeling pretty bad because you were right I haven’t been to every gold field and there are some ground types that can boggle the mind, and your absolutely correct I don’t know it all!! I was directed to just such a patch of ground only a few weeks ago, the guy had a good laugh when I rang him back. I have never seen saturation noise like it, even in severe!!! Yet he has scored some really nice gold with his trusty GPX 5000 and originally the GP3000, yet the 7000 is practically useless there, or put it this way he’s removed all the audible gold and I was not willing to pursue every target like ground noise to hopefully score a deep nugget in 40 degree heat!! Just so we are clear, IMHO the X coils do provide a sensitivity improvement over the ML coils, depth is relative because X coils do not make an exact size equivalent to the ML coils but they do have pretty good depth as is evidenced by users including me. In variable high X ground types, as is typical here in my home gold field and also in Victoria including a lot of areas in North QLD and in WA, the saturation signal can become an issue especially when using High Yield variants and more especially Normal Ground Type modes, as such the X coils in those conditions will struggle against the ML offerings. The latest X coils are a massive improvement over the first offering in my ground types. So getting back on track with the subject of this thread, my favourite coil sizes for the GPZ that will work in all the areas I frequent would still be a 12” round (spiral would be great), a 16 to 17” elliptical For general prospecting chores and a 17 to 18” round for depth, the coils need to produce minimal amounts of rub noise in General Difficult, saturation needs out be on par with ML coils, they need to be in Phase and they need to Ferrite Balance properly. I find in most cases once you go over 18 to 19 inch the resultant salt signal, even in dry conditions, negates the depth advantage so the coil then becomes very specific to confined localised areas. JP
  14. Watching This was enough for me considering what is now agreed upon by the vast majority of experts in this field. Keeping on topic, I think the dream size GPZ coil is entirely dependent on your personal detecting style and location. Having a few styles and even brands to choose from can only be a good thing. JP
  15. Not quite sure how to respond without things going AWOL. Suffice to say I have spent a pretty decent amount of time detecting in FNQ, both Palmer and Hodgskinson fields so am pretty conversant with the mineralisation types out that way and further west and north. There are noisy sections of course but the high rainfall tends to wash away the concentrations of magnetic materials hence why a lot of people up that way get away with not using the Ferrite and can quite often use Normal timings. Also the ground tends to be deeper in a lot of sections which also dilutes the magnetic materials to some degree which can mean less issue with residual X signals. Have/did not mean for this to be a fishing rod size competition and hope I have not offended. JP
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