Gold Catcher

Hi Jp, can you recommend settings for grounds that are plagued by high ground saturation? I usually reduce gain until the coil pumping keeps the threshold stable right above ground, but at times this means sensitivity of 6 or lower in HY/normal with the ML14 coil. Any other settings/tactics that can be beneficial without too much impacting performance? Thanks!

The way I read the ML FY20 half year result is that they just show the current fleet of detectors (with exception of X-terra). I don't think this necessarily means that the same fleet will be there next year. I still think the 4500 could disappear given it's life cycle and perhaps other changes are coming up too. I would be highly surprised if they would let us know in their current 1/2 year update for sure what will happen to their product line going forward. The only thing that we know is that they work on 5 new machines. This does not mean much since they could all be at different stages of development, with some possibly years out. The rumor mill needs to keep spinning I am afraid.

Thanks for sharing, RDD. Another example of how HY/high gain settings can miss targets

I have this exact headset and I love it. Never used it for detecting though as I was afraid the noice cancelling feature would add to EMI, or any other electronic component of the detector would be compromised. Do you recommend to use it, in combo with a booster like the SP01? Is this headset made for hearing the right detector audio frequencies? I know this can be an issue. I often hunt in howling wind which would make this a nice tool to have, assuming it would not compromise detector performance in any way. Thanks.

Much higher gain than that and I would not be hearing faint threshold variations anymore. Conservative settings work well for me but require a very focused hearing practice. Yet, this gives me better results than turning everything up into screaming mode

Great idea!

Thanks, yes this is always the best way to go. Assuming though you are close to your vehicle. I have done hikes with the SDC in my backpack and the GPZ resting on my shoulders, but this can be quite tiring 🙂

Thanks, JP! I have not yet have much experience with my 19 in coil, but will do some testing to get a feeling for what nugget size will be detected with the slow timing and at what depth. This might even be advantageous in trashy areas with small surface trash (bb's, tiny wires...etc). The slow timing might simply make them go away...Should also work with the 14 inch coil I suppose. The question will be what remains still big enough to not slip through the time gaps 🙂

JP, what are you thoughts on the ML 19 in coil with the extra deep setting? Any advice you can share with the 19 and how to best use it? Thanks

Thanks for pointing this out, JP. I have made a habit to screen a new area first in HY/normal (if possible) at whatever sensitivity is tolerated, and then in HY/difficult, with sensitivity increased a few clicks. However, I found that increasing sensitivity to make up for the difficult is often not needed. The ability to hear threshold variations in difficult better than in normal seems to make up for for the loss due to filtering. Great threads, keep it up!

Thanks, JP. I really appreciate your detailed reply. This is the kind of info that is the most valuable to me and one of the main reasons I joined this forum, just as I am sure it is for many others. We all love our machines (whatever brand), but making the most of it requires an in depth understanding of all settings, their purpose, their best application and the awareness of how important the operator's handling of the detector is. The latter part includes coil/range of motion control just as you say and I thank you for providing your expert opinion on all of these topics. Ever since I own the GPZ, I have extensively experimented with all settings and often spent 30 min or more over a given target, just to detect it with various setting-combinations before I actually dug it up. I also did field testings with various nugget sizes, shapes and consistencies to familiarize myself with target response and detector behavior as a function of ground conditions, depth, gold-densities/shapes and the way I swing, etc.. Now, by no means I have done a pro-type field testing, but I have tried as much as I can to learn the most of it. One thing that I can definitely conclude from all this is that not one timing/setting fits all situations. This of course should be clear to everyone and is somewhat old news, but surprisingly many operators seem to have favorite settings that they try to use with brute force in all situations, just to adhere to their personal philosophy. I have had situations where HY/normal timings are superior, but I also had many situations where HY/difficult was by far outperforming any normal timing, up to a point where in normal the targets where not detectable at all with everything else being the same. The GPZ is an incredible versatile machine, and in my view understanding what settings to use in what condition is the most important part, rather than adhering to "dogmas" and "one fits all" strategies. Keep up your great contributions JP. I know a lot of operators are learning from it (including me)🙂 GC

Great thread, JP. Thanks for setting it up. Are you using HY/difficult in these grounds? How high are you able to go with the gain to still hear deep faint target? Thanks.

It would surely have registered on my scale 🙂 You should see some of the small stuff that I find at times (BB size or smaller). Really fun to recover those with the 14 in coil...Thanks for sharing the pics. Very cool! Aussie land is just on a different level than anything we have here in the US.

Nice going, JP! How much trash did you dig in comparison to get these 17 pieces? I average about 20-30 pieces of trash per nugget. That would be at least 340 pieces of trash here in CA 🙂

Thanks Fred! Never knew there was any difference. 🙂

I have to agree with you on that one, JW. It is that 'aha' moment when you get a nugget in the scoop, always recognizable beyond a doubt and reason for instant jubilation (I often do the Walter Huston dance if nobody is looking...). On the other hand, with meteoroids you might not know right away if it is one or not, so not much of an "aha" moment (more of a head scratcher), unless of course you are truly an expert in meteoroids (which I am not).

Very much agreed. I believe though that hiking to remote areas that are not within reach of any ATV holds good promise. Hence, a lighter GPZ would make a difference (even though I hiked with the GPZ 12 miles yesterday....I feel like dead)

Staying mostly on the sidelines, I have to say I learned a lot from this thread regarding technical details and experiences and I am looking forward to future discussions on this topic. Having close to no experience with the X-coils, I am intrigued by the potential these coils seem to present in situations favorable for their design. I very much enjoy all the experts in the field and consider an optional X-coil purchase myself. That being said, I also very much appreciate JP's expertise and his advise regarding the in's and out of the ML machines and all his technical expertise. It is rare to find someone with his skills and experience, just as it is a pleasure to learn from all you other guys who truly champion the passion we share. I try to learn every day to improve my performance in the field and your posts are a vital component for my learning, just as I am sure it is for many others on this forum. Let's continue to share our passion for gold hunting and learn from each other, regardless of your preferences fro equipment.

This relates to point that Bruce Candy made (see above post). In my uninitiated view, this means that for grounds with large X-signal the Xcoils may struggle

This is a great educational read, tells you all about X/R signals and why mineralized soils (where usually most of the gold is) produces large X-signals. METAL DETECTOR BASICS AND THEORY (Bruce Candy) Just google it to get the pdf link, it's on the minelab homepage Some exerts: "As with most introductions, the above brief description is over-simplifi ed. The signal induced in the receive coil, by the magnetic fi eld of the eddy current, can be thought of as made up of two simultaneous components, not just an altered component: • One component is the same shape as the transmit signal. This is called the reactive signal (“X”). Because it is the same shape as the transmit field, the signal, by definition, responds immediately to what ever the transmit signal is doing. • When this X component is subtracted from the eddy current induced signal in the receive coil, the shape of the remaining signal depends only upon the history of the transmitted field, and not the instantaneous value. This signal is called the resistive or loss component (“R”)." "Unfortunately, soils are magnetisable and thus also detected by metal detectors and cause signals which interfere with metal target signals. The degree of the magnetic properties of soils varies considerably. This magnetic property of soil is usually called “mineralisation.” The mineralisation produces almost entirely X and only a small fraction of R signals. The R and the X signals of a deep metal target are typically much less than the soil X signal, so obviously it is better to use the R signal to locate metal targets, rather than X." "USA goldfields are typically different from Australian goldfields: • The USA soils are mostly mildly mineralised but in some areas may contain either nearly pure magnetite black sands or rocks, which are problematic for metal detectors as they have very high X components (strongly attracted to magnets). • Australian gold fields have highly mineralised soils, but very few black sands or rocks that contain nearly pure X magnetite. The magnetic materials are in the forms of magnetite-rich small pebbles and rock coatings, clays and general “sandy” soils. These all contain magnetic materials that produce high levels of X signals as well as R. The ratio of X and R is random, and the R component arises from extremely small magnetic particles called superparamagnetic materials, which are discussed below." "As stated earlier, mineralisation produces a large X component and a much smaller R component. Unfortunately X and R are unrelated and their relationship varies randomly from one location to the next. Salty soils produce R signals from the mineralisation, as well as from the salt conductivity. However, most goldfields do not have salty soils, and in these non-salty soils, the soil R/X ranges from about 0.5% to some extreme “hot rocks” with R/X about 5%. However, the nearly pure magnetite black sands and rocks exhibit very low values of R/X; <0.1%. In very highly mineralised soils, such as Australian goldfields, median soil R/X is between 0.5% and 1%, but this ratio varies from location to location. Some non-salty non-goldfield soils have R/X as high as about 10%."

Nope, more a strategic decision to have both. Once I cash in the gold I bet she will be up for a date...;) Of course even without that gold I claim my chances will be rather good 🙂

I'd prefer the 1000 kg "gold coin" anytime...

Wow!!

Any, both are huge

Well it actually look bigger...lol. I wonder though how far you could push any detector with respect to depth of huge gold chunks. Would the GPZ with the 19 in coil and set to extra deep detect the coin in lets say 20 or 30 feet of depth?