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Thread: How to metal detect for gold when its in black sand

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  1. #1

    Aug 2017
    Georgia/Alabama
    Minelab GM1000 White's GMZ White's Spectrum XLT
    201
    87 times
    All Types Of Treasure Hunting

    How to metal detect for gold when it's in black sand

    Hey everybody, just out of curiosity, how are you guys metal detecting for small gold nuggets when there's an abundance of black sand? Dumb of me, I didn't do my research prior and ended up getting a Minelab gold Monster 1000, which had received all the hype. Sure it has a fancy display for ferrous and non-ferrous targets, and besides that just a sensitivity and volume. If I would have known better I would have gotten the Fisher gold-bug 2 or something with an adjustable ground balance and threshold instead of a silent Searcher that isn't adjustable to the ground. So if you're in my situation and have a silent searcher that you can't adjust ground balance for the given area, how have you been able to locate nuggets? What I find is the areas with blacks and will obviously give an iron signal, and if I try to put it on discriminate it'll constantly give a mixture of non ferrous and ferrous signals because of the soil and not because of gold. Even when I try to use the discrimination and auto tracking for the soil that I'm in, the detector will still go crazy between ferrous and non-ferrous. I'm just trying to figure out if any of you guys have figured out a solution to this. Also sorry if this reads strangely, I'm using talk to text

    Sent from my SAMSUNG-SM-G891A using TreasureNet.com mobile app

  2. #2
    us
    Northern California

    Aug 2007
    Southern California
    XLT, GMT, 6000D Coinmaster
    3,373
    3074 times
    All Types Of Treasure Hunting
    Howdy Just Curious,
    That is a very specific but interesting issue. I had to re-read your input and then consider my equipment ( a GMT) and of course I have not ever even considered this issue but it did make me question the fact that I also work in and around a lot of black sand. I will need to test this out the next time I have an abundance of black sand with some gold pickers. I'm certain that someone on here will offer a solution or at least "a way around". Best of luck with the answer and your equipment..................63bkpkr
    ProspectorBill likes this.
    Out searching w/GMT & friend under my arm

  3. #3
    us
    Nov 2012
    Whites TDI
    41
    27 times
    Metal Detecting
    Whites TDI detector has the ability to discriminate out the black sand. Do some research regarding this info . Best of luck on your detecting !!
    ProspectorBill likes this.

  4. #4

    Aug 2017
    Georgia/Alabama
    Minelab GM1000 White's GMZ White's Spectrum XLT
    201
    87 times
    All Types Of Treasure Hunting
    I recently got the GMZ which allows ground discrimination and salt. The problem is, there's no screen, and regardless of target all sounds are the same

    Sent from my SAMSUNG-SM-G891A using TreasureNet.com mobile app

  5. #5
    Charter Member
    us
    Make America Great Again!

    May 2010
    White Plains, New York
    Tesoro Cult Member & Overlord - Mojave; Vaquero; Lobo Super Traq; Tejon; Sand Shark - Minelab GPZ 7000
    13,315
    14446 times
    Metal Detecting
    http://www.minelab.com/go-minelabbing/treasure-talk/my-gold-monster-1000-methodology-manual-vs-auto-sensitivity

    My GOLD MONSTER 1000 Methodology – Manual Vs Auto Sensitivity


    August 29, 2017 12:39pm

    Steve HerschbachI am just back from a little detector outing and while I was at it I reflected on how once again I seem to do things a bit differently than other people. I am usually shy of talking about my specific settings because I am the last person to claim I know what's best when it comes to other people and how they detect. Ground conditions vary as do people's personal styles and preferences. Therefore I will include my usual caveat here that I am not claiming what I am doing is "the best" way of doing things. On the other hand, I do seem to be able to make detectors deliver for me and I am willing to share how I do things in case it may help somebody else. Hopefully that proves to be the case with this post.
    For me, the key is knowing my detector and how it reacts on my ground. I then let the detector tell me what to do when it comes to balancing sensitivity and ground responses. The task at hand has a lot to do with it. The Minelab GOLD MONSTER 1000 (GM1000) is from my perspective two different detectors in one package. There are two basic tasks I usually expect to perform with it:
    1. I have an acre of ground I want to detect from end to end. This for me requires using the larger of the two coils included with the GM1000, a blunt tipped 10" DD elliptical. Due to the GM1000 being a very high gain detector in more ways than one, my basic goal here is stability. I want the machine to be well behaved so that I can cover ground relatively quickly without having to deal with spurious false signals that require analysis. I am going to sacrifice a little theoretical "hots" in order to efficiently cover large areas that may or may not contain gold.
    2. I have a 20 foot by 20 foot area that I already know has small gold in it. My goal here is not to cover ground but to clean out the gold. This will at minimum mean running the GOLD MONSTER as hot as possible, and may very well include going to the smaller of the two coils, a 5" round DD. However, I can find gold down around the 1/10th grain (480 grains per Troy ounce) region with the 10" coil and it will hit the larger bits at greater depth in milder ground so I am generally going to stick with the 10" coil unless I really am trying to get the very last flyspecks.
    What follows is predicated on the moderately mineralized ground of northern Nevada, where alkali (salt) ground is as much or more a consideration as small hot rocks. Even small depressions like a hoof print will collect water during a rain, and when almost but not completely dried the small damp spot may create a positive signal if the GOLD MONSTER is running at high sensitivity levels. Once again I will warn that the specific settings I mention will vary under different ground conditions.


    Under the first scenario where I am trying to cover large areas I have found both manual sensitivity and auto sensitivity to be useful. Deciding between the two is as simple as knowing how variable the ground is. If the ground is relatively homogenous with minimal variation then manual sensitivity can work very well. If the ground gets too variable requiring constant burdensome adjustments of the sensitivity control to keep up, then going to auto sensitivity is more efficient.
    What does that mean in actual practice? Let's go over that but first I need to discuss the power up procedure. Much has been made of the necessity to hold the coil in the air as opposed to on the ground when the detector is first powered up. I will admit I am perhaps less stringent as regards that procedure. If I have any nearby electrical power sources, like a power line, cell tower, another detectorist nearby, etc. then I will raise the coil off the ground and point it directly at the tower or other person. This gives the GM1000 the best chance of "seeing" the interference during the few seconds frequency scan so possible interference can be eliminated or at least reduced as much as possible.
    However, in the interest of being completely honest, I have not found the GOLD MONSTER at 45 kHz to be particularly sensitive to electrical interference and while in the middle of nowhere Nevada I often just turn the machine on and go about my business will no ill effects noted. The raise coil and point at nearest electrical source is a very good habit to develop, but in my experience at least it is not as critical for me as it appears to be for others.
    I am always going to use the deep seeking all metal mode whenever possible. This is not just because this mode goes deeper, but also because the coil is more forgiving about reporting items that are not centered well under the coil. The discrimination mode has the net effect of reducing the overall size of the detection area under the coil. This means that when running in the iron discrimination mode more care should be used to overlap sweeps. When my goal is covering ground that little bit of extra ground coverage per sweep does add up and all metal mode helps reduce the chance a nugget will be missed on any given sweep.
    The GOLD MONSTER is noteworthy in that Minelab finally seems to have realized that the speaker actually needs to be loud enough to hear! I am quite enthralled by the boosted audio and the way the smallest targets pop even with my admittedly poor hearing. In fact, the GOLD MONSTER bangs out so loud without headphones that I will often run a notch down from the maximum volume setting - it's so loud that in quiet locations it can be too loud. The volume control is also a secondary sensitivity control in a way, and so I usually run it full out. I do this as much to help create a forced threshold sound as to enhance my ability to hear small targets. More on that later.
    One of the greatest features on the Minelab GOLD MONSTER 1000 is the automatic ground tracking. In my ground at least it is very efficient at effortlessly keeping up not only with ground conditions but in taking the edge off many hot rocks that would be problematic for other detectors. The beauty of this is that it eliminates the need to keep up with and make small adjustments to the ground balance control as would be the case with a detector that lacks an efficient automatic ground balance. I think most companies are equivalent when it comes to many features, but I do think when it comes to automatic ground tracking technology that Minelab has been and continues to be the industry leader. I was a "manual tuning only" diehard for a long time, but my experiences with the Minelab SDC 2300 in particular taught me to let go of that old thought process.
    The automatic ground tracking shifts the burden to the sensitivity control as the prime operational control on the GM1000. Minelab has positioned this control close enough to the center of the control panel that it is easily manipulated up or down with a thumb press by either left or right handed individuals.


    To summarize, I will raise the coil and point it at the nearest electrical source and then I will power the detector up and wait until it completes the frequency scan. The GOLD MONSTER defaults to the last settings and so my machine will already be in all metal mode, but if not I will switch to that. From there I will go to manual sensitivity setting 7 and do a short walk around sweeping the coil over the ground. For me this means the coil is sliding lightly over the ground or no more than a few millimeters over it.
    So far for ground I have been frequenting the magic settings are 6 - 7 - 8. With the GOLD MONSTER at full volume what I am seeking is a very minimal amount of ground feedback. These are very soft sounds that are quite unlike the hard edged pop of a genuine target. These sounds are created by the sensitivity being so high that ground noise is just starting to overcome the ground tracking ability to silence the ground.
    The problem with a silent search machine while in manual ground balance mode is that without a threshold you can end up leaving some performance on the table. If a setting of eight generates a little ground feedback, and you decide to go with 7 to make the machine completely silent, there is nothing wrong with that per se. However, if the ground changes and gets milder you may have the ability to run at a higher level of sensitivity, and without a change in the audio to alert you to a change in the ground, you will just leave the setting where it is.
    In my case if a setting of 7 is completely silent, I will bump to a setting of 8, and this almost always gives me that little ground feedback I want. If 7 is too noisy, I will drop to a setting of 6 and this will probably do the trick for me. The range between each setting seems about perfect for a person to settle on a range of three settings, too little, too much, and just right. For my areas 6 - 7 - 8 are the magic numbers. For worse ground the range may shift lower, to 5 - 6 - 7.
    Try and picture this. At sensitivity 7 I am just scanning along, coil lightly on the ground, with soft ground feedback, waiting for that hard little signal that even the tiniest target will generate. Then all the sudden the machine goes dead quiet. I have entered less mineralized ground. One thumb tap to sensitivity 8, and I get my "false threshold" back.
    Or, at a setting of 7 the machine gets noisier. Maybe a little alkali patch or more mineralized ground. A quick tap down to 6 reduces the feedback to my desired minimal level. What I am doing is letting the ground tracking do its job, and then just bumping the sensitivity up or down a notch to ride the ragged edge of best performance for the ground.
    "Gee Steve, sensitivity 6 - 7 - 8, aren't you giving up lots of depth running at 6 or 7 or anything less than 10"? My air testing...."
    A pox on air tests! They have uses but have little bearing on how to get the best performance out of a detector in the field. I do like to run my detectors hot and that does often mean with some ground noise, but it has to be kept within manageable limits. For the purposes of covering a lot of ground pushing the GM1000 to the edge is good but any farther and everything sounds like a target and knock sensitivity shoots up dramatically, especially at the hyper sensitivity settings of 9 and 10. The reality from what I have seen so far is that the Minelab GOLD MONSTER 1000 at settings of 6 - 7 - 8 will match or exceed most detectors in its class. Let's save manual sensitivity 9 or 10 for my next detecting scenario up next.
    Again, a reminder that 6 - 7 - 8 is working well for me in moderate ground. In more mineralized ground it may be 5 - 6 - 7 or even 4 - 5 - 6. If you simply listen to the machine it will tell you where you need to be. Too high, too low - just right. I have actually found gold with the sensitivity as low as 3 when in some nasty salt encrusted ground. People seem so adverse to lowering sensitivity I often wonder how many would just give up before going that low. It just can't find gold set that low, can it? Yes it can. You either tame the ground or go home and even though depth is reduced you can still find gold a low sensitivity settings if that is what it takes to get stable performance in the worst ground.
    So what about auto sensitivity? Simple really. If you are finding that you are having to bump the sensitivity up and down too often (you will know when that is for you) then it is time for Auto sensitivity. Auto sensitivity is different than manual in that you can trust it to keep the detector at the optimum level even if running silent. In general Auto is the silent running mode whereas Auto+ usually introduces a slight amount of ground feedback at full volume. As I mentioned earlier the volume control acts as a secondary sensitivity filter and running it lower can reduce or eliminate slight ground noise while still allowing targets to sound off loud and clear. Auto+ works best for me in most places but if need be I can drop to simple Auto for more difficult variable ground where Auto+ may get too noisy.
    OK, we have been hunting as described above and get a target. What next? If you are digging everything, a good practice, then just recover that target. If it is faint, either bumping the manual sensitivity up two points or dropping out of Auto into a high manual setting can aid greatly in pinpointing and recovering the target.
    What about trash? Too much and I don't want to dig them all? I am hunting in all metal mode and I rely on the meter to make a dig or no dig decision. In some ways it is a probability thing. If a few sweeps over the target from various directions produce a series of "hard left" ferrous meter responses, the target is likely ferrous. My goal is to try and coax a non-ferrous response with the meter kicking to the right. Just one non-ferrous response raises the odds you have a non-ferrous target. Even then I might pass in a trashy area, but two or more non-ferrous responses and you had better just dig it. Small nuggets in mineralized soil are fighting the ferrous content of the soil itself and in bad ground the ferrous ground response often wins. If you are looking for gold look for reasons to dig targets, not reasons to walk away. The amount of trash will help determine just how aggressive or lax you decide to be in these dig or no-dig decisions.
    Running is disc mode should be reserved for situations where there is no other option. It may be needed to eliminate a certain hot rock response. Or there may be multiple trash targets per swing - you can't analyze them all. The iron discrimination mode can be a real lifesaver in these instances.
    However, consider the borderline nugget that will read ferrous seven out of ten swings. That means you only have a 30% chance on a single pass over the target of having the machine give an audio non-ferrous report while in iron discrimination mode. The odds are even worse if you are not perfectly over the target, a bit too high, or swinging a little too fast. If the detector decides ferrous on that first pass, you get no sound and go right by, never knowing it was there. This is where detectors with a ferrous tone have the advantage in alerting you to every target so you can double or triple check. With a silent rejection system you get just one chance at the target and if the detector is wrong, the nugget is missed.

  6. #6
    ca
    Honorary Member of the Central Alabama Artifact Society (C.A.A.S)

    Jan 2008
    Canada
    F-75, Infinium LS, MXT, GoldBug2, TDI Pro, 1280X Aquanaut, Garrett ProPointer
    719
    1324 times
    Prospecting
    Banner Finds (1)
    Quote Originally Posted by Just_curious View Post
    Hey everybody, just out of curiosity, how are you guys metal detecting for small gold nuggets when there's an abundance of black sand? Dumb of me, I didn't do my research prior and ended up getting a Minelab gold Monster 1000, which had received all the hype. Sure it has a fancy display for ferrous and non-ferrous targets, and besides that just a sensitivity and volume. If I would have known better I would have gotten the Fisher gold-bug 2 or something with an adjustable ground balance and threshold instead of a silent Searcher that isn't adjustable to the ground. So if you're in my situation and have a silent searcher that you can't adjust ground balance for the given area, how have you been able to locate nuggets? What I find is the areas with blacks and will obviously give an iron signal, and if I try to put it on discriminate it'll constantly give a mixture of non ferrous and ferrous signals because of the soil and not because of gold. Even when I try to use the discrimination and auto tracking for the soil that I'm in, the detector will still go crazy between ferrous and non-ferrous. I'm just trying to figure out if any of you guys have figured out a solution to this. Also sorry if this reads strangely, I'm using talk to text

    Sent from my SAMSUNG-SM-G891A using TreasureNet.com mobile app
    Hi Just Curious,

    From your description, it looks to me that youíre getting erratic false ground signals typical of searching highly magnetic susceptible black sands when your sensitivity is set too high.

    We can readily use high sensitivity settings to search over mild-to-moderate magnetic susceptible iron-mineralized ground minerals without incurring false signals as a rule. Such ground conditions permit a relatively wide ground balance window, which means that there is more room to lower or elevate the coil without inducing false ground signals. But in soils dominated by magnetite (re: black sands) or maghemite iron minerals, that window is greatly reduced. Thus even small changes to your coilís elevation can induce false ground mineral generated erratic signals and hence we are obliged to operate at reduced sensitivity settings.

    Therefore, try to operate with your searchcoil at a uniform elevation above the ground as much as is possible, and to reduce your sensitivity until you can satisfactorily mitigate or eliminate the false erratic ground signals that you have been experiencing.

    On a different note, the Gold Monsterís automatic ground tracking should detect most small gold within range of the searchcoilís electromagnetic field but it isnít the most effective tool for detecting tiny gold that is situated at the fringe of detection depth. This is precisely why most prospecting-capable units do possess a manual ground balance feature that enables you to fine tune it to the ground mineral conditions, and to effectively deal with areas littered with iron trash so typical of mining country.

    Automatic ground tracking isnít a good tool to use in iron trash littered areas because the ground balance software is constantly adjusting to variable ground phase readouts from rusty and / or disseminated iron, immediately followed by trying to readjust itself to the actual ground mineral conditions. In such scenarios, the detector will frequently be completely out of proper ground balance with the soil, and some small gold, particularly the marginal deeper signals, will be ignored.

    One thing more, if you continue to re-sweep typical small gold signals while using automatic ground tracking, it is likely that such signals will disappear because theyíre simply ground-balanced away. So ensure that when you evaluate signals by swinging the searchcoil back and forth over them, in the absence of any feature to disable the automatic ground tracking, that your coil sees plenty of ground on both sides of the target signal.

    Hope this is helpful to you, take care.

    Jim.
    Time, oh good, good time...where did you go?

  7. #7
    us
    Aug 2015
    Montana
    etrac, GM 1000, GGT, pan, shovel, buckets, DIY classifier & hand dredge, AM sluice....
    77
    153 times
    Metal Detecting
    I'll be watching this thread closely.....my Gold Monster will be here tomorrow and I'm sure I'll have a few questions in the future. Spent 25+ yrs shootin old coins but new to prospecting and especially nugget shooting.....
    Terry Soloman and Rail Dawg like this.

  8. #8
    RTR
    RTR is offline
    us
    Roger

    Nov 2017
    Smith Mt. Lake Va.
    Old cheap ones
    141
    163 times
    All Types Of Treasure Hunting
    A Falcon MD-20 works great on finding gold hiding in black sand.A real time saver.Worth is weight in gold

  9. #9

    Jan 2008
    208
    196 times
    For a little more you could get the White's TDI SL. Get the miner john folded back coils which are specific for smaller gold nugggets (Reg Sniff design-killer!).

  10. #10
    us
    Mar 2014
    Central Arizona
    Minelab SD2100 V-2, Gold Bug SE, SDC2300, GPX4500
    191
    353 times
    Prospecting
    I would suggest you study the article posted by Terry that is specific to your detector. Then I suggest getting to know your detector in an area that isn't as black sand rich if possible. Fact is if the black sand is in bands that are pretty much all black sand, like 2-3 inches thick, it won't matter what detector you have. Not even Minelab Pi or GPZ can detect in solid black sand concentrations without frustrations. However, if you get to know your machine in less difficult ground 1st, you will get a better understanding of how it operates and learn it's limitations. Then you will have a better idea of what settings to adjust for the more difficult ground. Many are using that machine in Iron rich soils in Arizona so it can be done. I think you need to better understand your detector to succeed at that location. Dennis
    Lanny in AB likes this.

  11. #11

    Apr 2003
    Alberta
    Various Minelabs(5000, 2100, X-Terra 705), Falcon MD20, Tesoro Sand Shark, Gold Bug Pro, Makro Gold Racer.
    4,384
    3958 times
    Prospecting
    Hi there,

    You've sure been given some great advice so far, and I imagine part of it has to do with the fact that if the mineralization from the black sand is greater to or equal to the signal from a piece of gold resting in it, the black sand is going to mask the signal of the gold so the detector can't see it.

    All the best,

    Lanny
    Rail Dawg likes this.
    Nothin' quite as fun as chasin' nugget gold! http://www.treasurenet.com/forums/me...mysteries.html

  12. #12

    Oct 2012
    NM/AZ
    V3(i), ATX, uMax, Gold Bug, TM808, Custom
    207
    437 times
    Get a pulse-induction type machine.

    Short of that, do whatever you can do to set the thing you have to a non-linear audio threshold. Compress the bottom of the range so the "fuzz" is quiet and the valid blips just tickle through. Dig the tickles.

    This is different than setting a detection threshold. You want max sensitivity, but a compressed audio range. Some might say this is the same thing (it's not). Your machine may not support it, but on a purely technical basis, this is the right one of the two to apply.

    If you get a hit, kick the ground, and if it goes away, it might have been or is likely to have been a black sand lump.

    Good luck - black sand is a pain. I'll take discrete hot rocks over sand any day with my CW machine.

    (CW aka "VLF", though VLF is a weird marketing distinction that applies to all machines, VLF or PI, revealing the somewhat hand-wavy nature of the average level of technical competence in the hobby market. I met the Fisher "expert designer" in El Paso and tried to have an actual technical conversation once...).

    (Yes, PI try to have "sharp" transmit pulse edges which per the Fourier Transform should be wideband spectrally, but they are band-limited by the coil and feed circuitry such that the emitted "wave" (near-zone 1/r^3 or 1/r^2 circulating reactive fields) ends up in the same VLF band. The difference is, PI charge the ground to a steady state, and only listen to the ring-down. Magnetic versus conductive objects have different equivalent RLC circuits and the PI machine computes the ring-down slope and the better machines even look for little bumps along the ring-down. Of course, this is just speculation based on first principles and other experience - I bet the MD manufacturers have better-sounding marketing technical-ese for all the magic.)

    (A better way to go for all this is with HF/UHF/VHF (for GPR) and even SHF (for nuggies/coins), but cheap electronics and 1950's-era circuit topologies and sensibilities can't solve the dynamic range problem. Half the status quo on the market uses a cheesy micro-controller PWM output as a "transmitter" - yes, I'm an RF snob, but for good reason...)
    Lanny in AB likes this.

  13. #13

    Aug 2017
    Georgia/Alabama
    Minelab GM1000 White's GMZ White's Spectrum XLT
    201
    87 times
    All Types Of Treasure Hunting
    Quote Originally Posted by nmth View Post
    Get a pulse-induction type machine.

    Short of that, do whatever you can do to set the thing you have to a non-linear audio threshold. Compress the bottom of the range so the "fuzz" is quiet and the valid blips just tickle through. Dig the tickles.

    This is different than setting a detection threshold. You want max sensitivity, but a compressed audio range. Some might say this is the same thing (it's not). Your machine may not support it, but on a purely technical basis, this is the right one of the two to apply.

    If you get a hit, kick the ground, and if it goes away, it might have been or is likely to have been a black sand lump.

    Good luck - black sand is a pain. I'll take discrete hot rocks over sand any day with my CW machine.

    (CW aka "VLF", though VLF is a weird marketing distinction that applies to all machines, VLF or PI, revealing the somewhat hand-wavy nature of the average level of technical competence in the hobby market. I met the Fisher "expert designer" in El Paso and tried to have an actual technical conversation once...).

    (Yes, PI try to have "sharp" transmit pulse edges which per the Fourier Transform should be wideband spectrally, but they are band-limited by the coil and feed circuitry such that the emitted "wave" (near-zone 1/r^3 or 1/r^2 circulating reactive fields) ends up in the same VLF band. The difference is, PI charge the ground to a steady state, and only listen to the ring-down. Magnetic versus conductive objects have different equivalent RLC circuits and the PI machine computes the ring-down slope and the better machines even look for little bumps along the ring-down. Of course, this is just speculation based on first principles and other experience - I bet the MD manufacturers have better-sounding marketing technical-ese for all the magic.)

    (A better way to go for all this is with HF/UHF/VHF (for GPR) and even SHF (for nuggies/coins), but cheap electronics and 1950's-era circuit topologies and sensibilities can't solve the dynamic range problem. Half the status quo on the market uses a cheesy micro-controller PWM output as a "transmitter" - yes, I'm an RF snob, but for good reason...)
    Man, it sounds like I need to pick your brain lol

    Sent from my SAMSUNG-SM-G891A using TreasureNet.com mobile app

  14. #14

    Apr 2003
    Alberta
    Various Minelabs(5000, 2100, X-Terra 705), Falcon MD20, Tesoro Sand Shark, Gold Bug Pro, Makro Gold Racer.
    4,384
    3958 times
    Prospecting
    Quote Originally Posted by nmth View Post
    Get a pulse-induction type machine.

    Short of that, do whatever you can do to set the thing you have to a non-linear audio threshold. Compress the bottom of the range so the "fuzz" is quiet and the valid blips just tickle through. Dig the tickles.

    This is different than setting a detection threshold. You want max sensitivity, but a compressed audio range. Some might say this is the same thing (it's not). Your machine may not support it, but on a purely technical basis, this is the right one of the two to apply.

    If you get a hit, kick the ground, and if it goes away, it might have been or is likely to have been a black sand lump.

    Good luck - black sand is a pain. I'll take discrete hot rocks over sand any day with my CW machine.

    (CW aka "VLF", though VLF is a weird marketing distinction that applies to all machines, VLF or PI, revealing the somewhat hand-wavy nature of the average level of technical competence in the hobby market. I met the Fisher "expert designer" in El Paso and tried to have an actual technical conversation once...).

    (Yes, PI try to have "sharp" transmit pulse edges which per the Fourier Transform should be wideband spectrally, but they are band-limited by the coil and feed circuitry such that the emitted "wave" (near-zone 1/r^3 or 1/r^2 circulating reactive fields) ends up in the same VLF band. The difference is, PI charge the ground to a steady state, and only listen to the ring-down. Magnetic versus conductive objects have different equivalent RLC circuits and the PI machine computes the ring-down slope and the better machines even look for little bumps along the ring-down. Of course, this is just speculation based on first principles and other experience - I bet the MD manufacturers have better-sounding marketing technical-ese for all the magic.)

    (A better way to go for all this is with HF/UHF/VHF (for GPR) and even SHF (for nuggies/coins), but cheap electronics and 1950's-era circuit topologies and sensibilities can't solve the dynamic range problem. Half the status quo on the market uses a cheesy micro-controller PWM output as a "transmitter" - yes, I'm an RF snob, but for good reason...)
    Excuse me for jumping in here, but why do you know so much about the technical aspects of how detectors work? Are you in the business, or are you just a passionate hobbyist?

    I just enjoy my machines and appreciate how they find gold, but I am in no way a technical expert, so, just curious.

    All the best,

    Lanny
    Nothin' quite as fun as chasin' nugget gold! http://www.treasurenet.com/forums/me...mysteries.html

  15. #15
    us
    May 2009
    Sailor Flat, Ca.
    Gold Bug Pro, Gold Bug 2 Burlap, fish oil,
    4,241
    9060 times
    All Types Of Treasure Hunting
    Banner Finds (1)
    He hasn't even got the machine yet...and he's worried it was a poor choice..bummer

    The chances of you swinging over a pocket of black sand so dense its gonna "mask" nugget. Or with the GM cause falsing. Pretty slim.

    If you get erratic noise turn down the sensitivity

    Read Steves write up study your manual...take it slow

 

 
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