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Gear In Use:

  1. Anyone know about the M8 & M15 Coils price and availability date? They have been up on the Minelab site for a couple of weeks but no one is advertising them yet.
  2. Anyone know of any person or company, worldwide that sells coil shells? Thinking about building a smallish CC coil for the Legacy Minelab PI's. I only know of a Bulgarian and Ukrainian seller but neither has coil covers to accompany their shells. The Ukrainian one (Pictured) is only a 9", so the receive coil will be C.5" at best.....so should be sensitive but not great overall depth for larger targets. Any ideas????
  3. I tried to finalize the purchase of a Troy Shadow X5 coil and it seems that the only way to pay is by making a deposit into a bank account, money order & money gram, which is strange or suspicious for any company that considers itself serious. Note: The same coil is on an auction website for twice the price.
  4. Something I've been wanting to do for a while now..I got another x ray generator couple weeks ago and wanted to try it out on my DR System.. Heres most but not all of the coils I have. 1. CTX 6" 2. TDI Pro 12" double mono 3. CTX 17' 4. XP Deus 9" 5. Miner John 8x12" mono 6. x cal 8" 7. Gold Monster 6" 8. Fisher Gold Bug two 6" 9. Nox 6" 10. Nox 11" 11-14 GPZ 7000 stock coil
  5. Looks like M15's are hitting retail at the moment, a guy in NZ has secured one, not me unfortunately, I may have been to slow to order by the looks of it but at the early stages I wasn't even sure I was going to bother with my Manticore, now I've decided I'll give it a chance. Hopefully my spots not too far away. I've ordered both coils.
  6. Just curious if any of you folks still use a concentric coil and if you do, when and why versus a DD. I picked up a Tesoro Sidewinder with the 8" concentric coil a short while back and did some parking hunting with it last week. It did remarkably well. Yes, I did dig more trash than I would with my Legend or Equinox 800, but the Tesoro did reward me with a good pocket full of clad and a shallow wheatie. I had forgotten how easy it was to pinpoint with a concentric coil. And the detector was really fun to use. No updates to install, no menus to trudge through. Don't know if I will use it a lot but it was a nice change of pace. Bill
  7. I need some help in Choosing which big Mono Coil to purchase for the Axiom I currently have the 13x11 DD and the 11x7 Mono which were in the package I purchased, I also picked up the 11x7 DD I am wanting to add one of the big Mono's for the Axiom, but can not decide if I want the 13x11 mono or the 16x14 Mono Someone please sway me one way or the other LOL How much depth will I gain with the 16x14 Mono over the 13x11 Mono if any, I know this depends on several things ??? how much sensitivity to smaller gold will I loose with the 16x14 Mono or the 13x11 Mono if any ???, I also know there is to many factors to consider on this one also price is only like $20-$30 more between the two so not an issue in my opinion So there is my dilemma, so again give me some reasons to choose the 13x11 mono or the 16x14 mono for me it keeps coming down to (if I am going to go big go the biggest I can currently purchase) LOL Thanks for reading my RANT
  8. On all my VLF detectors I usually run the coil cable straight up the top of the shaft securing it with Velcro type cable straps, I usually do this all the way up the lower shaft and then wrap the coil cable around the Mid shaft to the control housing, this has always worked for me my question is, is it ok to do the same thing on a PI like the Axiom or should the coil cable be wrapped all the way up the shaft starting with the first wrap over top of the shaft ???, or is straight up the shaft ok ??? in the photo is how I have the coil cable on my Axiom
  9. Big idea from a bloke with no idea!!! Hoping that this forum can be of some assistance 🙂 Well, with another trip to Western Australia done and dusted my last statement to my brother in law before I left was that "I don't think I will be back without a drag coil". Aaaaaaaand I am hoping to go back next year 🤣 We did OK considering we were genuinely 'prospecting' and we knew that it may be a boom or bust type situation. The issue is that we passed over so much country because it is just too big. Vast. Expansive. And much of that vastness looks exactly the same - where the hell do you start? And of the patches we did find, then gridding out from those located pieces would be far more efficient and easier on the body than the side-to-side, slowly moving forward, small step action that gridding requires. I'll proceed with what I want to do, what I don't want to use, what I hope I can build and then questions re: what is actually feasible. I have looked through a few topics on here and there are snippets that can be picked up but not specifics and the cans, cants and have to's and how to's. I am really hoping to build a thread that anyone can follow and build their own basic coil design or at least have the basic idea of where to start. I'm hoping that @Reg Wilson @Chet @jrbeatty @Aureous @jasong @Geotech and others with technical expertise and prior experience can be helpful. Disclaimer - I checked out Geotech forum and although I am sure it is a fantastic forum I am sorry to say that it is all just too far over my head. I really need things in laymen's terms. I guess it is a case of if you never learnt it you just don't know it and I don't have the time to go and do a diploma in electronics. I help student/new nurses go through a step-by-step-by-step process of changing vacuum dressings on huge abdo wounds or changing PICC dressings or setting up a syringe driver for a palliative care patient. They are technical things and they need guidance, unfortunately I am asking for the same guidance here 🙏 My basic plan - to make a 5 or 6 foot wide, oval or rectangle shape, mono coil that I can drag myself - not with a vehicle of any sort. My goal is coverage more than depth although depth is always a welcome advantage I suppose. I would be hoping such a coil could pick up shallow gold pieces that are 2 grams and up?? Mount the windings inside plastic tubing (inch poly??), solidify those windings inside the tubing with either some sort of foam or resin, affix that to the top of a folded piece of non-metal conveyor belt, place a solid timber on the front edge/folded edge of the belt and tow with a rope. All connected to a GPX series (4000/4500/5000) detector that can be carried on a harness with the battery, etc. As I am trying to keep-it-simple-stupid I am hoping that the windings can simply be bundle wound and that a gel type resin will both provide some weight, some rigidity and keep the windings in place. I do not want to use a vehicle due to the extra cost of purchasing a vehicle, transporting it and the EMI complications it can bring. As I will be pulling the device it needs to be reasonably light weight but not so light weight that it is not durable and that it does not remain as flat as possible. I know there is a pre-fab ready-to-go option with an @Coiltek 40 inch drag coil but I am wanting something a little wider to really make the process efficient. And I might learn something along the way 👨‍🎓 So before getting into the what I need and how to do it, I really need to start with 'Is it possible?'. Noting Reg's post below re: as things get bigger they develop more problems - is a 72 inch wide coil even feasible? Is this why Coiltek don't make anything over 40"? The build itself it adaptable but I am guessing the physics is not, so that is the first hurdle I need to over come. Question 1 - Will physics defeat me before I even start? Look forward to your responses 🙂 Cheers, N.E.
  10. Oh crap. I get out my GPX coils and find 3 with bad cable insulation, the inner plastic insulation may be brittle too. They don’t have a shield so I’m wondering if some thick stranded AC power cord cable may be a sufficient replacement- any thoughts?
  11. I bought several coils over the years for my GP Extreme and just now am getting around to trying them. I discovered that some DD coils wouldn’t work - they result in alternating high-low tones without sensitivity to any targets. Is this indicating an issue in the coil or more of an incompatibility. The manual says some coils can act erratically - is this that?
  12. I just recently bought a nice Spectrum XLT that came with the 9.5 coil. I have been trying to search for what other coils are compatible but haven't came up with much of anything, other than some older posts on other forums saying some people favored an 8 inch coil over the 9.5. But they don't tell what the name of the coil is; just the size. Any help is appreciated.
  13. Today I had a conversation with a colleague in which we talked about being able to use coils from one brand in detectors from another for which they were not manufactured. I stand aside due to my lack of knowledge, but he argues that it is possible to adapt certain coils that were not designed for a detector for which they were not designed. Is that possible? Making mods is one of my favorite hobbies so the topic caught my attention. Specifically, we were talking about placing Whites coils that are used in the M6, MXT, BHID, DFX and some others that I don't remember, and installing them in the fisher cz21, cz3D, which share similar frequencies, configuring adapters and wiring. Do you think this could work?
  14. With the official announcement on May 15 of the (hopefully) mid-summer release of the Garrett Apex there was considerable discussion of the (only) stock coil planned for release and its affects on depth. Within that discussion Chase gave me incentive to do some testing. This post is a result of that, but since I think my testing is applicable to more than just the Garrett Apex I'm creating this post in the general DetectorProspector forum. The gist of the topic there was how much compromise the 6" (wide) X 11" (tall/high - my choice of word) Apex stock would have on depth. As I mentioned I have quite a few coils for each of my detectors, but subsequently I realized there was one detector (Fisher Gold Bug Pro) and coil combinations (5" DD round and 5" X 10" DD elliptical) which would best address this issue. (I also have some other options -- White's TDI SPP and Minelab X-Terra 705 -- but those are a bit less ideal as will be discussed later. Since I have two other coils for the GB Pro I decided to include those for completeness although they add more variables/concerns and thus don't fit quite as neatly as the other two. I initally started with my variable depth test stand which allows me to vary the depth of small targets in 1/2 inch increments from ~ 1" down to 12" depth in the ground. However, in the midst of that part of the study I realized that I have some (likely iron) trash targets in the field-of-view which compromise the tones/measurements. Fortunately I also have two cleanly placed buried coins -- a copper alloy Lincoln Memorial USA penny buried at 5" depth and a Jefferson nickel alloy 5 cent piece at 6 inch depth. Neither of these currently suffers from nearby trash targets. I subsequently altered my study to use those targets for the coil performance tests. Unfortunately these also aren't ideal since under the conditions of testing they are too shallow to determine in-ground depth limits. What I did as a hybrid compromise is to carefully (i.e. measurably, with shims) raise the coil above the ground until the signal disappeared. For a second (more/less confirmation) test, and one that should be easily repeatable by anyone with the same/similar detector and coils, was to then perform a standard air test. Let's start with the conditions of the tests: 1) Ground conditions -- moist ground (we've had a typical wet Spring season), Fe3O4 mineralization measure of 2.5 bars on both the Fisher Gold Bug and Fisher F75 (2.5 meaning that about half the time I see 2 bars and half the time 3 bars). 2) Gold Bug Pro running in "all metal" ("motion all metal" in USA terminology which I like to call minimally filtered), max gain, threshold at 11 (which is about where Kevin Hoagland calls "mosquito buzzing in your ear"), no headphones (so detector's speaker). 3) My precision for "depth" is 1/2 inch. That coincidentally was the height of the shims I used in the hybrid test and also my ability to control the hand-held coin distance in the air test. 4) My determination of (maximum) depth limit was simple. I increased the depth until I thought I could barely detect an audio signal. I then decreased the target-->detector distance by 1/2 inch and required that I subsequently heard a clear signal. If not I reduced the depth/distance and repeated. Here are the raw data results. I'll explain the meaning of the columns shortly. You can see the four coils I tested. The first three are all Fisher manufactured and the last is the NEL Tornado. Rather than to use the nominal product quoted dimensions ('dim' short for 'dimension' in the column headings) I actually measured the coils and interpolated to account for the fact that a coil doesn't typically have a single extent but rather is a bundle, and further that the bundle obviously fits inside the housing. For the closed coils this is obviously more vague but in those cases I just used half an inch less than the housing dimension. An addition oddity is that DD coils aren't really simple ellipses but some overlap of two independent elliptical coils. 'geom mu' is the geometric mean of the two just determined transverse dimensions -- more specifically the square root of their product. Hopefully you'll see later why I calculated that quantity. It's not really relevant for the main conclusions I draw. The last two columns are the actual distances between the target and coil for the limiting distance (see item 4 above). In the case of the air test that is obvious. In the 'part ground' test that is the sum of the depth of the coin in the ground and the height of the coil above the ground for both coins. At this point I think it's worth discussing some caveats/assumptions/limitations of this test. Then if you've stayed with me I'll go a bit farther and hypothesize on how to use these data to draw conclusions for other coils. 1) Although I chose a detector/coils combination that was as consistent as I could be (same manufacturer and same 'width' coil), it has been discussed on this forum previously (sorry, no link) that the quality control of coil manufacture is a difficult task. It's certainly possible, although not necessarily likely, that my 5" x 10" elliptical coil is a high end tail performer among its peers and/or my 5" round is a low end performer. 2) With any measurement, there are in particular systematic errors and biases. I can't "double blind" my method. That is, I do know which coil I'm testing at a given time and if I have a prejudice for or against a certain coil that could show up in the results. Also, statistical uncertainties (more succinctly, how repeatable are my data) can contribute to errors. It is worth pointing out that swinging the heavy NEL 15" coil effectivly makes taking in-ground measurements with it difficult. As a result I was unable to confidently get a max depth reading for the penny using that coil, which is why that cell is blank. No problem with air tests because there, as is standard (?) I mounted the detector in a stationary horizontal position and just 'swung' the targets to determine the (max) limit distances. Again, it's really the 5" round DD and 5" x 10" elliptical DD that are most relevant. The others are include for information purposes but also to add to the plots I show later. As you can see, in these tests there is a clear and significant advantage for the 5" x 10" elliptical over the 5" round in both the hybrid test and in the air test. OK, I now go a bit deeper. Is there a mathematical relationship which can predict coil depth performance if I know the coil dimensions? Compared to above this is another leap into the unknown with additional uncertainties. However, here are a couple plots which seem to indicate relationships between the potential maximum detectable depth and the geometric mean of the coils width and height dimensions. (Sorry for the confusion but the Blue dots in both plots are for the 1 cent piece and the red dots are for the 5 cent piece.) It's better to look first at the 2nd plot -- air test. There appears to be nearly linear relationship between max depth and the geometric mean of the coil's dimensions, although it appears to trail off with the large (NEL) coil. Superimpose upon that the effects of ground noise and you see a further deterioration both in absolute depth and also in the trend which is shown in the first plot. Simply put, it is well known that mineralized ground, even moderately mineralized as in my back yard, negatively affects attainable depth. The larger the coil, the more ground it "sees", and thus the more ground interferes with performance. I'll finish by pointing out that this isn't the first study I've made. Back 3 years ago when DetectorProspector member Karelian made detailed measurements of a large collection of mono coils on a White's TDI in both ground and air, I noticed the depth vs. geometric mean relationship. However, without a theoretical (physics/engineering) reason to expect this relationship, at this point it's merely a convenient correlation. Karelian's data are further muddied by the fact that the coils studied have many manufacturers: Coiltek, White's, Miner John, Nugget Finder, Minelab,... I could show those results but I think I'll await the reactions to the above. I can also do more tests (e.g. with the X-Terra although there is not clean comparison of round vs. eliptical coils with the same width, at least in my collection) or repeat these. I await your posted reactions (including yawns 😁).
  15. I did a coil test some time ago using a Tdi Pro OZ, quite a variety of coils involved. Just a bit of information not wanting it to go to waste. The test area was located in the middle of the Golden Triangle in Victoria, Australia. Looking at the images the test site is located on a area that produced large nuggets. Heavily mineralized to give the depth tests some authenticity. Targets were varied as were the coils tested. The Tdi Pro was ground balanced, gain was at 5, conductivity was in ALL, pulse delay was 10. Frequency was set in the middle and the audio was boosted by a Nokia MD-11 external speaker. Only clear repeatable signals were recorded. All targets were buried in the ground sideway from a miners hole, so as not disturb the soil on the surface or above the target. Only the 1 grain ingot and one 0.5 gram gold coin were buried from the surface disturbing the ground. Not sure how useful this is for Tdi SL users, deduct 10% maybe.. Just gives a sense of what is realistic is this one location at that one time with the Pro with the variety of coils available back then. All the best, Karelian
  16. Do you tape or seal metal detector search coil scuff covers / skid plates? Pick an answer that best describes what you do.
  17. Has anyone had issues with the coil covers falling off? I have. Garrett acts like this is new to them. They sent me another cover for better fitment, but it fit the same. Then they sent a coil and cover, but there was no difference in fitment. NEXT ISSUE: I did an air test win a small gold piece. The Axion detected it at 2.5-3”. I air tested the same piece of gold with my GMX Sport, it detected it at 4-4.5”. This was also the case with the ATX. is the air test the issue?
  18. I figured it was time to change the battery for my X--35 9" coil, I watched all the videos on how to do it , I figured it would be a cinch, but after i got the little plastic plate off the bottom of the coil a hard piece of foam was glued in so hard over the little battery connector I could hardly get it out , then i looked to find the connector to unplug the old battery and could not even see it , It was totally covered in epoxy glue I pulled on the wire and it broke off, apparently the temp worker filled it with glue and completely covered the battery plug in making it impossible to remove, why me ? why does it work for everyone else but when i go to do it its covered in glue, ? I was pissed now it will cost me 300.00$ to get the HF coil . I will never buy another X-35 because I have no assurance the battery plug will not be glued over again . at least the HF coil its possible to change the battery
  19. Based on some posted consternation based on the anticipated price point for the Minelab Manticore accessory coils, I thought I would put out some price points for popular Simultaneious Multi-Frequency (SMF) metal detector accessory coils, and coil prices for other popular single frequency, selectable single frequency, SMF and PI detectors, for reference. These are approximate retail prices for new coils (in US $) scraped off the internet and don’t reflect dealer discounts, package deals, or sale specials. Legend LG 28 - 11" Stock - ~$135 LG15 6" Round - ~$120 LG24 9.5x6" - ~$135 LG30 12X9" - ~$150 LG35 14" - ~$170 Nox 6" Round - ~$180 10x5" Elliptical (Coiltek) - ~$235 11" Stock - ~$229 14X9" (Coiltek) - ~$260 15x12" - ~$240 15" Round (Coiltek) - ~$290 Manticore Stock 11" - ~$?? M8 - ~$341 (Pre-release estimate based on currency conversion) M15 - ~$417 (Pre-release estimate based on currency conversion) Deus 2 9" Round - ~$399 11" Round - ~$399 13X11" - ~$399 Other Coils: Fisher "Triangulated Biaxial 12" Coil" for F75 - ~$199 Detech Ultimate 7" (Teknetics and Fisher F75) - ~$130 Detech Ultimate 13" (Teknetics Greek and F75) - ~$180 Detech Arrow (Simplex, Fisher, Teknetics Greek and G2+) - ~$150 - $165 Nel Snake - ~$120 - $130 Minelab XTerra Pro - ~$?? Minelab Vanquish (Multi IQ) - ~$100-$140 (size dependent) Minelab CTX3030 11"/17"(FBS 2) - ~$350/$400 Garrett AT Series Coils - ~$130 - $160 (size size dependent) Garrett Ace Apex Coils - ~$135 - $190 (size dependent) Nokta Simplex+ - ~$110 - $170 (size dependent) Nokta Impact - ~$110 - $230 (size dependent) Nokta Anfibio/Kruzer - ~$110 - $220 (size dependent) Pulse Induction: Garrett Axiom Coils - ~$280 - $320 (size dependent) Minelab Commander 10x5" DD (GPX) - ~$225 Minelab Commander 11" Mono/DD (GPX) - ~$270/250 Minelab Commander 15X12" DD (GPX) - ~$375 Minelab Commander 18" Mono - ~$441 Coiltek GoldenHawk 10x5" Mono (GPX) - ~$420 Coiltek 14" Anti-Interference DD (GPX) - ~$410 Detech 12.5" DD (GPX) - ~$300 Detech 15" Spiral Wound DD (GPX) - ~$425 Detech 15" Ultra Sensing Mono (GPX) - ~$425 Commentary - Legend accessory coils are a great value overall consistent with the detector itself, even compared with single frequency detector accessory coils. The unofficial Manticore accessory coil prices (if they hold) are somewhat consistent with Deus 2, perhaps its most direct competitor, although the Deus 2 coils pricing is complicated by the fact that they are wireless, smart, and, therefore, are self-powered which is not the case with the Manticore coils other than perhaps limited pre-filtering and ID chips. The Coiltek NOX coils demand a slight premium vs. the Minelab OEM Nox coils. The higher end Deus 2 and Manticore accessory coils are priced similar to GPX pulse induction coils.
  20. I’m interested to see if there are noticeable differences in performance for the available coils that are out. I see manufacturer specific coils and then some made by Coiltek and others (I don’t recall their names). My question is, do any of you suggest a particular coil manufacturer over another? I don’t mean 6” vs 9” vs 11” and so forth, just curious if a particular coil manufacturer appears to make better product. I have a a 5x10 coiltek for my 900 and I don’t really feel it works any better than the standard coils.
  21. Has anyone on this forum gone about the process of designing their own custom coils to go with some of the more popular detector models on the market? I only have a Gold Bug 2 at the moment and it does alright for what I purchased it for but I was wondering if I might be able to get some more coverage and detection ability out of it when I take it down to the beach I live near to see if the rich people have lost anything. It does just fine out in the desert with the stock 6" coil and I have never felt the need to buy one of the larger coils as I just do not think those would really fit how I most use the detector out in the desert. Anyway I obviously am considering trying to build a couple different sizes and geometry coils to use with my GB2 but also would love to hear about what other people have done with other detectors. Would love to get a little more guidance than my sorta basic electronics knowledge, intuition, and searching the web.
  22. Since the 15'' Coiltek coil for Equinox detectors has been out for a while, I'm wondering if there have been any meaningful comparisons? Especially regarding sensitivity and depth.. Any feedback would be much appreciated.. 😁
  23. While running my hands along a coil cable, I noticed a pin-sized thorn had pierced the cable, broken off, and embedded itself inside. Tweezers were of no use as the splinter was too deep and brittle. It got me a wondering if any one has any experience regarding the potential impact of such an injury to the coil cable and it’s insulation. Any thoughts?
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