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I also have fun making other projects in the forge, mind you I'm still learning and have only been hammering hot metal in the forge for a few months really, but I enjoy it, and it's fun and it fills in time between detecting trips. 😀 Just a couple of the project I have finished This is forged from a Railroad spike and this from another Railroad spike cheers dave

On Thursday I hit up the beach I normally hit and found it sanded in. Even in the good spot. So I went further down and found even more nothing. Upon my return trip back to the entrance, I happened upon a target and discovered it to be a heavy and somewhat tarnished ring. Inside was stamped Mexico but it didn't have any other markings besides that. I got too ahead of myself I kept thinking it was 10k gold because it was tarnishing green and somewhat gold in color. Unfortunately when I finally did get back and ran an acid test on it, it was not 10k gold so im a bit disappointed in that. Oh well a ring is a ring. Today I hit up 6 beaches to find a beach that would produce. Went to all my regular spots, but found practically nothing except this one silvery pendant that I initially thought was a junker (due to the gemstones initially looking like plastic in the sun when I dug it out). It has the color of silver and when I looked again, the gem in the middle looked like it was cut, while the ones above and below shone like opals. I reckon that they're likely to be real. Still it was odd that it rang up as 24-26 on my legend. No luck on the beach search though, everything is pretty much sanded in for now. The last beach I did go to had a pier or something that went out towards the ruins of an old ship. Unfortunately that pier got wreaked in a storm, and so did the ship, so they tore it down recently. It would have been good to look there after they removed the pier but I was 2 days too late. Missed out on some silver but its alright. There's always new opportunities elsewhere.

I was asked for a review on the Manticore: I'll say this: There are a lot of machines around that are promoted as having "fast process". The Manticore also has "fast process" but it also has "depth of process".--call it "thoroughness." This is what all that advertised power is doing. What this means is that it can "go around / through things" such as viscosity in ground ie black sand, fast salt water, iron or other alloyed targets, a reject block, or even it's own speed for example. Very impressive in this respect. At the same time it's still limited by simple physics so some of its Sensitivity is hard to deploy. I like Neils idea of stacking all the filters ie edge "firewalls" in the FE Limits plus segmented audio plus All Tones. The processing is certainly better than the NOX and this is evident from how it does not need that heavily digitized slightly latent response (Prospecting mode-ish) The Mcore sounds a lot more like the CTX and processes at a simiilar level with Multi IQ acting to stabilize it around iron. Also a superb iron masking "ratio" it hits small coins with a big spike in the hole --never seen that before. I have a few notes and may publish something eventually but still a lot to learn. cjc

I've been detecting for gold nuggets for several years without finding any Au. As many of you know, almost everything else is found: bullets, fragments of bullets, fragments of fragments of bullets, bullet casings, nails, hob-nails, foil, lead sinkers, lead shot, and the list goes on-and-on. We'll I finally found some Au! The first time out with my new Garrett Axiom after some backyard and nearby gulch practice I went to a southern Arizona location with a local detecting buddy. We have both been on a quest to find some gold. On a steep rocky hillside and after finding several lead bullets and a big jacketed rifle bullet I thought I found another when a large signal was heard. About three inches down was a flat dark dirt covered rock that was unusually heavy. My first thought was "that's a funny piece of lead." I called my buddy over to take a look at it. He hollered and identified it as a specimen piece of a gold vein! After all of our searches we were finally on the gold! After hundreds of hours of detecting my only hope was to find some small or tiny piece of a nugget....anything. What I found was about 3.6 ounces of specimen. I'm not certain how much Au is inside but I'd guess about one-half of it. I've scrubbed it with dish soap and also liquid Bar Keeper's cleaner but the gold is not clearly visible except on the edges. The piece is about 2.2" long, 2" wide and 1/2" thick, so it clearly is a piece of mineralized vein. I may consider cleaning it with Muriatic or hydrofluoric acid to remove everything except the Au and quartz, but it is such a nice example of a thin gold vein it I'd rather not damage it. I'm most impressed with the Axiom. I was using the 11" mono coil on a steep brushy and rocky hillside. The detector is well balanced and easy to use with only a little practice. My detector settings were Fine, Slow, and Manual ground balance. Unlike my past VLF detectors the Axiom virtually ignored the mineralization and hot rocks. This meant I could detect almost continuously with only an occasional manual ground balance. I'd guess compared to using a VLF machine I covered twice as much ground with far more confidence in hearing targets. For all of you still searching for your first gold detect I say stick with it. Perseverance pays off. One of the best suggestions I've heard from an experienced detectorist was to first be sure I was detecting in an area of known gold. Good luck and keep detecting. Az_Ed

Really nice find. It must be specimen week for Axiom in AZ! Yours is a lot nicer than mine, but I'm tickled anyway.

There has been quite a bit of discussion about the Deus audio and how target TID can differ from target audio. In my effort to learn the D2 more thoroughly, I've been trying to learn the sounds and diferences between Tones vs Pitch vs Full Tones and PWM vs Square audio. I came from a square tone world so working in PWM has taken some getting use to, but I am finally starting to get the hang of it. I still like Square audio and really like Pitch tones, but have forced myself to use Full Tones in PWM to train my ears. One of the main advantages I am learning with PWM is that it gives more subtle audio information that can help with identifying targets. I was reminded of this again last weekend when I was invited by a detecting buddy to help out on a Ring Rescue mission. He is the consummate jewelry detectorist and a member of Ring Finders. So I met up with him a tiny house to look for a lost wedding ring set in a small gravel covered yard. It was a short hunt and we both covered the area with no luck. Since we still had an hour or two to kill and some sunshine to burn, we decided to hit a small park that I had never been to. This is when the D2 decided to teach me another lesson. I decided to start off in the Silver Slayer program (Fast, Notch to 40, No upper Notch, Pitch in Square audio) to cover more area in the short time we had. I had only travelled a short way across the field glancing at every good sounding TID looking for nickel and dime to quarter range signals when I noticed a recurring 57 number popping up. That's usually a junk target in my parks, but as the D2 would explain, not always. That's when I stopped and changed back to my Fast Full Tone program with PWM audio and retraced my steps. I could hear a familiar wavy/scratchy with iron bump sound with most of the 57s but one sang out hard and round. I dug all the 57s and I'm glad I did, because the really good sounding one turned out to be a 10K gold ring with a heart shaped Fire Opal two small diamonds! The D2 reminded me to stick with the lesson program and complete my training and I will, although I'll happily accept more lessons like that! 😎 To recap the lesson plan: See with Your Ears...

To summarize: For every target there is an optimum coil size, and going to a larger or smaller coil than that optimum will get you less depth. To repeat, going to a larger coil can lose depth if the coil you have is already best for your target. People swinging super large coil sizes are losing depth on the most common targets sizes and only winning with the largest. Conversely, there is an optimum target size for each coil, and both larger and smaller targets than the optimum will lose depth compared to using a coil optimized for that size. Most detectors are optimized for coin size targets using an 11" coil. Smaller targets benefit from smaller coils, and larger targets from larger coils. I should mention mineralization and EMI also. Large coils see more of both relative to target size. These two factors work against larger coil sizes and can negate some or all of the theoretical gains.

Interesting. Minelab added the entire month of April to the GPX 6000 promotion. Sales must be hurting pretty bad, due to a huge sales decline in Africa with the detecting gold rush they’re finally petering out. Then add in the benefit of this being a response to the Axiom at $3995. Just shows that this was a $4500 detector all along I guess, and competition is forcing Minelab to give up the extra profit they were pocketing. The GPX 6000 is worth $500 more than an Axiom, but it sure is not worth $1500 more and sales may have reflected that. 25% off for two months - wow! And will it end there, or is this just the new MAP price? How do they go back to $5999 after doing this for two solid months? Sales would stop dead if they do, as after two months it looks more like a $1500 price increase, not the end of a sale. Minelab Promotions for the Month of April: Minelab GPX-6000 $4,499.25 Extended Sale Minelab Equinox 600/800 with Free 15" Coil $599.00/$899.00 Minelab CTX-3030 with Free 17" Coil $1,999.00

Old clad, 100+ years from now zincolns might be sought after 🙂 Heres a few from today. Small button, cap and top to old tube maybe some lotion or paint. has a lead or pewter with brass screw cap, large cent (no readable date), another possible kg half penny but also in tough shape, 43 war nickel (first find of the day) and a nie 1773 seated dime. Used the Tejon with 8x9 concentric, handled the small iron like a champ, good targets had nice tones and easy to pick out even the dime that was 9" down.

I made up this crevice tool, it's for scratching the gold out of the cracks in the rocks and rock bars. The scraping part of the tool is hardened and tempered 5160 spring steel, and the basket twist handle is made from 6mm mild steel rods. I think it might just work ok, you know those little bits of gold that get jammed in the rocks that the pointy end of the pick is just a bit to wide for. The Crevice Tool cheers dave

I'm from Idaho and we just got back from a detecting trip to Maryland. I found this button but I'm not very familiar with stuff this old. I have Albert's book, but I can't find one exactly like this. I know you folks know everything so I'm asking for your help. Could it be British? There is a circle around the shank on the back but no writing that I can see. I don't really want to clean it much more than I already have for fear I'll lose important parts of it. It's a bird sitting on a fouled anchor, but the bird looks like it has a crown on its head and the wings are spread differently than most of the US buttons. Thanks

I learned something from this story. I never imagined. How one woman helped start the California gold rush (fox40.com)

Ditto that! I think we've had 3 public updates since the D2 release and the V0.71 was substantial and gave us a lot of what we had been asking for. When I bought mine it came with the second version of V0.6 and I used that for a month or so before updating to V0.71. Even for a XP noob like me, I could tell there were marked improvements. Now, after using V0.71 for almost a year and learning the D2 more, I'm really liking it and I can work with this. I still feel the D2 was the best purchase I could have made for the types of detecting I do and haven't felt the need to buy any of the other new ones. JMHO.

The coil output is fixed, so you get a more intense small field with small coils, and a larger weaker field with big coils. Keep in mind also that when comparing concentric and DD coils with mono coils, it’s the area of the receive coil that matters most, not the physical size of the entire coil. This chart shows how medium coil sizes are the happy medium, and the benefits of going smaller or larger. In this case they should have tested a half pennyweight nugget, which would have done best with the 10” coil. Coil Size vs Depth Fisher Gold Bug 2 Source - Field Testing the Gold Bug 2 by Gordon Zahara

Click to view field book

The very use of different coils on the detector with which you detect ... is a bit of rocket science ... where the physics of the size of the coil determines the following depth and separation properties. not only in various tests ... but ... which you can also notice in practical detection on certain terrain...when you change different coils on your detector...and you have at least 50-100 hours of detection on such terrain.... First of all, you can notice...that on a modern detector with an adjustable recovery speed...the 11" coil can do a lot of work.....but it cannot detect all targets...whether deeper or masked by iron.... Remember that it's an 11 coil, it's a standard coil .. and it's a compromise between good depth and pretty good separation... if you want better depth or separation ... you must have another coil ... of a different size ... And that's why, in further detections, other coil sizes come into consideration... which can really pull out other targets in the field... Many people think that the smaller the coil, the more it can unmask more targets than an 11" standard coil... but the truth is that really small coils can better unmask targets in iron only to a certain depth... and for coins masked at a greater depth already such small coils do not have enough power to unmask a deep target... Now we can ask ourselves the question,,,,, what size coil can best unmask very deeply masked targets?.... From my observations from detection...from the field.....but also specialized... 3D deep separation tests confirm one thing and that is that the 8.5-9" coil can best detect very deeply buried and camouflaged targets quite close it depends....where not even 11" standard coils but even small 5-7" coils can do it so well... In.. *Super deph 3D Separacion test: very small 14mm -0.45 gram silver hammered coin placed at a depth of 17.5 cm...in terrain.. 1.test 8.3" x 9" DDcoil /23CM DD Rutus coil/ vs. 11" Standart Rutus coil.. in 2.Test: ------------------------------------------------ But if we take into account that we have a relatively clean field with a minimum of iron.. which is little or slightly mineralized.... then the best deep results are achieved by large coils.. in this next test, I tested different coils on 3 deep targets to find out what sensitivity I need to set on my detector in order to reliably hit all 3 relatively deep targets... The first marked column of the table is the minimum sensitivity when working on multi-frequency /M/, the second marked column is the minimum sensitivity required to detect targets on 1 frequency of 15.8 khz.. .The third labeled column/M/ indicates, for some coils, what minimum sensitivity we need when shooting at multifrequency to reliably detect the deepest target on my test field, a 50 euro cent coin at a depth of 37cm... As you can see the ATrex on the big 15" coil needs only 55 sensitivity on one frequency15.8 and only 65 sensitivity on multi frequency out of.. 99 - maximum detector sensitivity .. to reliably hit all 3 deep targets... on my test field...

I found one SL half dime in my whole life (so far).---An 1854-O & it was found on 6/15/'19.----Found with the ORX & 9" h.f. coil---read like a zinc penny.-----I want to find a Bust (anything) coin---have never found one of them.

Hi all. I’ve had a few people on Facebook ask about my shaft setup so I thought why not make a thread about it in case others would like to try something different to the stock shaft. I’ve changed it around for a few months and found this is what I prefer. Only thing I would like is for the length to be a bit more adjustable. I may make a shorter interchangeable version. This version is also made to minimise chances something will break out in the water. Nothing worse than calling quits early because a part broke. personally, I do not like the original d2 shaft, it was too floppy, and I found that sometimes the drag on the coil would detect the aluminium upper shaft. This design is made to have little to no metal that can interfere with the coil. The other weak point is the mount, which would often come apart in the water if I bumped it wrong. I found that I do not look at the screen TID when detecting. My initial setup is putting the volume to full and changing to auto ground balancing, so I’m not bothered covering up the screen with straps. I used a T section as originally I had the d2 mount inserted inside it to mount the screen but I didn’t like it. Mind you, this setup isn’t cheap to make, I just have a lot of spare parts laying around so it didn’t really cost me anything. parts needed: detect ed aluminium equinox arm-cuff (plastic equinox cuff will also work but will break eventually and damage the shaft) $70 detect Ed carbon upper shaft: $120 ish I think 9” carbon tube (or broken carbon lower shaft) 1.5-2mm thick (not needed but helps): $? equinox 800 lower shaft: $45 minelab GP/SD handle: $35 stainless steel bolts (original will rust. I used some from my GoPro bolts and cut them down): $4 Pvc T section, about 1” : $4 brass washers and small stainless screws: $5 nylon coil bolts from GPX x2 (short and long are ok) $4 Velcro straps. I used 2 from bunnings and shortened them but you can get them online: $5 Zip ties ($2) changes: lower shaft is equinox carbon shaft. It is thicker so will not wear down and break as easy. Keep in mind that some models of this lower shaft don’t have a water drainage hole. drill it out if needed. I opted not to. A 10mm hole has been drilled through the bolt hole in the lower shaft . I can’t remember why - maybe to suit the Deus coil spacer. upper shaft has a roughly 9” carbon tube (old broken carbon lower shaft) glued inside to cover the equinox mounting holes, and to reinforce the top, as the screws need to be tight on the handle. Covering these holes also stop sand getting trapped in the shaft, otherwise your lower shaft will seize. Change the upper shaft collar bolts from stainless to the nylon ones. This lets you adjust them whenever, and won’t interfere with the coil. there’s a stopper in the top of the shaft, I drilled a 4mm hole in it to let water in and out. zip ties go around the coil antenna. They are also tight enough to hold it but not too tight I can’t remove them with my hand to ensure the coil is charging and light is flashing. drill 2 holes on the T section to thread your Velcro through. You can use zip ties instead but you’ll struggle getting the charger/headphone in and out. I also have a knife for cutting fishing line mounted to the side, but I found sometimes it jams with sand. You migut need a different knife to the one pictured. I hope this helps for anyone wanting to change it up

Even still...an iron filter/bias setting adjustment is only useful if you know it's there. My unit is new but didn't come with anything detailing what version it is and the hardcopy manual it came with doesn't have that in it. The download able version does, but I would have never found it had I not saw the posts here. Go easy on me...this thing just came Friday afternoon. I've still got to update it to whatever the newest version is too. All I've done so far is charge it. JCR - Correct on the soil. It's only 2-3 bar soil on the T2 platform. That was another reason I took it to that particular place...didn't have to contend with hot soil complicating things. And yes, the 11" round coil is the only coil I have. I didn't buy the Pro pack. I do have a 12x9 ordered though.

Depth gains are real but not dramatic unless the coil size difference is dramatic, as measured in square inches of coil size. This article below pretty much says it all. In your case if talking multi ounce nuggets, the 16" mono would be the way to go for now, until other larger options appear. But the gain will be a few inches at most, not double or some such thing. For every target there is an optimum coil size, and going to a larger or smaller coil than that optimum will get you less depth. To repeat, going to a larger coil can lose depth if the coil you have is already best for your target. People swinging super large coil sizes are losing depth on the most common targets sizes and only winning with the largest. Conversely, there is an optimum target size for each coil, and both larger and smaller targets than the optimum will lose depth compared to using a coil optimized for that size. Most detectors are optimized for coin size targets using an 11" coil. Smaller targets benefit from smaller coils, and larger targets from larger coils. I should mention mineralization and EMI also. Large coils see more of both relative to target size. These two factors work against larger coil sizes and can negate some or all of the theoretical gains. See the link below for details. Coil Size vs Detection Depth by Carl Moreland, on this website forum. A chart with notes from PI guru Eric Foster illustrates the relationship between coil size and depth.

Fantastic is the word. Your 1st gold has finally shown itself. What is most common (and it was in your desire as well) is the fact that most folks go many trips and even some a couple years or longer before they find the gold. Heck, even myself was the 3rd year of trying and purchasing different detectors before it happened. Now that you have a nice chunky specimen, be sure to not expect all signals to scream as loud. Practice to find the tiny gold and listen for smaller targets...so you don't miss the majority of nuggets. Great to see the enthusiasm and keep the swing going. Well earned.

I've almost had mine 4 months now, it's had quite a bit of use in that time mainly for looking for silver coins, it's had 1 prospecting trip and found me one single small nugget that was 0.06 of a gram, it performed reasonably good finding it considering I was using an 11" coil,, and if I was using the Nox with it's 11" coil I'd expect similar results, the jury is out until a smaller coil arrives there, so far everything is fine for that, the ever so slightest edge to the Nox 800 on the very smallest bits of gold, As for coins, hands down happy with the Manticore for a few reasons, I hunt in very mild soils and don't have a lot of trash so my opinion on mineralized soil or high trash areas would be worthless, however for my conditions its proving to be a great detector, it's better than the Nox 800 for EMI, I would say very noticeably better there, and the long EMI press actually works, and works very well. and I believe that's missing off the 900? Keep in mind I have no idea about the 900 so all I'm comparing to is the 800. The 2D target trace I find is a valuable tool, that's coming from soneone that liked the Target Trace on the CTX so I'm more familiar with using it and find it very helpful, the more information I can get about digging targets the better as I do dig in places I prefer not to dig many holes. The Target ID's are more bouncy than the Nox 800, I suspect mostly due to having the bigger ID range and also the higher sensitivity settings available on the Manticore, so if I keep my sensitivity lower I can get my Target Id's to perform on par with the Nox for the most part, even with having the bigger target ID range. Keeping lower sensitivity seems a good tip for the Manticore, if you're chasing depth it really doesn't even matter if you lower it, the Manticore is very deep even in lower sensitivity so if you have to stabalize the machine by running lower sensitivity you don't have to be worried you're losing depth. I at first didn't like the bigger ID range as it does cause more movement in Target Id's but the more I used it the more I found the benefits of it, prime examples were my common pull tabs, on the Nox they show up 16/17 sometimes flicking to 15 and on the Manticore they're coming up 42 to 44. The NZ silver threepence comes up 15/16 on the Nox but comes up 36 to 40 so with the Nox the silver and pull tab was coming up the same numbers, the Manticore has moved the Silvers slightly below the Pull tabs in the numbers so I can dig more silvers with less pull tabs. This obviously doesn't help with coins on edge but it sure helps dig less holes and less pull tabs than with the Nox. With the Nox I used the depth meter to try dig less pull tabs and more silvers, and the silvers were often deeper having been there longer. Now I have more ID information along with the depth meter so more information helping me dig less. Digging less is important to me as I don't like digging in the areas I detect as I want to annoy people as little as possible to retain access. The build quality is a lot better, I have no fear of breaking my ears and if I do its a lower shaft not a new coil so that's much better, everything about it seems better quality. It's got some messy adhesive around the seal area on the control pod, but looking at it closely it's not going to affect the waterproofing, it's cosmetic, the glue is doing it's job just fine. It appears they applied the glue, fixed the pod together and when dry trimmed off the excess glue that was protruding so it makes it look quite messy. It's more comfortable to swing than the Nox, perhaps the new raised arm cuff and different handle design. I've only had it at the beach for 5 days when I was staying near a beach area, it performed very well, unfortunately didn't find me much as my beaches in that area are very desolate of targets, so few people doesn't make for good detecting but I got a good feel for how it works in the salt and I was impressed, depth was great as was stability, the coil moved through the water just fine too. I wasn't concerned at all about drowning it which was a nice feeling not having that in the back of my mind all the time. So yes, I'm very happy, glad I purchased it and I suspect I'll be even happier when the other coils arrive. Is it worth the price difference between the 900? That's one only the buyer can answer as the value difference means more to some than others, for me it made little difference as it's just like buying another coil or something and the difference between the two detectors for me personally is well worth paying for. I'd have a lot more trouble justifying buying the 900 than I did the Manticore as an upgrade to the 800.

Here's the equation I came up with for an effective diameter: Using nominal dimensions the 5x10 is 6.32 and the 7x11 is 8.35, both remarkably close to GB's numbers. To add to Jason's post, increasing coil diameter has a double effect, both on the TX side (which Jason covered) and on the RX side. The two are similar, in that curvature of the B-field limits the effectiveness of the coil depending on diameter vs target size. If the target is small enough, its eddy B-field presents both the positive and negative flux to the RX coil, resulting in cancellation and no detection. But right at the edge of the coil, geometry works in your favor and you can detect it. Eric Foster made a chart of coil size vs optimum detection depth: "Here are the curves I have used for many years. The range reaches a maximum when it is equal to the radius of the coil. Coils larger or smaller than this optimum will result in less range. To show how this works, along the bottom axis you see coil diameter, which is obviously 2 x the radius. So for an 11in coil, if we go up the vertical scale to A, we have 5.5in. Also note the diagonal line and the series of ever increasing semicircles. Everything to the left of this line shows increasing detection range up to the maximum where it intersects the line, then decreasing range to the right, where the semicircles are shown dashed. If a certain metal object is just detected at 5.5in with the 11in coil, then going larger in coil size will cause a reduction (going down the dashed side), and going smaller in coil size will have a similar effect. Initially, it won’t be much, i.e. going from an 11in to an 8in coil will only make 0.5in difference but below 4in diameter, the range will drop rapidly. Now, suppose with the 11in coil, you can detect an object at about 12.5in (B on the vertical scale. This indicates that the coil is not an optimum size for that particular object. If we carry on up the curve (direction of arrow) we can see that by using a 20in coil, we could gain another 2.5in (C). The curve peaks at 15in with a 30in coil. But the extra inch gained hardly makes such an unwieldy coil worth while. Other factors come into play of course. The curves assume that the number of turns and the coil current is the same in all cases; which it isn’t necessarily. For the same inductance value, a smaller coil has more turns, which counteracts to some degree the loss in range. Also a smaller coil will pick up less electromagnetic noise, earth’s field noise and ground effect, which make for a smoother threshold. The end result is, that with a small nugget that can be detected at between 5 and 7in with the 11in coil, so that it is on the top part of the curve, an 8in coil may well give a similar range. That is not to say that smaller coils do not have other advantages. Small coils and probes are very useful in rocky areas or searching in undergrowth. They have less drag too for water hunting, and less pickup from mineralised soil or conductive sea water plus better signal separation on close or multiple objects. One other point regarding PI, is that the small object sensitivity is largely determined by the sample pulse delay. If an object is so small, or thin, or made of high grade stainless steel, such that all the signal has decayed before sampling takes place, it would not matter how small a coil you made, it would never be picked up. Eric." Jason, I'm curious what FEM software you were using. - Carl Edit: Thanks (Steve, I presume) for embedding the chart, I've deleted the link. Didn't occur to me that the link only works for Geotech members.

Hi everyone, my name is Chris im 49 and I live in S.W. Oregon, in pocket gold country right in between the Goldrush towns of Jacksonville and Gold Hill. I am into Hunting, Fishing and Hunting for gold! Basically whatever allows me to wander! I have never really been a forum guy, just some after sundown internet time for info and entertainment but not much posting because of all the mess that always seems to go along with the forums. Iv’e been lurking here for a while and I haven’t seen any of that yet here so I joined up! Im not sure how active of a poster ill actually be but am going to give it a try, anyways just checking in with my first post to intoduce myself and say how much I have already enjoyed the great info here!

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 😁).

That's one of the under-rated performance advantages the Manticore has over the Equinox 800 and I would guess the 900, it's ability to handle EMI better, either by the detector itself, it's long EMI noise cancel being better with EMI which to me it seems to be, and add the FACT that it's deeper in lower sensitivity levels than the Nox, this is a big advantage to the detector over the Nox. The Manticore on 16 sensitivity seems to keep up with the Nox 800 on deep coins when the Nox is on 24 sensitivity. It's why I believe I had good luck with the Vanquish over the Nox in high EMI areas, as the Vanquish handles EMI better than the Nox, to me the reason is unknown, frequency weighting? Frequencies being different enough to the troublesome EMI frequencies or the Elliptical coils perhaps. I did very well finding coins that I had possibly missed with the Nox due to the Vanquish being able to run in higher sensitivity settings than the Nox in these areas. You can see in this video I can run the Vanquish 1 notch off full sensitivity in jewellery mode (the most sensitive) with no real EMI troubles, in the same spot I have to wind the Equinox back to about 16 to get it as stable as the Vanquish in all modes, and with the Nox I'm using discrimination to knock out some of the EMI with all the default iron blocked out, if I go to all metal it's worse, the Vanquish I can have all targets wide open. So the question is, is the Vanquish v12 12x9" coil being elliptical less prone to EMI? If that's the case it's a demonstration of why the Vanquish did better at this particular spot than the Nox with it's 11" coil as I was getting deeper coins missed by the Nox because of the Vanquish's coil being slightly smaller and elliptical being less affected by EMI so I could run my sensitivity higher thereby giving the smaller coil more depth. I had the 11" coil on the Nox at this spot as with my usual 15x12" coil EMI was even worse, so the smaller coil was the better choice but dropping back to 6" cut the depth far too far and became counter productive, better with EMI but nowhere near deep enough to find anything worthwhile. I didn't have the 10x5" at the time but it's not deep enough to find many of the coins I find in these areas, that's been well tested.

This point cannot be ignored but that seems to happen too often, even in some posts in this thread.... Certainly Eric Foster understood this and said as much in at least one of the two posts quoting him here. "Know the assumptions!" is a lesson I was taught long ago but even with that and decades of experience I still lose track of it sometimes. Air tests have assumptions. If you ignore them you're eventually going to be wrong drawing conclusions when those assumptions don't apply.

That Gold Bug 2 chart is real and carries over to all types of detecting. I've had nuggets that a small coil picks up where as a bigger one won't see at all, and I've had coins where the 11" coil hits on them and the 10x5" coil misses them entirely. Most of my coins are deep, If I use a smaller coil I'll only find the junk modern targets that are often more shallow and next to no silvers as they are deep. Even with the GPX 6000 I found a nugget with the 11" stock coil that's JW's 17" GPX coil had no response on at all as the 17' just didn't have the depth of the 11" on this size target. I've seen people wondering if the new 12x7" Nugget Finder coil for the 6000 will be as deep as the 11", I'm confident it is not in the right targets, but it will be deeper on smaller targets, there will be a sweet spot target where the 11" shines over the 12x7", that's just a fact and it's how coils work. You use the coil that suits the job you do, for gold with my gold mostly being small but also quite deep I increase my finds by using smaller coils, for coins mostly being deep and not a whole lot of trash the bigger the coil the better. I'm fortunate to have a rather large collection of coils so I've had a lot of time using a variety of coils to work out which coils suit me best, especially with my GPZ where I'm fortunate to have almost every coil ever made for the detector so you get a bit of a feel about coils performance with target sizes and depths and if only buying one coil you want a middle ground coil that's good on everything but not the best of course, this is why VLF general purpose manufacturers have settled on this 11" size.

There's probably a way to reason this out with sufficient knowledge of how detectors work. The easy solution is to look it up in the book I've touted here a bunch of times over the years (cf. p55): Note the heavy gauge wire used in the TX coil versus the much smaller gauge RX coil wire.

Aureous - How is the Y axis noise of the Xceed vs the Coiltek 10x5?

I think all the coils available have their strengths & place. A couple of Concentrics would be nice. My last three Seated coins were all Dimes. 1876 was in the best condition. I would like to find a Half Dime too.

Snuck out to a permission nearby for couple hours and snagged some old clad and a nice silver spoon. Not shown was a couple small flat buttons and a buckle. All finds go to the owner of the property as she collects the stuff. Want to thank Valens Legacy. Took that Pentagram pendant and turned it onto a keychain. Guess it does bring good luck, who wudda thunk? :)

That's sort of the setup I have too. I bought the machine with the 9" figuring it would work the best in target rich environments, and that I'd get the 13" for beach/field use. I'll be there in England pillaging your fields starting at the end of this coming week! 😁

Wow! 25% off the GPX-6000 for the month of March and its just reaching its second year anniversary. It’s always good for the consumer when two competing companies are trying to keep sales up and use pricing to achieve that goal. If these recent sales prices our part of this goal and could remain in a long term competition, then its going to be a very competitive market for these high end detector. Note also, the 15% military discount Is now also offered by both companies. The prices added in the list below do a fairly reasonable job at separating out the performance verses current pricing options on the higher end PI detectors. The only caveat to this is If pricing and performances are close together I would always choose the three year warranty option though. Below is the price list including the most recent February/March sales prices offered on the most high end Pulse Induction detectors. ATX $2,379.00 Weight with 11 x 13 inch mono coil 7.0 Lbs. Water submersible. Lots to offer for coil sizes & coil configurations to achieve small and fairly large gold performance. Offers partial iron discrimination with DD coils. 2 year warranty SDC 2300 $2,550.00 February SALE vs. $3,499. Weight with 8 inch mono coil 5.3 Lbs. Water submersible. The MFP timings with the small 8” coil seems to handle higher mineralization pretty well. Very small gold performance. 3 year warranty Axiom $3,995.00 Weight w 11 inch mono 4.2 LBS. Very small and fairly large gold performance. Offers partial iron discrimination with DD coils. 2 year warranty GPX 5000 $3,999.00 Weight on arm minus battery pack 5.3 Lbs. with 11” coil. To be wireless you need to add Doc’s Gold Screamer battery and booster pack 6.3 Lbs. Largest offerings for coil sizes & coil configurations to achieve small and large* gold performance. Offers partial iron discrimination with DD coils. 3 year warranty The GPX-5000 could definitely use a price reduction also but is still one of the most versatile PI detector on the market. *Note: Coiltek Elite & Nugget Finder Evolution coils add more performance and sensitivity over previous released bundle wound coils. GPX 6000 $4,500.00 March SALE. Weight 4.6 Lbs. w 11 inch mono. Very small and fairly large gold performance. 3 year warranty GPZ 7000 $6,375.00 February SALE vs. $8,499,00. Weight 7.3 Lbs. w 14 inch DOD coil ZVT or 6.0 Lbs. with the Nugget Finder Z-search 12 inch coil and compatible CTX-3030 Li-ion battery. Minelab’s flagship detector with very small and exceptional large gold performance. 3 year warranty Please do not get to excited about the iron discrimination capabilities on the ATX, Axiom, & older GPX series, as it is only has partial discrimination at best. Works good on surface iron, but for any deep iron you will still need to dig quite a bit of dirt until your detector can determine it is iron. The only chart that I could find to show this was a GP-3000 Minelab chart showing its limited discrimination abilities, attached below.

Any signals which match a 'notched' TID will be 'rejected' and not make any sound. I think this works in multi/full and pitch tones - it would make sense if it did. If you use notch in pitch, you can preselect which TIDs (TIDs being a proxy for conductivity) will not make any sound.

When you save a program, you just save the active settings. So if you've selected pitch tones, that will be what gets saved. If you had previously been in, say 4 Tones and you had edited the 'stock' bins for that program, your changes would only be remembered until the machine was switched off. Tone bins only really mean anything when the conductivity (as approximated by the TID) governs the frequency/pitch of the sound you hear - which is not the case in Pitch Tones (it's a confusing name really!) - the frequency/pitch you hear in this case only varies by size/distance.

I didn't even see the version numbers up there before. I looked when I got home. Mine is 1.09. It'll have to stay that way for a while: busy week ahead for me. I bought the LG30 over the others because it seems to be the one everybody seems to be liking the best. I wouldn't have thought there would be much difference between the 11 inch round stock coil and a 12x9, just looking at the dimensions. I would have gravitated more towards the LG24 if it would have been me just going for a coil based on specs. But I've seen very very little out there about it. Seated silver doesn't come often for me either. East Tennessee just isn't known for producing large numbers of silver coins from that Era. It has been years since I've found a seated coin. My last one was probably 2009 or 2010 and was a couple of seated half dimes. This is the 1st seated 10c dime I've ever found.

I found a 1850-O SL dime 4 1/2 yrs. ago--CTX w/6" coil--would that do? 🙂

Controled tests mean nothing unless you have two 6000's, one with the stock coil and one with the 12x7 and run each one over a real target (Gold) undug, undisturbed to see how they both fare. Anything less than this and the results won't be accurate. Some people might be ok with leaving the 12x7, 5x10, 9x14 coils on all the time, but I can't afford to make that mistake again after having done so with the 9x14. The 9x14 was missing small gold! This went on for a month before I realized it couldn't compete with the 11"stock coil on small gold. I hunt for gold for a living with a detector and will continue to take each coil over same ground to make sure I don't miss anything.

A truly beautiful tool. Great job.....

Got more gold today on the local North Saskatchewan River. I ran the Geo Highbanker at about 8 degrees and it worked flawlessly! I also dug up a relic, a fossil and lots of petrified wood. https://youtu.be/wagfh2yD_ao

It's obvious that things are not going well for these guys. Having the actual entries here I know the ending. Of course with mining, sometimes you get lucky. And sometimes you go broke.

Wow Carl, I was thinking of exactly the post and chart from Eric, and it was on my list to track it down and post here. Here is another quote from Eric - I used this tidbit as a general rule for a long time: Coil/target optimisation can be quite complicated, but it can be broken down into a number of separate considerations. I will deal with just one, at the moment. The diameter of the coil in relation to the target size is perhaps the most dominant characteristic. If we look at a mono coil, which is the simplest to understand, the optimum coil size is one that detects the target at a distance equal to the coil radius. e.g. if you have a 10in coil that just detects a target at 5in, then going either up or down in coil size will result in less range. If, however, your 10in coil detects a target at 10in, then the coil is not optimum, and going to a larger size will give more range on that target. In fact, the optimum coil for that target is 27.5in diameter, and it will detect the target at 13.7in. Say your target was big enough to detect at 15in with the 10in coil. The optimum coil size would then be 46in diameter and the target range 23in. Coil sizes get bigger quite rapidly, and more cumbersome, but because the coil radius/range curve is very flat as you approach the optimum, you could reduce to a 30in coil and still get just under 23in. All this assumes that everything else stays constant. i.e. TX current, inductance etc, and also pickup noise. If I can find it, I will post a graph of coil radius/range curves. Eric. Anyway, thanks for posting that Carl, saved me a little time searching my hard drive archive. All ways of saying that for each target there is an optimum coil size, and going too much smaller or larger loses depth. But that is air tests - the caveat always is ground conditions. We have target masking, extreme mineralization, and EMI to deal with, and very often the solution is a smaller coil. Yet manufacturers have tended to cater to the burgeoning number of amateur testers that quote air tests or tests in clean low mineral soil, leading to machines actually optimized for those conditions with larger coils. White's move from the 9.5" coil on the MXT to the 12" coil on the "new" MXT 300 was that kind of a head fake. Same detector, but "new, improved model with more depth!" Well yeah, because the coil is larger. And frankly not exactly true. Depth actually was worse under some of the conditions I have described by going to the larger coil. I think new detectorists in particular would benefit from using more moderate coil sizes when starting out.

No such thing as "old clad". Clad coins generally didn't come about until the 1960s.

Still a good hunt as you were able to find some items, and get some exercise. Good luck on your next outing.

I'm curious. Why does the title of your post say clad? I was expecting something completely different. 🙂

I have all three, the one I use least is the 11 inch.

That's one elegant scraper Dave. Your smithing skills are a credit to you-

I personally felt the 15x12 coil for Nox was a fine coil for what it was. Great coverage, obviously, and excellent small target sensitivity for its size but because it was really just a 12-inch stretched coil, minimal depth gain over the 11" stock round. As a result, I would only primarily only use it for coverage on low mineralized sites (non-submerged beach detecting or non-mineralized farm fields) and even under those circumstnces, was hesitant to make the effort to bolt it on to my Nox because of the weight (despite being tied with the Nox 10x5 in swing coverage to weight ratio). Now I primarily just keep the 10x5 permanently bolted to the Nox as it is a more universally compatible coil for a variety of detecting situations and makes for a super light setup with decent swing coverage despite a moderate depth penalty. If I want to go deep, I'm using the D2 and it's 13x11 behemoth. Also remember, everyone here is extrapolating their 15x12" coil experience from the Equinox (600/800 primarily) to the Manticore (while the OP is considering the forthcoming Manticore variant). So all the speculation should be taken with grain of salt because we know the Manticore reacts to beach targets differently than the Nox 800 and even the 900; we have zero data on how Manticore behaves with any other coil than the stock; and we have no idea whether ML will tweak the 15x12 coil design for Manticore in some respect to trade off one performance attribute (e.g., depth) at the expense of another attribute (e.g., small target sensitivity) making the Manticore 15x12 variant behave a lot different than the Nox 15x12. So while they SHOULD behave similarly, there are a number known unknown variables that may impact the final outcome. Just a reminder...