GB_Amateur

https://www.ebay.com/itm/197808878981

TF MINI device works WITH built-in radar detection system to detect and search for radioactive ionization of precious metals buried underground. How many erroneous things can be crammed into one sentence? 1) Radioactive elements don't give off radio waves (which is what radar uses). 2) Ionizing radiation is rare for most elements found in the earth's crust. Uranium, Thorium, and their daughters (including radium and radon) are the exceptions along with potassium-40. Last I looked these aren't 'precious metals'. 3) Alpha and beta radiation (and the much more rare fission fragments) are charged and don't get through much material so to detect those the materials giving them off need to be on the surface or very close to the surface. Gamma rays and X-rays are neutral, being part of the electromagnetic spectrum, but still scatter if not absorbed, so localizing their source would not be so easy. Neutrons (also neutral) scatter more easily than gamma rays when they aren't being absorbed. Check out the currencies they accept. (Note they don't list a price but are glad to tell you they accept credit cards AND bank transfers): USA Dollars (of course), SAR (Saudi Arabian currency) and the UAE Dirham which apparently is also used some other countries in southern and eastern Mediterranean and Middle East. Aren't there other parts of the world where people can be duped? Oh, but the devices are actually made in the USA (according to them).... Move over LRL, you've got a serious competitor.

Nice video. It's impressive that you can do a cable replacement and make it waterproof. Waterproofing is one of the most difficult properties to maintain (stating the obvious after the much publicized Equinox debacle) and to be able to do it "in the garage" is particularly commendable. It's one thing to be a crack detectorist but to also have the skill and willingness to perform useful modifications goes above and beyond that. It's no wonder you are so successful. Your Fisher AQ experience is another example. While a lot of people were whining and complaining about its shortcomings, you modded yours and then went out and reaped the rewards.

Do you know how it's colored? I assume by this statement that it's not gold plated. One of the 'problems' (for detectorists) with pure tungsten and tungsten carbide is its density, which matches gold's closely. Even the carbide compound's density (or specific gravity) is close to 18k gold. That's one fewer diagnostic tools in our toolbox. Glad to see you found some of the real stuff anyway.

Feeling a bit guilty for veering off topic, here's part of my collection of magnification devices I use frequently, including for investigating MD'ing finds. I realize that Jim is looking for something he can rely on the field, but the subject line is more general so these should fit the topic: Only the two in the bottom right (metal housed and black plastic housed) are compound (i.e. containing more than one) lenses. And, yes, some are plastic 😉, e.g. the ones in the headset. I think the 10x lower right metal housed one is referred to by Barry in his earlier post, although not his first choice. I use all of these indoors but possibly the cheapest of all shown, the one in the middle (with faux alligator case), is my favorite to take into the field. It has a wide angle view which its portable neighbors don't. However keep in mind that I'm using it to identify coins, relics, etc. For geology use in identifying minerals, etc., I can't speak to that and pretty sure Jim was most interested in that application.

I wasn't questioning that acrylic lenses exist, only whether or not they are used in eyeglasses. In my post I linked a (detailed) Wikipedia article on corrective eyewear including materials used for that. It fails to mention acrylic (PMMA being the solid form) although the monomer MMA (methyl methacrylate) is sometimes used in today's soft contact lenses. Back in the early days it appears that PMMA was used in contact lenses but that practice apparently ceased decades ago.

I'm a bit confused. Your eyeglass lenses are acrylic? In my experience, when people refer to acrylic solids they are referring to PMMA which goes by many other names, including 'plexiglass' and 'perspex'. My eyeglass lenses are polycarbonate. A common (but far from exclusive) trade name is GE's 'lexan'. Here's a very good summary of materials used in eyeglass lenses.

Isn't the White's 4"x6" coil for the GMX the one which Garrett chose not to continue producing when they re-introduced the 24k?

Yes, getting a certification, and paying shipping and insurance is probably going to cost you about the value of the coin, or at least a good chunk of that. Some people have recovered coins and reported not getting that "Scarlet Letter" from the certification service. IMO, except possibly the coloring, yours shows no signs of being in the ground. Bottom line is that if you really wanted to cash in you could probably get decent money on Ebay, but keeping it as a display piece, etc. is certainly a good plan. That's what I would do if I found such a beauty.

Who is the manufacturer of that coil?

I highly doubt this was dropped recently, particularly for the reasons you just stated. Besides the initial condition when dropped, the 'final product' depends upon the chemicals in the location it rests. This one certainly has taken advantage of benign soils and you are the fortunate recipient! Over 80% of the USA 2 Cent pieces were minted in the first two years -- 1864-65. I think all the ones I've seen here on this site had one of those dates..., until now. And, yes, the condition is amazing. I'm not sure a coin can get an AU grade if there isn't some mint luster, but if that's the case then yours has to be among that grade's sub-categories.

That's good to hear, but how about telling us why? What are its best features that set it apart for you?

Nice writeup, Simon. A while back (as in a few years) I was lamenting the seeming lack of a comprehensive coverage of pinpointers here (where what is said can be taken seriously, else gets appropriately shot down). I won't say you've done the complete job (see below) but 80-90% of it anyway. I realize you can't buy every pinpointer on the market (well, you *can* but shouldn't be expected to 🙂 ). One that seems missing is/are from Quest. Could someone else here give a review on that/those? Personally I've been quite satisfied with both the Garrett Carrot (ProPointer AT) and White's Bullseye TRX. The former is, for me, appropriate for all the detecting I do (coins+relics and occasionally native gold). The TRX is along (and used) in parks and school yards with its forward ('flashlight') sensitivity great for honing in on small targets AND especially allowing me to dig around them, avoiding gouging into them. But I start with the Carrot's nearly isotropic (all directional) detecting view until it sounds off to get me in the ballpark, then switch to the high magnification TRX.

It really depends upon what you mean by this. Is it worth getting it operating (which sounds like in the least you need to find that weird battery)? I want to bring you down gently, but the answer there is "not very likely". Is it of value to a collector or someone with nostalgia? Probably not, but hard to give a definite 'no' since people collect a lot of things (I'm guilty of that🙂 ). Within less than 8 years of its manufacture the next major step in metal detector capability -- VLF technology -- was introduced and that pretty much put the Transmitter/Receiver (TR) detectors out-to-pasture. And a lot has improved in the 50 years since then.

Sorry? 25G's? You and me both else we'd each own one! I did a bit of digging and some back-of-the-envelope calculations, enough to realize I can't rule out their ability to "see through" gold plating. I used to get paid to dig into this stuff and could spend days/weeks/months on a deep dive. Not gonna do that and given the cost of the device and lack of experimental equipment, the best I could do would be writing a detailed simulation. No thanks. 🙂 The issue is getting the X-rays through the gold alloy plating and then getting the characteristic X-rays back through this same absorbing layer to the sensor/detector. The atomic numbers of the underlying elements (substrate) are low enough that their characteristic X-rays (that allow them to be identified) have low enough energy that fighting through highly absorbing gold can be an issue. The good news is that, apparently, even thick plating/gilding is only about 2.5 micrometers in thickness. So there isn't a huge amount of gold to kill the photons on their way in and out. But the devil is in the details. @jasong has looked rather deeply into XRFS guns and I recall a fairly long post of his where he outlined the pitfalls involved. (I'll see if I can find that. Shoulda bookmarked it... Update: Here it is. 'Absorb' to your heart's content.) As with many things, just trusting the manufacturer's literature and user's (limited) knowledge can lead to unreliable results, but only those who deeply question can be confident they are (or are not) getting what is claimed.