GB_Amateur

Wow, you spent a lot of time relaying this info to us, and I want you to know how much I appreciate your effort. This is exactly the kind of thing that will help me. I started my harem last year with two parks. Both sites were either homestead farms or industrial sites back in the 1800's. While still hunting the parks this year, I've added two schools built in first half of 20th C. Unfortunately one of those turns out to be private, which I should have known/found out before hunting without permission... Surprising what I still don't know after living in this town for 35 years. Please continue the reports. Wish I had someone locally as experienced and throrough as you to show me the ropes. I'd happily take you to my hunting grounds and watch you dig up treasure after treasure that I know I'm passing over, just to soak up the knowledge I would gain from that experience.

Does olive oil work on nickel coins (copper-nickel alloys) also? I found an 1867 Shield with rays a couple weeks ago and it's pretty crusty, having likely been in the ground for over a century.

"Pot committed" -- I like that and will add it to my aresenal of MD'ing terms! What is 57-60 typically on a Garrett AT Pro? I would think the White's Bigfoot or Tesoro 3x18in^2 would be helpful in general with these searches, although 5 inch depth (as here) might be at or past the edge of detection for such a narrow coil?

I think there are exceptions both ways. Part of that depends upon your definition of 'hot rock'. Negative hot rocks (also called 'cold rocks' by some) have ground phases higher than the quiescent ground phase. Postive hot rocks do the opposite. I have a couple very large (near bowling ball size with masses in the 9-13 kg range) positive hot rocks which are so conductive that they give a TiD of 40 with the discrimination circuit and a phase shift value of 0 in All Metal. One of these appears to have a very high concentration of graphite. The other, I don't know its composition. Also I've noticed that metallic conductive targets at the edge of detection in All Metal mode (and thus out of detection range on the discrimination side) can have phase shift values greater than 20. But I do think in the vast majority of cases your rules-of-thumb hold.

http://www.ebay.com/itm/Minelab-GOLD-MONSTER-1000-Metal-Detector-/192225678452?hash=item2cc18b1474:g:zfQAAOSwCkZZTHXw Buy-it-now, used for $650 including shipping. I know nothing about this (don't know seller, etc.). Just found it while searching metal detector page on Ebay. Looks like it was listed late yesterday as a 3 day sale. I don't expect it to last that long. SOLD about 2 hours after I posted this. Hopefully someone here got it.

Looks like you cleaned this up between photos. What were the steps you performed? Just brainstorming here, but I sometimes wonder how accurate these XRF measurements are. One interesting thing (IMO) is the 1.5% iron content. Looking at Wikipedia: https://en.wikipedia.org/wiki/Brass I see that there is something called "manganese brass" which is very close in composition to what you have, except with manganese instead of iron. Manganese is the next door neighbor of iron in the periodic table, and that means its X-ray line energies are close to iron's. Could the XRF identification be incorrect and this is manganese brass?

There might be, but it doesn't look like an official Garrett solution: http://www.detectorprospector.com/gold-prospecting-equipment/garrett-atx-metal-detector-accessories.htm#.UsCzAX-9KSM You might have heard of this Steve guy. I'm sure he'll chime in.

Jim, I found the following at Amazon. Are these the two? A Field Guide to Rocks and Minerals (Peterson Field Guides) 5th Edition Peterson First Guide to Rocks and Minerals (I think I reversed the order -- first one is 461 pages and 1.1 in thick; second is 128 pages and 0.3 in thick.)

Here's a video by detectingMO that illustrates the customizable tone frequency selection options of the RUTUS Alter 71:

John, did you see this thread? In particular on page 2, AussieMatt links to an exhaustive study done in Australia, both air tests and in-ground tests of about a dozen coils for the TDI. (This was done with one of the big-box TDI's.) Based on that I've since bought a (used) NuggetFinder Sadie and my early tests confirm it is great. I have data which I'm going to post there to add to / enhance what has been done, but mine so far are only in-air tests which everyone knows have their limitations.

While in Arizona this past February I found two tiny non-ferrous pieces with the TDI/SPP and had to buy a new scale to weight them. I was hoping to be able to do a decent specific gravity (density) determination using Archimedes Principle but even the new scale couldn't do that very well. The masses were 0.047 g and 0.058 g and they looked like copper under my strongest magnifier. (On my 'to buy' list is a stereo reflecting microscope.) Getting off on a tangent (I'm good at that...), 'g' means grams just about everywhere in the world. I think grains are abbreviated gr. I found out that this new scale (1 milligram = 1 mg = 0.001 g precision) is difficult to use because just about anything will give a force in the milligram range. I had a chance to buy a Mettler Balance in an antique store with even higher precision (factor of 10 smaller) one time and balked. I think it was about $10! Been kicking myself since I got back into detecting. I took two coils on that trip -- 3"x6" prototype and 5"x9" Miner John folded mono. I know I found one of the pieces with the smaller coil. I thought I found the other with the MJ, but not sure about that. I also don't know the depth since in both cases I used my pick to loosen the soil and then scooped through the loose stuff until I found them. But I strongly doubt they were anything deeper than an inch. Still, your 0.003 g with the MXT has my pieces beat by an order of magnitude.

There are a lot of varieties but I think this is the one: http://www.pcgscoinfacts.com/Coin/Detail/24 I don't know how to grade these. My guess is around 35 but an expert (one of the grading services) is the route to go with something this valuable.

A professional electronics tech (or even a good amateur garage variety ) could do that. My solution has been to put the receiver (in my case the Deteknix model) along with the excess cord in a shirt pocket with closing flap. But maybe your cord is longer (total length from headphone to 1/4 in jack on mine are ~32 in = 80 cm) or possibly you've stretched it out over time so as to not be dragging your detector through the rocks when you're digging. Appears from your thumbnail photo that you also like pockets with shirts. IMO you can't have too many pockets when out metal detecting.

I bet Nevada Chris (Ralph) knows all of these and will respond. In the meantime, I looked up a couple on Wikipedia and have cut and pasted the parts meaningful to your post: "Aluminum oxide --Al2O3 -- is commonly called alumina. It occurs naturally in its crystalline polymorphic phase α-Al2O3 as the mineral corundum, varieties of which form the precious gemstones ruby and sapphire." "Magnesium oxide (MgO), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase."

Here's a decent treatise at White's website: https://www.whiteselectronics.com/detecting-101/how-metal-detectors-work/?lang=gb

First off, welcome MontAmmie. Second, you don't sound like a 'newbie' to me. Third, IMO you are wise to take detector weight seriously. There's a reason Minelab sells a harness for use with its Pulse Induction (PI) units. Wonder how comfortable that would be on a hot Florida beach.... If I were you, I'd 1) hang onto the DFX. From all I've read it's still a capable detector and your familiarity with it has value. Might want to review ground balancing techniques -- Steve uses his in tough ground in Reno. 2) Don't under-rate buying used, for examples: Ebay, DetectorProspector (this site's) 'Recent Classified'. I've read other metal detector forums also have pages for members to buy/sell. Typically, not counting recent releases, the selling price for good used detectors is about 60% to 67% of new prices. 3) Last but maybe most important: prioritize your expected uses. For example, you mentioned the Gold Bug 2. From what I've read (a lot here) that is primarily for very small native gold. It's possibly the best detector ever made for small/tiny gold (still almost a quarter century after Dave Johnson designed it), but you wouldn't be using it for anything else. I just got finished with a purchase decision myself. I made an Excel spreadsheet and compared the features/capabilities, ergonomics, prices, etc. that I wanted for about a dozen candidate models. I read everything I could find (especially here but also on Treasurenet, Findmall, and Dankowski forums) and watched a bunch of YouTube videos. Having your priorities crystallized will help you narrow down the finalists. Pick one and have fun hunting with it! It's still dark here and I'm getting my gear together to start early and beat the summer heat today. Next best thing to metal detecting and making a nice find is metal detecting and not finding a damn thing! I'm an expert at the latter.

We were hoping for a show primarily about finding and recovering gold. Throw in the surviving as a sidelight. What we got is a show about surviving, with gold as the afterthought. You and I both, but I'm not getting my hopes up. These producers, etc. know how important it is to get things started right so the audience will return, and bring their friends. I'm concerned they've shown us what they think their audience wants to see (= surviving and whining, and not doing either of those particularly well). But I will also give them another chance.

If the first show is any indication I don't think you missed much, Tom. Would be interested in other viewpoints. I'm not even close to being on-top of prospecting & recovery as most of you. What I saw was a lot of 'surviving' and not much gold hunting. In regards to gold equipment, all I remember seeing (it was past my bedtime ) were a couple plastic gold pans -- one a Garrett Super Sluice; don't know the brand/model of the other. I assume they at least have sluice boxes with them, but being forced to pack in everything (including food), it seems unlikely anything heavier than that made the cut. We'll see. 2 of the 3 prospectors were featured in episode 1; the last (oldest guy) presumably will show up next week. I'm not holding my breath that this is going to set a new height on the already low bar of 'reality' treasure hunting TV shows.

There are two recent, active threads elsewhere on this site discussing detector frequency. I've started a new topic here because this is specific -- frequency for coin hunting. It probably has an impact on both relic and jewelry detecting as well, but only peripherally (I think) with native gold. To frame up my concern, I first should disclaim that, as with most detecting, there is no simple answer that treats all conditions. Ground mineralization, electro-magnetic interference (EMI) background, and goal target size, shape, composition and expected depth can all be variables (and usually are) in finding the optimal solution. For my situation the local mineralization is typically mild to at worst moderate. Living in a city, EMI background is certainly a concern although I haven't noticed severe cases and often it's unnoticeable. Target size, shape, composition (coins), and depths of a few inches to deep, since I want old coins, are my parameters. Now that I've laid the groundwork, I'll narrow the choices -- high single digit frequencies (6-10 kHz) vs. midrange frequencies (13-15 kHz). The former has the advantage of less susceptibility to mineralization (probably not an issue in my ground) but higher response to EMI. Lower frequencies favor high conductors (copper and silver and most of their alloys) compared to higher frequencies which cater to the lower conductivity metals, especially gold, lead, and nickel and most of their alloys. Higher frequency also gives better response to small items (e.g. small jewelry and the smallest coins). Iron is the enemy of just about every type of modern metal detecting. It's plentiful, easily corroded, and most items made of it are nearly worthless, unless you're talking very large stuff (cars, trains, bridges,...). Iron (I think) is more of an issue with higher frequencies, just like mineralization which is usually some kind of iron oxide, but lower frequencies see iron quite well, too. On top of that there is a hidden disadvantage at lower frequencies -- wraparound. My experience combined with quite of bit of reading has come up with an explanation for this unexpected weakness. The conductivity (ID-) scale is non-uniform at low and high frequencies. High frequencies expand the low conductivity range (especially iron) and compress the high conductivity range. Low frequencies do just the opposite. On the surface this sounds like another advantage for low frequencies. But the devil in the detail is that the compressed iron range causes more spillover, in this case wraparound to the highest frequencies where the high conductors live! I found this out the hard way using a 3 kHz coil on my Minelab X-Terra 705. The wraparound can be so severe that iron IDs as large silver alloy coins (such as US silver dollars and even in some cases half dollars) and smaller (e.g. rounds and bars of) pure silver. Yes, this isn't a steady ID but rather jumpy between iron and silver, but when you are in trashy ground (just about any site that has seen building construction or simply fences) you'd like to discriminate out the iron range. With discrimination on and you just hear high conductor and can get fooled, at a minimum having to go back into all-metal mode to see if there is a significant iron signal. This can be tedious and time consuming. Back to the two chosen frequency ranges: most modern detectors in the 6-10 kHz range are less expensive (<$400) devices, with an accompanying paucity of features and possibly other cut corners. Most of the 13-15 kHz detectors ("all around detectors") are of better quality, have more features, typically go deeper, and come at costs in the mid-range -- $400 - $1000. For me the cost isn't too much of an issue, at least between these two. (Minelab CTX 3030 is a different story.) For specific examples, the Teknetics Omega 8500 is low frequency (7.7 kHz) but has features no other detector currently selling under $400 can touch. At least that's my observation. For a limited time you can find it for $379 new -- it's usually about $650. Compare it to the new Teknetics Patriot (rebranded Fisher F70) at a current featured price of $400 new. By all accounts it's nearly equivalent to the First Texas 'black' flagships -- F75 Limited and T2 Special Edition. The Patriot/F70 is a true jack-of-all trades (i.e. coin, jewelry, relic, and even gold nugget) detector. But concerning old coin hunting, is it a match for the lower frequency advantages(?) that the 8500 has? Yes, finally a question.

Another issue with selectable frequency detectors is whether they compromise on performance (compared to straight-forward single frequency detectors) in order to deliver the option of choosing among 2 or more frequencies. It may be difficult to decide if they are compromising since comparing a single frequency detector (like the Fisher Gold Bug Pro @19 kHz) with a selectable frequency detector with an option of the same frequency (such as the Minelab X-Terra with 3 kHz, 7.5 kHz, and 18.75 kHz) means comparing two detectors with very different components. I'm guessing the big issue in compromise would come from the coils used. Specifically, if it's "one coil fits all (frequencies)" then one wonders how much you give up for this seemingly nice feature. To put it simply, ignoring cost and convenience, are you better off (in terms of performance) having three separate detectors that cover the ~2.5 kHz to ~20 kHz range or one detector that does all three?

Decade? You're being generous, Steve. The world can change fast. Internet sales outlets (Ebay and Amazon being the biggest players, including in the detector space) has grown quickly. I feel bad for the conscientious brick-and-mortar dealers (as you were) because they're the ones getting squeezed. The sloppy ones deserve to go out-of-business, but that has typically been true in the age of capitalism. Most people know that when you don't need to pay rent on a showroom, you save a lot of overhead and can then afford to sell at a discount. I've bought accessories (crevice tools, snake chaps, digging tools, etc.) at dealers because I appreciate that they provide a service and I want them to stay in business, even when it means paying full retail, which is the norm. But when it comes to detectors, "sooner or later we're talking real money" and unfortunately even the best struggle with providing value for the extra dollar. Welcome to (late in) the 2nd decade of the 21st century. I don't mean to be sarcastic or insensitive. Unfortunately the commercial world doesn't know the meaning of 'empathy'.

No, not just you. I watch to find out what settings are being used, what the VID looks like, what the target sounds like, how deep the target was, and at what angle it was oriented (if possible to determine). After that, show me the loot.

https://press.discovery.com/us/dsc/programs/devils-canyon/ Tom B., is this the show you auditioned for last year?

If advice/wisdom of metal detecting could be summed up in one sentence, this is probably that sentence. I should frame it and put it on my wall, then read it every day. Those three phrases sounds simple, yet you could write an entire book on each (and I guess some have tried) and still not cover them sufficiently. It sounds and looks so simple, kind of like swinging a weed-eater. How hard can it be? Go over a valuable, get a good signal, and dig it up. Soon you'll be supplementing your income with a weekend hobby! Likely this is why detectors get bought after the intoxicating advertising, and then put on the shelf or sold after a couple outings. How long does it take to get good at shooting a basketball? Hitting a stationary golf ball? Playing a musical instrument? Looks pretty easy watching a pro do it effortlessly. Well, come back in a lifetime and tell me the answer then.

Yep, got that, and thanks again. That was quite a long thread (like some here ) with a lot of good info. I've always been the 'doubting Thomas' type, which explains my choice of careers. I've also occasionally been burned accepting things at face value, but I'm sure that's true of everyone whose lived more than a few years. I want to accept that the F70 is every bit as good as the F75 Ltd because that means I can save lots of $, whether buying new or used. But I guess my skeptical eye also spills over to second guessing. E.g. I buy the F70/Patriot and when I'm not finding as much as I wish, I wonder if the Boost Process would have been the solution. This is what the marketers want, of course, and thus the several hundred dollar additional cost. (As you know and have stated here, there are a few other differences, such as manual ground balance on all 75's, so it's not just the Boost and Cache Processes that differentiate.) The flipside is that I spend the extra money for the F75 Ltd (or T2 black), never see any advantage in using those additional functions, and say "why didn't I just get the F70?" As life's challenges go, this is pretty insignificant.