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confused smiley Have you tested your detector(s) for Silver Coin Cache detection?

December 23, 2018 05:00AM avatar
Ever wonder how well your detector will perform for different applications? Of course you have, or should have, for the detecting you do. Just because a metal detector is designed to find metal objects that doesn't mean it always will, and the reasons are related to how they were designed as well as how you, the operator, adjust the controls to get the performance you want.

Some of the things we can control with most makes and models is target acceptance based on the Discrimination setting. If we use a model that has no rejection at the minimum Disc. setting, then the detector will respond to all metal targets, ferrous and non-ferrous. We will hear an audible response from an iron nail, an axe head, a wad of foil, a US 5¢ coin a Zinc or Copper 1¢ coin and all the way up the conductivity scale to include a 50¢ or $1 coin. Even one of those big ol' silver $1 we use to carry and spend when I was a kid.

We know that if we use a variable Discrimination control, we can increase it to reject the Iron Nail and Axe Head and even the small wadded-up Foil and still search for, and find, all of our common coins. We also know that if aluminum Pull Tabs are a problem and we increase the Disc. level to reject all of them, which can be more conductive than a US 5¢ piece, we have also rejected those coins as well as other lower-conductivity targets and that can include maybe 80% or more of the lost gold jewelry.

So sometimes, NOT being able to find something that we WANT to find can be our fault based upon the adjustment settings we use. The variable Discrimination control is dealing with metal rejection starting at the ferrous range and increasing it based upon conductivity. That is easy to show on a graph or reference I do on a marker board in my seminars, starting with an Iron Nail on the far left side and progressing, conductivity wise, to the right to include Small Foil, Larger Foil, a US 5¢ coin, then various Ring-Pull and Pry Tabs, a Screw Cap, Zinc 1¢, Copper 1¢ & Clad 10¢, then a 25¢, a 50¢ and finally a large silver $1 coin at the higher conductivity right side of the scale.

Very easy to depict on a visual graph or see if we are looking at one of the older needle-meter TID displays or many current LCD type displays.

I also use different detectors at my seminars to demonstrate detector behavior, and to also demonstrate the known and not-known, or should I say the understood and NOT-understood workings of a metal detector's circuitry, adjustment functions, and responsive behavior. I can offer up a blanket statement that many will not understand or might even laugh at, until I grab a detector or two to point out exactly what I mean.

For example, remembering back to early '88 when I was working at Compass Electronics my office was right next to Ron Mack who was the company President at the time. They were trying to get their new Scanner XP Pro out for sale and had a few sample models in the hands of some avid users across the USA. He got a call from one fellow in Alabama or somewhere in the SE US who, I believe, was more of a Relic Hunter than a Coin Hunter. He called Ron to complain that he couldn't find a 50¢ coin. Ron discussed this with him and reminded him that there are not that many 'halves' out there to be found. He called the next day with the same complaint.

This happened for two or three days and then Ron stepped into my office and told me about the guy's problem and asked me to take the next call from him as he was a bit annoyed. Well, the next day a call came in at Compass and Penny, the receptionist, transferred it to Ron and I could hear the conversation ... again. So I got up and stepped to his doorway and asked Ron to ask the fellow:

"Will it not find a 50¢ piece or will the detector not respond to a 50¢ piece?"

I could hear the reply when he got the answer I thought he would, and I said I'll be right back and headed off to the shipping department. Myrna wasn't thrilled when she saw me walk in and I wheeled the cart away that had all the Scanners and coils ready-to-box that had just come down from production. I took 10 Scanner's with their 8" coils and set them in a row on a table and checked them with some coins I used to always carry in my pocket. I told her to leave them there and went to get Ron. On the way I stopped at John H.'s office, the design engineer, and told him we had a problem.

I got Ron and John joined us as we headed back to shipping and I proceeded to show Ron what the issue was. It wasn't that the fellow wasn't able to find a 50¢ piece, it was that his unit would not detect or positively respond to a 50¢ piece! I used to always keep a big Silver Dollar in my pocket because I had done that since I was a youngster. Partly for 'Good Luck' but mainly because I always liked those coins. Also because I use them and some other test samples to check metal detectors for performance.

Of the 10 units I set aside, 8 of them would NOT respond to the Silver $1 and 6 of those still wouldn't respond to a Silver 50¢ piece (or clad for that matter). I knew what the cause was from the time I heard the conversation and the fellow's answer because I had already dealt with some detectors on the market that had similar issues since '83, especially if the consumer misadjusted the detector. In this case it wasn't user error is was a circuitry design error or oversight. Sometimes not fixable with our most modern digitally-designed, software-controlled detectors.

So, you might be asking, what was the culprit? Ground Balance.

Specifically, the way the Ground Balance setting functions in the motion-based Discriminate mode. If the Ground Balance is set too positive for that search mode, it essentially is rejecting the higher-conductive targets because it has shifted them into the ground-rejection segment. This is easier for me to demonstrate with a marker board in a seminar as I show a sine wave and refer to the ground mineral region and how an errant GB adjustment messes things up.

To make it even easier to understand, I will grab a good manually-adjusted Ground Balance model. such as my Bandido II microMAX or modified Classic ID, and demonstrate how the Ground Balance adjustment is associated with target acceptance and rejection. As a side note, I also demonstrate with this model how to 'Power Balance' a detector for peak performance in the silent-search motion-based Discriminate mode.

Here I shared an actual occurrence as an example where a consumer/evaluator was not able to get a positive detection response from a single, larger-size 90% silver US 50¢ piece, or in my evaluations of finished, ready-to-ship product even more couldn't respond to a larger Silver $1 coin.

So in my seminar tote of display samples, which I also use when evaluating any detector, I have an even tougher test sample than a single US coin. This is what you might want to try when evaluating your own detectors and settings, not just for finding a lonely coin lost here or there, but just in case you happen to sweep your coil across a small-size potential cache.

Let me side-track for a moment and talk about a 'Cache' of 'Hidden' Money or other valuables. I first searched for and located a large box or chest of hidden silver money in November of '71. That container was not known in advance. In '74, I was contracted to search for hidden silver coins that were believed to be in metal (tin?) cans or glass jars with metal lids. In both those instances, the hidden valuables were high-conductive silver coins all tightly together in a container. But one container was tin type metal and the other were glass jars but had metal lids. Those could have been ferrous lids or ferrous metal rings that held a glass lid in place, or perhaps some of those zinc type bottle lids. That would have masked the contents due to the rusty metal container, or degraded the higher conductive silver contents with a lid or ring on the glass jar.

I have also searched for a shoe-box sized cotainer that was full of silver half-dollars so there was no other metal to interfere with the silver content. That is the important thing to know because very often, hidden monies, in coins and not paper currency, were not lowly Pennies and Nickels but the more valuable silver Dimes, Quarters, Halves and Dollars. If it is 'cached' in a metal-free glass container, a pottery or ceramic crock, a cloth or leather bag, then there is no offending, lower-conducive metal to deal with, just the higher-conductive Silver Coins.

Usually, hidden money will be in a greater quantity, but for my initial testing purposes I use six ... just 6 ... US 90% Silver Coins. I have 5 silver Walking Liberty 50¢ pieces stacked on top of 1 Silver Peace $1. There is no paper or film or plastic or cardboard between them, just bare naked coins all stacked together. The other sample I have used is 6 Silver $1 all stacked on top of each other.

So give this a try with YOUR detector and coils, following the suggested settings, and report back how well your detector handles this test scenario. Sweep the search coil directly over the stacked coins.

Test Sample:
• 5 Silver Half Dollars on top of a Silver Dollar ... or 6 Silver Dollars all stacked up.

• Discriminate mode with the least rejection you can tolerate

• Sensitivity as high as you can handle

• Discrimination Level as low as you can tolerate.

• Stack the silver coins on the ground in a metal-free area.

• Turn on and adjust the Detector for the above settings.

• Ground Balance the detector on the adjacent, metal-free ground.

• Sweep the search coil over the stacked silver coins with the coil about 4" above the coins so the center-axis of the coil passes over the coin stack.

• Listen for an audible 'Beep' and determine if you hear one, if it is broken or inconsistent or if it is a good, clear, repeatable response.

• If you have a visual Target ID / numeric VDI display, see how tight and consistent the read-out is as you sweep across the stack of coins.

Most of the models in my Regular-Use Detector Outfit will easily 'pass' this test, but not all of them. I like to know which are the better picks for me to use when I take on a search for a known silver coin cache, or when out hunting a site and want to search some of the more typical places to hide containers of coins.

I have used these test samples for a few decades and it is surprising how many modern detectors do not do very well, and there are explainable reasons. Even earlier this year on two of the Welcome-to-Hunt Outings and three personal demonstrations I gave, I set out several plastic containers of Test Sample targets including the one containing the 5 silver Walking Liberty halves stacked on top of a silver Peace Dollar. The results were a bit surprising to some. You should have seen the faces and heard the comments (well, most of them as a couple were not printable here) from some of the folks using a Minelab FBS model or new Equinox device or an XP Deus, or a couple of Nokta and Makro models, or a Fisher F19 or Teknetics T2.

Yes, I had some of my models that didn't handle that sample well, but I already knew they wouldn't. I also grabbed a few detectors I had along that responded wonderfully both with an audio 'Beep' and some with a decent visual display as well. Those includes the Tesoro Mojave, Silver Sabre microMAX and Bandido II microMAX. A White's MX-5, my modified Classic ID and the MX-7. A Teknetics Omega 8000 and now a Fisher F44. Also, the new Nokta-Makro Anfibio Multi.

Please, I encourage all readers to gather up 5 silver Halves and one silver Dollar, or six Silver Dollars, not in a carded holder or plastic container but just plain bare metal to make contact as if they were buried together long ago. Stack the 6 coins, then use the settings described, make sure you adjust the ground balance for the ground you are testing on, and perform this test.

Then, I welcome your report here in this thread to describe the Make and Model Detector used, the Search coil size and type used, and explain the results you had so AHRPS Forum readers and contributors can learn from the results. Aldo, if you have any questions, feel welcome to offer them here or, if you desire, shoot me an e-mail and we'll discuss it. This is especially pertinent to the use of some of the multi-frequency detectors on the market, selectable or simultaneous.

monte@ahrps.org ... or ... monte@stinkwaterwells.com

If you're stuck indoors for the season this can be a fun and educational way to spend some cabin fever time.


"Your EYES ... the only 100% accurate form of Discrimination!"

Stinkwater Wells Trading Post
Metal Detector Evaluations and Product Reviews
monte@ahrps.org ... or ... monte@stinkwaterwells.com
Detectors: Vanquish 540; CoRe, Relic, Impact & Simplex +; Bandido II µMAX & Silver Sabre µMAX; ORX
Pinpointers: Pulse-Dive .. Headphones: Killer B's 'Hornet' & 'Wasp' ... White's 'Pro Star'
Note: Detectors are listed alphabetically by Brand. Models are chosen based on search site conditions.
*** All working well today to make memories for tomorrow. ***

Edited 1 time(s). Last edit at 12/23/2018 05:01AM by Monte.
Subject Author Views Posted

confused smiley Have you tested your detector(s) for Silver Coin Cache detection?

Monte 663 December 23, 2018 05:00AM

Re: confused smiley Have you tested your detector(s) for Silver Coin Cache detection?

Druid 186 February 13, 2019 07:01PM

Drew, detector tests on Silver stacks, and for WTHO's.

Monte 234 February 14, 2019 10:13AM

Re: Drew, detector tests on Silver stacks, and for WTHO's.

Druid 230 February 14, 2019 10:20AM

White's 6.59 kHz search coil favorites.

Monte 264 February 14, 2019 12:04PM

Re: confused smiley Have you tested your detector(s) for Silver Coin Cache detection?

SvenS 326 January 20, 2019 09:00PM

Re: confused smiley Have you tested your detector(s) for Silver Coin Cache detection?

Onearmwilly 337 January 19, 2019 12:41PM

Jason, 'Thank You' for contributing the results you had.

Monte 333 January 19, 2019 05:14PM

Re: Jason, 'Thank You' for contributing the results you had.

Onearmwilly 297 January 21, 2019 07:47PM

I have also tested quantities of coins in Jars, Boxes and Bags.

Monte 341 January 22, 2019 04:51AM

Re: confused smiley Have you tested your detector(s) for Silver Coin Cache detection?

Remfire 350 January 01, 2019 04:29PM

Roger, 'Thank You' for the test reply.

Monte 342 January 01, 2019 08:40PM

Re: Roger, 'Thank You' for the test reply.

Remfire 368 January 01, 2019 11:16PM

Re: confused smiley Have you tested your detector(s) for Silver Coin Cache detection?

UtahRich 313 January 01, 2019 05:40PM

Is It All About Recovery Speed? Here are my Silver Cache EQ800 results.

UtahRich 478 December 26, 2018 01:10AM

► INFORMATIVE READ: Rich's results with an Equinox 800.

Monte 544 December 29, 2018 03:33AM

► Monte's results with his 9 different models.

Monte 424 December 29, 2018 10:36AM

Re: ► Monte's results with his 9 different models.

RickUK 384 December 31, 2018 05:42AM

A few of my Test Details -

UtahRich 356 December 29, 2018 06:36PM

Rich(Utah), here are the results of a Teknetics test a fellow asked for.

Monte 344 December 30, 2018 05:59PM

Teknetics Mark 1 results . . . .

UtahRich 382 December 31, 2018 07:15PM

Rich(Utah), 'Thank You' for the information.

Monte 330 December 31, 2018 10:35PM

The Old Mark 1 . . . .

UtahRich 321 December 31, 2018 11:23PM

Ooops, I forgot about sensitivity. . . .

UtahRich 325 December 30, 2018 05:47PM

Rich, I understand and I understand.

Monte 356 December 29, 2018 10:55PM

Will your detector BEEP if you swing over a Silver Coin Cache?

UtahRich 317 December 24, 2018 04:33PM

Comments and questions.thinking

Monte 328 December 25, 2018 07:16AM

Is Recovery Rate directly related to this Problem ?

UtahRich 318 December 26, 2018 06:12PM

Rich(Utah) wondered: "Interested to know your thoughts here. "

Monte 362 December 26, 2018 09:34PM

Don't see much interest from others on this Monte. N/T

UtahRich 349 December 28, 2018 06:37PM

Re: Don't see much interest from others on this Monte.

RickUK 335 December 29, 2018 10:05AM

RickUK, I appreciate your input.

Monte 348 December 29, 2018 11:23AM

A quick reply.

Monte 373 December 29, 2018 02:22AM

Re: A quick reply.

Druid 317 December 29, 2018 05:20PM

Drew, sorry, but no I haven't used a PI on this test scenario.

Monte 282 December 30, 2018 03:34AM

Re: A quick reply.

RickUK 327 December 30, 2018 01:20AM

Re: Don't see much interest from others on this Monte.

Hombre 389 December 28, 2018 07:25PM

Stack 5 Silver Halves on 1 big Silver Dollar and your Outfit would:

Monte 362 December 28, 2018 07:58PM

Re: Stack 5 Silver Halves on 1 big Silver Dollar and your Outfit would:

Druid 348 December 29, 2018 05:21PM

You will soon find out.smiling bouncing smiley

Monte 331 December 30, 2018 03:41AM

Re: Stack 5 Silver Halves on 1 big Silver Dollar and your Outfit would:

Hombre 369 December 28, 2018 08:24PM

Re: Comments and questions.thinking

Druid 362 December 25, 2018 12:25PM

Answers for you, Drew.

Monte 335 December 26, 2018 06:52AM

Re: confused smiley Have you tested your detector(s) for Silver Coin Cache detection?

Timbertodd 322 December 24, 2018 02:46PM

Todd, did you use one of the two described stacks of silver coins?

Monte 366 December 25, 2018 05:34AM

Re: Todd, did you use one of the two described stacks of silver coins?

Timbertodd 337 December 29, 2018 12:22PM

'Thank You' Todd. And those 6 silver dollars were naked?

Monte 331 December 29, 2018 01:21PM

Re: 'Thank You' Todd. And those 6 silver dollars were naked?

Timbertodd 354 December 29, 2018 02:21PM

Re: Todd, did you use one of the two described stacks of silver coins?

Timbertodd 334 December 25, 2018 07:26AM

5 should work but 6 is what I use to match 6 coins in the Half & Dollar stack.

Monte 305 December 26, 2018 05:59AM

Re: confused smiley Have you tested your detector(s) for Silver Coin Cache detection?

D&P-OR 353 December 23, 2018 10:09AM

Yes, they didn't. ... or ... No, they did.

Monte 365 December 23, 2018 03:32PM

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