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Can I explain why the big silver stack test? Certainly.

March 04, 2019 12:40PM avatar
It seems like no matter where we go on the many Forums or in a lot of open discussions a lot of folks just talk about 'depth' and / or 'separation,' and also fuss about how a detector performs in modern trash, and those of us who spend s lot of time in dense iron debris want better performance in a nasty iron nail environment. But very seldom do we hear or read about people with questions regarding higher-conductive targets such as a US Silver Half or Silver Dollar.

Through the years I have handled a lot of detectors that got diminished detection depth on a big Silver Dollar and even a Half-Dollar. Sometimes the cause was due to a search coil change on a model with a factory preset Ground Balance, such as on an original Tesoro Silver Sabre or a few other Tesoro models I have owned or worked with. Why the problem? Because of the detector's circuitry design that had a positive offset of Disc. mode's GB reference of the All Metal mode's GB setting. Usually, the models were 'calibrated' (which in this case means the GB was properly adjusted for the supplied standard search coil) so the detector wowuld usually work just fine and easily respond to a single big Silver Dollar.

However, a couple of things took place that created a problem for signaling (finding) a big Silver Half or Dollar, and that was either someone opened the unit and tinkered with the GB and set it too positively ... or ... such a GB shift occurred from the different search coil. That can happen with many detectors based on the detector's circuitry design and how the search coil is tied in with the circuitry.

You can take most Tesoro models and find 5 search coils that fit it and are supposed to work, including the stock search coil. You might find that one or two of those coils will have a spot-on or very close Ground Balance for the All Metal / Pinpoint mode, and the Disc. mode is still functional w/o chatter fro being too negative. But trying out the other search coils there might be one or two or all three of the others that are significantly 'off' from a proper or functional Ground Balance. If they are too negative, the detector will false in the Discriminate mode as the search coil is raised from the ground or swept over a hole or depression.

When that occurred, Tesoro would ask the user of a noisy Tesoro to send the detector and all of the search coils to the factory for 'calibration.' Again, 'calibrating' simply meant they would make a Ground Balance adjustment so none of the search coils would be too negative and cause false signals. The user would then be pleased they got all their outfit back and could use any coil and it wouldn't false anymore.

The problem, however, is that while some of the coils that shifted the GB too negative were now functional because the GB trimmer had been tweaked for those errant search coils, it meant the other coils would have a more positive GB, and some might even have a too positive GB, even to the point that the unit would not respond on a highly-conductive target. That could include a Silver Dollar or Silver Half, and I have even seen performance so bad a detector wouldn't respond to a Silver Quarter and was at the fringe of breaking up on a Silver Dime!

Those were cases that involved not being able to get a desired good signal from a single big, high-conductive coin. How about finding a much more conductive target? Not a lower-conductive US Nickel or a metal button or an Indian Head Cent, but something more conductive.

I've had people ask in my seminars if a US Silver Dollar was the most conductive coin we might encounter, and I responded with: Yes ... and ... No.

Have we minted a more conductive coin for regular circulation? No, we haven't. Therefore, Yes, a Silver Dollar is the higher conductive single coin that we might encounter. It is made of 90% Silver. So were the Silver Dime and Silver Quarter and Silver Half-Dollar coins. But we can easily see that the Dime has a lower-scale numeric VDI read-out and the Quarter is more conductive, and the Half is still more conductive that those, and simply due to the size of the big Silver Dollar, it is much more conductive than the big Silver Half-Dollar.

Do we have a silver coin larger than the Dollar? No, and it should be our highest-reading single coin, but what if there is more than one? How about if there were several Silver Half-Dollars stacked up and hidden, or a few Silver Dollars all stacked together and toughing each other, then what do we have? We have a hidden Stash or possibly a larger hidden Cache of big, high-conductive Silver Coins.

If anyone is searching older sites such as a ghost town, a homestead, farm house or outbuildings, or any place that was habituated long ago when those coins were in common use but they were isolated from a bank, or just didn't trust banks such as during the Depression Era, there is always an opportunity to chance upon a hidden Stash or even a dedicated larger Cache of high-conductive coins.

If they were hidden in a cloth or leather bag or a glass jar or pottery crock, that would make them findable in the motion Discriminate mode based on their metal alloy content. If in a metal container, it would be that metal that would be detected and often it could be a ferrous tin-can or other bigger size metal box of some sort.

During the earlier hey-day of this great hobby, back 25 to 50 years ago, I was contracted a number of times to do contracted searches for hidden caches. Sometimes the people knew the family gossip / rumors about the long-ago hidden money, but most of the time they didn't I had no clue if it was supposed to be in a metal container or some sort of non-metal object such as a wooden box, leather bad, cloth bag or glass container or ????

My success rate was quite good even when using a Garrett Master Hunter BFO, or a Compass, Garrett or White's TR, and later using main-brand VLF/TR-Disc. detectors. When I started using Tesoro's in mid-'83 I also found their VLF/VLF-Disc. motion Discriminate modes to work well in conjunction with the Threshold-based All Metal mode. Same with motion-Disc. models from White's and others. But when we started to see more 'turn-on-and-go" models with a preset Ground Balance, or the progression to many models that are even in use today that have Ground Grab or manual GB but a Disc. mode that is either limited in GB range or simply factory preset, I started to notice that many of these more modern detectors wouldn't respond on my 'short stack' of 5 Silver Walking Liberty Halves stacked on a single Silver Morgan Dollar when in the Discriminate mode.

Matter-of-fact, until I try to correct the issue, I have some of my favorite detectors for serious Relic Hunting in my current Regular-Use Detector Outfit that will not give a good response on that 'short stack' of Silver coins, such as my Nokta FORS CoRe or Relic or Teknetics T2+. All my other models from Fisher, Teknetics and Tesoro provide a very clean audio hit and those with TID also show a proper high-conductive numeric VDI read-out.

The reason some detectors will not hit on such a very conductive challenge is mainly associated with using a much too positive Ground Balance for the search mode being used. Unfortunately, many of those modern detectors have that adjustment function either preset or controlled in circuitry and we can't do anything about it. So, I do a number of tests during my evaluation of any make or model detector so that I am aware of their strengths and weaknesses to enable me to get the best in-the-field use and performance from them.

Last year, by the way, some of the attendees on two of the WTHO's had the opportunity to test their Minelab Equinox 800, E-Trac and CTX-3030 and XP Deus on the 'short stack' and none of them had favorable results. it could have been due to the search coils used, the settings that used, or , who knows, it might be associated with the detector's circuitry design?

I have Test Samples that use one or more Iron Nails to evaluate performance in ferrous challenged sites, and other comparisons I do, including the 'short-stack' and 'tall-stack' of US Silver Coins to learn about any weaknesses or strengths they have there as well.


"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
Regular-Use Outfit: Nokta / Makro: FORS CoRe, FORS Relic, Racer 2 and Simplex+
Tesoro: Bandido II ┬ÁMAX and Silver Sabre ┬ÁMAX .. XP: ORX
Specialty-Use Outfit: Fisher: F-44 .. White's: XLT and modified IDX Pro
Killer B's 'Hornet' -- Detector Pro Grey Ghost XP
Note: Detectors are listed alphabetically by Brand. Models are chosen based on search site conditions.
*** All working well today to make memories for tomorrow. ***
Subject Author Views Posted


Kickindirt 242 March 02, 2019 11:20AM


D&P-OR 182 March 02, 2019 11:52PM


Kickindirt 204 March 03, 2019 12:32AM

Where to Start?

UtahRich 132 March 03, 2019 12:54AM

What CAN it do that we need? What CAN'T it do for sites we hunt?

Monte 170 March 03, 2019 06:53AM

Re: What CAN it do that we need? What CAN'T it do for sites we hunt?

Elbert 153 March 03, 2019 10:07AM

Can I explain why the big silver stack test? Certainly.

Monte 168 March 04, 2019 12:40PM

Re: Can I explain why the big silver stack test? Certainly. Definitely eye opening! N/T

Kickindirt 156 March 05, 2019 02:30AM

Re: Can I explain why the big silver stack test? Certainly.

Elbert 138 March 04, 2019 10:26PM

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