Nail board tests:

[Silver Searcher]

Just dug through years of notes to find the following info. from John Earle who I think designed all the Scanner series for Compass.

"The Vari-filter series has added propriety electronic processing over other "2" filter designs to eliminate the ringing that results from a higher Q filter so that you end up with better ground handling than most two filter types yet it reduces the "ringtime" associated with 4 filter machines". (Ringtime being signal trailing that can make two targets sound as one).

So your correct. Nice to see some considered tests rather than those aimed at making some detectors appear worse than they in fact are if given an equal playing field.

Brian we need your imput more on Treasure Net, be nice to see you more in the main threads, like whatsits

SS

 

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[Sandman]

Nice video's Larry. The older detectors are not dead, just with newer materials they can be made lighter.

 

[LuckyLarry]

Yes Brian it was John, and I get most of my info from Keith Wills at East Texas Metal Detectors. Keith as you may well already know is the tech who worked for Compass - and Keith increased the air depth capabilities to 11"+ on coins from the earlier Compass detectors -which prior to then only achieved an 8" air depth on American clad coins. Keith knew very well that an air depth test is the only reliable indicator of a metal detector's in-ground depth potential. Notice I said "potential".

*Oh and as a side note, John Payne concurred with Keith regarding air depth test potential vs ground depth test potential, mostly because detectors are federally limited as to their radiating power anyway.

In Poland and the Czech Republic, for example, there are not as many regulations regarding transmitting power: Check out the air depth on this Mikron machine with the silver ring in his hand. Mind-blowing depth, maybe 2 feet? And look at how fast it recovers!

Hey Sandman, good to see you here! I'm not the author of the videos but they certainly do give pause to some of our questions, don't they?

www.mikronbg.com/NRG110.html

LL

 

[U.K. Brian]

The trouble with air tests are that they suit the high gain detector designs that gives great display for You Tube results but fail when it comes to "in ground" performance. I've put over 300 machines from 60+ manufacturers through the same test beds and alas the limitations of physics plus ground condition mean the wonder machine is still to arrive.

NRG are good detectors for the low price they charge but not quite what is made out. Buy a 110 now and you could regret not waiting a few more weeks for the 150 version due at the end of December.

Thanks S.S. but the trouble with detecting full time is lack of time for the forums because you have to put the hours in if there's no wage check or pension waiting at the end of the month. Just waiting for it to get light now !

 

[LuckyLarry]

Well Brian, there is a certain amount of truth to "high gain" detectors showing well in air tests yet not as (relatively, and I mean that in the real sense) well in ground. For example, the Tesoro Tejon, which basically sucks in high Fe soil, yet shows superior air depth.

However, in my own tests on Oregon and Washington State Fe/high-magnetite/hematite beaches, there seems to be a direct correlation between air tests and actual depth. So far, My old CZ-70 out-performs everything I've ever seen (or built) there in discrimination mode for depth, save for PI's of various setups. I've hauled buckets of that type of soil back home and found some very interesting results after making so-called "tests-gardens" with it. While the CZ did so well in actual use, the whole scenario reversed with several different detectors of several different brands, and other detectors detected it deeper in the test garden thaan the CZ did. So much for the validity of test gardens. Upon digging and removing the soil the strata had disturbed de-aligning the magnetic flux +/- patterns, and caused completely different depth readings in ground. Still, there was a direct ratio relationship between air test depth and actual depth in either case, disturbed, or un-disturbed, regardless of whether one had a better showing in air than in ground.

Regardless of all that we are still left with only one way to test a detector's likely performance in ground save for actually using it there, and that is in an air test. Yes, I could hook up one of my old scopes and test it using a differentiating mathematical equation, but that too is left up to quantum mechanics and WAY too many variables to plug in, which of course makes it unpredictable at best anyway. "Chance" (as in quantum physics) never does predict precisely which way a few drips of water will flow anyway, or so tests prove, and neither do simultaneous equations.

And yes I agree, there is no "wonder machine", although my ex wife seemed to entertain herself about that notion regarding herself. lol.

Thanks for the note Brian, and hey, what do you think about the future of magnetometers as being the new future of metal detecting?

LL

 

[Silver Searcher]

The trouble with air tests are that they suit the high gain detector designs that gives great display for You Tube results but fail when it comes to "in ground" performance. I've put over 300 machines from 60+ manufacturers through the same test beds and alas the limitations of physics plus ground condition mean the wonder machine is still to arrive.

NRG are good detectors for the low price they charge but not quite what is made out. Buy a 110 now and you could regret not waiting a few more weeks for the 150 version due at the end of December.

Thanks S.S. but the trouble with detecting full time is lack of time for the forums because you have to put the hours in if there's no wage check or pension waiting at the end of the month. Just waiting for it to get light now !

Full Time wish my body could take that ...good luck

SS

 

[U.K. Brian]

I can't see magnetometers making much impact with the lack of discrimination and drawback of the depth which is beyond most want to dig.
All tend to be heavy as well though the Quantro came in at only 12 lbs. I'd leave them for the wreck hunters and arkies but you don't know what breakthrough is round the corner.

I still advocate the use of in ground test beds but don't use the conventional type. First I dig a ditch to the side of the test area and knock a flat metal bar in sideways, remove this and then insert the test coin with a notched flat length of wood. The ground remains undisturbed above. I then either water or leave for a few days of heavy rain then give the surface a good wack just to close the soil down on the test item. Then for best results leave 20+ years.

Not being worried about anything bar ferrous/non ferrous discrimination and the minimum of that I don't worry putting in various types of target just rows of the same coin. Say all copper of the same size or all silver at varying depths from five inches down. You can then test exactly what happens to depth and I.D. with different settings and coils rather than making a guess that's often wrong.

 

[LuckyLarry]

Well that's better than nothing I suppose, but still not the same as in real life - because of the trench. Even after filling it in there are still two different strata sections, side-by-side, or, if done on the side there is the air space next to it, and that doesn't cut it at all. The actual field radiation of a low or high freq metal detector is more like two 6' diameter balloons squashed together (this can be proven by using iron filings and iron dust spread out over a plane covering the metal detector search head, to show the field). That trench or side slab you suggest interrupts the field too - and then you have the same case scenario as a built "test garden". When purchasing a new detector though, the only way one has to "suppose" the depth potential is to do an air test, and that too is subject to question. There is one better way to test the depth potential though but it's highly impractical, we used to do it when I worked for xxxxxxx Metal Detectors in R&D, and that is to bring a sample of ore along with you first, and ground-balance the ore sample to the detector, or include it in a pass over the search coil, along with various targets or other samples. It has to be the correct sample though, but it works well, even if it's only the size of a lipstick tube. Tesoro Electronics uses this method when testing their detectors in R&D - and it's highly accurate too. Whites did it in the past, and of course all others do it too. Few people bring along ore samples when purchasing metal detectors though, it's just not something that people keep close at hand, and the ore samples are not easy to find either.

BTW Brian, when I see a 70 pound child packing a 3 pound detector, the truth is that the child weighs about 1/3 my weight. If I did the math since I weigh about 3x that of the little boy, the equivalent would be me carrying a 12 pound hand-held detector, not exactly my wish for the day. lol. When I worked for the US Government in R&D on nuclear torpedoes we used some rather tiny magnetometers that weighed only about 3 pounds, and that was in the early to mid-70's. I cannot go into the complete details because the program was/is still top military-secret, but let it suffice me to say that we used them to locate test torpedoes that our dolphins could not locate with their sonar, and at almost unbelievable feet of depth. (I have to be very careful as to what I write here). We cannot buy those magnetometers though, because only the US Government has exclusive rights to them.

BTW, a Deepers 505 claims to find a pocket knife at 12-16", a pistol at 24-32", a 5 gallon can at 6', and it weighs only 2.5 pounds. Discrimination is possible, but not enough R&D has gone into it yet. ALL objects do have some magnetic qualities, and that is where mag research needs to find the answers to their discrimination questions.

deepers.com/English/Mag505-Complete-Description.html

On a side note, I seriously doubt that magnetic "spectrometers" will ever be practical because of their inherent size, but one never knows.

LL

 

[U.K. Brian]

We have to work with whats on the market...the Proton 4 comes in at 300lbs but is what you need for wreck hunting (I forgot you have to add the weight of two car batteries as well).

With "normal" detecting all ground is disturbed. If a farmer hasn't ploughed it then worms, mice, voles are at it none stop and winter comes and ground heaves and cracks so a modern coin ends up a foot down and a Roman one comes to the surface. There's also weight displacement ie stick a large rock in the middle of your lawn and it goes down over time and small items come up around it.

I always suggest with any new detector or coil to do an air test at the very least at a known setting. Perhaps all metal or where a small nail will start to give a broken signal. I use both pure metal coins and cupronickel. The cupro came in when I found a distinct drop in the number of "silver" coins that the pulse machine I was using had turned up. In fact copper performance was right up to spec. but cupro coins had become much harder to find. A coil swap restored performance and the problem was down to the coil having taken in some water. No doubt copper performance would also have dropped off as corrosion increased.

Totally agree about air tests also being an indicator. When I tested The flagship Whites/Garretts/C-Scope/Fishers against each other many years back the Spectrum did best in air but lost in ground performance quicker. Still was up there as a good performer but not Number 1 as the air test suggested.

 

[LuckyLarry]

Good post Brian. May the gold coin wizard reward you handsomely someday soon, if (she?) hasn't already.

LL

 

[U.K. Brian]

Got rewarded yesterday. Guy had bought a Sovereign GT off of E-Bay and couldn't get the performance he expected. We ended up down the beach and I had a gold Sovereign and a ring (9ct) with a TDI. As my old Sovereign was working at least 30% better than his newer Minelab we opened it when we got home to find a nice salt stain right across the circuit board.

Now he's going to have the fun of trying to get his money back !

 

[LuckyLarry]

Yeah Brian, lots of people like the Sovs, and in many cases they have good cause to too. It's nice to score a ring now and then and I think I'll go inside my Chinese cheapo and my Compass Compadre and open up the stops on threshold, they both do a better job at rings and older coins right now for some reason anyway, and an audio TH would add another inch or so.

What part of the world did you find the ring in?

PS: I don't buy anything from e-Bay, I have little patience for some of those dealings. I've done well enough right here for trades, sales, and purchases.

LL

 

[U.K. Brian]

Rings are a major source of income for me. The gold sovereign was a better suprise. I need to find at least two gold per week on average. Unfortunately the sand has been deep for months but hopefully the winter storms will sort that out.

Though I have BBS/FBS and twin frequency detectors I really don't like them. Slow in use and not as deep as most think. The poor pinpointing with the Minelabs really helps with claimed depths of detection as most just dig on by the target and ignore the fact it then falls into the deep hole they have just dug.

 

[CaptainRobin]

LuckyLarry... I have an old Garrett Deepseeker, think I purchased it in 1980. It was top of the line back then, would really punch down in Missouri soil (I 'uz stationed on FLW, ever find an old training area where you took $70-80 face in silver?). Mighty heavy compared to the AT Pro, and it's inoperational. Battery board is coroded. Any idea if Garrett or anyone else might repair it? I hate to throw it out, got three different coils for it, belt mount kit, arm rest, original operator's manual, etc... but I'm not much of an electrician. Staying out of the woods and old sites at the time as deer season is open, but I would like to get it repaired. As you wrote, it'll punch down. Large coil is great for cache hunting, sniper coil is great for trashy areas, mid-sized coil is great for coinshooting. It's just mighty heavy, but it'd be a good backup for the AT Pro. Any suggestions would be greatly appreciated.
Robin

 

[U.K. Brian]

Not Larry but I've always found Garrett to be poor compared to other companies when it comes to the repair of older detectors. Cut off line with a few of the big companies seems to be ten years.

That leaves you with getting an independant to do the work and the last comment I read on that subject relating to what I think is your machine (long box and lower (5 kHz) frequency) was that they could not get hold of the schematic and one or more componants were obsolete.

Doesn't mean you can't pick up a secondhand one cheap. I saw and tried a Garrett Groundhog of the same period a few weeks back that looked as new and had had little use as the owner found it to heavy. Stored for years but worked fine. Price £50 ($75).

 

[Keppy]

Though I have BBS/FBS and twin frequency detectors I really don't like them. Slow in use and not as deep as most think. The poor pinpointing with the Minelabs really helps with claimed depths of detection as most just dig on by the target and ignore the fact it then falls into the deep hole they have just dug.

Yes i always said that about the BBS/FBS detectors .... I found my Sovereign's were no deeper than my other detectors.......... But then they think i am knocking Minelab..... And have no idea what i am talking about........ I just tell it as i see it....

 

[LuckyLarry]

Well guys, here is my view on it all..

Keith Wills at East Texas Metal Detectors (903-734-7773) can repair the Deepseeker, and like a car, there is usually only a minor problem or two when most things quit working anyway. I used to repair detectors and that was the case with them back then too. I'm (guessing) that Keith will charge you about $100 to get the Deepseeker back in use again.

My Sov worked well, smooth, ran quiet, up to specs, but coil-size for coil-size the Explorers and Sovs couldn't match the CZ's or the old Compasses, disc OR in all-metal in really bad ground, Or on west coast salt/heavy black sand beaches. The old Deepseekers and Fisher 400 series (coil size vs coil size) were absolute BEASTS for all-metal depth in extreme magnetite or hematite soils and salt/BS beaches, and the 400's were made for mining, if that gives you a picture. The Garrett 7.5" co-planer was very nice for ore sampling, but it LOVED iron.

I was impressed with both the BBS machines for running (very) smoothly over basalt and granite, salt beaches, black sand beaches, conglomerate rock, and still giving a good signal on silver and alloy rings, but if I put a piece of iron next to one - it was a complete DOA. They weren't made for that type of hunting, but the Compass GS and R&C were. They were bad ground gold nugget hunters, and darn good ones too.

In about a year I should have my new invention for old detectors perfected, but I can't release any info on it until then - because it will have to be patented and a place found to manufacture it first. Secrets, secrets, secrets.. It will likely surprise people at it's simplicity though. When it comes out you will know who designed it.

LL

 

[Keppy]

I will be watching for it Lucky L........ I would have to guess that if you had something to do with it ......... It will work better than any thing i have now........

 

[U.K. Brian]

Just hope its not going to be another windowing signal booster !

 

[LuckyLarry]

No Brian, nothing to do with noise or sound in any way...