NASA-Tom --

THANKS for the info on the ground balance. I wasn't aware of the "balance to the ferrite" idea. I'll give it a try...

Thank you!

Steve

Hi Tom,

Thanks for sharing that interesting experience with the MDT 8000. I didn’t see it mentioned (sorry if I missed it) but were you using the 12” coil, and if you were, would the stock coil require small or significant SB and GB settings to achieve the same results with the ground you were in? I too have found that by being able to ‘tweak’ these two settings with 12”, it gives the MDT a degree of fine ground adjustment that hasn’t been previously available on my other detectors, one of the best features of the Tarsacci. That gives me incentive to ‘work’ those adjustments when using the MDT both on beach and inland.

I spent about 2 hours yesterday evening on one of my private, Low Mineral(1 Bar on Anfibio & F5) sandy sites that has been hunted several dozen times & has gotten very stingy. Used NASA Tom's recommended settings; 6.4kHz GB 750 SB 48. Ran Disc mode -20. TH-2 Sens 8, 12" coil. The machine ran smooth even in the heavier nail areas. I am still going slow on the little falses, but can call the targets accurately now. I only got over 3 good sounding targets; .224 modern jacketed bullet near the surface, 1920's shotshell head @ 6" & a nice size piece of ornamental cast zinc that was brass plated & gold washed @ 7". The bullet is probably fresh, the other 2 should have been already found. The MDT or dumb luck? I'm not sure yet. It will take more run time. I have 2 test coins on the site; Penny & Nickle, both @ 8" both in ground 2+ years. Good response on both. I raised the GB to 800 the last 30 minutes and it seemed to be even smoother. There are high voltage line nearby & running Black Sand On does help smooth out the low background chatter you can hear when the coil is not in motion over the ground. Ground very dry to 12+ inches. Very hot & no breeze at all in the woods. It's hard to concentrate while mopping sweat out of your eyes!
I will be back to carry on with the education when it is cooler.

Chris

Chris....... depending upon how MUCH (ppm by volume) your ground is mineralized........and.......to a lesser extent: what 'type' of mineralization you have . , . , . , . , . , . , . , dictates whether you should employ standard Ground Balance (per engineering design)........ or........... use Ground Balance in a non-standard fashion.,.,.,so as to 'detune' a bit to iron. In SOME cases.......if you have lateritic iron oxide for your minerals.......you get a double plus!!! You Ground Balance out the bad dirt..... WITH a secondary side-benefit! = of ALSO desensitizing to iron implements!

Gary........I have been exclusively using the 12" coil; yet, the principality of operation/physics would still uphold .... if you are to use the 11"x8" stock coil. Just keep in mind; different-sized coils may require slightly different Salt Balance & Ground Balance numbers. In a wet-salt environment...... the Salt Balance setting(s) may be a fair amount different .... between the two coils. Our Florida salt is THICK! (Hotter waters hold more salt in solution). {{{Also....... my latest report about the chunk of iron with a copper penny underneath it.,.,.,.,.,., was a Deland incursion}}}.

Chris........ I would recommend a Disc setting of 'negative 30' (( -30 )). It is best to hear EVERYTHING............ in lieu of 'chasing ghost signals'.

--------------------

Something that I have now FULLY implemented (because time is a very 'finite' resource)......is: LIFE IS PREDICATED ON EMI.
I may have full intent of hunting ALL sites with the Tarsacci. BUT...... if EMI is present ....and forces me to run Sens on '5' (or below). , . , . , . , . , . , . I immediately switch over to the EQX. If I am forced to drop Sens to at/below '21' on EQX.,.,.,.,.,.,., I pack up ...and leave. What has been interesting is: about 45% of the EMI sites...... the MDT is least affected. At 45% of the sites........the EQX is least affected. Needless-to-say............ 10% of the sites..... BOTH of the detectors fall flat-on-their-face , , , , , , , plagued by EMI.........and I have to pack up and leave.
When you live in rural areas...... powerlines are a bit older.....and readily 'chatter' ..... to a higher order-of-magnitude. This is 'why' the EQX is EMI 'shutdown' at nearly 60% of the sites I hunt. (F75 is worse). Thank God the Tarsacci and EQX express nearly opposite EMI encounterings at various sites.

Tom, Do you ever engage Black Sand to try to mitigate some EMI? It may be a false sense of improvement if Silent EMI is still effecting performance, but it does seem to help with the audible EMI. It also seemed to help with ground noise the one time I have hunted after a rain on a Red dirt site that will cover a pocket magnet with Iron fuzz when you rub it in the dry dirt.

Chris

Interesting Tom. On the one spot I have that gives me EMI issues the Equinox is bad and the MDT does not even know there is EMI. So, spot on.

Chris,

I aggressively try all-tools-available .... in order to mitigate EMI !!! EMI is a MEGA performance-killer. The order-of-magnitude severity is nearly completely unsuspecting. THAT'S what hurts! ESPECIALLY "Silent EMI".
Yes...... there has been one time (and...... so far....... only once) whereby ...invoking Black Sand "ON" mitigated EMI. And I will never forget this experience because...... the 'amount' of EMI was shut-down severe! Invoking Black Sand nearly ridded EMI. I was dumbfounded. What's weird is....... this incursion only happened once! All other times..... Black Sand has not helped. I speculate that I had encountered a very discrete/specific 'type' of EMI....where Black Sand "ON" could help.
Most manufacturers RUN from EMI. VERY few seem to attempt mitigation. It is a near-guarantee that...... if a Mfr succeeds in.........say.................... 30% mitigation of EMI.....,,,,,,.......,,,,,,,,, THAT Mfr will take the World market-lead.

Chris...... your dirt mineralization (magnetized dirt)...... sounds severe. You NEED the Tarsacci......and/or Minelab GPX Series.

midalake....... yes. FORTUNATELY........ the two platforms (Tarsacci vs EQX).....express dramatically different resultant(s) ......compared to each other........ when exposed to various EMI types/sources. So far........ it has been a major blessing that.....,,,,,,,,,........where one unit 'terribly shuts down' due to EMI..... the other unit is (most-probably) "ok" in that EMI. ""WHY"" the units are nearly opposite of each other ..... in regards to 'how they handle' EMI........ is a Operating System (OS) blessing!!!
Before the introduction of the Tarsacci.............. the "norm" was: If one detector suffered severe EMI at a particular site....... so would nearly ALL other units!!! You were S.O.L. ------THAT site (and many other sites)....... were unhuntable..... due to EMI.
About 13 years ago........ with a proto F75.......... I quickly learned.....there were 'layers' of EMI. You may select a noise cancel channel....that ridded one 'type' of EMI that was in the air........... BUT...........there were several other types of EMI that were ALSO in the air..... that still needed to be ridded.

I have found experimenting, particularly On Site, pays a good dividend. If it was all easier it probably wouldn't be as interesting. I still want to find good stuff though!

Chris

Gold coin settings.
Hunting mid 1800s sites were some nice finds have been made including monogram silverware and jewelry.
Plenty of iron , minimum modern trash.
Ground acidic, low mineralized.
Dug many bird tags chasing lower conductors (F75)
Should I invoke salt balance. Positive GB
18k Freq. MDT, Thanks

While we are on the subject does anyone know what ID numbers correlate to US gold coins on MDT



Edited 1 time(s). Last edit at 09/05/2021 09:08PM by gman.

gman....... you are not looking for high conductors. So......... yes. 18-Khz. Do not invoke Salt Balance.......because........ you are NOT wanting to rid 'foil'.......but/rather....... detect it with maximum performance abilities. And............... depending on your soil conditions....... you may be able to use Ground Balance in a unconventional way........so-as to detune iron. BUT..... if your mineralization is medium...or higher......... you will need to use Ground Balance in the proper fashion/design engineering intent.

On my Tarsacci (with 12" coil)....... U.S. Gold Coins:

$1 = Bounce between 4 & 5........ attempting to be a solid lock-on to 5.
$2.50 = 7
$5.00 = 8
$10.00 = 12/13
$20.00 = 15

So far, I only have about 20 hours on my MDT 8000. Probably 15 of those in the field on hard hunted Iron sites; 2 with high minerals, 1 with fairly low. I have dug 6 good targets I feel certain my other detectors had missed multiple times. All 4 were 7-10" deep with plenty of Iron above & around them. This is exactly what I had hoped for as far as capability. Looking forward to getting more time in with it.

Chris

Chris........ I am experiencing the exact same resultant. . . . . BUT......... with stipulations. If a site is carpets-of-nails........ the Tarsacci falls flat-on-its-face........just like all other detectors. If a site is overloaded with aluminum soda tabs in the 5" - 8" depth range...... the Tarsacci can be very difficult to focus on JUST coins. If a site is fairly trashed out in nails, aluminum, tabs and other various types of trash...... the Tarsacci will find coins behind all other detectors. If the site is old....... and all non-ferrous targets have been removed from ALL other detectors....... the Tarsacci will shine again! If the site has medium mineralization (or higher)...... the Tarsacci will shine; yet, again!

When I hunt a new site (especially if looking for old coins)........ I always use the EQX. (Barring EMI failure). The exceptional high-resolution ID of the EQX is a euphoric/triumphant time-saver. THEN I will go into the site again..... with the Tarsacci...... and see: just how many high-tones I have missed with other detectors. THAT'S an eye-opener...... all unto itself.

Thank you for the insightful replies. Your comment on Carpet of nails surprised me some as to being so definite. I may not understand the term properly. One of the good targets I dug was in the densest nail spot I have. It was a Brass curtain rod ring at 9". A solid medium soft tone in Disc +29. If you listen to the Iron it almost constant. I have only been able to dig shallow items in this spot before the MDT. I will be back. I am also interested to see what ground moisture will change. Right now it is very dry down to about 10". I will continue to try and be observant.

Chris

More proof of MDT see-through ability. From very small old park that has been hit many times , got a strong signal in the middle of the the grass were many have hunted. Using Tom's high salt positive ground balance settings I crossed the target stopping in my tracks.
Rotating around Target I get high dig me tone 16 - 18 ID Digging down to around 5 inches located with my pinpointer I pull out an strange Target. About 1 inch in diameter and 3 inch Long .Wave it in front of the coil. Reading a bouncy 4 both directions. Rescan and still have coin reading in the hole. Dig another 2 to 3 in and retrieve 1962 Lincoln cent. Part 1 ...



Edited 1 time(s). Last edit at 09/10/2021 12:17AM by gman.

Tested the coin and object found with a 75 when I got home. F75 will read trash Target at 16 low foil range the Lincoln will come in at 68.
Using inch and a half piece of wood for spacing with trash Target on top F75 would report low tone 16 ID.
The MDT report a 18 ID two points higher than the 16 ID by itself. Most importantly with a high tone. Must dig.
If I chased the foil Target with F75 at the dig site although I really wouldn't have a reason,then waved it in front of the coil it would have gave me the foil ID at 16 and no reason to recheck the hole.

I used mine last week end ,took me a while to find the right spot on the beach ,but once i hit it stuff from WW2 were coming right left and center,it is a beach absolutly combed to death by the local(i am a part timer there) and i m glad my MDT was still finding me stuff ,half of them medium to large shrapnells.Gold was there somewhere but so was the tide............


RR

Chris........ there has never been a "definition" or "basis/base-reference" towards the definition of: "Carpets-of-Nails".
Sooooooooo........... my definition has always been (and maybe we can set forth a 'bench' definition): two or more nails underneath a standard 8" coil......at any given time.

gman = That is exactly what I am talking about. But....... to unfamiliar readers/users.,.,.,.,.,.,., maybe I should clarify your experience: A ID of '16' on a F75....is chewing gum foil conductivity. A ID of '16' on the Tarsacci.....is a (newer) copper penny and/or silver dime conductivity. With your settings...... your Tarsacci "time-domained out" the large foil-ID target; yet, could still correctly see and ID the coin that was beneath the large chunk of foil. (((You may start to like/appreciate/employ those non-standard Salt Balance & Ground Balance settings))).

RR....... you're 'due'. (Maybe even: overdue)!

Thanks, good to have an idea of relative terms. I'm going to call the spot I dug the curtain rod ring shag carpet!

Chris

NASA-Tom --

"Time-domained out..." What an interesting phrase, with so much information contained within -- more than at first glance. Explanatory, descriptive, and instructive. As you might say, "lesson imparted." Thank you. It has set my mind to thinking even more about how the unit functions...

Steve

Chris....... not too shabby shaggy!

Steve...... If only I could expound further.

Regarding how to define 'iron trash density' , there's the 'Trash Density' scale that I proposed some years ago, which could equally be applied to iron:

Level 5 = 4 targets per 10"
Level 4 = 2 targets per 10"
Level 3 = 1 target per 10" (the medium level)
Level 2 = 1 target per 20"
Level 1 = 1 target per 40" (= about 1 sweep length)
Level 0 = minimal trash (often many sweeps before a 'hit')


Original discussion here:
[www.dankowskidetectors.com]



Edited 1 time(s). Last edit at 09/11/2021 08:35AM by Pimento.

Pimento....... I wonder how/why I missed this.
I like it!

One thing to add on my coin / trash find with MDT If I remove salt bal and lower ground balance the target would come in at a very bouncy 10 ID also bouncing between high and mid- tone with the audio

Still a possible dig me, but not a must dig.

Tom is there any other machine made currently that has the see-through capability.

gman........ No.
Because......there is no other detector out there with a separate control for Salt Balance and Black Sand , . , . , . , . , . , that is coupled with time-domain O.S. parameters.

Live stream done 5 days with the gentleman behind Tarsacci- Mr Dimitar Gargov
[m.youtube.com]



Edited 1 time(s). Last edit at 11/22/2021 04:10AM by tnsharpshooter.

David........thanks for the link.
Notice: Dimitar has Office, Lab, Bed, Library and Food......,,,,,,all-in-one-room! Hmmmmmmmmm!!! (((Sign of a real Engineer))).

Yes, thanks for the link!

Steve

Today I sent an E mail to Mr. Gorgov asking a question I came up with after a hunt this past weekend about the Ground Balance range on the MDT 8000. He was kind enough to call me on the telephone and we spoke a good while. He certainly is a nice fellow and wants his users to be able to get the most out if the detector. In addition to explaining the question I had we talked about hunting in Iron trash/nails. He confirmed NASA Tom's experience of using 6.4kHz & high GB & high Salt Balance. The added hint he gave was to use a low Sensitivity setting. The denser the Iron, the lower the Sensitivity, even down to 1. Also, the Standard coil would perform some better than the 12" in the dense nails. Perhaps not the detectors best environment but it will see targets that have been missed by traditional VLFs.

Chris

Chris...... the BIGGEST thing Dimitar and I want...... is for Tarsacci owners to see/experience/first-hand-witness what the Tarsacci will REALLY do. It is a World flagship.........and for good reason.
The Tarsacci is a very different Operating System. Hence; lots of documented data/training/experience(s) on this forum (and especially this thread).

I (somewhat) shot myself in the foot....when I became the Tarsacci distributor/dealer. It then badly skewed/tainted my words and trustworthiness when I would 'praise' the Tarsacci........as........it would look like I was "peddling" sales. I'm not sure I can recover from this status/condition........and regain any form of Tarsacci data trustworthiness.