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ON THE HORIZON = MDT-8000

Posted by NASA-Tom 
JCR
Re: ON THE HORIZON = MDT-8000
November 23, 2021 04:42AM
Tom... I do not think you have compromised you credibility by also being a Dealer. Firstly, your character and dedication to the detecting community is well known and appreciated. Secondly, no serious detector user want to deal with someone who is not knowledgeable and enthusiastic. Without your input on this forum I would not own a Tarsacci, or an Anfibio or have the intermediate to advanced understanding to use them well. Your posts on the F75, Equinox, Deus and many other detectors past & present have helped educate me. Thank you sir and to the other members here that seek excellence.

Chris
Re: ON THE HORIZON = MDT-8000
November 23, 2021 06:46AM
Re: ON THE HORIZON = MDT-8000
November 23, 2021 09:50AM
NASA-Tom Wrote:
-------------------------------------------------------
> Chris...... the BIGGEST thing Dimitar and I want..
> .... is for Tarsacci owners to see/experience/firs
> t-hand-witness what the Tarsacci will REALLY do. I
> t 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 bec
> ame the Tarsacci distributor/dealer. It then badly
> skewed/tainted my words and trustworthiness when I
> would 'praise' the Tarsacci........as........it wo
> uld look like I was "peddling" sales. I'm not sur
> e I can recover from this status/condition........
> and regain any form of Tarsacci data trustworthine
> ss.

Morning to All i m Not sure if Dimitar has uploaded my pics on Facebook or whatever it is called now

RR
Re: ON THE HORIZON = MDT-8000
November 23, 2021 12:31PM
You have a lot of passion for this machine Tom. I do as well. Call me a "fan boy" but i have no skin in the game ..... the machine has just been one of the best ive used in the water. It produces...... and my repairs have really went down. I loved my Xcals.... i had three but the repairs seemed to be constant AND i upgraded them all at an added expense. Sold um all..... as well as a CTX. Ive kept the Nox but i rarely use it. I dont add much to the dirt conversation just because ive not used it there. But thanks for those of you who do. Your comments often give me things to test as well.
Re: ON THE HORIZON = MDT-8000
November 24, 2021 04:43AM
So, this is going to be a bit long...don't say I didn't warn you!

As some know, I bought an MDT 8000 from Dimitar a few months ago, but other than working with it some in my test garden, I haven't had time to get it out "into the field." Today was that day.

I decided to do something that was probably unwise, for a first time using the machine outside of a sanitized (no trash) test garden -- I decided to head out mid afternoon to a spot in an old city park. For background, our town (and -- this entire portion of our state) dates to 1891, the year that this portion of Oklahoma was opened to "white settlement." Our city park is on the original city plat, but not sure when it actually came "into use." I have dug two Seated coins from this park -- one an 1891 quarter in pristine condition from about 8" deep, so that likely confirms usage back into the early 1890s.

ANYWAY, this one little "hot spot," as I came to call it, centers around some type of small concrete pad, with metal embedded. I've hypothesized maybe a flagpole, or water fountain at one time, not sure. Anyway, whatever the case, we figured out (in hindsight) that whatever was here, drew a crowd...because this concrete pad proved (in hindsight) to be the centerpoint -- or bullseye -- of literally dozens of old coins. Each coin dug was in the 7" to 9" depth range, and none newer than 1908. Once we happened upon this spot, we hunted it relentlessly for weeks, until it eventually went dry. We found probably two dozen Barber dimes, at least that many Indian Heads, one to two dozen V-nickels, and a Barber quarter, plus two Seated dimes. With nothing "newer" than 1908 found, we speculate that whatever drew folks to this spot, disappeared at that time (leaving just the little concrete pad).

Once this spot began to play out (most coins were dug by my hunting buddy running an E-Trac, and me with an Explorer SE Pro), we then invited other guys to help clean the rest of it out; several other machines were used, including an F75, Gold Bug Pro, additional E-Tracs, etc. Finally, everyone gave up on the spot, but since this park is close to where I live and is my "go-to" park when I have nowhere better (or not much time), I still spend at least an hour or so in the hot spot each time I hunt this park, "just in case." Five or six years ago, I got a lone Barber dime with my Explorer, at about 8" deep. After I got my CTX, I then ran it through this spot thoroughly, but all I was able to uncover was a single wheat cent on the "fringe" of the hot spot (which was odd, as it was the "newest" coin found in this area; a slightly older Merc dime was also found with my Explorer on the fringe of the area, 7 or 8 years ago). Anyway, that wheat cent was the only additional coin I was ever able to locate in this spot, with the CTX -- and I worked HARD at it! That was about 4 years ago, and I haven't dug another coin from the hot spot since. Still -- I have always felt strongly that there HAVE to be additional, old coins in this spot, just a bit beyond the maximum depth that even the deepest machines can reach (about 9" in our dirt, on a dime). That's why I spent so much time there with the CTX, trying to find just one more silver coin (to no avail).

SO -- that brings me back around to today, and the MDT 8000. Again, it is obviously not the smartest plan, on the very first outing with a new machine, to take it to a spot with lots of old, deep nails, and with any coins left likely to be at a minimum 8" depth or beyond, and then to crank the machine up nearly as hot as it can go, hoping to achieve the necessary depth. BUT -- that's what I did. I set the machine up at 6.4kHz, DISC mode, zero discrimination, threshold -1, sensitivity 8, and then I set up salt balance and ground balance as NASA-Tom has been doing, to limit the machine's sensitivity to small rusty iron, and foil (Salt Balance 48, Ground Balance 750). Well, first of all, the machine set up this way was absolutely quiet, EMI-wise. I probably could have gone to 0 on the threshold, and 9 on the sensitivity, but decided to hold back at least a little!

I must admit, after the first hour, I wanted to wrap it around a tree. SO much noise (ground, not EMI), and I had no clue what the machine was telling me. I was getting tons of iron low tones, that would mix with high tones (and some with some mid tones mixed in), but these were all iron/nails (the Tarsacci seems to like to high-tone on very small, very thin/fine nails). Meanwhile, I was getting TONS of high-tone chirps, and because I knew any coin would be deep and subtle, I was trying to decipher each of the high-tone chirps I was hearing, and thus it was slow going, trying to investigate every one of those. Finally, I couldn't take it anymore, and decided those high tones may have something to do with ground balance, so instead of my pre-set at 750, I ground balanced to actual conditions (and then several times thereafter; ground balance ranged from 665 to 714 during the hunt, as the clay is not as red in this park, as most other portions of my area). When properly balanced, this cut down substantially on the high-tone chirps, and kept them all as low-tone chirps (so I wonder now if it was tiny iron/rust flecks, that were "wrapping around" at times into the upper 20s and thus high-toning, due to ground balance being slightly too high, at 750?)

After this, it got a little better, but I dug all manner of iron (especially very small thin wiry pieces), but also screws, bolts, etc., plus some non-ferrous junk (a bullet, aluminum (can slaw), tabs, and other bits of various metals). BUT -- just about the time I was wondering if I was ever going to start understanding the machine's language, I got another soft high tone. This one was repeatable essentially all the way around as I rotated around the target, without quite as much low-toning iron mixed in. Not ENTIRELY different from a number of other, small nails that I had dug, but I felt a bit more confident that it was non-ferrous (IDs generally low 20s). Imagine my shock, when -- after popping out a deep plug, there at the very bottom of the hole was the glint of silver! A 1903 Barber dime! I could NOT believe it. I cannot tell you the countless number of times this exact spot was swung over with other units; it was a mere 10 feet from that concrete pad, that marked the centroid of all of the coins we have found here (and therefore the portion of the area that received the greatest number of "coil swings"). I am not positive on depth, as it was in the deepest part of the hole, so it clearly was right at the base of the plug and may have slid to the deepest part when I removed the plug, but it was every bit of 9" -- well beyond the length of my Garrett Carrot. (OH -- and there was a small nail 3" deep, and about 3" from where the dime was located -- responsible for some of the low tones that I was hearing).





This dig allowed me to learn a few things, and confirmed that A -- there ARE INDEED additional coins in this spot that were just out of reach of all of the other machines, and B -- that the Tarsacci is capable of exceeding the maximum depth range of all other Flagship machines that have been run through this spot countless times.

So, I continued onward for a bit longer, digging a bunch of can slaw that bounced between mid and high tone, a few ring tabs, etc. It was getting dark by this point, but I wanted to run through the portion of the hot spot where the two Seated dimes were found, for just a few minutes, before calling it a day. A few more non-ferrous trash digs, and then I hit a target that had some mid and low tones mixed in -- similar to so many other targets today -- but I could get a pretty consistent low 20s from several directions, similar to the Barber dime from earlier. I dug a deep plug, and there in the very bottom of the plug (roughly 8" deep) was yet another Barber dime!

I know, I know, two Barber dimes is not the world's most amazing hunt. BUT -- because I know how many hours and hours and hours were spent criss-crossing this hot spot, with multiple top-performing machines, by multiple, experienced hunters, and because I know how long it has been since a single silver coin was dug from this spot, AND given that calling me "green" on the MDT 8000 is an understatement, I have to say that I am MORE than impressed. It has been ten years since my last two-silver day from this spot, and I estimate 5 years since the last time I dug a single one. THIS, to me, is really, really amazing, and speaks to why NASA-Tom refers to this machine as having "world flagship" status.

My early take is that NO -- it is not an everyday coin hunter in a park full of trash. I feel that the ID is not accurate ENOUGH to allow you to cherry-pick, but it IS accurate enough to get you "in the ballpark." I don't like the tones; to my ears, the mid tone is the most attention-getting, and the high tone is a bit "muted." BUT -- I began to sense some intelligence in the tones; a rapid pre-amble and post-amble seems to exist with "better" targets. If you are getting some mid and high tones mixed in with lots of iron tones, but you just can't quite get the non-ferrous tones to "settle into one specific spot," these seemed to prove to be falses off the nails. I dug one square nail that gave a really nice, consistent high-tone false about 3" or 4" from the head of the nail. There is some modulation in the tones with depth; it will take some getting used to, but you can learn rather quickly to begin to tell a deeper (or smaller) target versus a shallow one. IF it's not too trashy, pinpoint helps there, also, as pinpoint audio is well modulated; volume (and signal strength) are quite diminished when pinpointing deep (or small) targets. Ground balance -- at least for a newbie who doesn't want to deal with a bunch of ground noise -- is IMPORTANT; it has to be "spot on" for the machine to behave "properly," from my view. So, obviously, LOTS of learning to do, but what a great start. To say that I am "impressed" would be an understatement...



Steve



Edited 2 time(s). Last edit at 11/24/2021 04:51AM by steveg.
Re: ON THE HORIZON = MDT-8000
November 24, 2021 07:38AM
Well done the MDT is my detector for the beach pounded.by nox users.Qnd i still find stuff.

RR
Re: ON THE HORIZON = MDT-8000
November 24, 2021 12:12PM
Great write up steveg. Everything you said, I agree with even the part about wrapping it around a tree. I have said the same about the tones especially the high being too soft. When you GB, how are you doing it? It does require an accurate GB to calm it down. Which coil were you using?
Once you pay close attention and adjust your thinking about the machine, it will start to reveal its language. It does like deep nails and gives a high tone whisper like my 3d, ya have to dig them. When I'm at an old area and a high tone comes in and the pinpoint is very quiet and not ear blasting, I get a little rush. I have found some deep Barbers and a nice deep LC, 1856. The large cent was a surprise out of that park.

Also, RodPa has dug some nice Barbers from there using a Nox. This park is not far from a Detector dealer who also detects, so there have been many many swingers in the past. Rodman and I know there are still coins in the ground there but we have to get our coils over them. Thought I'd mention, years ago I pulled a deep 10" seated out of there with my original f-75 on all metal. . . . .it was just a barley an audible sound. .. and bingo.

Steve, ant thing else you can share with us on your findings with the MDT, I'm all eyes and ears, again, thanks for the write!
Re: ON THE HORIZON = MDT-8000
November 24, 2021 01:26PM
If the tarsacci could adjust where the arm cuff is located I would be a buyer again. It's only like 9" from the front of the grip to the back of the arm cuff. That ends up mid forearm for me. Make the detector way off balance. Cuff needs to extend back to 12-13 inches . At least for me. That's why I don't swing one.
JCR
Re: ON THE HORIZON = MDT-8000
November 24, 2021 04:41PM
Steve, Very nice write up. Your perceptions & beginner's experience are very similar to mine. The audio understanding will come with use. Try Disc +30 to deal with the small thin nail falses. Proper GB is crucial if there are minerals in the dirt. I struggled most with understanding/adjusting the GB along with it's relationship with the Salinity balance. I had an enlightening conversation with Dimitar and things started to make sense. At this point if I am on mineralized ground I make sure to set the Salt balance active about 27 before I Auto Ground balance with a Ground grab. Then I will fine tune the Salinity. Then I will fine tune the Ground Balance MANUALLY. This is a lot of steps to get initially setup BUT it will result in very smooth, quiet operation. From here you can monitor the GB by momentarily changing to Mixed or AM. Tracking seems to work just okay.
On low mineral Sandy sites you can just run NASA Tom's high GB & SB set up and be fine. On hotter ground you have to go to the trouble to set up Balanced or you get all the noise/falsing.
Do not be afraid to lower the Sensitivity if the ground is trashy. Even -3 is deep. Same with Threshold if there is tiny trash or EMI, even -7 will see a coin. Black Sand On will also help with EMI or moist rust dirt.
Like any detector Stability will let you hear/understand what is going on.
I stopped using the included headphones and now use high ohm Killer Bs thru a Garrett Z Lynk setup. This has really helped clear up the audio.
I like Mixed mode, Disc 0 the best if the ground is not too busy.
Thanks again. Please keep posting.

Chris
Re: ON THE HORIZON = MDT-8000
November 24, 2021 04:44PM
Steve. First: You are CRAZY!!!! What you did was akin to throwing the keys to a Formula-1 racecar to a 15-year-old learners-permit equipped boy! Let me start to learn how to paddle a canoe ......starting at Niagra Falls or Grand Rapids!!! Again..... you are CRAZY!!!
BUT.........IF you can handle/learn/progress with patience/perseverance/temperament/headache-mitigating methodology...........you can crawl out of the fire....back into the frying pan.,.,.,.,., with a nice golden glaze. Good thing was/is............. you knew in advance.....what you were getting into........before-hand!
You could have VERY easily got yourself into the predicament of wrapping-the-Tarsacci-around-a-tree in VERY short order. , . , . , . , . , possibly even unsuspectingly..........on this very first outing.
Now all I can say is.......... if you hunt anywhere else..........it'll be a cakewalk.
Yes.............. use the Ground Balance in an unorthodox way......to mitigate iron flecks/flakes (and even bent nails) ..... that can false micro-audio-bursts as high-tone(s). Same with Salt Balance.
I DO wonder...... on your 2 (nearly uncirculated Barber) dimes ......... WHAT the signal response would have been......had you tried Black Sand "on"........vs.........Black Sand "off".......on either dime. I speculate Black Sand "off" (window is clear/white) would be better; yet, your dirt may not be simplex; but/rather: complex.
What is the exact overall length of your pinpointer? (My F-Pulse is 9.5").
Now go BACK there..... with Thresh on '0' this time!!!

CONGRAT'S!!!!!
(especially on your perseverance with that exceptionally painful/psychotic maiden-voyage learning-curve).
Re: ON THE HORIZON = MDT-8000
November 25, 2021 01:36AM
Rivers rat -- thanks! I can see why you are able to make finds hunting behind other machines!

ozzie -- I appreciate your confirmations of alot of what I described. Sounds like your experiences early on were very similar to mine. And it sounds like you also have a park where that extra depth the MDT offers may pay off for you. Sounds like it's been a great spot, despite being well-hunted...

basstrackerman -- I hear you, on the ergonomics. It's DEFINITELY imbalanced; there is definitely some strain in my wrist and forearm using this machine (with the big coil on it). I hadn't noted the rather short distance between handle and cuff; I'll check it out next time. But it definitely could use some "butt-end weight."

JCR/Chris -- like ozzie, it sounds like you relate to the challenges I had on the first outing. I appreciate the advice, and the pointers you gave. Interesting that you switched headphones; I have always liked Sunray Pro Golds; perhaps I should give them a try (though I'll need to find a 1/4 to 1/8 adapter). Hmm...excellent thought there, thank you! Also, you briefly mentioned "monitoring" GB by momentarily switching to Mixed Mode or AM...can you elaborate?

NASA-Tom -- yes, I understand; I'm sure it wasn't advisable to do what I did! But, having done so, and still accomplished the objective (to locate something that was "out of reach" with other machines), really shocked me a bit. If I was able to find coins deeper than other units -- which I have hundreds of hours of use on -- in the first go-round, I can only imagine what I might unearth after learning the language. I have ALOT of spots in mind, now, that I need to return to, once I understand the way the Tarsacci "speaks."

Interesting question on what the response may have been on those dimes with Black Sand ON (I ran it OFF, as you probably figured, but I forgot to mention). I will try to "try" a few adjustments next time I am over what I think might be a good target, though it might be a little while, as I am not yet able to KNOW that, at this point, pre-dig. Every time I find an interesting target, with a machine I am familiar with, I interrogate thoroughly, and try to "call" the target, or at least the possibilities, in my mind. I find that this really helps me to learn -- especially when I dig something that is NOT what I expected. But, that's part of what was so difficult yesterday, having no experience...there was NO CHANCE that I was going to be able to "call" any target...and I'm really out of my element when I'm that lost, in terms of how what is under the coil relates to what I'm hearing (and seeing on the display). BUT -- I will keep that in mind as soon as I can achieve a little more experience so as to "suspect" that I've located a target worth experimenting with...

OH -- the Garrett Carrot is 9 1/16" long. While the coin was sitting at roughly 10" deep, or a hair more, when I found it, the bottom of the hole (and base of the plug) was "slanted." So, it's of course possible that the coin was toward the shallower side of the hole, but fell/slid to the deeper side as I removed the plug. So, given that uncertainty, 9" to 10" deep is my best guess...

OK -- since I'm obviously a glutton for punishment, I'll go to threshold 0 next time, and run it "full bore." Why not?! I can say that it does not appear that EMI (at least, AUDIBLE EMI) will be a limiting factor in terms of being able to run it "wide open? in this spot...

THANKS!

Steve



Edited 1 time(s). Last edit at 11/25/2021 01:40AM by steveg.
JCR
Re: ON THE HORIZON = MDT-8000
November 25, 2021 02:16AM
Steve, The Sunrays are very similar to the KillerBs; 150ohm. I found the adapter at a Guitar store. Pretty sure it is the stereo version.
As far as monitoring GB; you have to switch out of Disc into Mixed or AM to hear if the ground is clean and hear any feedback from the ground. It is just one press of the Mode button to get there & 2 presses to get back to Disc. If there is a big change in GB you want to re check the Salinity balance also. The last few hunts for me have been on a site where the ground changes frequently. It is high mineral red clay dirt that was solid hardwood forest 80+ years ago. It is all cow pasture now. I suspect the spots were big trees once stood and the stump & root ball decomposed are the reason for the variation. That has made me really have to learn about how important GB is to quiet performance with the MDT.
I took a different difficult crash course than you. I started out with the MDT on a heavy mineral AND heavy Iron site! Not the best choice in hindsight to learn on but they are the kind I got the MDT for. Early on, I too had some pleasant deep surprises on hard hunted ground that encouraged me.
After you try Tom's challenge of Threshold 0, try running Sens @ 5 and TH&-03. It is still deep and you can listen better to learn. Also try Mixed mode with Disc @ 0 on some ground that is less busy. It's really nice.
Keep us all informed on your experiances.

Chris



Edited 1 time(s). Last edit at 11/25/2021 03:02AM by JCR.
Re: ON THE HORIZON = MDT-8000
November 25, 2021 03:02AM
Steve...... if you are able to delineate deeper mid-tones....... I strongly recommend digging all of the deep mid-tones.,.,.,.,.,., considering the age of the site. ((There's also another ---possibly unsuspecting--- reason/justification)).
Re: ON THE HORIZON = MDT-8000
November 25, 2021 04:43AM
Chris -- yes, I thought that the Pro Golds and the Killer B's were very, very similar. And the guitar store is a good idea; that should fix me up with what I need. Yes, it sounds like you gave yourself a crazy crash course, as well. I can definitely say that after just a short while -- as you discovered -- ground balance seems like it holds alot of importance on this machine in particular, and apparently for more reasons than one. I'll give those settings a shot, especially when the "challenge" at a particular site is coins on the fringe of detectability. I am CERTAIN it would be a much easier, less taxing way to learn, not running the machine in "overdrive!"

NASA-Tom -- I will do so, and I think I know where your mind may be at, on that. The one complicating factor is can slaw. There is ALOT of it in this park, and the small aluminum shards pose, of course, as deep targets. But, that's just the nature of the beast. I will say that what you suggest is how we were able to recover so many V nickels; all those years ago, after we cleared out all the high tones in that "hot spot," we focused on the mid tones. As I better learn what the machine is trying to tell me, I will be sure not to neglect the ones that sound deep...

Thanks!

Steve
Re: ON THE HORIZON = MDT-8000
November 25, 2021 12:26PM
Been awhile since i was an active dirt hunter. What i found in some cases MORE isnt always the better produced. When i hunted real trashy sites i often found after going over an area that reducing the sensitivity would increase my finds in the depth range that you know other should have found those targets. The machine just didnt have to take in so much material and process everything in it.....not to mention EMI.
Re: ON THE HORIZON = MDT-8000
November 25, 2021 01:37PM
If I were still active in hunting, the MDT would be the machine I would have to have in my hands. Sometimes it's all I can do to just not bite the bullet and buy one.

Steve - When I was using it, I found the little high chirps of disc mode to be hard to concentrate on ciphering between an actual target, a false, or junk. I much preferred the Mix mode audio...I could "size up" items better and any falsing chirps were easily ignored. Give it a try and see what you think over targets.
JCR
Re: ON THE HORIZON = MDT-8000
November 25, 2021 02:29PM
Daniel is correct on Mixed mode. It will also help you deal with surface targets because it is modulated by target strength. Disc is not. I will often go to Mixed to interrogate & isolate a target I'm not sure of.

Chris
Re: ON THE HORIZON = MDT-8000
November 25, 2021 05:42PM
But..... DO continue to try different Ground Balance settings........and see if the short high-tone chirps goes away.

Steve.......... another comment that I meant to include:
It IS a huge/monumental/big deal to:
1. Find 2 Barber dimes in a couple-hour mid-afternoon hunt.
2. Find more non-ferrous targets in an area that has been beat-to-death by you.
3. Find these coins at record-breaking depths beyond all previous equipment.
4. Achieve plateau-shattering performance in your first real-World hunt with the Tarsacci.
5. Cut-your-teeth via maiden voyage with Tarsacci in an exceptionally challanging trash conditions environment.
6. Survive via NOT getting fatally discouraged with all the multiplicity decelerators.
Re: ON THE HORIZON = MDT-8000
November 26, 2021 12:51AM
Dew -- point well taken, and I agree with you. In this case however, I was specifically attempting to validate a long-standing hypothesis that there HAD to be additional coins in this spot, but just out of reach of prior units. And test-garden testing showed me that it would require a very "hot" setup of the unit, to achieve MAXIMUM depth. So that's what I aimed for -- maximum depth, for that one specific reason. But had that not been my agenda, then I agree with you that running "less hot" in very trashy areas, can sometimes be a productive way to "skin that cat."

Daniel -- I am glad that you, too, found the high-tone chirps "distracting," as they often demand a bit of attention (time) when you are aware that any non-ferrous target left in a given spot will also likely be a similarly subtle high tone. And so, your Mix mode suggesting is well taken. Funny thing is, when I was testing this machine in my garden, I rather quickly gravitated to Mix mode, and from there did most of my testing in that mode, expecting that it would be the one I would use "in the field." After running the Equinox in "50 tones," and my CTX (and before that, Explorer) in "full tones," having just three disc tones is foreign to me. So I expected that Mix mode would offer more intelligence. BUT -- at the last minute, I decided on that first hunt to stick with Disc mode, based on NASA-Tom's statements that Mix mode, in target-rich areas, is much more mentally "fatiguing." And I figured that since I was going to set the machine up way hot, on its maiden voyage, that Mix mode might have been enough to put me over the edge, mentally, LOL! BUT -- that said, I understand the logic of what you are saying, and it will definitely be something I will try in the near future.

Chris -- I appreciate your further endorsement of Mix mode, and your point is well taken that even while hunting in Disc mode, it might behoove me to switch over and "interrogate" a located-but-uncertain target in Mix mode; definitely another piece of "information" during the "interrogation" is a logical idea.

I will say that I was able to recognize SOME modulation in disc mode, though a bit "subtle" to my still-untrained ears, but definitely NOT as much as pinpoint mode. I will compare modulation in Disc vs. Mix mode next time out, as that would be another, possible helpful tool in Mix mode.

NASA-Tom -- setting ground balance to the actual ground DID seem to noticeably reduce the high-tone chirps. When they'd return, a re-balance quieted them back down. And so, it was a tradeoff -- as really felt I needed to do something to ease the "audible overload" that I was experiencing, but at the same time I knew that using the ground balance in this more "traditional" way was sacrificing a bit on the alternate approach/idea of using it to "desensitize" the machine to rust flakes/small iron. The GOOD news was that the LOWEST balance number I recall at any point was 664 (the highest I recall was 714). SO -- I'm not losing ALL of the "desensitizing to rust" approach to balancing, since balancing to my irony-red soil is to some degree fortuitously analogous...

I appreciate the kind words/encouragement. I certainly feel, looking back on what transpired, that it went far better than I could have reasonably hoped, on pretty much all accounts...which speaks in my opinion to the capabilities of the machine. I asked you in a private message awhile back whether you felt an MDT 8000 with 12" coil would be likely to help me surpass the depth limit of my prior machines, and your answer was that though you were confident that it would, but that you expected that it would take a few hunts under my belt before the additional depth capability could begin to be utilized effectively. So, that it took just a couple of hours for that extra performance to begin to show itself, speaks -- again -- to the fact that this machine does take depth capability to "another level," in dirt where mineralization is an otherwise limiting factor. In other words, engineering/design intent realized/confirmed in the real world, and in short order...

One question, if you find time...can you elaborate just a bit on your statements earlier about black sand on vs. off...you said that you SUSPECT black sand off will be the best bet for me, UNLESS my dirt is "complex," vs. "simplex." My guess is that by "complex," you mean more than one type (iron oxide, in my case) of mineralization...but if you have any more knowledge to impart regarding exactly what you mean here, I'm all ears...

Thanks all!

Steve
Re: ON THE HORIZON = MDT-8000
December 11, 2021 01:19AM
OK, so I headed out again today, for a very short hunt, with the MDT 8000. I took it to the same spot I worked the last time I was out testing the Tarsacci (the little "hot spot" we found about a decade ago, and have cleaned it entirely of all "detectable" coins).
And wouldn't you know it, that once again, I managed another coin that was just beyond the depth capability of prior units; this one was roughly 9 1/4" deep, and was only 15 feet from the "center" of the hot spot (that small concrete pad I described in the prior post). I only dug about 5 or 6 targets during the hunt, and the coin (a toasted, "no-date" Indian Head Penny) was the first target dug...

It's ugly, but I consider it "victory," as -- again -- any coin dug from this spot is a coin that was "invisible" to all the other machines we hunted this small section of park with, over the years...



Also, I learned a number of things today. The last (first) time I had the Tarsacci in this spot, there was essentially ZERO EMI. Today, after the first few minutes, EMI became AWFUL. The only thing I could attribute it to, was that there were some workers nearby who were putting up Christmas lights in the park. They had hundreds of feet of lights strung out, ready to be hung, and perhaps those lights were somehow the culprit. WHATEVER THE CASE, the machine was essentially unusable. I tried lowering sensitivity, didn't help -- it just made the EMI "quieter," but it was quite audible. I tried lowering threshold, but to get the machine quiet I had to run threshold so far down, that there was no use even trying to hunt fringe-depth coins. I tried black sand on, and it mitigated EMI a bit, for a little while. But ultimately, it was just impossible to "hunt deep" with all the chatter going on. I was just about to pack it up, but thought of one other thing -- I decided to try other frequencies (I was running 6.4 kHz). I tried 9, just as bad. I tried 12, and while a BIT better, it was still unhuntable. Finally, after switching to 18 -- SILENCE! I was able to run threshold back up to 0, and sensitivity up to 8, and there was essentially no audible EMI.

SO -- I decided to hunt a bit longer, in 18 kHz. And let me tell you, that machine is a totally different unit, running 18 kHz vs. 6.4 kHz. After running at 18, going back over the same areas I had been hunting with 6.4, I found out that getting a repeatable mid tone is a relatively "rare" event, when running 6.4. Suddenly, in 18 kHz, there were mid tones -- good, repeatable mid tones -- EVERYWHERE. I dug a few; one was a deep .22 projectile. Several others were VERY small pieces of random metal. One was a deep, short piece of twisted copper wire. It liked SMALL targets, and it produces alot of solid mid-tone IDs, when running 18 kHz. But that wasn't entirely surprising. What WAS surprising was just the totally different behavior of the unit. It is a MUCH more "stable" unit running hot, in 18 kHz, vs. 6.4. The nail falsing is WAY calmed down; the staccato high tones are essentially eliminated; it seemed MUCH less sensitive as far as requiring spot-on ground balance. As a result of all of this, I very quickly gained confidence in what I was hearing -- i.e. what and where the targets were that the machine was reporting. It's hard to describe, but all I can say is the machine much more effectively conveyed "intelligence" to me in 18 kHz. I "clicked" with it much more readily, and understood much better what it was saying. Again, this was sweeping over the exact same ground I had just hunted in 6.4. Very, very interesting. I really wanted to bump it down to 12, as I knew if I could run it at a lower frequency, it should be more "resonant" with the deep high conductors, but trying to do so reminded me quickly that on this day, the only "usable" frequency was 18 kHz. I am just really amazed at what a different machine it was, and how much more "familiar" or "understandable" it felt, as compared to running it at 6.4 kHz. Just a TOTALLY different machine. Fascinating...

Steve
JCR
Re: ON THE HORIZON = MDT-8000
December 11, 2021 03:51AM
It's a different sort of animal for sure. I learn a little something new each time I hunt with it. Good post. Thanks,

Chris
Re: ON THE HORIZON = MDT-8000
December 11, 2021 04:07AM
Steve. Proper use of the controls/tools!
As this detecting community matures with Decades of experience; it appears life is predicated on EMI mitigation.
Good thing you 'found' 18-Khz. Not only did it put you back into the game.........but with full depth performance (that 18-Khz --conductively-- provides). If you would have stuck with 6-Khz.......and had to run a Sens of 4....with Thresh of -5....... enough depth would have been lost that....... you would have (most-probably) NOT found any remainder (handicapped) coins.
And now that we see how 18-Khz performs in your specific dirt (and oxidation/decomposition status of iron targets.......falsing to high tone)....... you have a new 'love'...and easier learning-curve to (more quickly) 'master' the Tarsacci.........in rapid fashion. THEN...... you could dabble back into the deeper 6-Khz with a new-found skillset with the Tarsacci.

I know one coin may seem insignificant to many; yet, I FULLY understand the monumental/euphoric success it truly means........in a 'totaled' site.
Re: ON THE HORIZON = MDT-8000
December 12, 2021 05:17AM
Chris -- thanks, I appreciate it! Yep, it is a very unique unit, and it takes a bit...

NASA-Tom -- I am very happy that EMI mitigation is "on your radar," and I know it is -- in a significant way.

Yes, I really enjoyed running the unit in 18 kHz. IF -- IF -- I can figure out how to glean enough intelligence from the audio to begin to understand what those very tiny targets sound like, as opposed to a coin-sized target (so as to ignore them when coin hunting), then 18 kHz certainly seems like a frequency I can really enjoy hunting in...ESPECIALLY during this "learning curve" period. I know it's not the deepest freq. for high-conductor hunting, but that notwithstanding, it took about 5 or 10 minutes to realize how much more "intelligible" the unit was for me running it in 18 kHz. I'm really looking forward to seeing if 12 or even 9 kHz might retain some of the "intelligibility," and yet be a little better in terms of depth on high conductors. More to learn!

And yes, that ONE COIN...I know you are one who understands that, completely...

Steve
JCR
Re: ON THE HORIZON = MDT-8000
January 20, 2022 03:02AM
I received a stock size coil for my MDT 8000 yesterday to go along with the 12" Beast coil I have been running. I want to see if it will give me a different/better peek between the nails on my relic sites. Dimitar said it would help some. We will see. I still want a smaller coil for this type of work; 7" round or 6X8 elliptical. We will see about that also. I think he will make one with a little more encouragement from Tarsacci users.

Chris
Re: ON THE HORIZON = MDT-8000
January 20, 2022 10:41AM
JCR Wrote:
-------------------------------------------------------
> I received a stock size coil for my MDT 8000 yeste
> rday to go along with the 12" Beast coil I have be
> en running. I want to see if it will give me a dif
> ferent/better peek between the nails on my relic s
> ites. Dimitar said it would help some. We will see
> . I still want a smaller coil for this type of wor
> k; 7" round or 6X8 elliptical. We will see about t
> hat also. I think he will make one with a little m
> ore encouragement from Tarsacci users.

Think you’ll like that stock coil. It’s the first one I used and I really have learned to really appreciate the work Dimitar put into the development. I prefer it for some hunting…
Re: ON THE HORIZON = MDT-8000
January 20, 2022 02:24PM
I have a couple of the stock coils, but for my use found the 12" a better choice in the water here in the Gulf. What i like about this machine is you constantly learn something from the targets you dig. SteveG you know the learning curve the Explorers had..... like this machine it starts to click. Its not a out of the box average hunter machine. Toms always said he likes machine that skirt the envelope. They make for better machines next time and other companies have to keep up...... we benefit.
Re: ON THE HORIZON = MDT-8000
January 20, 2022 04:35PM
Chris......... see what you think of the 11"x8" coil first. Give it a good workout..... on two different hunts (on two different days). Especially in thick trash (and/or thick iron). Then let us know your prognosis!
Re: ON THE HORIZON = MDT-8000
January 21, 2022 01:53AM
dewcon4414 Wrote:
-------------------------------------------------------

> . SteveG you know the learning curve the Explorer
> s had..... like this machine it starts to click.
> Its not a out of the box average hunter machine.


Indeed, Dew. I agree with your analogy with the Explorer...

Steve
Re: ON THE HORIZON = MDT-8000
February 23, 2022 09:56PM
Something I've been needing to mention.....and very worthy of teaching. Let's talk about Tarsacci with Thresh set on '0'.......and the 12" coil........since most are using the 12" coil now. (And on 6-KHz).
The Tarsacci has a Sensitivity range from 0 - 9. (9 being max Sens).
Something to NEVER underestimate (due to unsuspecting ---somewhat non-linear--- scaling).

With Sens on '2'...... the Tarsacci will detect a 10" deep dime (with about an additional 1" air-gap above the 10" deep dime).
With Sens on '4'...... the Tarsacci will detect a 12" deep dime (with nearly zero air-gap forgiveness).
With Sens on '6'...... the Tarsacci will detect a 14" deep dime (with nearly zero air-gap forgiveness).

In ANY of the Sens settings........ the Tarsacci looses about 1.5" of depth on a buried dime...... for EACH point of Thresh you employ.
Moral of the story: TRY to run Thresh on '0'. I'd rather see you run Sens on a lower setting...... RATHER THAN using any form of Thresh....... IF YOUR CONDITIONS ALLOW!
JCR
Re: ON THE HORIZON = MDT-8000
February 24, 2022 03:58AM
My testing is not as exacting as NASA Tom's but shows the same performance. I have found that in High mineralization lower Sensitivity will give better target acquisition. Too much and fringe targets get washed away in the ground response. It will still hit but gives a solid -30 or -29. This was surprising to discover but can be used to advantage since no normal iron will lock on -30. Lower levels (2-4) seem a nice balance And Threshold @ 0. You need the hot threshold to hear those fringe depth targets. The same goes for EMI. Keep the TH high and reduce Sensitivity if you need to.

Chris
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