Lawrenzo has triggered a few thoughts of mine. . . . (and I may be partially repeating some of my previous posts).

* About a decade ago...... the T2 and GMP were introduced to the market. The engineering design of both units have similar performance intent/resultants; that being: finding more targets in higher trash environments. This is performed through better/enhanced adjacent target separation characteristics...... and 'some' partial iron see-through (unmasking).

There have been thousands of times where I would mark a real-world/real-dirt target that was very "iffy" to a CZ, MXT, 1266X, DMC-IIb (and a host of other detectors). Then I would take the T2 and/or GMP (now a F75) to these undug 'marked' (usually with a golf tee or red poker chip) targets....... and these 'iffy' targets became so exceptionally audibly clear..... that there was no 'iffy' about the target(s) any more. Absolute positive confirmation.

Going one step further........... I would then hunt with exclusively the GMP & T2 (before F75 inception)...... and mark hundreds of "iffy" targets to the T2 and GMP. Then....................... I would take the CZ, MXT, 1266X, DMC-IIb to these "iffy" (questionable) targets............. and they either ID'd as 'iron'.............. or did not audibly exist at all. Completely undetectable. This solidifies a real eye-opener/game-changer.

There have been plenty of places/sites in Florida that I have hunted through the decades with generations of different detectors. . . . . and came up completely empty-handed with targets. Then.............. with the T2 and/or GMP............. for the first time in history............ the site started to produce. And sometimes in great volume.

We have made strides in technological improvements. It is all-too easy to deny this. It may not happen at the rate/speed we wish for it to transpire; yet, it is indeed happening. I badly need much greater depth....... before my hunting days expire. We (very much) need better unmasking abilities.......... yet, it may not happen at the speed with which we request.

* Audio skill-set learning. Yes.............. as we become better/more-educated detectorists........... it becomes clear that 'learning the audio' is paramount to better success. There is a steep learning-curve when you are in 'desperation mode'. This is.............. when you go back to areas that you have beat to death................ and hunt them yet again................ in desperation,,,,,,,,,,,,,,, now digging more questionable, or lower-conductor (foil range), or "iffy", or........ or......... or............... etc.................... targets.
In this mindset............... you learn a lot......... and in short order. When you are digging more "iffy" targets........... you can really learn audio nuances to a much higher level. Then.............. when you do have the opportunity to hunt a new area.............. your 'efficiency' level (due to enhanced skillset) is substantially better.............. with the end-resultant being a much higher/better good target ratio.

Skillset intelligence is heavily weighted!

Best thing to do is get an Ace 250 and concentrate on location. Out of the vehicle and start detecting. Beep Beep don't look at the screen.

Pasttom Wrote:
-------------------------------------------------------
> I post more on other forums, but I read and learn
> more on this one.

Someone said it before me...x2 absolutely. PMs to different guys have also set the record straight(or at least straighter)on how things work and why. That is always what I want to know....WHY? Great forum!

NASA-Tom Wrote:
-------------------------------------------------------
. There is a steep learning-curve when you
> are in 'desperation mode'. This is..............
> when you go back to areas that you have beat to
> death.............


I can sure relate to that...most of my sites have long since gone dry......spend my time digging weak iron signals looking for non ferrous on the edge of detection.....they say necessity is the mother of invention but I think it is also the mother of skill....if you want to make finds on worked out sites you need to develop skills...anybody can dig a two way non ferrous signal...no skill involved.....when you start digging the iffy and iron signals and they are mostly good targets that's when you become a good detectorist.

* Sooooooo many people hunting in thick carpets of iron........ as of recent. Says a lot. (So glad to see this). This is where the bulk of the finds will be. (((Even Mfr's are 'inventing' ......... accordingly))) We have come a long way.

Tom you hit the nail on the head! That's all we hunt...........

NASA-Tom Wrote:
-------------------------------------------------------
> * Sooooooo many people hunting in thick carpets of
> iron........ as of recent. Says a lot. (So glad to
> see this). This is where the bulk of the finds
> will be. (((Even Mfr's are 'inventing' .........
> accordingly))) We have come a long way.


Spent a few hours for the last couple of days in nails. Finding lots of non-ferrous stuff. Nothing earthshaking. But still, some of it was masked from other units. (using Racer w/ 5in coil......2 tone...) The buttercups are really 'lighting up' all of the old homeplaces. One would do well to drive thru the country and make mental notes, or better yet......GPS the places or mark them on a map.

I am in awe - All my hero's in one place -

Thank you thank you thank you Mr Tom Sir - with the upmost respect

Now I have somewhere to study & learn from the best in an effort to follow my passion.......

You're welcome rustic charm.

((( Another bullet/thought ))) =

* Dave Johnson created another monster. I've been waiting years to see detectorists 'evolve' ...... and make intelligent/hard-core use out of the Fe3O4 bar-graph tool. . . . . . and subsequent: "what can be learned from this". Initially...... it appeared that it would be taken and used as simply a 'bells-n-whistles' toy. Initially it was perceived as such; yet, has evolved properly in many applications. Folks have learned 'how bad' mineralization/dirt can truly be...................and..................... the subsequent 'performance outcome' certain types of dirt can have on depth reduction and mis-ID. It has opened the eyes of astute detectorists........ and all other Mfr's. (Somewhat of a double-edged sword for Dave Johnson & crew)........ yet; I just assume EDUCATE all! In the long-run....... greater intelligence will ensue...... for all to benefit. History & Archaeologists inclusive....... with subsequent better/greater finds. It also 'exposes' just how inhibiting VLF Induction Balance units truly are. Mfr's adjust/shift accordingly.
Detecting 'thought-process' has changed forever....... due to Fe3O4 intelligence! KUDO'S again....... to Dave Johnson. ((( Geophysics educator ))).

* Out of time................ but MUCH more to say about PI.

It would be even more enlightening if it were possible to give a more detailed readout of the 'Fe3O4' level. What I had in mind was a dedicated mode for ground-strength, and giving the reading on the 88 display. Unfortunately, 88 is limiting. [1 digit mantissa, 1 digit decimal exponent, eg. "53" = 5000, "22" = 200, "11" = 10]. If there was a 188 readout, (or 888), then it would be easier. Or you could give a 00 - 99 readout with an arbitrary contrived scale (in the same way that ground balance figures are given), and have a table in the user manual to convert back to real figures if needed. Eg. 20 points per decade: "80" = 10000, "60" = 1000, "40" = 100, "20" = 10, etc.
Note: the manual details the Fe3O4 meter scale as
3 = 7500 x 10-6
1 = 2500 x 10-6
0.3 = 750 x 10-6
0.1 = 250 x 10-6
0.03 = 75 x 10-6
0.01 = 25 x 10-6
These appear to be CGS metric units, rather than SI metric.

One other point relating to this: I'm pretty sure the Fe3O4 bargraph is calibrated for the stock coil. Sticking the 5 inch, or an Ultimate 13 incher will mess up the scaling, as the machine doesn't know what coil is fitted.



Edited 1 time(s). Last edit at 04/24/2015 01:52PM by Pimento.

Pimento......... fully understand your non-linear scaling dilema; yet, in one regard, , , , I question if folks would 'appreciate' the effort/depth of such accurate measurement capabilities. BUT....... as a qualifier, , , , , folks on this forum seem to 'want' this much technical tools....... even if not fully understood...............,,,,,,,,,,,,,,,,,....................... then..................... in time................. will take the educational effort to truly 'learn' what such 'said' tool would/could bring to the proverbial table.

Not only have we coined the phrase: "I have 4-bar dirt" ...... but are now widely/commonly using this form of measurement communication........... as one of the major inputs in gauging one-anothers environmental conditions. It's major. And it's commendable. "Value-added".

Hi,,,,Am I wrong or are these Fe3O4 bar-graph readings totally inaccurate cause soon as there's a speck of rust or a nail etc. near by it also reads that?..... You would have to find a super clean spot to get a good accurate reading which is almost impossible sometimes.....Another words if you was watching the meter and the scale went up, it don't necessarily mean the soil itself got worse in that spot, it could mean that there is more rust flakes iron etc. in the ground too...... The key to success is learning how to adapt/cope with the area you are hunting at the time and make the appropriate changes.....Just my opinion....JJ

The search coil sees everything below it - the ground and its rust/minerals, and any other metal objects close by. So, just as you should choose a 'clean' spot to do a ground-balance operation, you should find a 'clean' spot to 'pump' the coil above, in order to get a reading on the Fe3O4 meter.
And, just as it can be near-impossible to ground balance properly in some places, it can be tough to get a reliable reading on the Fe meter.

It is absolutely amazing to see all the 'buzz/interest' on PI's.............. as of late. This speaks VOLUMES. Since there is very little/limited/no Discrimination abilities with Pulse Induction (as of current-day technology)....... what is it about PI's..... that's generating sooo much interest. In no uncertain terms: DEPTH. I need to say it again: This speaks VOLUMES. And PI's (with virtually no discrimination) can cost many times more than VLF units. Some being in the $10,000.00 range. Yet, folks are willing to pay 10X more money (over a VLF unit)..... for a "no discrimination" unit...... in no uncertain terms: to gain more depth. AGAIN: This speaks VOLUMES. And when Minelab came out with the GPX 4500...... the volume of sales (demand) instantly depleted their inventory, with a total imbalance of: over-demand vs under-supply. Need I mention the $5000.00 price tag. Then.............. again.......... the release of the GPX-4800, then the GPX-5000............ with the same supply & demand resultant....... and with the same $5000/$6000 price tag. Same with other Minelab (previous Gen) PI's. AGAIN............... This speaks VOLUMES.
In intermediate summation: I would like to assume this would be a: clear/in-no-uncertain-terms/obvious ""need"" of the detecting community....... to any/all of the metal detector manufacturers around the world. And we no longer/needn't hear the excuse: "These extreme-niche detectors are only for African gold mines...... which presents limited sales numbers".

I commend those/these forum members of whom are willing to learn a 'minimum discrimination capability' PI unit.............. so as to gain a few more inches of depth. The amount of desperation, curiosity and 'hunger' for more (and better/older) finds ...... at a huge physical/laborious expense..... and financial cost.......... speaks VOLUMES.

What is the ultimate hunger? =
In final summation: DEPTH

Your above remarks, Tom, regarding interest in PI machines and the quest for depth begs a question that I have asked myself numerous times: If Tom is so fixated on achieving maximum depth in his detecting, why does he not use a PI machine?

Yes, I know your FL soil is inert and PIs are known for achieving depth in mineral; but not so much (greater depth attainment) in good dirt. Is that why you don't use a PI? Or do you?

Do you have comparative depth data on PI vs VLF in your FL dirt, or other good/low mineral dirt elsewhere?

Thanks

Wayne

Pleasant Garden, NC
AT Max, Nokta Impact, MX Sport, Nokta FORS Relic, GPX 4800, Infinium, Racer, Deus, F75SE, Nautilus DMC II (order of acquisition, last to first)

Does an archeologist argue with a plow? A bureaucrat with a bulldozer?

There are many who will argue that no Minelab PI detector has ever been deeper (on the size targets which relic and coin hunters look for) than the original SD series. The later GP and GPX machines increased versitility, ability to cope with varying ground conditions better, and EMI resistance but many dispute that they offered more absolute depth.

As far,as the runaway sucess of the GPX4500, that was a one time thing when the gold rush in Africa started and word got out that exactly THAT detector was what was needed. The GPX5000 came along about then but it's sales were disappointing to ML because it wasn't the "magic" 4500. By the end of last year, Minelab was dumping GPX5000 in Australia and the US for prices WAY below minimum advertised price to raise cash and reduce inventories. The current runaway bestseller in Africa seems to be the Gold Bug Pro. With 5 guys with picks and shovels for every guy with a detector, they just,start digging as soon as the first nugget is located, the "depth" gets reduced prettu quick I imagine.

There is currently a lot of discussion on the forums about to,what,extent, if any the ULTIMATE depth of the GPZ7000 (their new $10k machine) exceeds that of the GPX5000.

It would be very instructive to see a depth test of a new F75 LTD in boost mode compared to a GPX5000 in inert ground such as Tom's. I will not attempt to predict the outcome.

If somebody wants a GPX5000, there are lots of them for sale used at very attractive prices.

Rick Kempf
Gold Canyon AZ- where there is no gold

Hi,,,I know I want more depth but a PI machine is not feasible for me because of it's inability to discriminate out items that are so prevalent in the areas I hunt....The Park Rangers would chase me down the road with an ugly stick after they seen all the holes I dug while using one....LoL......JJ

I do have a PI. A AquaStar-II. It has poor depth on coins...... and superior depth on gold (and low conductors).

I do not use it inland................ as it does not have ferrous/non-ferrous differentiation.

NASA-Tom Wrote:
-------------------------------------------------------
> I do have a PI. A AquaStar-II. It has poor depth
> on coins...... and superior depth on gold (and low
> conductors).
>
> I do not use it inland................ as it does
> not have ferrous/non-ferrous differentiation.

Tom, does this not repudiate your belief that the final summation of the greatest hunger is for more depth?

Or are you saying that others hunger for greatest depth but you opt for ferrous/non-ferrous differentiation?

I get the feeling that while you want/believe that greater depth is the key to unlocking many more finds, you are not willing to forego ferrous/non-ferrous differentiation in order to achieve it. Yes or no?

(good naturedly trying to pin you down <g>)

Wayne

Pleasant Garden, NC
AT Max, Nokta Impact, MX Sport, Nokta FORS Relic, GPX 4800, Infinium, Racer, Deus, F75SE, Nautilus DMC II (order of acquisition, last to first)

Does an archeologist argue with a plow? A bureaucrat with a bulldozer?

Wayne....... my Pulse Induction unit is highly modified/customized....... so as to better detect small/low conductors........ at the expense of losing quite a bit of depth on high conductors (due to pulse delay). Because my primary intent whilst beach hunting..... is to find small gold....... and not coins........ the trade-off is nearly welcomed.

With most PI units........ depth is comparable (on coins) to most top-end VLF units. . . . . in air-tests and low/no mineral soil. In heavy mineralization, PI's are less affected; hence, retain good depth............. whereas VLF units can drastically lose depth/performance.

Because most (not all) of my Florida dirt is fairly inert; a VLF is much preferred ....... due to ID abilities....... over PI units.

If I could gain just 1 more inch of depth with a PI (over my best VLF unit)........ I would go out of my way to find areas where I could apply the added benefit.

In general (approx 80% of my rationale/justification) I don't hunt with a PI ......is due to zero ID abilities. When the day arrives whereby a PI is invented ..... that can just simply differentiate between Fe vs non-Fe (at depth)....... I will own one.

It is quite eye-opening..... to see the large numbers of PI's being used at the GNRS and DIV hunts. ((( No longer a "niche" )))

(Did I answer your questions?)

NASA-Tom Wrote:
-------------------------------------------------------
> Wayne....... my Pulse Induction unit is highly
> modified/customized....... so as to better detect
> small/low conductors........ at the expense of
> losing quite a bit of depth on high conductors
> (due to pulse delay). Because my primary intent
> whilst beach hunting..... is to find small
> gold....... and not coins........ the trade-off is
> nearly welcomed.
>
> With most PI units........ depth is comparable (on
> coins) to most top-end VLF units. . . . . in
> air-tests and low/no mineral soil. In heavy
> mineralization, PI's are less affected; hence,
> retain good depth............. whereas VLF units
> can drastically lose depth/performance.
>
> Because most (not all) of my Florida dirt is
> fairly inert; a VLF is much preferred ....... due
> to ID abilities....... over PI units.
>
> If I could gain just 1 more inch of depth with a
> PI (over my best VLF unit)........ I would go out
> of my way to find areas where I could apply the
> added benefit.
>
> In general (approx 80% of my
> rationale/justification) I don't hunt with a PI
> ......is due to zero ID abilities. When the day
> arrives whereby a PI is invented ..... that can
> just simply differentiate between Fe vs non-Fe (at
> depth)....... I will own one.
>
> It is quite eye-opening..... to see the large
> numbers of PI's being used at the GNRS and DIV
> hunts. ((( No longer a "niche" )))
>
> (Did I answer your questions?)

Yes, Tom, you answered my questions (in a most informative way-no surprise). Thank you for that.
You also raised another question when you said this:
Because most (not all) of my Florida dirt is fairly inert; a VLF is much preferred ....... due to ID abilities....... over PI units.
If I could gain just 1 more inch of depth with a PI (over my best VLF unit)........ I would go out of my way to find areas where I could apply the added benefit.

About that bit of your Florida dirt that is not fairly inert, does a PI gain you that 1 more inch of depth, or not? Just how much depth does the PI gain you in your worst FL dirt?
Clarification please - is that one more inch with your small-gold-specialized PI, or a PI without the loss of depth you mention?

Again, Tom, thanks!

Wayne

Pleasant Garden, NC
AT Max, Nokta Impact, MX Sport, Nokta FORS Relic, GPX 4800, Infinium, Racer, Deus, F75SE, Nautilus DMC II (order of acquisition, last to first)

Does an archeologist argue with a plow? A bureaucrat with a bulldozer?

Wayne,

Fortunately........ I had one very specific documented head-to-head experience with exactly this. This Florida 'bad dirt' is 4-bar dirt..... and borderline 5-bar dirt. A CZ will correctly ID a dime to 4.5" in this heavily mineralized dirt. Any depth beyond 4.5"...... and the CZ will ID the dime as 'iron'. The F75 LTD will properly ID a dime to 4.7". Again.............. anything beyond 4.7"............ and the F75 ID's the coin as 'iron'.

At exactly 9" deep......... both F75 & CZ will not detect the dime at all. This is to say: 9" (or deeper)...... and the coin does not even exist.

Using a Minelab SD-2200............ and the detector could absolutely care less about this particular mineralization............ and clearly detect the dime to 12". Zero performance reduction for Pulse Induction.

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

In normal (low/no mineralization) ..... a CZ/F75 is 12" capable on a clad dime ..... and with reasonably accurate ID. In the case above....... max depth, regardless of ID...... was 9" with these VLF units. And accurate ID was only down to depths of around 4-1/2".

((( This really drives home a point about PI's and bad mineralization )))

Brilliantly stated and demonstrated---thanks Tom.

NASA-Tom Wrote:
-------------------------------------------------------
> Wayne,
>
> Fortunately........ I had one very specific
> documented head-to-head experience with exactly
> this. This Florida 'bad dirt' is 4-bar dirt.....
> and borderline 5-bar dirt. A CZ will correctly ID
> a dime to 4.5" in this heavily mineralized dirt.
> Any depth beyond 4.5"...... and the CZ will ID the
> dime as 'iron'. The F75 LTD will properly ID a
> dime to 4.7". Again.............. anything beyond
> 4.7"............ and the F75 ID's the coin as
> 'iron'.
>
> At exactly 9" deep......... both F75 & CZ will not
> detect the dime at all. This is to say: 9" (or
> deeper)...... and the coin does not even exist.
>
> Using a Minelab SD-2200............ and the
> detector could absolutely care less about this
> particular mineralization............ and clearly
> detect the dime to 12". Zero performance reduction
> for Pulse Induction.
>
> ---------------------------------------------
>
> In normal (low/no mineralization) ..... a CZ/F75
> is 12" capable on a clad dime ..... and with
> reasonably accurate ID. In the case above.......
> max depth, regardless of ID...... was 9" with
> these VLF units. And accurate ID was only down to
> depths of around 4-1/2".
>
> ((( This really drives home a point about PI's and
> bad mineralization )))


Tom-----How deep will an Explorer/Etrac/CTX detect a dime in this situation you describe?--------Thanks----------------Del

Del...... I've only tested a CTX-3030 there. . . . . . and it was on a different day. It would correctly ID a clad dime to 4.4". Interestingly..... it would ID the clad dime from 4.4" to 4.9" as "non-ferrous".... but certainly not a coin. When the dime was pushed to 8.7"...... it was no longer detectable. (I speculate the large stock coil was analyzing too much dirt/mineralization).

NASA-Tom Wrote:
-------------------------------------------------------
> Del...... I've only tested a CTX-3030 there. . . .
> . . and it was on a different day. It would
> correctly ID a clad dime to 4.4".
> Interestingly..... it would ID the clad dime from
> 4.4" to 4.9" as "non-ferrous".... but certainly
> not a coin. When the dime was pushed to 8.7"......
> it was no longer detectable. (I speculate the
> large stock coil was analyzing too much
> dirt/mineralization).


Very interesting!----Thank you Sir.

I probably (more-so) should direct this thought to Carl M. ; yet, will publicly post:

* In all of my real-world experimentation........ I have tested Pulse Induction platforms up against VLF IB units. We know that PI (in general) will handle heavy mineralization with minimum effort. But, recently............. I have encountered a bit of a epiphany that is worthwhile of mentioning. Whilst hunting in a nail infested area....... a PI will suffer masking of targets near and/or below nails....... at the same failure-rate of VLF units. A PI is not immune to this physics phenomenon. Electromagnetic energy...... whether from a VLF or PI....... is still nearly equally susceptible to masking.

When the dirt consists of only oxides of iron and iron mineral........ a PI is nearly immune to performance reduction. This is 'known'. BUT......... the epiphany was encountered when a PI can nearly ignore flecks/flakes of rust that is from nearly completely decayed iron objects/implements and nearly completely ignore this type of soil that is fairly heavily 'peppered' with an abundance of rust flecks/flakes. I highly suspect this is due to the "pulse delay" (and subsequent hysteresis/time-domain) of the Pulse Induction operating platform of the unit. A VLF IB unit will suffer tremendously in this type of environment; yet, not the PI.

In many areas that we hunt (especially relic sites)........ nails and rust flecks/flakes are abundant. IF a PI could ignore only the rust flecks/flakes................ that's 50% of the equation........... and a 50% performance increase.

I'm certain it would behoove us to investigate/capitalize off of this EM PI phenomena......... and sink some R&D time into this epiphany .... accordingly.

Decay-based PI (almost all PI's) have only a resistive channel, not a reactive channel. Therefore they can only see the eddy response, not the magnetic response. This is also why PI's don't discriminate. Small enough iron flecks either don't create enough eddy response to be seen or they die out much faster than the minimum sample delay. Normal mineralized ground is ignored the same way.

Everyone wants a PI that can discriminate, but it's likely that the addition of a reactive channel will make those iron flecks suddenly show up. Nullum gratuitum prandium.

I would like to see just a crude idea of what's in the ground with a P.i.

That resisitve channel only does pose the problem...

even a comparitor channel would be of no use ..

Keith

“I don't care that they stole my idea . . I care that they don't have any of their own”
-Nikola Tesla

Excellent info Geotech. BTW Hillary seys if you will vote for her she will give you one (free lunch) lol