Ramblings on what the future holds for dirt depth

Detectors that do well in iron sites are doing because of adjacent target handling..the DNA of the unit itself being setup to cope with iron saturation in ways like fast shutdown bleedy filters blending of tones to negate start up shutdown hiccups and such in high concentrations of iron...

One of the way this is done is with the Bleed of filters ..So that can also be used in the ability to Punch through an Oxide in the soil...It's less biased towards any disc'd item being by the bleedy filters.DD coils coupled with the bleedy filter helps too..

Bleedy filters are nothing new ...fisher has done it for 30 years ...126-/1265/1266/1270... they all pretty much bleed through the disc more so than probably any today made..

And on a side not the old tough ground wasn't a problem for a 1266 to go deep with a concentric coil and fixed ground ball..I am almost sure most of the deepseeker made right now are a direct descent of a 12XX series....just modernized..Minelab targeted the 1266 with there musky specifically no secret there ..and its alot like a 1266 ...

it takes low freq to really penetrate bad soil...but they can be somewhat less reactive too lower conductors in iron and or out of iron..

But higher freqs have came into their own inf the last decade by being able to also punch through with new ideas of filters and coils and such..

BUT and here's a Huge BUT..when they decide to go back to low freq's and add the newer ways of reporting and analyzing we will see a low freq say 5khz unit be able to run like 19 khz in iron but punch to the next level in the soil..

And when they decide to go full multi freq and give it all the attributes of what's making high freqs work then great things will be seen..

the 15-19khz has been the proving grounds..wait till the Multi freq and lower freqs get the TREATMENT they deserve in NEW WAYS of doing things..

VLF is far from dead it just needs a kick in the pants..to especially to get depth moving again...

FBS and BBS are great for handling CERTAIN soils better than a VLF can..but at the same time Lower Freqs and Multi Freqs given the treatment of the Blendt/Bleedy 21st century setups would squash depth numbers I do feel..

lots of other ways to skin a cat..

I'm certain more depth is coming..we may have to use our brains a little more to make it work like we did with all the rung changing deep units in the past ..But more depth is coming I can feel it..

Keith

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

I think more depth with VLF,,hardly achievable.

We have had smaller,,more sophisicated electronics for a while now,,,and no gains made.

Limited purely by physics I'm afraid.

Will take new way to get.

May not be cheap either,,especially at first.

Would expect if any substantial gains made,,,would spawn off of pulse induction.

Hard to get around using Vlf,,,time= frequecy,,,and the ground.

And for even a detector to get purchased in huge numbers to warrant design and engineering,,,detector likely to have meter with ID.

More actual research and testing though could bring some thing out.

But metal detectors,,,not a thing all or many folks want or really need.

Might Ought to be proud of what we have.

I guess I'm lucky as My Moderate to Mild ground I can use Depth Monster VLF Detectors like the Nautilus.
I can't wait to get My 10" Coil back from balance as that coil turns it from deep to a BEAST! I love when I'm out with the Nauty and a Newb comes up to Me with a puzzled look and says where is your meter. I point to My ear's and say rite here. They look at Me like I am nuts and go their way. LOL!

Depth is one thing retrieving is another...I honestly believe there are targets too deep for us to reach, however may be good for the farm fields, beaches, boondocks etc. but in many places dig too deep of holes and will be given an exit pass....Just a thought as many places I have hunted have been the exit pass areas....
I realistically feel for the most part any more appreciable depth is not going to be had but have been wrong before....

I would be happy if Minelab just came out with another Sovereign BBS model with an expanded iron discrimination range. Add an option like the Deus reactivity adjustments and Oh Momma!

Dan-Pa. Wrote:
-------------------------------------------------------
> Depth is one thing retrieving is another...I
> honestly believe there are targets too deep for us
> to reach, however may be good for the farm fields,
> beaches, boondocks etc. but in many places dig too
> deep of holes and will be given an exit
> pass....Just a thought as many places I have
> hunted have been the exit pass areas....
> I realistically feel for the most part any more
> appreciable depth is not going to be had but have
> been wrong before....
I agree as you don't need a Shovel if you know how to use a Hand trowel and you know your machine. I have retieved coin's down 11" with no more than a 6" radius plug and a bandana to back fill. When I am done you can't tell.It just takes a little care and common sense which with some isn't that common.

I meant to say 6" diameter. Don't want to get that wrong in case Newbs are reading above post I made.

There not limited ..

I think the future may open quite a few eyes..

I've seen detectors get deeper and deeper over the years then stall....abut 20 years ago..

Now they have Newer ways of Processing the signal..

If you follow the evolution of detectors there's HINTS in them that create a constant..


If you can only have 2 more inches....and I think VLF can give us 2 more inches with proper I.D.


Keit

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

Was hoping the omega 8500 would be a step in this direction. A high gain, threshold based lower freq machine with a tight DD coil and fast recovery should be a no brainer. Honestly if the racer could maintain its swing attributes and hit minie balls like a 1266 type I wouldnt need another machine for the land.

Filmed a deus dig a breast plate at a measured in the hole 21" in 8 khz a few weeks back. Optimal conditions but it was an eye opener.

I can't remember where I saw it but there was a video (Maybe on youtube) of a hunter using (I believe a pulse machine) to scan a yard, then dug holes and used an etrac probe to find the items. I want to say they recovered a standing liberty quarter at an amazing depth that the Etrac would never have found. Does this video sound familiar to anyone? IF technology can make such a thing as DISC PI we would all be in business and digging 25" deep holes lol. I am sure that manufacturers could make them deeper but maybe due to FCC output rules they are limited? This brings to mind someone else lol. Not sure who it was but they increased the power output on a Tesoro detector and reach phenomenal depths. How they went about this I do not know. I am by no means into electronics. I want to say they were able to doubled the output power of the machine and were truly amazed at the depth they were achieving. That is why I mentioned earlier FCC rules on output possibly being a factor to the limit we have with VLF machines. Ehhh what do I know? I turn the machine on, set the controls and hunt

I don't think we need more depth...but let me explain what I mean

I am hitting quarters (even pennies) well over 12'' in my sand...maybe closer to 15-16''+ with my CTX. It's too deep and is not fun...My beaches have very low mineralization so a PI can't out do my CTX...at least the DF cannot...I guess the TDI and other more powerful ones could if you wanted to dig that deep but digging through the trash to get there would be never ending. VLFs need to get better depth on small gold and better depth in bad soil rather than more depth overall although I'm not sure the those are independent of one another. I do know that it would totally suck to be digging quarters are 24''.

_________________________________

Nox600, CTX, CZ21, Excal II and White's DF with 920i stealthscoop...I live and hunt at the beach in Wilm NC

Some company needs a hybrid machine that can give way more depth better ID and more freq and see through iron. But that seems to be a dream at this point

LowBoy

TAKE A LITTLE TIME KICKBACK AND WATCH SOME OF MY DETECTING VIDEO'S BELOW ON YouTube

[www.youtube.com]

If you don’t dig it, then how are you going to know what you’re missing!
How can you have your pudding if you don’t eat your meat!

"IF technology can make such a thing as DISC PI we would all be in business and digging 25" deep holes"
You're making a rash assumption here - that a discriminating PI would have PI depth. This is unlikely to be the reality, I think. Just as VLF's can't achieve discrimination to the same depth as they can find stuff in all-metal / zero-disc mode.
"I mentioned earlier FCC rules on output possibly being a factor to the limit we have with VLF"
This has been discussed many times before. FCC rules have NO bearing on detector output power. And increasing output power has very little effect on depth, all it does is increase the strength of target signal and ground signal by the same amount, the result is your machine still can't tell what's a target and what's ground 'noise'.

I have no idea what the future holds for detecting technology either VLF or Pulse,neither does anyone else i guess its all based on speculation and what we would like,i can only use what is actually been made at this moment in time or obviously machines from the past.

Most of my permission's are on pasture or deep ploughed and rolled fields,as we in theory cannot hunt parks etc due too health and safety issue,then depth is more important to me as mainly our history goes back 1000s of years,so although in theory most finds are in the top 6-8'' a normal detector will in theory find these targets,but over the decades since detectors became available to the normal man in the street finds will of course be depleted.

So the quest to go slightly deep is the best way and normally a bigger coil will give you the extra depth,but we then start hitting the limits of 'current VLF' technology,so i guess we have too try and adapt with what we currently have,one way forward is using Pulse machines,yes i do use them for not only very bad ground conditions that VLF machines just wont work,but PI machines with bigger coil can gain you extra depth and some are far better than others due mainly by the inclusion of a crude form of discrimination,it may not be in the same league as VLF discrimination but its a step in the right direction.

A detector can be the most expensive or technically advanced machine on the planet but that means nothing on its own,its the skill and knowledge of the operator that makes all the difference and not the machine on its own,a operator adjusts the machine to gain maximum performance for the ground conditions and hazards that he is detecting on.The detector is only as good as the operator and not the other way round.

No one machine does it all and we all hunt for different targets,the only common denominator is they are all made of 'metal',i dont have a clue about gold nugget hunting but saying that someone from Aussie land may not have a clue about how too hunt a trashy roman/saxon site.

For me its all about using the best tools that are available for my type of detecting some are reasonable new machines but also i still use some machines that are many years old.

What the future holds i dont have a clue,at the moment i have mislaid my crystal ball,this is of course just my personal take on my type of detecting.

tnsharpshooter Wrote:
-------------------------------------------------------
> I think more depth with VLF,,hardly achievable.
>
> We have had smaller,,more sophisicated electronics
> for a while now,,,and no gains made.
>
> Limited purely by physics I'm afraid.
>
> Will take new way to get.
>
> May not be cheap either,,especially at first.
>
> Would expect if any substantial gains made,,,would
> spawn off of pulse induction.
>
> Hard to get around using Vlf,,,time=
> frequecy,,,and the ground.
>
> And for even a detector to get purchased in huge
> numbers to warrant design and
> engineering,,,detector likely to have meter with
> ID.
>
> More actual research and testing though could
> bring some thing out.
>
> But metal detectors,,,not a thing all or many
> folks want or really need.
>
> Might Ought to be proud of what we have.

Keep your eyes on the prospecting world. The GPZ is not a PI, more like a VLF they say... but different. I think this is where the newest technology is going to come from... a totally different technology. What we prospectors are hoping for is discrimination on the GPZ. There are rumors.....



Edited 1 time(s). Last edit at 08/15/2016 07:30PM by bado1.

Vlf has been under a magnifying glass a long time by some rather smart and educated folks.

PI not as long or as much.

Actually,,,I am surprised a new tech to compete with PI hasn't surfaced.

I do find it a bit strange too,,,,how did Minelab wind up with it seems the more advanced tech anyways.. Really with both Vlf and PI tech.

Coincidence????

It may very well be a newer manufacturer like Xp or even Makro/Nokta answer the calling here.

I truly think some of the older manufacturers,,,well they just sat fat catting,,,,rather than push forward,,,and in the end--- who is really benefitting NOW.



Edited 1 time(s). Last edit at 08/15/2016 08:02PM by tnsharpshooter.

I think Minelabs tech is the way it is because of Mr Bruce Halcro Candy, he seems to think outside the box so to speak and it helps that he's a dr in physics and one heck of an electronics engineer, I think his true passion is sound not detectors. Look up Halcro audio and check out the amplifiers he's designed/engineered there truly advanced technology and go for around $40,000. the ZVT tech is very interesting "gpz7000". more depth would be welcome but more depth with a fine tuned vdi at depth would be awsome. I think the next step is a new way to discriminate targets at depth, imagine a machine that could give a positive id on a target at 20". They can expand or compress the iron range I just wonder if they can do the same for gold while taking aluminum outta the picture ha. From what I hear that gpz 7000 can reach 20" targets and it's not a pulse machine maybe it'll open up a whole new way targets are discriminated if it ever gets disc added to it.

John

For a long time we have lost focus on the job and become focussed on wanting a machine that can use a 5 inch coil that can go 3 feet down, And our Quest for a super machines is somewhat lost and going now where,

In the past we would swap coils and off we go but now we shift the blame to the companies and the machines all because we want to use our favourite Coil, Detecting is getting stupid, We already have DISC systems that can deal with 90 - 95% of the junk, even my tiny Coils can see things/coins 6 inches deep and my largest coil can see them 18" to 24" Plus and I have already dug Small items in the 12 to 17" range using my minelab musketeer Advantage running at 5khz and a Sovereign GT, And In a lot of areas the dirt only goes down to 14 to18" before we hit the hard pack layers, which I have dug using a 10" coil,

The thing is if we want more depth we just need bigger Coils, and Complaining about the weight of machines is ridiculous because either people want to find a 10ozt Nugget or they don't, but they tend to forget that they are quite happy to swing a 5 lb Pick every time they find a target but a 4 lb VLF is a sin against humanity yet the same people are willing to swing a 7.3 lb GPZ or 7.lb GPX for 12 hours a day, Which to me speaks volumes about their persona, and such prejudice carries very little weight with me and I cant take such people seriously. And the need to Man Up or Stay Home.

John.

John, wow you must have some really good ground. I can't get those kind of depths in my ground. The beaches are a different story. Our beaches are pretty nasty but I can hit coins in the 12 inch range using the Sunray 8 inch.

Mike G. Wrote:
-------------------------------------------------------
> John, wow you must have some really good ground. I
> can't get those kind of depths in my ground. The
> beaches are a different story. Our beaches are
> pretty nasty but I can hit coins in the 12 inch
> range using the Sunray 8 inch.

Yeah Mike, It is really weird because one site the soil is rock hard and a sandy colour with a type of chalk layer about 15" down and then you need a pick and the Other place has dark black soil that turns brown at about 6 to 8 inches and then a browney Green colour and yet a 100ft away there is black top soil in the top 4" and then it turns to yellow Clay

In the Brown Soil I found the remains of an old brass oil lamp that had turned all soft and flexible almost like rubber coated cloth, that was down about Elbow Deep with my hand out stretched and then I was digging 5/8 musket balls at 6 to 8 inches and then a toy soldier at 17 inches, None of it makes sense, But I should never of got those depths with a 10" coil, But when I put on a 15" DD I found nothing because of the junk.

All my Coils are great but I really don't like changing from the 10" DD there at that site, Now I think the depth plus the recovery is going to boost the finds rate/

John.



Edited 1 time(s). Last edit at 08/16/2016 12:25AM by auminesweeper.

TNSS,
You said that you were surprised that that a new tech hasn't come along to compete with a PI. The ZVT tech has done exactly that. Not PI tech. More like VLF but much more powerful than either. It certainly competes with PI tech and then some. It can see very small nuggets and large nuggets at depth with the same coil. I think Minelab will expand on this breakthrough tech and we will see some new, very powerful, machines come out of it and not just prospecting units.

Dean

bado1 Wrote:
-------------------------------------------------------
> TNSS,
> You said that you were surprised that that a new
> tech hasn't come along to compete with a PI. The
> ZVT tech has done exactly that. Not PI tech. More
> like VLF but much more powerful than either. It
> certainly competes with PI tech and then some. It's
> can see very small nuggets and large nuggets at
> depth with the same coil. I think Minelab will
> expand on this breakthrough tech and we will see
> some new, very powerful, machines come out of it
> and not just prospecting units.
>
> Dean


Okay,,Zero voltage transmission tech vs PI tech.

And again Minelab's tech.

Seems the tech is expensive too.

bado1 Wrote:
-------------------------------------------------------
> TNSS,
> You said that you were surprised that that a new
> tech hasn't come along to compete with a PI. The
> ZVT tech has done exactly that. Not PI tech. More
> like VLF but much more powerful than either. It
> certainly competes with PI tech and then some. It
> can see very small nuggets and large nuggets at
> depth with the same coil. I think Minelab will
> expand on this breakthrough tech and we will see
> some new, very powerful, machines come out of it
> and not just prospecting units.
>
> Dean

I have never used a machine that has ZVT technology,so i am assuming its the new GPZ7000 machine,which yes i will agree its deeper that is if we believe all that is printed,but does this ZVT technology offer any form of reliable discrimination ?? from feedback and reports i dont this it does,of course i stand too be corrected on that one.This is why i guess the GPZ machine is mainly being used 'solely' as a gold nugget hunting machine and of course its the best machine for that job as trash in the outback is not as bad as say in a local park.

So we have made progress in the depth department but still not mastered the discrimination side of the technology,will it come on the GPZ i dont have a clue,so basically its site conditions that currently dictate what technology we use,if you live in Aussie land and after small and large gold then PI and GPZ technology rules but in a inner city park or trashy farmland site then good old reliable VLF technology still rules.

Lots of good comments..


My title says dirt depth and by this I mean don't we all want to be able to properly I.D. a 10/11/12/ inch dime in any soil????

I don't think that's asking too much..

I'm not sure Pulse will ever be able to discriminate reliably or like Pimento states if it does the depth will drop off ..it handles the soils well but its intricate to get it to disc..and requires alot of power to do it..

George payne Built iron discriminating pulse machine in the 70's...but was a battery hog so Iron disc is doable but at a cost..

And Pulse you have to remember has been around since the early 60s so its had alot of intelligent designers work on it Eric foster..George Payne...Dave Johnson...Dave Embry even claimed to have done it but still no show...If Bruce Candy cant make a Pulse discriminate in terms of better than VLF we have Problems..

I know it is the Holy Grail Idea..but I'm SURE if it is ever done it will have drawbacks..I hope and pray for a Disc circuit P{.I. butb the again why does P.I. have to be the answer..why cant there be another answer..I think that may be the Mind blower out of left field hits us between the eyes..been there all along but not developed ..

We have Bruces BBS and FBS and in alot of ways this is a VLF Pulsed..if that makes sense...he uses a different style transmission method for the VLF (STYLE) and its called BBS and FBS..It's VLF but transmitted in a time domain...alot like the pulse unit's do...So in alot of way's Bruce's CREATION is a blend of VLF phase shift disc in a Pulse type transmission..It very much different than a CZ or V3 in terms of transmission..

And that's the point I'm trying to get across there different ways to do things with a VLF detector..VLF is far from dead it just needs a kick in the pants..

and coil design still erly right now..I can envision printed coils of say 8 inch diameter that will go 12 inches on a dime in any soil...and ability to say turn on and off sections of the coil to make it smaller ..Or even a Virtual coil..

How about a coil that discriminates in the coil through maybe resonance detection before passing the PURE WANTED signal to the box for digital processing..

the sky's the limit VLF is a basis for technology to expand off of..

Keith

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

One thing I think gets overlooked.

For instance,,,what are the deepest Vlf detectors???

Are these detectors actually real quiet running???

Even if we take the F75 unit,,,and we study what the Dst upgrade did for the unit.

Seems some depth was lost,,even coil height above ground was lost---yet DST units run quieter overall.
And this also extended for this update to the all metal side of things.

Generally folks don't like noisy detectors,,,,so this is one area that must be overcome while at the same time increasing depth.

Depth also,,,this topic taken for face value,,,,big difference in making a deeper detector for mild ground vs making one deeper for more minerlaizied ground.

When we really look at this,,,what we might see,,,if a deeper detector Vlf wise,,but only capable of distinguishing nonferrous from ferrous.

And the percentage here,,how high would it really have to be.

For example if a detector could distinguish a 13" dime in medium mineralized soil,,,and point out this nonferrous dime on an average of better than just 50 percent.

Would folks be interested???
Or even a 12" dime???

Using say an 11" sized coil or something close.

We also have to remember ,,, some folks here,, likely to more tolerant with such a detector if made,,,but would a bigger percentage of the detecting public be in fact interested.

And yes,,there are some spoiled by the fbs/fbs2 tech,,,and will be leery of leaving for something seemingly as unreliable ID wise.

Now if such a detector as I have described would give as accurate a ID down to at least the depth the fbs/fbs2 units do currently,,,with the added depth with more limited ID accuracy on deeper targets they might be interested and buy.

Also,,I really don't know the answer to this question,,,how much value to metal detecting manufacturers place on ethics when it comes to detecting say in public places like parks, etc.

Could even if they made a detector like I describe,,,,could this possibly have long term effects on the hobby--- causing more spots to be placed off limits.
And in doing so,,,,cause folks to lose interest,,,hence detector sales slowing follows.

Actually if a detector could be made to have a real good depth meter,,,and could show shape moreso,,,meaning distinguish from nail shape.,,,this too would help locate deeper nonferrous like coin shape.

Maybe really the All metal function needs to be studied more,,,and see if a targets shape can moreso be relayed tone wise, depending on coil position.

I mean one thing we can presume on most sites,,,,real deep targets,,most likely old nonferrous or iron or nails,,,not modern trash,,,so just give me something to show me a deep nonferrous target,,,anyway anyhow.



Edited 1 time(s). Last edit at 08/16/2016 02:41AM by tnsharpshooter.

Here is something not talked about either.

Imagine if a detector even running AM.

Reckon if a visual presentation could be painted of target shape using graphics.

Wonder if soil mineral levels would be considered by detector programming at actual spot of detection.
Target depth would also be used in calculations.
Imagine if coil swing speed was built into program,,,and this program was geared to coil size and swing speed,,,and coil swing speed could be measured using GPS or some thing else for op to swing at a precise speed.

I mean running all metal,,,we see the comments here,,where folks say sounds round sounding,,,,so why not be able to put this into actual graphic with definite higher certainty of target actually being round.

I really think it is visual (shape wise) is the direction to go,,,not numbers, VDI, etc.

How to do???

You got me,,,but somebody might be smart enough to devise.

Now such a system might not do as well with say coins on edge,,,but might work nonetheless for some targets.

Now such a system could be an add on system to an already more standard Vlf detector,,,so would be used morsel on deeper targets,,out of range for what we currently see depth wise for ID of targets.



Edited 2 time(s). Last edit at 08/16/2016 03:02AM by tnsharpshooter.

After watching a recent Video I am not convinced that the GPZ is really that deep, Where another machine had a 12" Coil and the GPZ had it's 14" coil there was little or No Difference, Certainly not enough not enough to justify an $8000 Dollar price difference and then I saw another Video with a modded GPX-4500 and It really Smoked the GPZ in a Big Way.

And if Fine shallow Gold is the Target then the SDC or a VLF will see it even in Hot ground with the right coil, There is too much of this mind set where you have to have a GPX or GPZ to find Gold, people need to think back to how on earth did we manage to find any Gold from the 1960s onwards before minelab started to use Eric Fosters Ideas in the 1990s. Remembering that the biggest nugget ever found with a detector was found with a Garrett ADS 12 inches Deep in Australia, But as an Aussie I do not believe that life beings with minelab and in the past I have spent a fortune on their machines and products,

They make some great machines, But they can't do anything that I have not seen other machines do and I have had more success using Whites. For the past six years I have been going over the same ground that I have done in the previous 6 years and I found more in the first week than I did in the 6 years of using my minelab machines,

Just because minelab brings out a new machine means very little to me and my answer to that is "So What" Garrett, Nokta and Makro and Whites are Still very much in the forefront when it comes to detecting, And the TDI Pro is a powerful machine despite what certain people say and that 40% more thing is just Hype as a Video has proven just this past week, The thing with the TDI Pro is you can pick your Targets if you learn the machine and it can be quite brutal when set up right, and the TDI SL can hold it's own too when operated correctly,

I think our wants or expectations with certain machines are way above reality and some of the claims are just as far fetched, and I have seen one guy detecting in the Red Dirt in OZ using an MXT where his GPX would not run and he did find Gold, It appears that most folks fall for the Hype because they need to believe that the Extreme out lay is justified, Classic example is the Gold I found a while back using the MXT 300 with the 12" coil in a junk filled site that had seen every detector made since 1968 Buried only 5 inches deep. The Laws of Physics makes the Laws as to what a detector can do, Not detector companies, They just give them the abilities to operate within those Laws.

John.



Edited 2 time(s). Last edit at 08/16/2016 03:18AM by auminesweeper.

I would also like maybe to know more about cursor function on Minlab CTX.

I mean besides where the cursor is positioned,,,it's shape and size seem to mean something.

So it seems Minelab may already be doing something similar here in what in I'm referring,,,just maybe on a more limited depth basis.

Something else to mention here,,,just wonder if Minelab has already discovered and has even made a deeper detector with great ID.

Why would they release???

I mean if thiei current detectors are selling well,,why do it???,

Keeping an ace in the hole so to speak.

Meaning just how far along are they???

Is it possible they have already for example made even 2 more deeper detectors using same or different technology???

I think so.

Just remember one thing,,,,it is all about the $$$$,, nothing less, nothing more.



Edited 2 time(s). Last edit at 08/16/2016 03:24AM by tnsharpshooter.

portable MRI is what you want ..but the power to run it would require a long drop cord..



Keith

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

Its been talked about that imaging is being further developed. Look at the advances in 3D depthfinders in the last 5-10 years. My buddy took a screen shot of a sunken deer stand recently, you can count the rungs on the ladder.

A secret that few know, GPR is already being used to locate disturbed dirt from civil war action. You can find hut sites and covered trenchs reliably.