What is the absolute deepest detector you have ever seen. (In your humble opinion)

[skookum]

Hi,
I`m with hershey1 on this one.
A friend who I go detecting with, brings his GPX 5000 on some of the hunts we go on.
It is not the newest version but he has gotten upgrades made to it /the newest tuning hardware installed.
He also mounts the monsterous 21" x17" SD coil on it, most of the time.
He can detect targets that neither my 1270 nor the XLT is able to give the slightest response to.
I can do whatever it takes to tweek the utmost out of either of my detectors - no chance at all.
This depth ability does however come with a very large price tag and to boot - the GPX is a heavy bugger that needs a large power supply

 

[Larry (IL)]

I can't remember the details but the TV show Meteorite Men had something like a 10 foot coil behind an ATV finding deep meteorites and a backhoe as a recovery tool...........

 

[skookum]

Hi,
Found an interesting myth-buster test done by Gary.
Worth reading and may come as a surprise to some.
http://www.garysdetecting.co.uk/hoard_test.htm

hh
skookum

 

[Neil]

Hi,
Found an interesting myth-buster test done by Gary.
Worth reading and may come as a surprise to some.
http://www.garysdetecting.co.uk/hoard_test.htm

hh
skookum

Well I tell you I think that link is partially rubbish as it also states that a detector cannot detect deeper in the ground than in the air and that is not true. Some can.

I agree with another poster here, the Etrac and Sov but I would say they are equal if the Sov is in all metal pinpoint. Otherwise in disc the Etrac is the one that Ive gotten the deepest targets with.

 

[Elton]

Now I'm not talking starter detectors..I'm talking major brand middle and upper detectors.. They all hit real close in depth.
Ones dirt plays a role too. Not all detect the same depth in different areas for sure............

I have to say overall in my dirt the Minelab Se Pro did seem to have the edge on depth....( we are not talking feet here we are talking inches)...... Very close to that was a Whites 6000 di pro SL with signal balance on dimes...and my F-75 was right up there too.. depending on EMI at the moment. If EMI free the 75 was the deepest in certain areas............

 

[skookum]

Well I tell you I think that link is partially rubbish as it also states that a detector cannot detect deeper in the ground than in the air and that is not true. Some can.

I------------------------------------------------------------------------------------------

Hi,
Well all of my detectors are unable to detect deeper in the ground than when doing an air test.
Why should they ??
Air offers a lot less resistance to the signal than ground does.
I used to believe that myself and argued it back and forth with a bunch of detecting buds.
After some almost heated debating we actually made tests and no sir - no gain in depth when coins were buried.
I have yet to do it in wet sand on the beach - maybe the high water content might enhance signal transfer - but I sort of doubt it.

Same goes for the overrated halo effect.
I

 

[Big Red 1]

I agree, Discovery Electronics CoinTrax II, in "Boost Mode" with Iron ID on, is awesome! Love that Staccato sound effect on iron! And Minelab Sovereign GT with 15" WOT Coil? Like the "iron null" on the GT. Just my opinion, but have not used some of the other detectors mentioned, such as Nautilus DMC and Fisher CZ Series, but heard they are very hot detectors, in their own right! Older Fishers (1266 et al!) drove me crazy with pinhead sized nails detection, but were deep! Always felt they were too biased toward iron? Saw the same thing with Tesoro Lobo on iron and my new F-5 Fisher, although pretty deep, can't seem to get past a bottle cap either! Disc. is no help!
And yet a cheap (but good!) Teknetics Euro Pro, can Detect and I.D. iron and even has a way to turn off the sound of "iron"? And then they, (Fisher) decide not to put that (great!) feature on all their more expensive detectors, go figure?.....No, depth is not as good on Euro pro, as on F-5. Garrett 2500 can be deep, but unstable and biased on iron, as well.....It really depends on your soil matrix, as to how deep you go anyway, so depth is really determined by where you live? So, in my Volcanic/Magnetic soil, it's Cointrax II and Sovereign GT. Big Red

 

[Neil]

do your airtest on a Sovereign, Explorer, Etrac.......then take them to the wet sand at the ocean.
Those are the ones I know that will.

 

[HaloEffect426]

[size=medium]Hello to all,

I was scanning through the forum and your discussion about the halo effect caught my attention. I have been a treasure hunter since around 1975 when I was officially addicted, if you will. I am not a scientist or expert by any means on the subject, however, I have many years in the field using a wide variety of metal detectors from low end to the top of the line with White's, Garrett, Bounty Hunter, Teknetics over the years.

I noticed some interesting thoughts referring to air testing detectors' ability or maximum limit and then ground testing. Anyway, these are some of my thoughts and real world experiments that I consider ;

Halo effect thoughts.

..It would be difficult to compare [[but not impossible]] a freshly buried (let's pick a mercury dime for an example) To the same mercury dime (with a supposed "Halo Effect" surrounding the coin given to it over time and natural effects of the soil etc....time wise lets say, 1941 and assuming the same ground conditions like an old school yard, here's is the hard part

. How can I prove that the "halo" mercury was detected deeper than a freshly buried one? Ok, the trick would be to take the time to note the accurate depth as you would dig up the "halo" target and have a ruler handy and really get a good measurement upon discovering, in fact, you are fortunate enough to have found a Merc.!. Once this unknown figure is eliminated and noted. let's give it 7 inches on the dot.

One could re-bury the new find right away... w/in a few inches of where our "halo" dime came from..at exactly 7 inches, tamping down the dirt pretty good and a few good foot stomps sod plug back in etc.but with enough care to have our dime staying at the 7 in. depth. Now as it is freshly buried,???? CAN you detect the dime with your machine???
I have actually done this in the past at various depths with diff. types sizes of coins, silver quarters, a beautiful Barber Half Dollar at 11 & 1/4 inches comes to mind///Ironically an 1911 S as a matter of fact!///!!!!///and yes, very, accurately measured.

An 1906 S Barber Dime in extra fine condition or?better? with ONLY bags marks visible! (Thank GOD I didn't scratch that one with my digging knife!) at an impressive 9 & 3/8ths inches.... This one was on that "fringe"....audible ...barely.....really.. a ??? in sound.....freshly re~buried.

Or an 1848 large ONE CENT piece ..lady liberty.. sporting the braided hair design at a measured discovery depth of exactly 10 & 7/8 th inches for another time consuming "halo" test and comparison and discovered that I could NOT hear the same coin with the same soil conditions at the freshly buried, same depth as the "halo" find.

Another thought, with this "halo" effect occurring under ground and taking years or decades to form and dissipate the metal of a coin [[ or any similar treasure]] into the surrounding soil..and ( I am throwing out an educated guess with no data to back up amount of metal dissipation here) on a very small amount. Probably extremely small amounts to us but to our detector, an enlarged target signal is found.
.
With this principle understood, once an original, buried for long time periods, even decades or centuries! is unearthed, The "halo" minus the coin is now very scattered and dispersed about as you would dig up the coin and by the time you would grab up, even every particle of soil that once made up a combined coin/halo/'ed corroded, blended, oxidized, rusted. how ever you wish to call it. and tested the soil with your machine, it is just not enough of it alone to trigger a significant response.

For whatever all my efforts are worth, over the years, that's what I had discovered and I agree with everyone here.

There are so many variables...as with the thoughts of the wet sand... very different effects I've seen excellent depths personally with this one, including a silver Spanish Real or Reales of 1659, hopefully to your benefit.as this one was my very lucky day {caught me off guard!!!} and I did not have my measuring equip...and after unearthing that in VERY sloppy, wet sand honestly,,I didn't CARE!!..

...sorry, by the way, to read about those frustrating little nails... nightmare!

I believe it is one of a seemingly astronomical number of those variables with this hobby..obsession, whichever, that make it an excellent challenge every time one clicks on that fascinating machine and begins the daily hunt......and ?? Wonder what I may uncover today?? ;-)

Signed,

HaloEffect426 [/b][/size]

 

[Canewrap]

Sorry, the halo thing is a myth. The effect going on here is simply introducing voids that will eventually settle out after a time. The voids (small air pockets) act to scatter the signal and are why it's more difficult to detect a freshly buried coin. There is such an insignificant amount of metal leached out of anything that does not rust as to completely invalidate the idea of a "halo".

 

[Larry (IL)]

The halo effect is very much real canewrap, I have dug thousands of targets that had a halo, some halos are even visible. You must have the right conditions for this to happen, so for some people, they have never experienced a target with a halo. Our ground in most of Illinois is prime for halos to develop with mineralized ground, moisture and time. Anytime you have two dissimilar metals (mineralized ground and a metal target) in a dielectric (water, fertilizer salt really helps) you will have natural electrolysis over many, many years. The less noble metal (usually minerals in the ground) will turn to oxides which are detected with a metal detector making the target appear larger than they really are. This is why we can find deeper targets when the ground is saturated, usually in the spring.

The best example most people can relate to is iron oxide, rust, but some electrolysis happens to all dissimilar metals in a dielectric.

 

[ironsight]

Ahh, the infamous halo effect.
I think it might occur with non-precious metals such as a copper penny or iron but much much lesser with a more noble metal like a silver dime.
Ever notice those old Indians are corroded sometimes beyond recognition, yet that barber dime comes out of the ground shiny as the day it got dropped.

I agree halo's also have to do with soil conditions, alkaline or acidic, then add moisture via rain produces an electrolyte. Two dis-similar metal targets nearby or a conductive soil and bingo, the electrolysis effect. The deterioration of the lesser noble metal will take place but would likely affect both in the long run.

Take corroded nails and their large observable halo's for example.
In order to detect the nail's halo, the corrosive particles (oxides/ions) around the nail need to have a strong magnetic property . I'm not a chemist and don't know this for a fact but i suspect the iron halo from a severely corroded nail along with its left over conductive carbon components could be the reason some corroded nails ring in as silver.

In order for a detector to ID iron, the iron target must have a for a lack of a better term, a pure residual magnetic field after the coil energy briefly magnetizes it. Scattered iron particles would present random opposing magnetic fields. Those opposing magnetic field phase relationships would likely cancel out each other or be extremely weak. The resultant residual magnetic field could be minimal to non-existent. Or those scattered iron (oxide/ion) particles are likely non-magnetic.
Add to that a bent corroded nail or severly deformed nail due to corrosion.

If the iron corrosion is dispersed enough in the soil, it would not present a solid magnetic object to the detector thereby either confusing the detector or the detector will ignore the dispersed iron corrosion and home in on any of the nail's conductive properties.

So at least, the halo effect does exist with a corroded nail sometimes affecting the detector's ID accuracy.

 

[Larry (IL)]

With silver and gold being more noble, it is the metallic minerals in the ground that oxidizes, causing the halo effect. The green on copper alloy coins is often copper acetate or copper hydroxide depending on what chemicals are in your ground. I have dug old IH cents that were in a ball of green goo (hydroxide) that read as a dime and I have dug perfecty looking IH's in sandy soil that read where an IH should be. Most of the IH's in my area have a pretty green patina but no halo. It all just depends if you have the right stuff in your ground to cause halos.

 

[Nauti]

do your airtest on a Sovereign, Explorer, Etrac.......then take them to the wet sand at the ocean.
Those are the ones I know that will.

Is'nt this all to do with the ground tracking and the way certain detectors filter out ground?
For example,minelabs such as the sov use digital filtering to overcome ground minerals and they need to be balanced to the ground you are searching for this to work.So if you wave a coin etc under the coil in an air test,the machine will do it's best to balance out such a target,thinking it is ground, it never will but it will effect it enough to give less depth in an air test than the detector would get if the coin was in the ground and the machine was balanced to the soil.
Whites always recommend that when doing air tests that their machines are put in track lock so that the detector does'nt see the tested object as ground and try to track it out.As I said above,the machine will never be able to fully track such an object out but it will do enough to get less depth on the object in air.
So Neil,you could be right, as a lot of detectors need to "see" the ground first before they get maximum depth on metallic targets.

 

[Neil]

That could be it right there the tracking/adjusting they constantly do. Ive read many times that minelabs need soil to compare a signal to. They still air test well, as good as many detectors, but on the beach that depth they get can really surprise you. l
The tracking on an Xterra will track out a target at depth, loose the target but on the Sov or Explorer series it actually seems to enhance the target as you confine and narrow your sweeps.
I don't know a thing about physics that people often quote but I sure know what Ive seen in many years of detecting with the minelabs. They are really the cream of the crop for salt water beaches.

 

[slingshot]

Sorry, the halo thing is a myth. The effect going on here is simply introducing voids that will eventually settle out after a time. The voids (small air pockets) act to scatter the signal and are why it's more difficult to detect a freshly buried coin. There is such an insignificant amount of metal leached out of anything that does not rust as to completely invalidate the idea of a "halo".

In the 80's I had an A H Pro TR Discriminator. For those that don't remember or even know, this TR detector would detect a quarter at about 6" air test IF you had the threshhold perfect. Of course, back then, whenever you lowered the coil to the ground it went slightly into the null. I was in PULLTAB discriminate and got such a big wide signal I automatically said "Aluminum can." I could raise the coil about 4" and STILL get the signal. "Knowing" it was a can, I took my knife with 6" blade and thrust it into the ground thinking I would just lift the can out-nothing. Puzzled, I cut a 6" plug and thrust the knife all the way to the handle and then heard a "klack" sound which kinda gave me a sick feeling because I know knew this was a harder metal. It was an 1800's silver dollar! Theoretically, this weak detector could have picked it up at 15"! Sorry, the halo effect is real.

 

[Pastor bob]

I dug a full 11" deep Indian Head (1864) with my X-Terra 305 with 11" DD Coil and I dug a full 11" deep 1887 Seated Dime with my AT-Pro. Haven't gone that deep yet with the SE Pro but I would bet I will.

 

[ChicagoJohn]

I noticed that my machine can pick up coin as deep as 6 to 7 inch deep easily. Deeper than 7 inch seem to be depends on the ground or weather.....after rain seem good to search for old coins. I found my first 1901 barber dime at 8 or 9 inch deep after morning rain. My machine did tell me something below ground that deep around 10 inch but all I got is old nail at that deep. I have coin garden at my house. Wheat at 6 inch, quarter at 7 inch and Nickel at 6 inch. I can pick up all of it easily but mercury dime at 8 inch deep is not always pick up. Some day can and other time I cant.

 

[REVIER]

The deepest unit I have ever seen with my own eyes in person is my F70.
In the devil dirt in Alabama nothing went very deep at all and I did hunt with friends that had other units but that unbelievably bad soil put a damper on everybody so it was all a wash and I don't count that whole experience regarding anything to do with depth.
I relocated and have great soil here in Kansas, some of the best as far as I can tell, so it is a much better testing ground.
Limited experience with the F70 so far, maybe only about 40-50 hours and still trying to find the optimum settings, but I have had these experiences so far.
With a setting of 19 on the sensitivity out of a possible 99 which is 1/5th power level, I just picked up a clad dime at a measured 5".
At a park in an area near homes and power lines and an extreme amount of EMI I found an Indian Head spill at about 8" with the sensitivity set on 80.
Away from all that heavy EMI in the middle of that same park with maxed out power settings I located and dug a trash target, the thumb ringer piece off of an old bicycle bell, with solid tones on every pass from several directions and a jumpy but still pretty decent VDI ID at 14 or 15".

Looking forward to to the hunt where I come across a good coin or jewelry target that I can find with a good ID that is somewhere at 10" or deeper.
Hopefully that will happen soon.

 

[MichiganJason]

I must have had a dud f 70. It wasn't deep at all, I had the stock coil and the 11 inch did coil for it. The Omega was much deeper in my ground.