Why do VLF's units detect deeper in moist ground????

I have noticed this on all of the units that I have owned. My dirt is in the 'moderately mineralized' category. I first saw this anomaly when I was using a Teknetics G2 in my test garden. I had a bullet buried to 10 to 12 inches (cannot recall exactly). I was all excited because my G2 was slamming it. I kept going outside and running the G2 over it just to hear it hit a deep bullet. Summer arrived. The ground dried and became hard and VERY difficult to dig in. And my G2 would no longer hit that bullet with a hi tone. It would barely give a low tone. Sometimes it would be repeatable. Sometimes not.
We had a lot of rain yesterday ....and alot of snow last night.....but it is sunshining today and headed up to the mid 50's (slightly under). Should be a good day of hitting a site that has produced only bullets and one button.
Just curious as to the "why" of this or wondering if anyone else has discovered this.

Moisture is water. Water is conductive.

Discrimination is the root of all evil.

Thanks PittsburgWill. Mineralized ground is conductive, as well. But it seems to retard that detectors ability to reach deep, while water/moisture seems to help with depth.
Just sitting around waiting for the weather to get warmer outdoors and figured that I would pose a question that has been nagging me. I appreciate your response PittsburgWill.

Maybe because the water is conductive, but it's not metallic. Of course iron mineralization is metallic. It also seems to me that when dealing with heavy mineralized soil moisture can hinder the detectors ability. Like it amplifies the masking effect of the ground. So I figure the moisture amplifies the signal whether it be the signal from a target or the ground signal itself.

Discrimination is the root of all evil.

I think its largely conductive salts that "turn the ground on" when its wet. That's up to a point though. After the dirt is completely saturated its actually detrimental in a lot of cases......



PittsburghWill Wrote:
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> Moisture is water. Water is conductive.

I agree with Streak. I have noticed that over saturation will or can become detrimental.

Just remember its a two sided situation....Remember also affects the junk that surrounds the target causing more target masking...Also heard of real deep finds after an electrical storm due to the static electricity...
PS: wait till the storm is over don't want your metal wand your swinging to put you in a hospital or perhaps in the ground....

Thanks guys, for the sincere input. I have always conducted myslef on the premise that there are no dumb questions if you don't know the answer. And I was HORRIBLE in high school physic. All me and my Physics teacher could talk about was duck hunting. Actual PHYSICS was secondary.
Not to sound TOO self-effacing, but I could use a good guide on how the VLF machine works. Basic principles. My ignorance of the subject is my own fault. I have jumped straight from "opening the box, scanning the user manual, and start detecting" to "the way they (VLF's operate". I feel that there is alot of info in between that I have purposefully overlooked. I was very distracted in school as a teen. I loved the outdoors (hunting...fishing) and loathed bookwork and studying. Just musing out loud.
Still yet, I appreciate the feedback.
I have kept this Tek G2 longer than I have ever had any other machine. In my soil, and the soil in surrounding areas, the G2 seems to be able to compete with all I have tried. The 11 inch coil being most used in open areas. The 5x10 in trashy areas. I can, alot of times, predict what I am about to dig (a 22 casing, shotgun hull, CW bullet, etc).
I guess, I am finally coming to the level of learning where I am understanding that EXPERIENCE trumps alot. Thanks again guys. Heading out to a spot.

Water is not conductive. It's the dissolved minerals, fe, etc in water that make it conductive.

Demineralyzed (pure) water is actually a poor conductor.

Hi Kevin,,,It can be good or it can be bad as far as hitting a coin deeper in the ground...I have seen the grass wet on top that really hindered my depth....Dan described it pretty good........JJ

....I like to hunt when the ground is slightly moist down to target depth but not saturated. Ground that is too wet will light up the rust halo around small ferrous junk like small square nails and they sound too good. Just my take on the subject.

Hi Hombre,,,exactly there seems to be a magic moisture content that really seems to illuminate the nonferrous targets that makes them accessible .....JJ

Yes, I agree. I like the ground have SOME moisture in it. It is in the heat of the summer that detecting really becomes a chore. The ground gets so hard around here that I could jump on my Predator shovel and STILL not get it to sink in!!! I reckon that would be a good time for other things.
I appreciate all of the replies and feedback. I wish, logistically speaking, that all of us members could have a rendezvous (I think that's what it's called when members of a Forum have a gathering).
I think that we would understand each other better. Alot is lost in the written word. I would be willing to bet that 99% of the folks here would be a pleasure to know. (I allowed 1% for the spamming threads that crop up from time to time). Anyway.....thanks guys.
P.S, If any of you have a favorite link on the basics of VLF detectors (besides this forum, which is awesome, but goes over my head sometimes), please feel free to post it. I am starting to get real curious about what happens when the detector is scanning. Maybe something along the lines of: "An Idiot's Guide To VLF And Pulse Induction units".
I am going to hit a spot tomorrow afternoon that would be well suited to All Metal or a Pulse Induction unit.

Hi again Kevin,,,,I reread your question and decided to get rid of the other variables and give you a more definitive scientific type answer ...LoL...Providing you are in an iron & trash free area, the reason you will get more penetration, is that salts occur naturally within soils and water.....Salt that is contained in the soil when it gets moist releases negative and positive ions charges which are able to transmit current which increases conductivity...When it's dry the reverse happens and the ions are bound to the salt contain within the soil...Salt by itself is not very conductive if at all due to the salt crystals.... Thus hypothetically speaking you should get more depth when the ground is moist.....When the ions are flowing at their peak is the best time to detect...I just have not figured out when that is....LoL...JJ

PS: Temperature plays another role on the above subject too, which we might discuss at a later date

Thanks JJ. I have also heard, from a few old time detecorist around my town, that the moon's phases also have some impact. I could never get a definitive answer on exactly which phase of the moon was optimal. They might have been yanking my chain. But the moon's DOES impact lot of stuff here on earth.....tides...etc.
Interesting stuff really. Thanks for your feedback. Y'all have a great weekend. kevin

Kevin B, Just drop the core unit in there with both the stock and small coil. Keep in mind, some of the things Keith mentioned in his post concerning Core unit in 5 bars ground.
And if you have time go to FM and read a few of Monte's comments concerning the FORS Core unit. I also suspect more nuance will be discovered with a little more time. And here's what I'm waiting on-the next Nokta flagship!! If it performs better than current Core, uh oh! Another step above, bad dirt VLF machine that will work in disc mode will allow a lot of nice things to be discovered in areas usually avoided.

Thanks TnSharpshooter! Yes, the FoRs Core is a sizzlin hot unit. In DI-2 it doesn't seem to miss a thing!

Hi Kevin,,,,yes the moon controls the tides by it's gravitation pull....So yes if you water hunt you could hunt further out etc....So I guess they are right....JJ

The most common technical reason is simple.
Just about any VLF detector out there is designed to discriminate the signals from ground interference when the search coil is very close to the soil. The VLF will all pick up a slight to a strong positive signal from the soil if the coil is close enough to the soil surface. So in dry conditions this close proximity positive ground response is much less prominent than in wet conditions. When the soil is wet the close proximity positive ground signal combined with any non-ferrous target signal becomes greater in value than what the discrimination can prohibit. Therefore a louder audio response will occur.

Another reason for better detection in wet soil is the fact that the soil particles are closer together and the ferro-magnetic properties of the soil is better for detection. In very dry soil there are often a lot of cracks that form air gaps. The air gaps naturally will inhibit some of the detection range adding to that a confusing discrimination readings. Good example for this is the soil in farm land.

I appreciate that reply Nexus.

And believe it or not, last winter here in Tn, it got so cold and stayed cold, the ground starting cracking in many areas. So I could see this possibly complicating the detecting scenario. Especially with Minelabs. My experience with them, the tighter the soil the better.

So reading all of this brings to question, can it's be found deeper in the ground than in air test. I think yes, but have read just the opposite in posts from engineers etc.

Walt,

From the GA-FL line

Silver microMax, CTX 3030, Excal 2, ATPro

Hi Fletch88.....IMHO....The answer in no, a machine will not go deeper in the ground than it air tests....This question was basically referring to wet ground Vs dry ground and the wet ground is the winner.....There's a popular brand of detectors that I have heard that they don't air test well, but will go deeper in the ground, well even the manufacture of the machine debunked this statement, but I can't find the post.....Here's what I found to be true, certain brands of machines will lose a lesser percent of their penetration in the dirt Vs their air tests over some other brands....Perhaps Tom could clarify this even further and maybe even concur what I have said.....JJ


PS:#1.. If two different brands air tested the same,,,one brand may penetrate the soil deeper due to design....But neither brand will go deeper in the ground than their air test

PS:#2..If brand A air tested at 10" and brand B air tested at 8"....Is still very possible that brand B could out preform brand A in the dirt

PS:#3.. This is where people on forums knock the validity of air tests,but in my book they are very important...On a side note over the years I have a pretty good idea of what brands loose more % in the ground

Yes I'm very familiar with that brand (had ctx,etrac,excal, sov, xterra) and on mult freq machines I would agree that their airtest are less than real world depths. I don't think so with single freq machines.

Hi.....Next comes the Halo Saga this one has really been a topic for years....The experts say Iron--yes it makes it larger.. Coins etc.- no.........I say Yes -Yes but who am I to argue with the experts..........JJ

Fletch88 Wrote:
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> So reading all of this brings to question, can
> it's be found deeper in the ground than in air
> test. I think yes, but have read just the opposite
> in posts from engineers etc.

The common consensus is no to your question.

However.

If any detector will detect deeper in the ground than in air will have to be in relation to some kind of a constant. In this case the constant will be the ground it self. Only after a proper ground balance is made on any particular site comparative measurements will have any meaning. Comparison between in ground and in air detection range would have meaning only if the ground interference is taken out of the equation, meaning the detector have no further problems with ground after the ground balance is made.

I was one of the most fears supporters of the idea that VLF detectors can not detect deeper (or at least better) in the ground than they ever could in air. Our best ever results in some conditions were air to ground same measurements, but never better in the ground.
The new Nexus Standard MP change that. The measured average signal detection in ground with the MP is 12-14% better than in air, BUT ONLY AFTER THE GROUND BALANCE IS DONE.

In absolute values VLF detectors will always be more sensitive in air than in ground, simply because their sensitivity in air can be boosted almost indefinitely and for detection in ground that same sensitivity will have to reduced dramatically for proper functionality.

So if one chooses to compare the absolute values then the answer is no.

But if one chooses the values in the real working environment then the answer is yes.



Edited 1 time(s). Last edit at 01/26/2015 08:35PM by Nexus.

ATTENTION::::ATTENTION::::NEWSFLASH::::The laws of physics cease to exist for Nexus...."The new Nexus Standard MP change that. The measured average signal detection in ground with the MP is 12-14% better than in air, BUT ONLY AFTER THE GROUND BALANCE IS DONE."......"This is phenomenally,astronomically greatness in it's rarest form"......says JJ from Tom Dankowski's renown forum, (as reported by the Boston Globe).....Shame on me for thinking you had a hidden agenda all this time....LoL....JJ


PS: Me got to get me one of them magical,miracle,meticulous machines.

Laws of physics it seems are violated with XP Deus and XP goldmaxx.

For a detector to go deeper in the ground verses air tests, the ground would somehow have to boost the signal...my common sense, not based on fact.

I've noticed my f75 will air test better than the MLSE....but the MLSE will get closer to its air test numbers in ground, than the 75.....the 75 is still a bit deeper.

I'm no rocket scientist or a nuclear physicist like some of you guy, but here my take on the ground verses air test it's like this if I shoot my 1911 45 across an open field that round will travel about 850- 900 FPS until it runs out of energy which will be about a mile and then fall to the ground, now if I take that same 1911 45 and point it at the ground and shoot it, it will travel about 12" into the ground why because of the resistance from the ground same with the radio signals from my coil, resistance will keep the coil from detecting deeper in the ground than in the air. and that's all I have to say about that.