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Ground make-up + various amount of Water = ???

October 19, 2019 02:53PM avatar
It can cause just about no change at all, to various challenges we might, or might not, be prepared for.


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dixiedigger57
Monte or anyone, does moist ground really have that much effect on a single freq detector?
No, not really. Moist ground is just that .. 'moist' .. and the main difference is that the ground surface or a shallow amount of the ground is moist or damp or at least it might no longer be dry and possibly hardened. We used to have problems in the earlier days of detecting when the search coils and wiring were not shielded and we got falsing from wet grasses and weeds.
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But issues from "moist ground" isn't an issues with only a single frequency detector. Multi-frequency detectors also transmit an EMF and therefore will have to deal with the same effects. Naturally, it would stand to reason that if a single frequency has to deal with the effect of ground moisture, a multiple frequency model would have to deal with it multiple times. Logic.

However, the detector and search coil design to shield the unit from any negative effects can take care of the problem. But you have to wonder, if you think it through, is there a possibility that a simultaneous frequency detector handles the ground moisture effect but with some slight loss in overall performance from doing so?

The frequencies used are not transmitted simultaneously but sequentially in fractional-second order, and that means all signal processing is also done as it occurs. All detectors have to handle the ground signal and target signal and deal with the ground signal, as well as rejected or Discriminated target signals, and then pass along the favorable accepted target response. When you change the ground signal it might make it more difficult for the detector circuitry to process, and that means it's more pass along the target response.

Fortunately, most of the time we are only dealing with either a dry ground or moist ground surface, and that means that most of the time we can just hunt-away at a site and enjoy the pleasure of hunting, regardless of the detector and coil used and with a "so what" attitude or concern about the ground we're hunting.

Kind of ....thinking


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dixiedigger57
i know water can carry a current or be a conductor. moist ground is certainly easier to open up.
True, water can have an effect on our detecting success. We just have to be prepared for it and know how to deal with it. Sometimes it might mean switching to a different detector than what we might use, all based on the ground mineral make-up, the amount of moisture present, and a detectors design capabilities.

I like to hunt in a wet ground condition because target recover is usually going to be easier to do, and after a cleaner target recovery it is easier to tidy up the recovery site. I currently live in Vale in the far-side of central eastern-Oregon in the Great Basin High Desert Plateau where it is generally drier. For about 48 of my 70 years I lived in Portland, Oregon, where it is much wetter and drearier. As you can see in the comparisons below just for rain, I have had ample experience detecting in a moist to very wet and saturated ground environment .... ←over there on that side of the state.

Here are some weather averages for Vale, where I live now, Portland Oregon were I lived for too long, and for the USA.

----------------→ Vale - Portland - United States
Rainfall ........... 10 ...... 48................ 38
Snowfall ......... 12 ........ 6 ................ 28
Precipitation .. 69 ..... 160 .............. 106
Sunny .......... 209 ..... 137 .............. 205


Trust me, I know about hunting in wet ground. I DO like to be able to easily make a quick recovery with a rounded off screwdriver or a hand-digger if needed as it's much easier than working in hard-surface dry ground or a very loose and powdery dirt and grass mixture to try and restore nicely, or keep from browning out. But I DON'T like to maneuver around in a muddy, gooey mess, deal with my cane sinking or sticking in the super-wet grass or mud, or trying to recover a located target from a big hunk of muddy crud. I enjoy 52.55% more sunny days, 79.15% fewer inches of rain. and overall about 57% less precip per year and since I like to stay dry and not deal with mud, that's fine with me.


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dixiedigger57
wet wet ground is messy.
Yep! And it is the wet, wet ground that I like to avoid, especially when it's in the middle of getting wet, wet, wet!


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dixiedigger57
does super wet seem to carry to much of a signal response, maybe overload a unit?
Two different questions:

'Carry Signal Response': An interesting thought. Water, not just moisture but a solid body of water or at least a very, very wet, level of water (saturated) might "carry a signal". A 'signal' is a change in the eddy current flow, but which one? The eddy current flow caused by the EM transmit field from the search coil? The eddy current from that is absorbed or induced in the metal object? The eddy current flow, or change in that flow, to or effecting the Receive winding? The response or eddy current from caused by the saturated water and the effects of high iron mineralization, or salt or alkaline content in the soil matrix?

The science and study of water, or the amount and type of water used (fresh to salty to otherwise contaminated), and the effects on a "signal response" or eddy current flow or retardation, I think is a more technical study that I'd bet many of the typical design engineers don't get into. They gather and assemble the parts for a detector, check it out to see if it works, sometimes compare them with other detectors on the market, and if it appears to handle the general conditions, they are fine with it.

Certainly there can be more to this topic than is usually discussed or studied, and all I can tell you is that from my 5+ decades of experience using detectors and even evaluating some prototypes that never made it out of the factory, there comes a time when ample water can, and will, have some effects, both favorable and not, on a metal detector's performance.

Maybe cause an Overload condition: A simple answer is Yes, it can sometimes cause an overload or have a negative effect on the EMF. A good case is looking at the detectors taken to either a freshwater or saltwater beach and used on very wet beaches or working several inches to a foot or so below the water. The other factor is the ground mineral and salty/alkaline level, if any, of the water or soil composition.


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dixiedigger57
make ferrous harder to deal with?
Yes, and that includes both lost, man-made ferrous objects as well as ferrous or iron contaminated soil. Consider this. Our detectors make use of Ground Balance to help handle the ground mineral signal.

Ground mineral conditions can be 'layered' such as a hard rock layer with clay on top and maybe sand on top of the clay, all layered in the upper 10" or so. It could be a very iron mineralized surface layer of 2" thick on top of a different layer of less mineralized dirt on top of a rocky base. It might be good workable dirt in the upper 4" and then a more iron mineralized layer of dirt under that.

The search coil choice also is an important consideration as to how that 'type' handles different mineralization combined with the potential depth of detection or EMF size. How many layers are we having to deal with at a site? What effects will the different mineralization layers have on impeding our induced search field and depth potential? How well can we, and / or our detector circuitry, handle the mineralization, ground cancelling, and to this topic, any effect a very wet, saturated mineralization layer might present us with?


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dixiedigger57
we have been in severe drought and it finally rains . when it moves thru a few hunts before surgery.. careful no strain hunts that is. park, no tripping up hopefully. then lay up for 2 to 3 months.angry smiley
Sorry to hear about your drought. We had a very hot summer and it was mostly dry around here, but that followed a late, wet spring that reduced our hunt time. Now we have some fall rain storms passing through, again reducing how much we, actually I, can get out detecting. I hope a mild fall returns for a while.

Take it easy out there, and use caution to avoid tripping. I wish you some success if you get some hunt time in, and especially during the surgery and mending process. At least you'll have 2-3 months to rest up, mend up, and be ready for spring. It will give you more time to visit the AHRPS Forums, re-read your owner manuals, maybe do some bench testing to keep familiar with your detector's behavior.

Don't be too concerned about the water and moisture and all that stuff. Just be thankful for enough of it to make target recovery easier. That's the valuable aspect.

Monte

"Your EYES ... the only 100% accurate form of Discrimination!"

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Subject Author Views Posted

now that it finally rained.. a ground condition question

dixiedigger57 73 October 15, 2019 10:36AM

Ground make-up + various amount of Water = ???

Monte 38 October 19, 2019 02:53PM

Thanks Monte. Reading and videos while healing

dixiedigger57 19 October 20, 2019 08:55AM



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