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Depth and ground conditions

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  • Depth and ground conditions

    Can someone in easy English explain why finds in compacted ground are deeper. I can see the affect because when the bottom of the hole gets aerated you loose the beep unless this is just the target getting spun around a bit. Pretty sure it's not the halo affect as I have only ever seen this on iron. Sometime you can remove an iron object and in all metal mode you can still detect the target never had this with any other metal.


    Think I understand why wet ground appears deeper.

    If I think of mineralized ground as a rough sea with each hot spot as a wave. The the small peak of a target is lost within all the other peaks

    When it rains the peaks even out more like calm sea so peak of a target is more pronounced.

    So you loose less depth over air tests

    Am I correct.

  • #2
    thinking in easy english there will be ITMD second edition release that give all good stories on those cases.

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    • #3
      Provided it undergoes some serious basic/special English proofreading.
      Did you know that Voice of America uses a reduced dictionary called Special English? It is in all aspects English, only put together so that many infrequent and complicated words are not used at all.
      The concept came from the Brits, of course, in a form of a Basic English. Churchill was fond of it.
      Most complicated things can be said using a reduced dictionary, and as such they are easier to follow.

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      • #4
        Finds in compact ground not are deeper compared with in air, but they are deeper in homogenous ground
        compared with mixed soil, mineralized rocks and other elements like roots or different humus depths etc.

        If you disturb the soil by digging a hole of course you destroy that formerly more or less balanced system of
        mineralization versus EM-field values which can lead to no longer detectable (pretty small and deep) finds.

        This also has to do with the detectors "zero level setting" (everything below will be seen as mineralic ground
        and will give no longer a target signal; even per instance also mineralized soil or layers of loam can be seen
        as a detectable target). So depending on how high is the mineralization around the hole, weak signals could
        become undetectable (as long as the coil will not get moved into the hole or closer to the find).

        Soil drenched with rain or water will provide higher EM-field values and can reduce disturbing
        differences in ground-mineralization level. Especially if the wet coil gets scrubbed over wet grass
        the whole detection contrast-factor can be raised because the EM contact will be closer to the find
        as if everything would be dry and there is 5-10cm air-space between the mineralized soil which already
        can create signals just if the coil is not moved exactly all the time with the same distance over the ground.

        Per instance also PI-detectors can have a huge depth gain under salt-water or at beaches drenched with this.
        Here the salt also works as electrolyte that leads electricity and EM-fields better than if it would be just rain
        ground- or river water. So thats why its also imporant if the soil is rather alkalinic or acidic (the soils pH value)
        to get more conductivity. A sour ground also will lead to stronger rust and corrotion of the finds but that way it
        also can create a huge haloeffect of metalized ions around the find which can lead to deeper detection (10-30%).

        http://en.wikipedia.org/wiki/Soil_pH
        http://en.wikipedia.org/wiki/File:World_Soil_pH.svg

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