Problematic soil

[Riss]

On August 9th there was a meeting of gold prospectors. I was “armed” with a stone of pure magnetite and a piece of ceramics. A deep hole was dug for tests. The soil had low humidity. From a previous meeting in the same place I knew that this soil "raises blood pressure" – in the zone of 1 cm – 6 cm there is a direct inflection of the signal (+ -) in the channel “all metals” and the detectors are very “noisy” – complete cutting out of the soil effect is practically impossible. As I expected – all modern detectors ( Minelab E-Trac ; EQUINOX 800 ; Nokta The Legend ; XP DEUS 2 ; but there were no PI detectors ) showed a significant loss of depth (about 30-40%) in the soil compared to an air test. By simple measurement ( I have magnetite and ceramics ) I found out where the vector of this soil is (the measurement result coincided with my expectations ). Can you guess where the vector is? and why is it so?

[ivconic]

Yes, your experiences are not unusual but very standard for today.
I often wonder myself; has it always been like this... or has something changed in nature in the past 30 years?
Maybe it's always been like this, but I didn't notice it then, it's a trick of the mind, to remember only good moments.
There used to be many more findings, so it's easy to forget bad moments during the day.
And today there are practically no finds in known places, so the whole day is "bad" in such places.
Accordingly, all modern detectors do not show any special virtues.
When I think back, 20-25 years ago, with an "ordinary, outdated, weak" detector, I had loads of findings during the day.
And today with the "most modern miracle of technology" I can hardly find a pair of lead bullets, even that is considered a success!

[Carl-NC]

Not from what you describe. Soil has 2 attributes that are important to detectors: loss angle, and susceptibility. By "vector" I assume you mean loss angle, but depth loss is more a factor of susceptibility (strength of ground) than loss angle (phase). And really strong ground also creates a stronger lift-off effect, which makes the detector harder to ground balance even though the loss angle is well within the GB range.

[ivconic]

Such rallies are not a good place to test detectors. Because more detectors work in a small space.
There is too much noise and interference. It is not "virgin" soil.
Even if the other participants turn off their detectors, while only one tries; that surface is still "endangered" and "polluted" by the presence of so many people and technology.
It is very far from the situation when you go alone or with a couple of colleagues far into the wilderness or high into the mountains.
The good side of such rallies is that people socialize, get to know each other and exchange experiences.
The downside of such rallies is that there are often ego clashes.

[ivconic]

Not from what you describe. Soil has 2 attributes that are important to detectors: loss angle, and susceptibility. By "vector" I assume you mean loss angle, but depth loss is more a factor of susceptibility (strength of ground) than loos angle (phase). And really strong ground also creates a stronger lift-off effect, which makes the detector harder to ground balance even though the loss angle is well withing the GB range.

Vector direction shall be nearly vertical, pointing upward or downward depending on local magnetization.
Reason: shallow magnetite grains produce a strong vertical component that interferes with VLF/multifrequency detectors, causing noise and reduced depth.

[ivconic]

I was very optimistic and a little euphoric when I added an elliptical HF coil to the Deus 1 the other day.
I expected "miracles". And of course, I immediately "attacked" my favorite "enemy" terrain!
It is a hill 12 km from my house. I have been visiting it for 30 years. That's where I test the detectors.
There used to be a fortress from the Middle Ages. Today there is nothing left.
Unfortunately, the white HF coil did not prove to be overly superior to the black 22.5cm.
It's noticeably "quieter"... but that's about it.
There were no "hidden" findings. After 3-4 hours of walking, only one small and very bad coin.
That terrain, that hill, is "synonymous" with very difficult soil conditions.

[Riss]

Not from what you describe. Soil has 2 attributes that are important to detectors: loss angle, and susceptibility. By "vector" I assume you mean loss angle, but depth loss is more a factor of susceptibility (strength of ground) than loss angle (phase). And really strong ground also creates a stronger lift-off effect, which makes the detector harder to ground balance even though the loss angle is well within the GB range.

By soil vector I mean the detailed explanations in this patent - https://www.geotech1.com/pages/metde.../US4030026.pdf - Fig. 3 and Fig. 4. I also had a neodymium magnet, but I forgot to check whether the soil sticks poorly to the magnet. I forgot to take a sample of this soil. The soil is located in a karst area - about 200 meters from it there is a very large cave with stalagmites and stalactites, which is a tourist site. The test hole is at a level about 4 meters higher than a huge clearing resembling a crater. About 7 meters from the hole there are large shapeless limestone stones. Millions of years ago there was a sea there. Years ago the soil had much higher humidity and was even more problematic. Then there was a Minelab GPX 4500, but we forgot to check how much the depth loss was.

[Riss]

I was very optimistic and a little euphoric when I added an elliptical HF coil to the Deus 1 the other day.
I expected "miracles". And of course, I immediately "attacked" my favorite "enemy" terrain!
It is a hill 12 km from my house. I have been visiting it for 30 years. That's where I test the detectors.
There used to be a fortress from the Middle Ages. Today there is nothing left.
Unfortunately, the white HF coil did not prove to be overly superior to the black 22.5cm.
It's noticeably "quieter"... but that's about it.
There were no "hidden" findings. After 3-4 hours of walking, only one small and very bad coin.
That terrain, that hill, is "synonymous" with very difficult soil conditions.

On Serbian territory you can still eat real food (Serbian pljeskavitsa and not only that...) and your wines are like in the good old days. These are good reasons to recommend that you buy a detector, complete with a three-story probe. For example, this one - https://www.ebay.com/itm/136192645234
I am convinced that after this purchase your visits to this forum will decrease drastically... and your cute cats will enjoy your company less and less

[ArchibaldSTM]

Some empty topic for discussion. There will be nothing new here. We need to go to the fields and dig, and not shake the air, sitting on the couch

[ivconic]

On Serbian territory you can still eat real food (Serbian pljeskavitsa and not only that...) and your wines are like in the good old days. These are good reasons to recommend that you buy a detector, complete with a three-story probe. For example, this one - https://www.ebay.com/itm/136192645234?itmmeta=01K30NT3TP6PPN82YVQT8E7FD4&ha sh=item1fb5b6d872:g:G2YAAeSwx-tofm-d&itmprp=enc%3AAQAKAAAAwMHg7L1Zz0LA5DYYmRTS30lfN sX QimVJJOfKRSqnfVhmwbj1kKh2tG0xqx5DyAlBfsVp1P7BGz7Gj qrIIuQg9lK%2FMWPSlw84sJbQ%2Fj4ftN3B9n44TQy%2BCqEBk bkQRZjZ5XNIblgnrUnUA6tvdQln%2FHseNgHZQ3sK8nmIPI0u2 edkWRqMD0WHxBMW4NC0Bu%2BRsl6nfZQ3Y6Bq8Q07Gi56lTMiy JzEsjvH0Xd7dpQ%2F0AV6y96Q6pu%2BT22D%2FfAf3Pgt2A%3D %3D%7Ctkp%3ABk9SR7i96JWYZg
I am convinced that after this purchase your visits to this forum will decrease drastically... and your cute cats will enjoy your company less and less

Wow it is in very good shape!
The other day I god Garrett GTI1500 with Imaging coil.
The collection keeps expanding.

[ivconic]

Some empty topic for discussion. There will be nothing new here. We need to go to the fields and dig, and not shake the air, sitting on the couch

Of course!
But in my area it is dangerously hot during the day, it is not the period for such ventures.
The conditions will be created only at the end of September. I can't wait!

[Riss]

Wow it is in very good shape!
The other day I god Garrett GTI1500 with Imaging coil.
The collection keeps expanding.

I do not recommend this detector for a collection, but to work with it if it is completed with a three -storey antenna (it is quite thick) by the same company. I remedied the same model detector model about 20 years ago. In a rather "junk" settlements you will understand why I recommended it to you ...

[Carl-NC]

By soil vector I mean the detailed explanations in this patent - https://www.geotech1.com/pages/metde.../US4030026.pdf - Fig. 3 and Fig. 4.

I find his diagrams to be confusing. Figs 3 & 4 deal with the coil phase error and Figs 5 & 7 deal with ground error. Rotate the plots 90° to get them roughly to the same orientation as ITMD3. Even then, George uses the TX voltage drive as his reference whereas I prefer to use the TX current drive so there needs to be an additional Θ rotation.

[ivconic]

I do not recommend this detector for a collection, but to work with it if it is completed with a three -storey antenna (it is quite thick) by the same company. I remedied the same model detector model about 20 years ago. In a rather "junk" settlements you will understand why I recommended it to you ...

What was that?
Can't understand.

[Riss]

we forget about fig.4. we look at fig.3 vector 298 are natural ferrites – magnetite (hot rocks). They do not introduce energy losses into the spatial region around the transmitting coil. however, everything that is clockwise after vector 298 introduces losses – from conductivity and (or) from remagnetization. vector 296 – there is ceramics. it does not introduce losses from conductivity, but from remagnetization. the reason is inertness. Only natural ferrites (magnetite and others) do not exhibit inertness – their magnetic domains are practically without inert in magnetic fields at frequencies below 100 kilohertz. Iron objects introduce losses from remagnetization and from conductivity, and their vectors are ALWAYS after ceramics clockwise. Anyone who has looked at the oscillograms of iron objects obtained from the receiving coil of the Fisher CZ5 Quicksilver knows this. The oscillograms of iron objects have rounded fronts, and magnetite - extremely steep fronts. The vector of the ceramic is about 5 degrees behind the ferrite (as explained in the patent US4030026). And so - I ground reject precisely on the problematic soil. Then I waved the piece of ceramic in front of the probe and oh - miracle! - the ceramic had a negative reaction ... the patent explains that the vectors of all soils are between the ferrites and the ceramic - this is really so. When we ground reject the soil, then the ferrites have a negative response, and the ceramic - positive. The fact that the brick (ceramic ) had a negative reaction indicates that the vector of the soil is located after the vector of the ceramic clockwise. which means that this soil incurs greater losses than ceramics. When it is wet, things get even worse and the vector approaches iron objects. As an operator, I am not particularly afraid of mineralized terrain, but I am terrified of such soils