CONDUCTIVITY OF SOILS

[Esteban]

How I comprobe is soil is good conductive or not? I made an oscillator and inject via 2 copper stakes certain frequency in soil. I use here a loop-magnetic pistol. Now, in soil with poor conductivity, the pistol detect the area of the stakes at few distance, but in salty terrain, the detection area is more extended and is at more distance too, so also THIS METHOD IS USEFUL FOR TO MEASURE CONDUCTIVITY OF THE SOIL!!!

[Theseus]

Originally Posted by Esteban

... inject via 2 copper stakes certain frequency in soil.

Certain frequency????

Here we go again.

[Esteban]

Originally Posted by Theseus

Certain frequency????

Here we go again.

Because the frequency must be accordding with frequency of loop-core for to be more noticeable. Even if the injected frequency is not in concordance of the resonance frequency of the loop-core system, the difference is notorious too, but, of course, low frequency between 5 to 8 Khz was used.

[J_Player]

Originally Posted by Theseus

Certain frequency????

My guess: more than 1 Hz, less than 10 Khz. Probably in the audio range, maybe 400 Hz.
Voltage - My guess: More than 1.5 v, less than 250 v. Probably between 6 and 12 v.

Ground resistivity has been measured by many experimenters and geologists. I have read reports of DC being used from a 12v automotive battery to check current flowing between copper rods driven into the ground at spacings from a few feet, to over a hundred feet. I have also read reports of over 1000 volts being used to test longer distances, where the negative rod was driven in a reference location, and test rods on the positive terminal placed at various locations to survey the relative resistivity of the soil. This technique is also used to test signals used for induced polarization, and other related ground surveying methods.

In Esteban's example, the objective is to make a portable hand-held device for quick, convenient field tests. This would require using low power disposable a battery powered tester. If low voltage probes are used, then it is necessary to cancel the current caused by any telluric currents in the test area that might skew the readings from the tester. Using an oscillator will allow testing the current flowing in both directions (polarities) to yield an average current flow while ignoring the DC portion that comes from outside sources in the ground. With the proper circuitry, you could also detect the DC component, indicting the flow of telluric current.

You can read more about how to measure ground resistivity in the geotech sections of the forum as well as websites dedicated to geological testing methods. Much is written.

Best wishes,
J_P

ps. Seems I posted too late. Esteban finished his reply before I submitted my guess

[Max]

Originally Posted by Esteban

Because the frequency must be accordding with frequency of loop-core for to be more noticeable. Even if the injected frequency is not in concordance of the resonance frequency of the loop-core system, the difference is notorious too, but, of course, low frequency between 5 to 8 Khz was used.

Why don't simply make a test for conductvity of soil... ?

Complications ...just for the fun of using LRL ?

Cannot resist... sorry

Kind regards,
Max

[Esteban]

Originally Posted by Max

Why don't simply make a test for conductvity of soil... ?

Complications ...just for the fun of using LRL ?

Cannot resist... sorry

Kind regards,
Max

Simple... is for to compare. As target is better detectable in salty soil, I think is similar when you transmitt frequency into soil. But ferrous soils are different, these mask the detection. Also when you transmitt frequency to the soil, detection is better. And is not a complication, is a "facilitation"!

[Max]

Originally Posted by Esteban

Simple... is for to compare. As target is better detectable in salty soil, I think is similar when you transmitt frequency into soil. But ferrous soils are different, these mask the detection. Also when you transmitt frequency to the soil, detection is better. And is not a complication, is a "facilitation"!

Using LRLs is a "facilitation" ???

Where... ?

Maybe in LRL-land !

Here seems I get much randomic beeps...

Must ask Morgan for the 7th... secret PCB design...

Kind regards,
Max

[Esteban]

Originally Posted by Max

Using LRLs is a "facilitation" ???

Where... ?

Maybe in LRL-land !

Here seems I get much randomic beeps...

Must ask Morgan for the 7th... secret PCB design...

Kind regards,
Max

At the end, te device is not for to measure conductivity of soils, but with it you can discover things...

[ivconic]

Esteban...it is much more easier to make resistivity meter... I made one from Carl's projects and it is working very good. Now i am up to make newer design from EPE projects with data logger.

[Fred]

A non-contact resistivity meter is probably very usefull to study halo effects

[Esteban]

Originally Posted by Fred

A non-contact resistivity meter is probably very usefull to study halo effects

You understand the idea!

[Esteban]

Originally Posted by ivconic

Esteban...it is much more easier to make resistivity meter... I made one from Carl's projects and it is working very good. Now i am up to make newer design from EPE projects with data logger.

I think that the long range detection is associated with good conductive salty soil. I transmitt a frequency and see if also frequency is detected from more long range. Yes, the absorptive pistol detect at more long distance the frequency injected in this type of soil. The signal is more disperse too. In common soils the absorptive pistol detect the injected frequency shortest.

But is not the same mineralized soil by iron, even if conductivity is better in this type of soil, because iron minerals mask detection.