microvolt receiver with antenna..

MisterBill2

Joined Jan 23, 2018
6,329
I still have not seen the answer to the question of whether there are large patches of ground with voltages above or below that or the rest of the earth.

Often DC voltages are remotely sensed by capacitive coupling. The thing to be measured can be considered to be one plate of a capacitor, which in your case is grounded (because it is in the ground) a second plate is set up, in this example, 50 meters away. A grounded chopper wheel, more commonly referred to as a field mill is placed between the voltage to be measured and the remote sensing plate. The filed mill serves to modulate the DC electric field so it can be observed by capacitive coupling.

A back-of the envelope calculation was made. If using a 1 square meter sensor with a rotating grounded disk that has a 1 square meter opening that will allow either the entire 1 square meter to be exposed or when rotated another 180° shields the entire 1 square meter plate, with the field mill rotating at 100 revolutions per minute, looking at a large area 10 microvolt charge 50 meters away will present almost square wave with an amplitude of about 350 E-18 amps (350 atto amps). That is not much current.

Although sophisticated processing techniques such as lock-in amplification are available, it is unlikely that the 350 atto amp signal can be successfully amplified to the point that it can be measured, or even detected.

Another problem is that if the sensor plate moves with respect to the ambient electric field it will throw off the reading. I remember walking one night in an open filed with an AC electric field meter with the sensor plate pointed skyward and seeing hundreds of volts RMS being displayed just by the meter's motion through the ambient electric field.

If you take this issue to CERN you might find hope, but this kind of sensitivity in a home-made instrument would be very difficult it even possible.
The system described does not seem to be something that would be portable at all. Yes, theory says that it would work, but it would certainly not be easy to build or to use. My guess is that the Russian military system used a different arrangement, probably quite a bit more costly.
 

Thread Starter

styven

Joined Jun 1, 2016
36
This thread makes me think of a company that can do something with very high currents and correspondingly small measuring voltages almost simultaneously: SkyTEM
yes i know that company
But i see here going difficult to have i dea how we make reciever antenna for negative ions...
 

DickCappels

Joined Aug 21, 2008
6,459
Here is one way to make such an antenna. The sensitivity is directly proportional to the area of the pickup plate exposed by the aperture. It uses a spinning disk driven by a motor.

http://www.instructables.com/id/Adruino-Based-Electrostatic-Field-Mill/

Google the term electric field mill to see other examples.
http://lmgtfy.com/?q=electric+field+mill

The output of a field mill is AC so you will need a detector to convert the signal to DC. I recommend a lock-in amplifier to obtain the maximum sensitivity and to reject ambient electrical noise.

https://www.zhinst.com/applications/principles-of-lock-in-detection?gclid=EAIaIQobChMIibvWs4W92wIV0yMrCh1T0g6_EAAYASABEgJemfD_BwE
 
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Thread Starter

styven

Joined Jun 1, 2016
36
Here is one way to make such an antenna. The sensitivity is directly proportional to the area of the pickup plate exposed by the aperture. It uses a spinning disk driven by a motor.

http://www.instructables.com/id/Adruino-Based-Electrostatic-Field-Mill/

Google the term field mill to see other examples.

The output of a field mill is AC so you will need a detector to convert the signal to DC. I recommend a lock-in amplifier to obtain the maximum sensitivity and to reject ambient electrical noise.

https://www.zhinst.com/applications/principles-of-lock-in-detection?gclid=EAIaIQobChMIibvWs4W92wIV0yMrCh1T0g6_EAAYASABEgJemfD_BwE
Very interestink all this you saw to us..
thank you..
 
Bob I explained to you again I want to locate any metal in the ground, if that is gold, or steal, or coper, or silver, or alouminium, I do not mind the depth, every metal at some moments of the day emit negative ions of the microvolt class, I will detect these microvolts at a distance of 60-80-100 meters, can i?..i want one antenna dipol, and i will scanned the area, somethink that in pic i send in forum..and also you saw the microvoltmeter in pic too...
thank you styven
Styven, I've been reading through this post and I have to tell you I am very impressed by the patience of the persons replying to you. I know you feel that you have explained what you are trying to do but the fact is we really don't quite get what you are trying to do. Repeating yourself is obviously not working so perhaps if you could find other ways to describe what you are trying to do we might find a description that makes sense to the rest of us.

From what I've read what it sounds like to me is this: you are trying to detect metal up to 100m underground by detecting metal ions above ground, and you may or may not be using an excitation coil of some form and measuring the electric field in the vicinity of the coil to detect these ions.

I don't know if I have that at all correct, but if I assume I might be close then I have the following to offer:
1. Metal ions would require (I think) a metal salt to be dissolved (probably in water) to realise the ions but they are not free ions so I doubt a passive detector would work
2. The metal ions will not float up through the air, even if there is an electric or magnetic field unless they were really really powerful fields I suppose
3. Normal metal detector type detection of a metal at a depth of 100m would require, I think, huge coils and seriously sensitive detectors, neither thing is practical without military grade funding

I have probably totally misunderstood the problem but maybe the above and any response it might get from the OP in combination with the replies of others will help us close in on whatever the problem actually is. Over to you Styven. :)
 

Thread Starter

styven

Joined Jun 1, 2016
36
Styven, I've been reading through this post and I have to tell you I am very impressed by the patience of the persons replying to you. I know you feel that you have explained what you are trying to do but the fact is we really don't quite get what you are trying to do. Repeating yourself is obviously not working so perhaps if you could find other ways to describe what you are trying to do we might find a description that makes sense to the rest of us.

From what I've read what it sounds like to me is this: you are trying to detect metal up to 100m underground by detecting metal ions above ground, and you may or may not be using an excitation coil of some form and measuring the electric field in the vicinity of the coil to detect these ions.

I don't know if I have that at all correct, but if I assume I might be close then I have the following to offer:
1. Metal ions would require (I think) a metal salt to be dissolved (probably in water) to realise the ions but they are not free ions so I doubt a passive detector would work
2. The metal ions will not float up through the air, even if there is an electric or magnetic field unless they were really really powerful fields I suppose
3. Normal metal detector type detection of a metal at a depth of 100m would require, I think, huge coils and seriously sensitive detectors, neither thing is practical without military grade funding

I have probably totally misunderstood the problem but maybe the above and any response it might get from the OP in combination with the replies of others will help us close in on whatever the problem actually is. Over to you Styven. :)
Good evening ser)thnxs for your ittention, i know it is difficult to build that, that the reason ask for some idea, but honestly i saw that to work in russia, and work very good in scale for all metals, but that machine come from army and they build that with them tehnology, and they do not give to me any info about it))..i will try here in my country with some engineer to give me some ideas
but any way would love to say all of you thank you..and i keep tuch for sure with forum, beacuse people in forum are very polite and serious,,also last year too some one give me very good ideas to make one simelar machine.-))
Styven
 
Here is one way to make such an antenna. The sensitivity is directly proportional to the area of the pickup plate exposed by the aperture. It uses a spinning disk driven by a motor.

http://www.instructables.com/id/Adruino-Based-Electrostatic-Field-Mill/

Google the term electric field mill to see other examples.
http://lmgtfy.com/?q=electric+field+mill

The output of a field mill is AC so you will need a detector to convert the signal to DC. I recommend a lock-in amplifier to obtain the maximum sensitivity and to reject ambient electrical noise.

https://www.zhinst.com/applications/principles-of-lock-in-detection?gclid=EAIaIQobChMIibvWs4W92wIV0yMrCh1T0g6_EAAYASABEgJemfD_BwE
I've had a look through the instructables article because I was curious as to why the output would be AC. The instructable is quite clever and inventive but didn't make sense to me because the electric field would have very small impact on the reading relative to the current injection of the ADC sample and hold and there is no reason that I can see for the aperture to be rotating as it is. A Wiki article on these things clears up the misinformation in the instructable and explains why the output would be AC as well. Also explained is the fact that these are used to detect the fields associated with lightning which is most definitely not an E field measured in microvolts even over very short distances. We would have to be talking about 100's of volts per metre as a minimum and any measuring system of this nature would also have to take into account the teraohms source impedance and the femtofarads of sensor capacitance are not compatible with an ADC sample and hold without a buffer (at least) in between.

I suspect that many a homebrew field mill is detecting ambient RF and ADC artifacts more than anything else. If the input stage started with a good instrumentation amplifier and the mill had the requisite dual detector plates the results might be a lot more interesting. :)
 
Good evening ser)thnxs for your ittention, i know it is difficult to build that, that the reason ask for some idea, but honestly i saw that to work in russia, and work very good in scale for all metals, but that machine come from army and they build that with them tehnology, and they do not give to me any info about it))..i will try here in my country with some engineer to give me some ideas
but any way would love to say all of you thank you..and i keep tuch for sure with forum, beacuse people in forum are very polite and serious,,also last year too some one give me very good ideas to make one simelar machine.-))
Styven
What are the chances that the thing you saw in Russia was not working the way you think it was working? Or maybe it was not doing what you think it was doing? It's the metal ions thing, I can't work out what that is all about, it doesn't make any sense to me.
 

MisterBill2

Joined Jan 23, 2018
6,329
What are the chances that the thing you saw in Russia was not working the way you think it was working? Or maybe it was not doing what you think it was doing? It's the metal ions thing, I can't work out what that is all about, it doesn't make any sense to me.
Not only does the Russian military organization have really huge resources and a whole bunch of brilliant scientists and engineers, they also have a penchant for not disclosing how their secret stuff actually works. An explanation that a system was "detecting metal ions" tells me that it had nothing at all to do with ions of any kind. A Russian Military officer ordered to keep things secret is not going to say anything that may actually relate to what he is commenting about.
In addition, it takes a fair amount of energy to dislodge ions from metals, and so far there has been no mention of any energy supplied except in my post about metal detectors. Of course, I am aware that there has been considerable research on ground penetrating radar systems, and such systems would certainly require a fair amount of energy to get much of a return through the earth.
 

DickCappels

Joined Aug 21, 2008
6,459
A quick search of Google Patents should turn up some patents covering field mills and associated circuits and techniques.

With respect to sensitivity, FM receivers can work acceptably down below 100 uV/meter. More sophisticated processing techniques can improve on that.
 
Not only does the Russian military organization have really huge resources and a whole bunch of brilliant scientists and engineers, they also have a penchant for not disclosing how their secret stuff actually works. An explanation that a system was "detecting metal ions" tells me that it had nothing at all to do with ions of any kind. A Russian Military officer ordered to keep things secret is not going to say anything that may actually relate to what he is commenting about.
In addition, it takes a fair amount of energy to dislodge ions from metals, and so far there has been no mention of any energy supplied except in my post about metal detectors. Of course, I am aware that there has been considerable research on ground penetrating radar systems, and such systems would certainly require a fair amount of energy to get much of a return through the earth.
We are very much on the same page. I don't know if either of us actually understands what the OP has in mind but our interpretations and conclusions are of a kind. I'd like to know if we understood him correctly though. It also occured to me that what he was told wasn't intended to hide the actual technology but maybe support a myth that the thing even exists. Smoke and mirrors and all that.
 
A quick search of Google Patents should turn up some patents covering field mills and associated circuits and techniques.

With respect to sensitivity, FM receivers can work acceptably down below 100 uV/meter. More sophisticated processing techniques can improve on that.
100uV/m is actually a pretty good signal strength for an FM receiver. If the frequency band is limited as it is with an FM receiver then this may be feasible, but wide band the input stage is likely to be overloaded just with ambient signals. I have the impression the OP has wide band in mind, but how wide band I do not know. I'm also not sure how you would couple an FM receiver to the differential output of a field mill in a wide band kind of way (which precludes a balun I think).
 

DickCappels

Joined Aug 21, 2008
6,459
The 100 uV/m comment was in regard to the hundreds of volts per meter comment by you in post #27.

In 1992 I was taking field strength measurements like the one below. Units are volts per meter in the VLF band, measured 50 cm from unit under test. It looks like the smaller field was about 250 mv/meter, well below hundreds (those occurred too).
upload_2018-6-7_16-0-57.png
 

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Danko

Joined Nov 22, 2017
938
Buy portable mass spectrometer. It is exactly what you are trying to find.
Edit: Military grade handheld mass spectrometer (PDF)
For example, one more:
Portability™ Transportable Mass Spectrometer
Overview
The PortabilityTM mass spectrometer is one of BaySpec’s newest portable instruments. Designed to bring the benefits of MS chemical analysis to the field, the PortabilityTM can service a variety of bulk or trace detection applications with its compact form factor and intuitive user software. Small enoughto be carried by one person, the PortabilityTM is compatible with in-situ and direct analysis techniques.
Key Features
  • ppb-level detection
  • Person portable with battery power
  • Linear Ion Trap Technology
  • 17 lbs., 13 in × 11 in × 9 in
 
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MisterBill2

Joined Jan 23, 2018
6,329
A portable, or non-portable, mass spectrometer is typically used to detect residual vapors from materials. Usually the vapors are not in the form of charged ions. Mostly the vapors are from organic (carbon based) compounds, seldom including metallic elements. The vapor pressure of most metals is low enough that they would not be detectable at any reasonable temperature. Mercury may be an exception, I am not sure.
 

Thread Starter

styven

Joined Jun 1, 2016
36
@styven: Honestly, you do not need any ions, microvoltmeters and so...
You trying to find metals, right?
Concentration of metal in soil is quadrillions times more than it can be in air.
Simple take soil sample and put it to mass spectrometer.
If you do not want to own mass spec, send samples to laboratory, as geologists usually do.
Detecting Trace Metals Using Inductively-Coupled Plasma-Mass Spectrometry (ICP-MS)
All this it is very good info and ideas for me-))
im very happy to read all this and thank you for your ittention..
but i was I've published to build antenna for that microvoltmeter i saw in pic, i think miss understand
my writing..i need antenna, build from feritte or I remember when I saw this coil consisted of a cable that contained 13 very fine wires inside somethink like that in pic.But 13 like that..
 

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MisterBill2

Joined Jan 23, 2018
6,329
For an antenna composed of litz wire, as you described, wound on a ferrite core of some variety, you first need to decide what frequency you want to receive. Then you need to decide how frequency selective you want the antenna to be. Then you can determine the physical dimensions that you want, and acquire an appropriate piece of core material. Cover the core with an insulating material such as kraft paper, tape the paper form in place, and wind on the wireuntil you have a reasonable number of turns for the frequency that you picked. The remaining steps are to connect a suitable capacitor to resonate the antenna at the chosen frequency, and to add a connection for your microvoltmeter. None of it is hard, although much of the process is tedious. That antenna will allow you to receive signals at the selected frequency.
 

Thread Starter

styven

Joined Jun 1, 2016
36
For an antenna composed of litz wire, as you described, wound on a ferrite core of some variety, you first need to decide what frequency you want to receive. Then you need to decide how frequency selective you want the antenna to be. Then you can determine the physical dimensions that you want, and acquire an appropriate piece of core material. Cover the core with an insulating material such as kraft paper, tape the paper form in place, and wind on the wireuntil you have a reasonable number of turns for the frequency that you picked. The remaining steps are to connect a suitable capacitor to resonate the antenna at the chosen frequency, and to add a connection for your microvoltmeter. None of it is hard, although much of the process is tedious. That antenna will allow you to receive signals at the selected frequency.
Thank you -)
so, did not have a ferrite, I will explain to you, the cable was in a circular aluminum and did not have one frequency, had a range of frequencies from 1 HZ to 3 MHZ, and I think it had a signal amplifier and a circuit that changed the frequencies, somethink like that in foto.
and a circle diameter of 22 cm..that it, but the question is, how many times I will wrap the cable.?
 

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MisterBill2

Joined Jan 23, 2018
6,329
The frequency ratio for such a wide band of frequencies is large, while the capacitance ratio for most variable capacitors in real circuits is much smaller. So if you want a resonant antenna, which provides greater sensitivity, a switching arrangement would be required. But most such antennas only have one turn of wire, centered inside the shielding tube by means of beads of a suitable diameter to slide freely while still holding the wire centered. This is done to reduce the capacitance to the tube, which would reduce the tuning range as well as the sensitivity. For a detailed circuit of such antennas visit the "schematics for free" website, which has all kinds of circuits including a number of amplified loop antennas.
I don't provide a link, you will need to visit the site and use the directory tree to locate the circuit drawing. That does require a bit of focus and a minute or two of clicking, but the site is interesting enough that the search can be fun.
 
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