Coils for LRL

[Funfinder]

I found essential info about the most important part of any short or long range MD - the coil!

Read this:
http://www.vlf.it/matteobruna/ULF_Induction-Coil.htm

On some other article of this page
http://www.vlf.it/minimal2/minimal2.html
i found this info:

Mechanical stabilization Let’s return to the practical problem. One of the worse troubles we find in using the minimal loop is the microphone effect: a loop millimetric mechanical oscillation produces a big interference, this is because the antenna works fitted in the terrestrial magnetic field. Since we can’t turn off the heart magnetic field, we need to make the loop perfectly stable.

and:

We can't place the receiving loop near metallic fences or other iron structures: their mechanical vibrations deform and modulate the earth magnetic field, producing the same microphone effects described before.

We should keep this in mind if we want to detect metal from far distances.


And if the Alonso PD really works at around 60kHz, the coil would need alot turns. And the thicker the copper wire the better, because of the electric resistance of the copper.

Here's the easyloop receiver:
http://www.vlf.it/easyloop/_easyloop.htm

Just we don't want to listen to VLF (very low) or ELF (extremly low) signals but need those low freqz. for better ground penetration.

The coil has to be unshielded for most gain and will detect the magnetical "interference" between earth and buried metal object (plus perhaps the electrostatic).

We should find out what coil has the best gain.

An usual air-core-coil or a ferrite-core-coil.
The directional effect should be the same, but instead of air the ferrite or other high permeabe material cored coil would be much smaller and light weighter.

1000-2000 turns around a 15cm ferrite should work. For making it more broadband and less "selective" scramble winding could be used.

For the beginning I guess also not very-low-noise op-amps will do it. Because we want to detect the change in electroMAGNETIC-field metal objects cause and not 1000km away radio-signals.

Perhaps also a VLF-transmitter should be used if the "background energy level" isn't strong enough.

btw. if the special magnetic coil really is very very sensitive and directional, it could detect even far metal only by "impedance changing effect".

In this case a very sensitive and stabilized oscillating coil would detect the magnetical losses or changes if some metal is "near". Using high voltage this circuit also would recognise if an electrode or cathode = the attracting metal object, is near. Depending on the humidity even buried ones.

Combining those both techniques including very selective and sensitive electrostatic plus eventually extra gradio- or magnetometer at least has to lead to some real working LRL device!


I'm just hoping I'll finding more and more such important info by for getting puzzle piece by puzzle piece the whole picture...

[J_Player]

Originally Posted by Funfinder

I found essential info about the most important part of any short or long range MD - the coil!

Read this:
http://www.vlf.it/matteobruna/ULF_Induction-Coil.htm

On some other article of this page
http://www.vlf.it/minimal2/minimal2.html
i found this info:

and:

We should keep this in mind if we want to detect metal from far distances.


And if the Alonso PD really works at around 60kHz, the coil would need alot turns. And the thicker the copper wire the better, because of the electric resistance of the copper.

Here's the easyloop receiver:
http://www.vlf.it/easyloop/_easyloop.htm

Just we don't want to listen to VLF (very low) or ELF (extremly low) signals but need those low freqz. for better ground penetration.

The coil has to be unshielded for most gain and will detect the magnetical "interference" between earth and buried metal object (plus perhaps the electrostatic).

We should find out what coil has the best gain.

An usual air-core-coil or a ferrite-core-coil.
The directional effect should be the same, but instead of air the ferrite or other high permeabe material cored coil would be much smaller and light weighter.

1000-2000 turns around a 15cm ferrite should work. For making it more broadband and less "selective" scramble winding could be used.

For the beginning I guess also not very-low-noise op-amps will do it. Because we want to detect the change in electroMAGNETIC-field metal objects cause and not 1000km away radio-signals.

Perhaps also a VLF-transmitter should be used if the "background energy level" isn't strong enough.

btw. if the special magnetic coil really is very very sensitive and directional, it could detect even far metal only by "impedance changing effect".

In this case a very sensitive and stabilized oscillating coil would detect the magnetical losses or changes if some metal is "near". Using high voltage this circuit also would recognise if an electrode or cathode = the attracting metal object, is near. Depending on the humidity even buried ones.

Combining those both techniques including very selective and sensitive electrostatic plus eventually extra gradio- or magnetometer at least has to lead to some real working LRL device!


I'm just hoping I'll finding more and more such important info by for getting puzzle piece by puzzle piece the whole picture...

This is an interesting post. I see a new approach to discovering the secret of long range detection that has not been advocated in this exact manner before.

We start out with the ultimate secret to long range locating of treasure with the essential information centered around the receiving coil. As we can see, the secrets are revealed in two website links posted by an Italian experimenter who tells us how to build VLF and ULF coil antennas that operate between 1 Hz and 22 KHz to listen to earth signals.
Cool! The secret to long range metal detection is hidden in this Italian experimenter's coil antennas for listening to earth signals between 1 and 22 KHz!
I never would have guessed it.
And all this time I was thinking Morgan had his antenna set to 60 KHz, while others set for 120 Khz for detecting metals long range.

But wait... The Italian experimenter did not say his antennas are good for locating metals at long distances. He said they are good for listening to strange earth signals from 1 to 22 KHz while ignoring a lot of noise signals. He never claimed his antennas or any of his experiments were capable of locating buried metal.

But not to worry... you have your back covered with high voltage electrodes and selective and sensitive electrostatic plus eventually extra gradio- or magnetometer, just in case the ultimate antenna doesn't work!

This raises an interesting question: How did this Italian ULF/VLF experimenter become the new solution to long range metal detection? I mean... how is it that methods to reduce noise while listening to strange ULF/VLF signals are the key to detecting specific buried metal objects (gold, for example)?
And it raises an even more important question: What exactly is the nature of the "treasure signal" that your proposed apparatus is intended to detect?

For example:
Do you intend to detect a spontaneous VLF signal that is emitted from a piece of buried metal?
Do you intend to detect a signal that is broadcast, then reflected from a piece of buried metal?
Do you intend to detect a change in a signal that is broadcast, then absorbed by a piece of buried metal?
Does magic play a major role in your methodology?

Do you have any clue what signal you are trying to detect?
I sure don't.

P.S. Here is an equally viable method for long range detection that was originally posted by Götz von Berlichingen :



Best wishes,
J_P

[Funfinder]

Stop your cruel, offending and cynical mockery against me because you are - like WM6 - already defeated, too!

Or do you like to tell us the Alonso PD is pure fake like all your other "non working LRLs"???

If so, prove it to us why it cannot work if you can!


OK, I have to admit at least your post was quite intelligent, funny and entertaining - especially that drawing - !

YEAH - this is "Hollywood" and reminds me of the 1 week ago seen movie of "Tenacious D - Kings Of Rock".
Fun or making fun out of whatever is what counts...


I'm feeling sorry with you J_Player that you are now already completly desillusionated and full of hate because of all those dirty, evil and cunning LRL-lies you've been going through so you need to find some "victims" for getting lost of your frustration but it's unfair disturbing my own researches and developments I have to do because most people here are not able giving out the really NEEDED information!

I'm shure the right magnetic coils are very important but even if the ELF or ULF should be the "wrong way" it's a worthful learning-experience because like alot others I have to find out that hole LRL-sh*t from scratch, from the beginning!


And if guys like you don't stop their unproductive and cynical comments no longer I'l tell any of my own discoveries!

In fact it's the same with WM6 who even can't understand that MDs like Jeohunter really work!
Some guys here must have been brain-washed!


If you are smart J_Player you should put your effort into proving that astrology really cannot work! This would be a much more useful task. Because the long range stars (same like those in Hollywood... ) are completly powerless if it comes to REAL life interaction!

Or even better - destroy the believe into gods/religions - which in reality only is deadly opium for the masses!


But don't disturb my/our scientific work and electronic-investigations!

[WM6]

Be calm Funfinder!
Don't destroy your Genius by uncontrolled anger.
This is Hollywood and you are only one LRL pistoleros in science fiction movie.

[J_Player]

Originally Posted by Funfinder

Stop your cruel, offending and cynical mockery against me because you are - like WM6 - already defeated, too!

Defeated? By whom? What defeat are you talking about? I have been watching attentively as you attempted several approaches at LRL projects which all seem to be abandoned as soon as you think up a new approach. Not a single of your LRL projects appears to be completed to a point that you can say they are working or have been determined not to work. Now you start a new project with the idea that a ferrite with many windings is needed as the Italian experimenter used in his ULF/VLF experiments. Yet there is no evidence or discussion which says this approach has any use in locating specific metals at long range. Does this mean I am defeated? I don't get it

It appears from my perspective that nobody has been defeated. From what I see all that has happened is you began another approach that I suspect you will abandon in the next few weeks because the basis for your approach was not well thought out, and not likely to work.

Originally Posted by Funfinder

Or do you like to tell us the Alonso PD is pure fake like all your other "non working LRLs"???

If so, prove it to us why it cannot work if you can!

I have said nothing about whether I think the Alonso PD is fake or not. What makes you think I would like to begin saying it is fake now?

And what are all these other "non working LRLs" you are claiming I have? I own no LRLs at all. Do you have a clue what you are talking about?

Originally Posted by Funfinder

I'm feeling sorry with you J_Player that you are now already completly desillusionated and full of hate because of all those dirty, evil and cunning LRL-lies you've been going through so you need to find some "victims" for getting lost of your frustration but it's unfair disturbing my own researches and developments I have to do because most people here are not able giving out the really NEEDED information!

Lies? Can you type out a reference to any lie I have posted in the Geotech forums? I would like to see where it is.

The fact is I am the only person that told the truth about the basic circuit approach that is found in the Alonso ferrite detector.
If you examine the circuitry, you will see it is as I told you it is.

Originally Posted by Funfinder

I'm shure the right magnetic coils are very important but even if the ELF or ULF should be the "wrong way" it's a worthful learning-experience because like alot others I have to find out that hole LRL-sh*t from scratch, from the beginning!


And if guys like you don't stop their unproductive and cynical comments no longer I'l tell any of my own discoveries!

Everyone I know who is interested in experimenting with a new LRL circuit has had to build from scratch. The people who are serious about actually building something usually start with a single idea and build circuitry to function according to that idea in a manner that makes some kind of sense, even if the underlying principle doesn't seem like it will work. They stick to their strategy and make modifications to their circuitry until they have the best they can produce to accomplish detection of a certain kind of signal that they defined beforehand. When their circuitry is completed, they test their apparatus, and determine how well it works to find the treasure they are looking for. They observe to see if it works well enough or not well enough, so they can decide whether they want to scrap their project, or keep it in their collection of treasure hunting tools. In cases where they scrap their project, they usually begin a new project that is designed to detect some different aspect of what they think is detectable from metals at long range.

I have observed this pattern from a number of LRL builders over the years. But I have never seen anyone start with an idea, then abandon it before it was finished and start successive projects which are all abandoned before completion, and still hope to end up with some apparatus they could test to see if it works or not.

If you go back and read what I actually posted instead of presuming what you are claiming about my post, you will see there are no lies. But I asked some specific questions that apparently you don't want to answer.
For example: What kind of signal are you trying to detect. From what I can see, you have not defined this signal, yet you are designing circuit methods to detect the undefined signal!

Originally Posted by Funfinder

But don't disturb my/our scientific work and electronic-investigations!

Scientific work? Are you disturbed by being asked about the details of the signal you are trying to detect?

Your approach in this new project does not seem to be scientific to me. But maybe I am wrong in my observations of what it seems to me you are doing. Assuming I am all wrong about the "scientific-ness" of your work, can you tell me the scientific explanation of the gold signal you are attempting to detect, and what method your circuitry will use to demodulate the part of the signal that identifies gold, or silver as the metal which is detected from long range?

For the record, I don't believe discussing the signal processing methods is counter-productive. I believe people all over the world are anxious to know more details about your technique for treasure signals and how to correctly extract it.

Best wishes,
J_P

[Mike(Mont)]

Just found this thread. I posted the same topic on another forum. I was planning to use an air core and 26-gauge magnet wire (not too difficult or thin to work with) to build a tuned loop antenna 2.5 feet square with 100 turns or about 1000 feet of wire. This way I can get by with one pound of wire a little wood and an old radio tuning capacitor. And it's not too difficult to build. Whether it will work or not to help detect an MFD signal line, don't know. I thought I could wear it like a backpack and have one more single loop of wire for an induction pick-up and maybe hook these wires to a set of L-rods or signal strength meter. This induction pick-up may not be needed.

What I do know is the tuned loop antenna is good at nulling out if you have it facing that direction. This might require you to move the transmitter to work around powerlines, etc.

I built a tuned loop antenna for the AM band range (seven loops of wire) and it really pulls in the stations, even with an old transistor 1960's radio. Of course newer radios probably don't need one.

I saw one of Carl's reports on a Raven LRL where there was a radio receiver and nothing much else. Anyway, I am going down a different path than the ferrite core antenna so it would be nice to compare notes. I still have to order parts so I'm a week away yet.

[J_Player]

Originally Posted by Mike(Mont)

Just found this thread. I posted the same topic on another forum. I was planning to use an air core and 26-gauge magnet wire (not too difficult or thin to work with) to build a tuned loop antenna 2.5 feet square with 100 turns or about 1000 feet of wire. This way I can get by with one pound of wire a little wood and an old radio tuning capacitor. And it's not too difficult to build. Whether it will work or not to help detect an MFD signal line, don't know. I thought I could wear it like a backpack and have one more single loop of wire for an induction pick-up and maybe hook these wires to a set of L-rods or signal strength meter. This induction pick-up may not be needed.

What I do know is the tuned loop antenna is good at nulling out if you have it facing that direction. This might require you to move the transmitter to work around powerlines, etc.

I built a tuned loop antenna for the AM band range (seven loops of wire) and it really pulls in the stations, even with an old transistor 1960's radio. Of course newer radios probably don't need one.

I saw one of Carl's reports on a Raven LRL where there was a radio receiver and nothing much else. Anyway, I am going down a different path than the ferrite core antenna so it would be nice to compare notes. I still have to order parts so I'm a week away yet.

This kind of air loop antenna has been shown on many amateur radio websites, and is said to be very good at tuning weak broadcast signals. It is often used in conjunction with an AM tuner to boost the signal the portable receiver finds. I have seen photos of a small portable receiver placed inside the loop in a location that produces a much stronger signal than the receiver can tune without the large loop in place. Of course there is an air capacitor that sets the frequency of the large loop, whether it is connected to the receiver or is used as a passive signal booster.

How well it works for long range metal detection, I don't know. But I do know it remotely resembles some coils Esteban uses in his experimental locators. The main difference is this loop is larger, and is probably designed to work for higher frequencies than Esteban uses in his coils. I would guess the larger size will provide an advantage in sensitivity, but may have some disadvantages related to pseudoscientific technical details.

Best wishes,
J_P

[Mike(Mont)]

I would like to find out more about the Raven LRL like where on the dial is it set for gold? Carl said he hooked up a speaker so he could probably get a good estimate of the frequency from a nearby radio station. If I went by the markings for GOLD on the case at 27.5 and assume this is a percentage on the dial range I could probably get in the general area, but I don't even know if it is from the top of the scale or from the bottom and for that matter even what scale they are using. The old ones went to 1620 and the new ones are 1700KHz.

I plan to use an MFD-type frequency generator, tune the antenna and walk through the signal line like with a set of L-rods just to see if I can feel anything. If I carry an AM radio it can at least help to point out areas of electrical interference, etc. and maybe even be able to work around it from the right direction. As it is now with a set of L-rods the user is basically working blind as far as interference is concerned. So maybe this set-up can help to "see" the area better.

I've heard of oldtimers using a crystal radio to locate mineral veins. I guess they could hear a popping noise in the headphones (piezoelectric activity?). So this is another option I will check out. BTW, be careful as this popping can damage your hearing. Another option is to hook up an amplifier with filters, etc.

Will any of this work? I really think it should help. As for the induction loop to a signal strength meter or even to the L-rods, maybe these do not even need to be connected, just close to the person's hands. I know I can feel some kind of capacitive change when I put my hands near the capacitor. It feels like a cool breeze, like a bumble bee.

[Mike(Mont)]

Just for fun I set up my frequency generator at 60KHz and held my AM tuned loop antenna (seven loops of wire on a 2 1/2 foot square frame) as I walked back and forth searching for the signal line and tuning the antenna on each pass. I ended up holding the antenna downwind and perpendicular from the transmitter. I tuned as best I could and did not see any improvement in signal strength but I did notice the coil felt like I was holding a shield (to block anything from downwind) so I only concentrate on the line back to the transmitter.

So then I thought about a parabolic shaped spiral wound antenna for the 60KHZ. One-hundred loops of wire would look like a giant spider web.

[J_Player]

Originally Posted by Mike(Mont)

I would like to find out more about the Raven LRL like where on the dial is it set for gold? Carl said he hooked up a speaker so he could probably get a good estimate of the frequency from a nearby radio station.

From what I read, nobody has located buried metal with the Raven. But with some simple modifications, it could probably be used to listen to AM broadcasts.

Originally Posted by Mike(Mont)

I've heard of oldtimers using a crystal radio to locate mineral veins. I guess they could hear a popping noise in the headphones (piezoelectric activity?). So this is another option I will check out. BTW, be careful as this popping can damage your hearing. Another option is to hook up an amplifier with filters, etc.

I have read these stories too. I read stories where they would hear weak signals become stronger when using an old-style AM radio. Are they true stories? Who knows? It only costs the price of an AM radio to find out. If you are using the kind of crystal radio that uses a crystal earphone, then there is no danger of ear damage. They can't produce a loud enough sound to damage your ears as far as I know.

Originally Posted by Mike(Mont)

Will any of this work? I really think it should help. As for the induction loop to a signal strength meter or even to the L-rods, maybe these do not even need to be connected, just close to the person's hands. I know I can feel some kind of capacitive change when I put my hands near the capacitor. It feels like a cool breeze, like a bumble bee.

I seriously doubt you will find any buried metal with this method. But you can have hours of fun trying. Let me know if it works. The next step is to visit Randi.

Best wishes,
J_P

[Mike(Mont)]

I built the loop in Figure 3:

http://users.tpg.com.au/users/ldbutler/Loop18MHz.htm


Here is some magnet wire:

http://www.elexp.com/cbl_mg30.htm


Here is a coil calculator:

http://brneurosci.org/loopfrequency.html

[Mike(Mont)]

Just a side note about feeling the cool breeze near the capacitor. I just recall reading that some people can tune a radio without the speaker connected. I thought the whole thing a bit weird but now I know it is possible to feel some kind of resonance.

[Qiaozhi]

Originally Posted by Mike(Mont)

Just a side note about feeling the cool breeze near the capacitor. I just recall reading that some people can tune a radio without the speaker connected. I thought the whole thing a bit weird but now I know it is possible to feel some kind of resonance.

Are you and Hung eating the same mushrooms?

[Mike(Mont)]

This article is not exactly about MFD, but there is some info that might be of benefit.

http://www.vlf.it/ed/earthprobes.html

The first thing that crossed my mind about the "cool breeze" feeling was the capacitor has ion charge. "Capacitance is ion seperation." Tuning a radio station without the speaker hooked up is not psychic, most people can feel ionic charge if they hold their hand near an ion generator. From what I have read this sensation is from tiny vortices of ions that are attracted to you. "Individual ions tend to drag surrounding air with them when they move."

[Mike(Mont)]

Here is a link for some ferrite antennas some are for ELF. Scroll down the right hand column to radio antennas. I still figure it is cheaper to go with the higher frequencies 62KHz.

http://www.stormwise.com

[goldfinder]

In the 1950s I had a friend who was always experimenting with alternative science projects. One of his was a dual coil device that he was shown by a friend of his that used to stop by and see him His friend was finding gold deposits using a dual antenna system plus a low frequency transmitter with probes stuck in the ground. The antennas were about 2 feet on a side. I'll try and draw and post below. Please don't ask me for details as what is in the diagram is all a remember.
Goldfinder

[Mike(Mont)]

Still waiting on the coil wire.

I placed an ion meter next to the AM tuned loop antenna I built and slowly turned the dial until the ion meter peaked, I had tuned the antenna to a strong nearby station.

[J_Player]

Originally Posted by Mike(Mont)

Still waiting on the coil wire.

I placed an ion meter next to the AM tuned loop antenna I built and slowly turned the dial until the ion meter peaked, I had tuned the antenna to a strong nearby station.

What's an ion meter?


Best wishes,
J_P

[Mike(Mont)]

Air Ion Counter. When I was young my father had a nice Hallicrafers receiver and I remember feeling that ion buzz when I'd get near the receiver. Certainly didn't know what it was then, just thought it was electricity.

BTW, the coil wire did arrive yesterday but got too much other stuff going on.

[Mike(Mont)]

www.trifield.com

[J_Player]

Originally Posted by Mike(Mont)

www.trifield.com

Hi Mike(Mont),
The only air ion meter I see on that page is the Alpha Lab Standard 2 million ions/cm3 version. This meter works by sucking an air sample in and measuring ions, then displaying the ion count in ions per cc of air (or other gas). The range selections are to 2 million, 20 million, and 200 million ions/cc. http://www.trifield.com/content/air-ion-counter/

We also see in the instructions it has a 20-foot ground cord to connect to earth ground before allowing the meter to stabilize for positive or negative ion reading of one of the three ion density scales. Then the fan is switched on in the sampling mode which draws an air sample in the top, and discharges it out the bottom during the measuring operation. http://www.trifield.com/content/AIC-Instructions/

This seems a bit more sophisticated than the home-built ion detectors I read about that are built around a high impedance amplifier connected to an antenna that is pointed in the direction of suspected ions.
I presume it also gives ion readings that are more accurate.

Two questions that come to mind are:
1. What readings did you see in ions/cc, from minimum to maximum when you found the peak while tuning your loop antenna?
2. Were the ions you measured positive or negative?

Best wishes,
J_P

[Mike(Mont)]

I certainly never claimed my results to be "scientific". I had the meter set on negative ions, don't even recall if I zeroed it first, don't think I did. Didn't ground it , either. Had the air intake close to the capacitor probably a couple inches max. There was definitely a time lag as I adjusted the cap. The readings were around 700 until it would spike over 1000 just a very narrow bandwidth. Ran the tuner back and forth several times just to be relatively certain it wasn't some fluke. I see they make antenna analyzers that can find the resonant frequency of the antenna, but I just used an AM radio to see where the antenna had been tuned. BTW, I could feel it when the antenna was tuned to that station.

[Theseus]

Originally Posted by Mike(Mont)

BTW, I could feel it when the antenna was tuned to that station.

[J_Player]

Originally Posted by Mike(Mont)

I certainly never claimed my results to be "scientific". I had the meter set on negative ions, don't even recall if I zeroed it first, don't think I did. Didn't ground it , either. Had the air intake close to the capacitor probably a couple inches max. There was definitely a time lag as I adjusted the cap. The readings were around 700 until it would spike over 1000 just a very narrow bandwidth. Ran the tuner back and forth several times just to be relatively certain it wasn't some fluke. I see they make antenna analyzers that can find the resonant frequency of the antenna, but I just used an AM radio to see where the antenna had been tuned. BTW, I could feel it when the antenna was tuned to that station.

Hi Mike(Mont),

Of course this was not a scientific test. For one, we have no idea of how the electronics inside this meter "counts" ions, or what it was calibrated to, or if it is still in calibration. And from what you posted, you did not have the meter grounded, and probably not zeroed. I wonder if a calibrated meter that was zeroed and grounded would find the same peak when you tune the coil. My guess is we would probably see a similar peak, but with different readings. (This is assuming the electronics in the meter you used actually counts ions, not simply detects electric fields).

Even though it is not a scientific test, the readings you took do provide some evidence of a change in the meter reading that seems to be repeatable when you tune the coil. This makes me wonder what is causing the change in readings, and it raises some interesting questions. According to the meter literature, this meter takes measurements in air that is drawn into the internal measuring circuit -- so it is not a simple static charge detector that can go haywire at the slightest movement of where it is held and pointed.


So what caused the air to give readings of negative ions?

Has the ion content of the air actually changed due to the coil being tuned to a resonant frequency?
Maybe an RF carrier wave at the tuned frequency has something to do with it?
Did the ungrounded meter respond differently than if it was grounded?
Could the internal meter circuit be effected by nearby receiver circuits, even if the ion content of the air does not change?

It would be interesting to see a circuit diagram of how this meter counts ions. This would give some insight into the answers to these questions. If we could establish that the ion content of the air actually does change around a tuned receiver coil, it may provide some evidence to support Esteban's theories of "ions in the air" that he says he detects with his experimental coils.

Best wishes,
J_P

[Mike(Mont)]

A capacitor is ion seperation. The way a tuned loop works is the energy is captured by the coil and a charge builds up on one side of the capacitor. Then since the other side of the cap has an imbalance the charge flows back through the coil to the other side of the capacitor and if it's tuned it will continue to resonate as the capacitor acts like a spring. I would think it shouldn't really matter which polarity of ions you are measuring because both are present.

The whole point of this discussion is that the human body can act like a tuned antenna. The body has some capacitance, and if you hold your arms out there is going to be a slight amount of energy that flows through the air from one hand to the other. So if you think of your hands as the vanes on a capacitor, the ions are right there. Comprende?