Nexus Coil Design

[Qiaozhi]

Hi Qiaozhi,

Has any testing been done with the Nexus in difficult hot soil like found in the Australian gold fields? I am curious to know about the discriminating abilities in the iron rocks that make it nearly impossible for most PI detectors to find the deep gold nuggets there. Currently, Minelabs makes the only PI detector that gives much success in these fields. But I was wondering if the Nexus can perform there as well as these PI detectors in the iron soil found in Australia.

Best wishes,
J_P

I'll ask Georgi and get back to you.

[Unregistered]

LRL

so does esteban have someting to do with Nexus is it LRL is qiaozha and esteban really grogi

[Unregistered]

repairs

if grogi go to africa and sean goes to north pole can esteban fix nexus and chinese detectors

[Qiaozhi]

so does esteban have someting to do with Nexus is it LRL is qiaozha and esteban really grogi

Who is grogi and qiaozha? Never heard of either of these names.
Or is that how you're feeling - Groggy?

[Unregistered]

Hi ivconic,I have heard some possible explanation with roots from the "halo effect".

This "halo effect" is said to be dis-proven by tests, but there are many people all over the world who still insist they have experienced what you described. According to the halo theory, long-time buried coins will develop a halo which make the signal stronger than coins in the air, and stronger than coins that were buried recently. When you dig a long-time buried coin, then you remove it from the soil with the halo condition, so it no longer can be detected from as many cm in the air. Testing has shown that iron objects can develop a halo from partially oxidized outer layers migrating into the soil. This will give a stronger reading until the iron object is removed from the ground, where the signal strength becomes less. But testing with non-ferrous coins showed there is no halo effect. However, there are people who still insist they observe this halo effect for non-ferrous coins that are very ancient, just as you described.

Now here is a test you can perform to determine if this "halo effect" is causing the deeper reading in the ground for you: The next time you dig a long-time buried coin, then you find the air test shows less cm detection, you can dig a new hole and bury it to the same depth as it was when you found it. Try to disturb the natural soil as little as possible, and then look at what depth you can detect it from in the new hole. This new hole should be close to the hole you dug the coin, but not the same hole, because the original hole may be halo-causing components that will invalidate the test.

If the new hole shows less detection distance than the original hole, then it would appear you had a halo in the original hole that increased the strength of signal. Also, compare the signal strength in the new hole to the air test distance. I know of no science that would support the halo theory, but I hear so many people talk about it, I think maybe it is worth the time to test to see if it is true. You may find Gorgi was correct for air test, except for the halo effect.

Best wishes,
J_P

At last someone with good common sense.
Only iron can cause halo effect, non ferrous metals can not. The reasons;
Iron is a metal causing negative phase shift in the RX of any metal detector. The soil is also causing negative phase shift. The average phase shift of the soil minerals is from -0.5 to -10 degrees. The phase shift from iron nail for example would be around -30 degrees.
If the iron get dissolved to some degree (oxides, diffusion etc.) in the soil that process will result in decrease of the negative phase shift caused by the surrounding ground minerals. For example the phase movement will change from -0.5 to -1.5 degrees. The result would be stronger ferrous signal. If the ground balance of the detector was initially adjusted for -0.5 degrees the momentary decrease to -1.5 degrees (around the nail) will appear as ferrous signal, combined with the signal from the iron nail.
The main reason for this result is the increased conductivity of the soil around the iron nail.
However it is a scientific fact that soil with higher conductivity will cause stronger negative phase shift in the RX, regardless if the main agent causing that is of ferrous or non ferrous origin.
For this reason as far as non ferrous content (coins) is concern halo effect is not possible and can not be validated by any practical experiment what so ever.
If some amount of non ferrous metal oxide powder is mixed with the soil and left for some time that will result in stronger negative phase shifts in the RX.
In this case the so called halo effect will actually decrease the detection depth for non ferrous targets. As it is well known that in highly conductive soil conditions the detection depth is poor for all metal detectors.
There is also another fact against the halo effect theory regarding non ferrous objects.
The patina of all coins is not electrically conductive. Therefore any oxides formed around a coin under the ground will be also non conductive as they (the oxides) will originate from the coin alloy. Non conductive materials can not contribute to any detectable signals for they will not accommodate the occurrence of Eddy currents. Without Eddy currents they can be no metal detecting at all.
Small test can proof this theory easily. For this test you will need a coin with good patina. Use Ohm meter and try to measure the electrical conductivity between two opposite sides of the coin without damaging the surface of the coin patina. The result will be very high Ohm value resistance, which is certain proof that hallo effect can occur around this coin.
This also is the very reason for the great difficulty of detecting hoard of coins deep. The coins are been isolated in between by the oxides on their surface and as a result they can not be detected as a big lump of metal.


Ah, I forgot. To my knowledge there are 80000 or so claims for alien encounters in the US alone, but no proof. That publicity seem hollow as the halo (hollow) effect, nice and exiting, but hollow.

[CrazymanBrad]

a wise man once said....

"Think twice before you once speak"

So maybe we should adapt that to:

"proof-read twice before once posting"

CMB

[ivconic]

...

"If you use a particular coin for an air test and then bury the same coin in the ground,
all detectors will detect this coin further away in the air test. I don't think there is
any dispute that this is a fact."
Huh...Yes Quiaozhi! I agree! Now when i think again; i missunderstood the point! If you
put back "fresh" coin to soil and cover with it, of course detection would be weak, much
worse than in the air! I absolute agree!
I was thinking on undisturbed soil and long time buried coin.....

"..I wonder how much of this is caused by compacted soil rather than disturbed soil.
Has anyone ever tested whether there is a difference?"
I tested it many times...Oposite stories from compacted and disturbed soils...

"In fact we are in total agreement"
Heh,heh,heh!
Yes, after reading again, i can see what you ment! I agree now! It was missunderstood.

"If you also made this OO coil fully resonant, there would be an even greater improvement."
Now,there i made mistake! I tried to avoid fully resonant OO coils!? This gives me idea
to make another for TGS and see changes. I'll do that for sure, in next few days...
If i gain even better results....than i own you!

"For me the best detector is the detector that has everyone of us...
Geo is right and I add: The best is the detector used properly. I see persons with excellent MD, and I gain them with my homemade. EVER!!! Experience, come here!!! "

Absolute truth! Minelab Musketeer is not best detector i saw, but best finds i had with it,
cose i was pretty used on it. Other hand, Sovereign is much better but i had a lot of trouble
to make it work, at the time...not used at all on its "phylosophy"...!
My friend has DFX which is also very good, but he still dont know how to use it properly so
i always collect more items with my hand made than he with DFX!
"Well Max, you must a master coil constructor.
Exactly 51 minutes after I posted that information you managed to read my post, dash to the workbench, construct a 4" OO coil, go out in the field to do some testing, then return to post your own reply about the superiority of your new coil. Bloody amazing..."

Hah,hah,hah,hah!!! Oh guys! This forum is nice place to be!
Max,Quiaozhi...i appreciate both of you much!
Best regards!

[Qiaozhi]

At last someone with good common sense.
Only iron can cause halo effect, non ferrous metals can not. The reasons;
Iron is a metal causing negative phase shift in the RX of any metal detector. The soil is also causing negative phase shift. The average phase shift of the soil minerals is from -0.5 to -10 degrees. The phase shift from iron nail for example would be around -30 degrees.
If the iron get dissolved to some degree (oxides, diffusion etc.) in the soil that process will result in decrease of the negative phase shift caused by the surrounding ground minerals. For example the phase movement will change from -0.5 to -1.5 degrees. The result would be stronger ferrous signal. If the ground balance of the detector was initially adjusted for -0.5 degrees the momentary decrease to -1.5 degrees (around the nail) will appear as ferrous signal, combined with the signal from the iron nail.
The main reason for this result is the increased conductivity of the soil around the iron nail.
However it is a scientific fact that soil with higher conductivity will cause stronger negative phase shift in the RX, regardless if the main agent causing that is of ferrous or non ferrous origin.
For this reason as far as non ferrous content (coins) is concern halo effect is not possible and can not be validated by any practical experiment what so ever.
If some amount of non ferrous metal oxide powder is mixed with the soil and left for some time that will result in stronger negative phase shifts in the RX.
In this case the so called halo effect will actually decrease the detection depth for non ferrous targets. As it is well known that in highly conductive soil conditions the detection depth is poor for all metal detectors.
There is also another fact against the halo effect theory regarding non ferrous objects.
The patina of all coins is not electrically conductive. Therefore any oxides formed around a coin under the ground will be also non conductive as they (the oxides) will originate from the coin alloy. Non conductive materials can not contribute to any detectable signals for they will not accommodate the occurrence of Eddy currents. Without Eddy currents they can be no metal detecting at all.
Small test can proof this theory easily. For this test you will need a coin with good patina. Use Ohm meter and try to measure the electrical conductivity between two opposite sides of the coin without damaging the surface of the coin patina. The result will be very high Ohm value resistance, which is certain proof that hallo effect can occur around this coin.
This also is the very reason for the great difficulty of detecting hoard of coins deep. The coins are been isolated in between by the oxides on their surface and as a result they can not be detected as a big lump of metal.


Ah, I forgot. To my knowledge there are 80000 or so claims for alien encounters in the US alone, but no proof. That publicity seem hollow as the halo (hollow) effect, nice and exiting, but hollow.

Very good explanation.
Why don't you register? It sounds like you would be a useful new member to this forum.
Logically everything you've said makes perfect sense. But it doesn't explain the many cases we've nearly all experienced where a coin (for example) has been recovered from a deeper than expected depth. A few years ago I detected a weak signal while using an inexpensive detector and was amazed to find a 1797 George III copper coin buried at a depth of 11". This was definitely out of the range of this unit. I am 100% certain that the coin did not fall into the hole from the side, and there have been other occassions as well where this halo effect appears to have been real. Personally I do not have an explanation.

The result will be very high Ohm value resistance, which is certain proof that hallo effect can occur around this coin.

I assume you meant to say "...that the halo effect cannot occur around this coin."

[Qiaozhi]

Now,there i made mistake! I tried to avoid fully resonant OO coils!? This gives me idea [/FONT]to make another for TGS and see changes. I'll do that for sure, in next few days...
If i gain even better results....than i own you!

Very good. I would interested to know the results.

[Sean_Goddard]

I agree, whoever that is knows his theory I reckon. I note Dave Johnson used to post here a LONG time ago, also ome guy who was designing a digital MD posted LOADS of very competent theory, then disapeared, as has Dave Emery of late, even his email address is dead.

D.E. WHERE ARE YOU???????

Halo effect, Erm I know what you mean but I have come across the same thing. I suppose it's like dowsing, science cant explain WHY it works, because it shouldn't, but it does, I've seen it in action too many times.

[Qiaozhi]

I agree, whoever that is knows his theory I reckon. I note Dave Johnson used to post here a LONG time ago, also ome guy who was designing a digital MD posted LOADS of very competent theory, then disapeared, as has Dave Emery of late, even his email address is dead.

D.E. WHERE ARE YOU???????

Halo effect, Erm I know what you mean but I have come across the same thing. I suppose it's like dowsing, science cant explain WHY it works, because it shouldn't, but it does, I've seen it in action too many times.

Actually Sean, science can explain dowsing. It's a result of the ideomotor effect. No dowser can pass a double-blind test, and therefore dowsing doesn't work.
Did you see the Richard Dawkins' program last week? Some of the dowsers that were tested couldn't believe they'd been unable to pass the test. One woman said she'd been dowsing for 30 years and was shocked! Nearly all the others were in denial and came up with some interesting excuses.

[ivconic]

George Payne is original....


It would be good to register here before posting some posts "Unregistered" !
There are just few descent people posted under "unregistered"...the rest are jokers!
So if you have something smart to say (it seems that you have for real) than please
register under some nick and join us!
Unregistered who posted this:
"At last someone with good common sense.
Only iron can cause halo effect, non ferrous metals can not. The reasons;
Iron is a metal causing negative phase shift in the RX of any metal detector. The soil is also causing negative phase shift. The average phase shift of the soil minerals is from -0.5 to -10 degrees. The phase shift from iron nail for example would be around -30 degrees..............."

Yes, this is absolute truth! I agree!
Just read my claims again:
" Otherwise, i dont know how to explain so much
simillar situations when i dug item (coin) from 20cm depth, and minute after i cant
detect same coin at 17cm in the air!? How do you explaining this!?
Only explanation is ; i am liar!? Am i? Yet this is unknown phenomena for me.
I noticed it few years ago. Was interested much about it an especially payed attention
on it. So many times i performed simillar checks to establish some rules or discover
what is all about - but without success!
BUT IT IS FACT WHICH NOBODY (NO NEXUS EXPERTS OR ANYBODY ELSE) CAN DENY! YES,VERY OLD
ITEM, SO LONG AGO BURIED IN THE GROUND WILL BE DETECTED DEEPER THAN IN THE AIR!
DIFFERENCES FROM ONE TO ANOTHER DETECTION DISTANCE WOULD BE PROPORTIONAL TO SIZE AND
MASS OF ITEM - LARGER THE ITEM, BIGGER THE DIFERENCE BETWEEN DETECTION DISTANCES AND
VICE VERSA."

As you see; i never said "halo" ! I never used that word! Also i stated "dont have clue"!
But whole story is true. Not only iron items but coins also are detected deeper in
undisturbed soil than in air later...
Not only one case in my life; but rule! Almost always! I dont know what type of coins you
can detect with your detectors, but i am mostly visiting roman locations from I-V century.
Coins i am prospecting are dated exact from I to V century...Bronze,silver and gold coins.
So to check my claims again you have to visit simillar location and locate some old roman
coin....Dont know, maybe there is difference between my coins and your???
I'll repeat again; dont have clue is it "halo", "hello" or any other "h..." effect!?
I just noticed that phenomena so many times in so many different cases...it became a sort
of rule.
After 20 years of me as prospector, you can not have doubts in my abillity to distinguish
about founds,depth...etc....or can you?
I think i have experience even more, cose i spend arround 200 days per year outdoor, on the
field, holding some detector in my hand...
I am not commited,engaged at any company, dont have ordinary work. I am free as a bird, dont
have usuall obligations. So i can allow myself to spend most of my time outdoor - prospecting.
The rest of time i am spending in my workshop - making and servicing detectors...That is my
life in last 10 years...
Unregistered how many days of this year you spent outdoor - prospecting? Hah,hah,hah!
Reading you very conversant explanations i have picture of George Payne in my mind!
The great George Payne , my teacher and my guru! Are you sure that last post is yours?
Regards!

[Unregistered]

Very good explanation.
Why don't you register? It sounds like you would be a useful new member to this forum.
Logically everything you've said makes perfect sense. But it doesn't explain the many cases we've nearly all experienced where a coin (for example) has been recovered from a deeper than expected depth. A few years ago I detected a weak signal while using an inexpensive detector and was amazed to find a 1797 George III copper coin buried at a depth of 11". This was definitely out of the range of this unit. I am 100% certain that the coin did not fall into the hole from the side, and there have been other occassions as well where this halo effect appears to have been real. Personally I do not have an explanation.


I assume you meant to say "...that the halo effect cannot occur around this coin."

Correct. Halo effect can occur around any non ferrous object.
There is one way only to measure the exact distance to "out of range" signals. It is by brushing out the soil above the signal inch by inch until is recovered in its original position.
There is another explanation.
Many detectors are picking up signals from air gaps in the soil or small areas with different chemical content, result of contamination on the original soil background. If a non ferrous target happen to be in that kind of spot it will be the ground disturbance which combined with the non ferrous target would produce strong enough signal that would create illusion of halo effect.
Ones disturbed that soil will no longer have those properties. That is why after recovery no one can confirm the halo effect.
If the soil is been galvanised by the non ferrous target, when it is placed back in the hole with the target most of the signal should still be detectable, at least 85%, but it never happens that way.
The so called halo effect appears as a result of random ground mineral phenomenons in proximity to non ferrous targets, but not because coins were in the soil for so long before they were detected.

[Unregistered]

It would be good to register here before posting some posts "Unregistered" !
There are just few descent people posted under "unregistered"...the rest are jokers!
So if you have something smart to say (it seems that you have for real) than please
register under some nick and join us!
Unregistered who posted this:
"At last someone with good common sense.
Only iron can cause halo effect, non ferrous metals can not. The reasons;
Iron is a metal causing negative phase shift in the RX of any metal detector. The soil is also causing negative phase shift. The average phase shift of the soil minerals is from -0.5 to -10 degrees. The phase shift from iron nail for example would be around -30 degrees..............."

Yes, this is absolute truth! I agree!
Just read my claims again:
" Otherwise, i dont know how to explain so much
simillar situations when i dug item (coin) from 20cm depth, and minute after i cant
detect same coin at 17cm in the air!? How do you explaining this!?
Only explanation is ; i am liar!? Am i? Yet this is unknown phenomena for me.
I noticed it few years ago. Was interested much about it an especially payed attention
on it. So many times i performed simillar checks to establish some rules or discover
what is all about - but without success!
BUT IT IS FACT WHICH NOBODY (NO NEXUS EXPERTS OR ANYBODY ELSE) CAN DENY! YES,VERY OLD
ITEM, SO LONG AGO BURIED IN THE GROUND WILL BE DETECTED DEEPER THAN IN THE AIR!
DIFFERENCES FROM ONE TO ANOTHER DETECTION DISTANCE WOULD BE PROPORTIONAL TO SIZE AND
MASS OF ITEM - LARGER THE ITEM, BIGGER THE DIFERENCE BETWEEN DETECTION DISTANCES AND
VICE VERSA."

As you see; i never said "halo" ! I never used that word! Also i stated "dont have clue"!
But whole story is true. Not only iron items but coins also are detected deeper in
undisturbed soil than in air later...
Not only one case in my life; but rule! Almost always! I dont know what type of coins you
can detect with your detectors, but i am mostly visiting roman locations from I-V century.
Coins i am prospecting are dated exact from I to V century...Bronze,silver and gold coins.
So to check my claims again you have to visit simillar location and locate some old roman
coin....Dont know, maybe there is difference between my coins and your???
I'll repeat again; dont have clue is it "halo", "hello" or any other "h..." effect!?
I just noticed that phenomena so many times in so many different cases...it became a sort
of rule.
After 20 years of me as prospector, you can not have doubts in my abillity to distinguish
about founds,depth...etc....or can you?
I think i have experience even more, cose i spend arround 200 days per year outdoor, on the
field, holding some detector in my hand...
I am not commited,engaged at any company, dont have ordinary work. I am free as a bird, dont
have usuall obligations. So i can allow myself to spend most of my time outdoor - prospecting.
The rest of time i am spending in my workshop - making and servicing detectors...That is my
life in last 10 years...
Unregistered how many days of this year you spent outdoor - prospecting? Hah,hah,hah!
Reading you very conversant explanations i have picture of George Payne in my mind!
The great George Payne , my teacher and my guru! Are you sure that last post is yours?
Regards!

Build up in quantity would lead to improvement in quality, but not always to correct results.
Only hard science can give accurate answers, not personal inexplicable experience.

[ivconic]

Tend to agree...