Nexus Coil Design

[Qiaozhi]

Forgot to mention, the reason the Nexus goes DEEP is the coils are VERY tightly balanced, unlike Tesoros which are miles out (around 1%) Nexus is around .05%.

Hi Sean,

Actually the most important point is that the Nexus coils are fully resonant.

[Max]

You have obviously never used a Nexus or seen one in real life. It's not the easiest detector to set up, so beginners beware, but it will beat the Bandido hands down - and that's with the tiny 4" coil!
There's also no point in saying "Could Nexus detect 1eur coin at 30+ cm underground with a DD 22cm diameter coil ?". This doesn't even make sense. The power of the Nexus is in the coil whether you agree or not.
Georgi has spent countless hours experimenting with different coil designs, and (although a bit querky) the OO design is the most sensitive. Why don't you try making one yourself? Ask Ivconic for his opinion.
That's also why the Nexus has that strange bent stem, as it helps to keep the coil parallel to the ground.
By the way, the depth comparison chart for the Nexus is for objects buried in the ground, and these are conservative measurements. They are not the result of an air test. Are your's?

Hi Qiaozhi,
"There's also no point in saying "Could Nexus detect 1eur coin at 30+ cm underground with a DD 22cm diameter coil ?". This doesn't even make sense."

For me have a lot of sense. Maybe not for you, but this is your opinion , that's fine.

What I've said means its circuit has no advantage respect e.g. BandidoII or GoldenSabre circuit on the depth sector.

When I read that the secret is in the coil... I can only say that the circuit is really like many other circuits that are flying around MD scenario from the 80's.
Isn't it an 80's design with just few mods ???
Isn't it like bulgarian detectors of last 70's and first 80's ???

It is also an old polemic here about its circuit design owner and so to who belongs... that I have no intention of reopening here.

I think that Georgi is a good designer anyway, don't misunderstud my words.

But circuit of Nexus is quite similar to those I've descibed above...
old bulgarian design...
well known design... old, working one of course, but NOTHING NEW.

Ask some bulgarian guy... he would tell you if you don't belive my words.

NO BIG IMPROVEMENTS. NO BIG NEWS. ALL ABOUT THE SAME.

Coil is the secret ??? Yes. Coil is the secret of its performances, I'm sure of that.

But I still think that my homemade BandidoII could beat it on soil, test garden, meeting same coil type and dimension condition.

Belive it or not, my unit do what I've said, and is just an homemade detector + an homemade coil... nothing special. And also an old Tesoro's design.
That say everything for me.

You can really compare units using same dimensions and type of coils.

Have sense comparing e.g. a Minelab unit with 11'' DD coil with a BandidoII with 8'' DD coil ?

Or also the same bandidoII unit with an OO coil and a round concentric coplanar coil ???

11'' and 8'' are not the same thing. OO and coplanar concentric aren't the same thing.

It's like a motogp-bike vs a 250cc-enduro on speed. This have no sense.
Or comparing PIs with VLFs or apple to oranges... like you said.

I think is a very good detector that Nexus... that it's worth buy one if e.g. a TH want really good depth and disc, OK. Also if it is for sure overprized.

But nobody claim here miracles. Nobody tell me there is some "new" technology behind... that multiply depth !

There are no miracles or black magic in MDs... just good designs (that are all about the same) and good coils make the difference.

Same coil type, same dimensions, same test garden.
That's the real test bench.
All the rest is advertising.

Kind regards,
Max

[JC1]

More Gain

Sheddy,

Forgot to mention, the reason the Nexus goes DEEP is the coils are VERY tightly balanced, unlike Tesoros which are miles out (around 1%) Nexus is around .05%.

Max has a point, If you fit a close balanced coil to ANY detector it will perform much better, thats why we experiment and make our own here, and THAT's why we are constantly learning and improving. Detector design is no black super art practiced by a few very clever people, it's a progression of what has gone before.

Garrett, first to put use DSP in a detector with the GTi series?? Nope, I sent them a design a long time ago before they did that, AND I have the documents to prove it, date stamped and signed by Nigel Ingram at Regton. I even coined the name GTi (Stands for Goddard Technical Industries) and called it the Digidec.

Yes and with the

coils well balanced

the Gain can be turned up

without saturating everything

with the Null signal which is never

zero.

Make it very low and keep it there <this is important

and you too can have a very very sensitive detector.

JC1

[Max]

Yes and with the

coils well balanced

the Gain can be turned up

without saturating everything

with the Null signal which is never

zero.

Make it very low and keep it there <this is important

and you too can have a very very sensitive detector.

JC1

Hi JC1,
yes I agree with you too. Smaller out-null voltage and you can increase also gain, without side effects on stability: true.

Only problem e.g. with OO coils is keeping them parallel to soil during sweeping to avoid umbalance due to the sweep movement from ground signal.
With small, parallel and slow movements this design is a winner on depth.

But as I said, all old style stuff... no news...old (and others) ideas.

As W. Shakespeare would say:
"Much ado about nothing"

Kind regards,
Max

[Sean_Goddard]

Hi Qiaozhi and JC1,

YES EXACTLY, the OO format coil is the best of all worlds (according to the article on coil manufacture on this forum). The lack of saturation of the front end and thus the demodulators, makes a much better detector. I also believe that Georgi uses a balanced DIODE demodulator, NOT a standard synchronous one. This, I am led to believe is less prone to overload at the large transmit signal levels (100V+) I believe is used in the Nexus.

NOT a beginners machine.. TRUE, the Nexus is very fiddly to set up and would not be for those with no patience but as Sheddy says, it definitely does what it says on the tin.

If you look at Sashos postings, one of the designs I saw which had a OO coil was almost IDENTICAL to the schematic Sheddy said I had lied when I said it was was the Nexus, yet I think I read in one of Sashos posts, that Sasho said he knew of Georgi and his design, and it's similarity to this schematic. I was also told by the person who gave me the schematic I have, that is WAS the Nexus and that Georgi had given it to the person in question asking his opinion of the viability of the design.

The attached PDF files are what I WAS TOLD were the Nexus. If not so, then I have not lied, I was passing on a non truth which I was told. You know what I mean!

BTW you can see that there is a circuit for nulling out the residual signal using electronics, rather than inter-coil positioning. Doing it this way, Georgi (maybe) has made it PERFECTLY possible to obtain 100% or near as damn it balance!

[Sean_Goddard]

Hi Qiaozhi,
Same coil type, same dimensions, same test garden.
That's the real test bench.
All the rest is advertising.

Kind regards,
Max

OH HOW TRUE MAX, Advertising "Lies, damned Lies and statistics" (99% of which are made up on the spot...ALLEGEDLY ) as someone once said. And numbers can be made to prove anything, just ask my neighbour (Ph.D in mathematics).

[Unregistered]

Chinese copies

I think people who claim to have Nexus only have Chinese copies and no proof of purchase from the manufacturer. Ha ha haaa! When you buy off Ebay you can be tricked into buying something you think is original, but it's not, so then people jump on forums and complain after they buy fake copies. There has already been a bunch of frauds on the forums trying to sell off their cheap copies of the Nexus which doesn't have close the same performance.

[Unregistered]

well said

well said Georgi

[Ultimate_Haze]

Hi,

Hi,
Have anyone make good OO coil?
What wire d?former d?Number of turns?Are this two OO wind in same direction?
I think that george use some other trick@@!!
He uses somehow 3 winding,but they are two!????@?
I just dont now enough to understand,but maybe Qiaozhi or someone else can get the trick.................................

[Unregistered]

Who?

Who is Georgi?????????????????

[Richard Lincoln (Sheddy)]

I find amazing that although George has seen this thread and what I have written regarding his refusal to honour his promise, he has chosen not to reply. I hope to hear from him or his representative shortly.

[CrazymanBrad]

This is my first post. As a new member to this forum, I find it extremely disappointing that people enjoy airing their dirty laundry and publicly humiliating themselves. It was entertaining for a few posts, but now it is becoming a soap opera material that would be better left for TV-wrestling, or Jerry Springer. Each have there place, but I would hope the admins and moderators would agree with me, that it is not here.

Please don't turn this forum into a field full of rusty nails, with only an apple seed's worth of treasure.

CMB

[Geo]

Money...money.....money, enterprises...enterprises, open brains, new ideas, pleasant life..... etc .... etc .... etc ......

So much money and it is sought you create new companies for more money .... Bravo ......i am sorry you .
Maybe i must look for another place with real people

[Unregistered]

Hi Peeps, make ur own metal detecting company then bring it here so all the dogs can jump on u and see how u like it then, huh?

[Unregistered]

[QUOTE=Max;57499]Hi Qiaozhi,
"There's also no point in saying "Could Nexus detect 1eur coin at 30+ cm underground with a DD 22cm diameter coil ?". This doesn't even make sense."

For me have a lot of sense. Maybe not for you, but this is your opinion , that's fine.

What I've said means its circuit has no advantage respect e.g. BandidoII or GoldenSabre circuit on the depth sector.

When I read that the secret is in the coil... I can only say that the circuit is really like many other circuits that are flying around MD scenario from the 80's.
Isn't it an 80's design with just few mods ???
Isn't it like bulgarian detectors of last 70's and first 80's ???

It is also an old polemic here about its circuit design owner and so to who belongs... that I have no intention of reopening here.

I think that Georgi is a good designer anyway, don't misunderstud my words.

But circuit of Nexus is quite similar to those I've descibed above...
old bulgarian design...
well known design... old, working one of course, but NOTHING NEW.

Ask some bulgarian guy... he would tell you if you don't belive my words.

NO BIG IMPROVEMENTS. NO BIG NEWS. ALL ABOUT THE SAME.

Coil is the secret ??? Yes. Coil is the secret of its performances, I'm sure of that.

But I still think that my homemade BandidoII could beat it on soil, test garden, meeting same coil type and dimension condition.

Belive it or not, my unit do what I've said, and is just an homemade detector + an homemade coil... nothing special. And also an old Tesoro's design.
That say everything for me.

You can really compare units using same dimensions and type of coils.

Have sense comparing e.g. a Minelab unit with 11'' DD coil with a BandidoII with 8'' DD coil ?

Or also the same bandidoII unit with an OO coil and a round concentric coplanar coil ???

11'' and 8'' are not the same thing. OO and coplanar concentric aren't the same thing.

It's like a motogp-bike vs a 250cc-enduro on speed. This have no sense.
Or comparing PIs with VLFs or apple to oranges... like you said.

I think is a very good detector that Nexus... that it's worth buy one if e.g. a TH want really good depth and disc, OK. Also if it is for sure overprized.

But nobody claim here miracles. Nobody tell me there is some "new" technology behind... that multiply depth !

There are no miracles or black magic in MDs... just good designs (that are all about the same) and good coils make the difference.

Same coil type, same dimensions, same test garden.
That's the real test bench.
All the rest is advertising.

Kind regards,
Max[QUOTE]


"When I read that the secret is in the coil... I can only say that the circuit is really like many other circuits that are flying around MD scenario from the 80's.
Isn't it an 80's design with just few mods ???
Isn't it like bulgarian detectors of last 70's and first 80's ???"

Nice theory, but there is more to that. Bandido as all Tesoro detectors is made with Colpits oscilator on the TX. That`s the lowest end of the transmitting circuit design. With that kind of transmitter you can not run any serious competition.