Nexus and transmit power.

[Nexus]

P.S.
Watching your video and part with coin covered with rocks; i think that it was closest to what i have here on that site.
But piles of such rocks are much larger here. Mixed with iron oxide and melted iron&ceramic parts.
That's why your video attracted my attention. It would be interesting to test Nexus here.

On the site where the video was made the soil is highly magnetic and littered with thousands of hot rocks fragments. On this site (the Overload test site) the MP can get a good signal of 30 mm coin at 30 cm with 13"DD if we consider that there are no residual signals from any hot rocks or soil what so ever. So if one would have the nerve to listen to some minor interference the depth can increase to 35 -38 cm. With larger coils is better, but you have to clear the site first.
On the Overload test site the GPX5000 with 10" mono coil is getting a small bronze Roman coin at the same depth as MP with 10"DD - 20cm. So when it comes to bronze relics the GPX is not much of a big shot. But if we are talking about gold nuggets it is unbeatable for now.
Judging from the picture you'v published I do not expect the soil in your area to be as bad especially if the Deus works well in there. On the Overload test site the Deus is a dad with very poor performance. So this is where my comparison point comes from.
Since the MP can go trough ceramics and red bricks like trough cheese I would not expect any significant problems.

One of the things I did not show on the video is that the MP prototype was able to get the test coin across 3 layers of red bricks, not just two. With 13"DD coil it can go over 4 layers in those conditions and with reliable discrimination.

[ivconic]

On the site where the video was made the soil is highly magnetic and littered with thousands of hot rocks fragments. On this site (the Overload test site) the MP can get a good signal of 30 mm coin at 30 cm with 13"DD if we consider that there are no residual signals from any hot rocks or soil what so ever. So if one would have the nerve to listen to some minor interference the depth can increase to 35 -38 cm. With larger coils is better, but you have to clear the site first.
On the Overload test site the GPX5000 with 10" mono coil is getting a small bronze Roman coin at the same depth as MP with 10"DD - 20cm. So when it comes to bronze relics the GPX is not much of a big shot. But if we are talking about gold nuggets it is unbeatable for now.
Judging from the picture you'v published I do not expect the soil in your area to be as bad especially if the Deus works well in there. On the Overload test site the Deus is a dad with very poor performance. So this is where my comparison point comes from.
Since the MP can go trough ceramics and red bricks like trough cheese I would not expect any significant problems.
One of the things I did not show on the video is that the MP prototype was able to get the test coin across 3 layers of red bricks, not just two. With 13"DD coil it can go over 4 layers in those conditions and with reliable discrimination.

Deus is working similar to how you described here: "..So if one would have the nerve to listen to some minor interference ..."
Small chatters and occasional short "beeps" here and there. Depths are not great, not greater than 15-20cm on Byzantine coins (more copper in alloy, makes a lot difference!).
Only one of such coins, the largest one and the last one i reported on other topic, the Justinian "M" (40 nummi) was discovered at tremendous depth approx 35-40cm!!!
I couldn't believe once i discovered it. Signal was not clear, half iron / half "colored" audio all the time. VDI was 98-99. It was real success for 22.5cm coil.
And there is no chance that coin was aside and slipped to the bottom of hole, because i "fingered" it hardly bellow the plant root at 32-35cm depth. I had 5 minutes job to get it out.
So... large and "fat" coins are not that hard target after all.
Gold coin from the same site was toughest target. It was in the same hole as Byzantine "K" coin, at ~20cm depth. Once i got out "K" coin; i checked hole again and i got very mum signal with VDI 40-42.
I am absolutely positive that i would not detect it if it was alone in the hole at that depth. Because of the very tough and bad soil around.
...
Your further descriptions on performances are rising interest and attention too. I will try to obtain or borrow MP this summer and see. Would be good if there is smaller coil with it.

[dfbowers]

There are a number of things working together with the Nexus line besides just TX power.
Obviously from the latter part of this thread, extended ground balance features and the flexibilty to alter Rx coil Q value of the MP?
The other things working in concert for depth is all metal mode for cleanest signal response, resonant coils, a slow motion ferrous/non ferrous identification,
low Rx gain and lastly, those crazy looking "OO" coils on the Mkii.
Obviously, it's not the right tool for every situation but for open pasture lands and deep relics, and for someone patient enough to learn
the technique, I find it an unbeatable combination.
Don .

[ivconic]

Most interesting aspect for me is fully resonant coil.
I think that it is also most significant fact too.

[CDI]

Deus is working similar to how you described here: "..So if one would have the nerve to listen to some minor interference ..."
Small chatters and occasional short "beeps" here and there. Depths are not great, not greater than 15-20cm on Byzantine coins (more copper in alloy, makes a lot difference!).
Only one of such coins, the largest one and the last one i reported on other topic, the Justinian "M" (40 nummi) was discovered at tremendous depth approx 35-40cm!!!
I couldn't believe once i discovered it. Signal was not clear, half iron / half "colored" audio all the time. VDI was 98-99. It was real success for 22.5cm coil.
And there is no chance that coin was aside and slipped to the bottom of hole, because i "fingered" it hardly bellow the plant root at 32-35cm depth. I had 5 minutes job to get it out.
So... large and "fat" coins are not that hard target after all.
Gold coin from the same site was toughest target. It was in the same hole as Byzantine "K" coin, at ~20cm depth. Once i got out "K" coin; i checked hole again and i got very mum signal with VDI 40-42.
I am absolutely positive that i would not detect it if it was alone in the hole at that depth. Because of the very tough and bad soil around.
...
Your further descriptions on performances are rising interest and attention too. I will try to obtain or borrow MP this summer and see. Would be good if there is smaller coil with it.

Which version of software you are using? 2.0? 3.2 or 4.0?

[ivconic]

Which version of software you are using? 2.0? 3.2 or 4.0?

Read all from here to the last post in topic (not much):

http://www.geotech1.com/forums/showt...r-coil!/page15

[Nexus]

Most interesting aspect for me is fully resonant coil.
I think that it is also most significant fact too.

The fully resonant coils do few things.
1. Add 20 times amplification that happens in the resonant circuit (the RX coil) it self. Therefore making it possible to achieve very high sensitivity with very low noise.
2. Discriminates better in depth than alternative non-resonant system.
3. It is by far the most stable system regarding electrical interference as the resonant RX being a very narrow-band spectrum is acting as a bandpass filter against mains power interference.

What is the catch?
More sensitivity to heavy ground, more sensitivity to mud and no chance to work in heavy mineral soils.
The other drawback is the tank RX capacitor. As it keeps charging and discharging it tends to make the system a bit slow in trashy sites. With small and high frequency coils this is well in control, but still not as fast as non-resonant system.

Recently the MP after the upgrade from 1.09.2016 have matched the air sensitivity of the best resonant model the MkII and in the ground is definitely deeper. Adding to that the fact that MP can work everywhere the resonant tuned detectors will not stay in production for long.

[Nexus]

...
Your further descriptions on performances are rising interest and attention too. I will try to obtain or borrow MP this summer and see. Would be good if there is smaller coil with it.

Let me be clear.
When I talk about some interference the only such I refer to is some ground interference at high sensitivity. The MP works with perfect threshold in total absence of any chatter or electronic noise even at maximum sensitivity unlike the Deus which works in a rather scratchy fashion. There are no similarities of any kind.
If you have worked with GPX this is how the MP works, very very smooth.

Make sure you get (borrow) the upgraded version from 1.09.2016. The first version of MP have Turbo Audio controlled by a 3 pole switch on the bottom of the control box. The same switch on the upgraded version is only 2 pole as the Turbo Audio was omitted.
Also the first MP version is with with 4 times lower TX power and some noise in the threshold at maximum sensitivity.

[ivconic]

Let me be clear.
When I talk about some interference the only such I refer to is some ground interference at high sensitivity. The MP works with perfect threshold in total absence of any chatter or electronic noise even at maximum sensitivity unlike the Deus which works in a rather scratchy fashion. There are no similarities of any kind.
If you have worked with GPX this is how the MP works, very very smooth.

Make sure you get (borrow) the upgraded version from 1.09.2016. The first version of MP have Turbo Audio controlled by a 3 pole switch on the bottom of the control box. The same switch on the upgraded version is only 2 pole as the Turbo Audio was omitted.
Also the first MP version is with with 4 times lower TX power and some noise in the threshold at maximum sensitivity.

Thanks for clarifications!
...
So far i had only GP3000 and was thrilled with it. Only reason why i sold it was it's size and weight. Totally horrible to work with in described conditions.
At my first attempts to go there and work with it i got involved and trapped in dense thorn bushes, so that friends had to come and have me removed from there.
It is not joke at all to stay locked and helpless on the cliff edge just above the abyss!
Now with Deus is easy. My hands and arms are free to climb while Deus is held by the teeth at some moments!
Deus remote is hooked up on shirt lapel just bellow my cheek (i can hear it loud and see VDIs easy) and the coil and stem left as only 815 grams!
No cables, noting to worry about.
Nothing competes that.

[ivconic]

And if you think just for a moment that my previous story is funny, nonsense and stupid... please DON'T!
Because i had several of most precious discoveries on most impossible places that you can think on!
For example, several years ago i "detected" (Troy Shadow X5 was than) gold Roman fibula (sold later for 800 euros) in the dirt right in the center of abandoned hawks nest, on the vertical cliff, some 60 meters abyss below me.
Similar to that story occasionally i do find very rare and expensive coins on similar cliffs on most impossible places!
How the hell they got there?
Only logical explanation could be that hawks collected such items along with chunks of rotten meat from a killed soldier and took it to the nest.
There is no other logical explanations.
Having learned from such experiences now i have dangerous habit to regularly check such spots, whenever i see them.
That's why Deus is good also.

[green]

That will depend on the particular circuit that you are working with. In general if you can double the voltage supply to your TX that will result in most cases to 4 times power output if there are no other changes.
You will find that increase of TX and lesser use of electronic gain makes a better detector.
High TX is no danger for mineralized soils, because the bulk ground interference is a result of both TX and electronic gain. So if you reduce one or the other or both the end result will be always the same.

The Nexus Standard MP works with constant 60.3 Ampere/turns and it is astonishingly stable in all conditions if one does not over do the over all detection range.

I actually intended to publish one of the MP prototypes TX and RX ends, which are much different than the production MP now, but still outperformed every other IB on mineral conditions. That is if anyone would be interested to see how it was done. I am talking about the MP prototype on the video link bellow.

I use an IB coil with my PI detector. 160usec on time at 6250 amps/sec constant rate. 23 turns Tx. The Rx ground signal is almost flat during Tx. How do I compare 6250 amps/sec, 23 turns with 60.3 Ampere/turns?

[Nexus]

I use an IB coil with my PI detector. 160usec on time at 6250 amps/sec constant rate. 23 turns Tx. The Rx ground signal is almost flat during Tx. How do I compare 6250 amps/sec, 23 turns with 60.3 Ampere/turns?

What is the off charge time, the listening period between pulses?

[green]

What is the off charge time, the listening period between pulses?

Thanks. The off time is 840usec. Ground signal is proportional to Tx rate of current change with my PI during Tx. I've been trying to determine typical rate of change for a VLF. Probably not what I need to know. 60.3 Ampere/turns is what I should be using.

[Mehranfar]

Hi , please send sechematic and pcb nexus 🙏

[Mehranfar]

Here we go.
The attached picture is showing all you need to know to make just about any IB detector work in the worse mineral conditions. For work on very strong black sand the value of the parallel potentiometer to the RX will have to get down to 5 Ohms or even less. This will allow getting coins no deeper than 2.5", but non of the existing IB detectors (except MP) can even work in such cases. For milder mineral conditions the potentiometer value will be higher resulting in higher sensitivity of the whole system.
If the parallel RX potentiometer is above 1k value this will allow the resonance of the search coil to add to the over all sensitivity.

To have the TX and RX in full resonance ideally both loops should be with the same inductance and coupled with the same capacitors. This is the easiest way to go about it. Different TX and RX will require different capacitor values to achieve full resonance if it is needed.

TX and RX can be just about any value, but to prevent the differential amplifier from drawing too much current TX is advisable to be with few Ohms active resistance and probably above 5mH inductance.

The THS4131 is a fully differential amplifier that will prevent any amplitude change what so ever making this transmitter probably the most stable TX amongst all IB schematics. In the case with MP_II prototype the power supply for the THS4131 is 20 Volts, which results in 38 Volts between the two differential outputs and then multiplied by 2 from the coil sections = 76 Volts p-p.
The TX coil does not have to be made with amplifying sections. I just did it this way as I prefer higher Voltage swing for my TX designs.
The TX coil have to be completely tuned in resonance to the source oscillator to minimize the current drain of the differential amplifier and also prevent over heating caused by output distortions.

This design solution works excellent on highly mineralized grounds. In fact it works way beyond what CTX3030 and other sophisticated digital detectors can even come close to. However it is an approach that will not allow very high sensitivity for super depth on normal conditions, because of relatively high noise level. At least my prototype was noisy beyond my requirements for Nexus noise figures. Other wise of you do not find the noise disturbing you will be kicking a lot of claims down the drain with this.

For IB detector to work properly on highly mineralized ground there is one condition that is important above all.
Either the transmitter have to be very stable or the receiver, but never both of them. Since getting a super stable receiver is near impossible this condition will fall on the transmitter naturally.

The production MP circuit uses a different approach with a free resonant transmitter, which is the same as in all other Nexus detectors, together with an input circuit that deals with the mineral conditions in a different way.

[ATTACH]39289[/ATTACH]

This was the second MP prototype and there were 6 in total before the production MP came out.

Hello ,
How is this circuit connected to the Nexus circuit?