northwest If we are serious about a VLF deep , mega nugget detector!
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Doug
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« on: Monday January 28 2019 14:15:45 AEDT PM »

If we are serious about a VLF deep , mega  nugget detector!
This is the sort of detector that in my opinion is needed!
GEM-3&GEM-3 Array
  
  
  
  
doug smile
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« Reply #1 on: Monday January 28 2019 16:10:45 AEDT PM »

  
If we are serious about a VLF deep , mega  nugget detector!
This is the sort of detector that in my opinion is needed!
GEM-3&GEM-3 Array
  
  
  
  
doug smile

These systems are deep, but also ridiculously retarded and slow to use. For archaeology this is not a problem as the area searched would be rather limited. Fr mines too as those need to be detected slowly and removed slowly.
But in practical terms you need time to get over the big nuggets in the dessert and that space is vast.
My two box is far better as it allows to search huge areas in very short amount if time without detection of Iron, hot rocks or any junk smaller than 8" or so.

I have build to customer requests long time ago detectors with dual 40" coils (175cm x 100 cm) that were super deep, but also got all of the Iron on the planet. The name was Nexus Exselsior and the price was 15000 Euros. Never advertised those comersially as they were for tha mad men only.

Getting the super big nuggets, not detecting any trash and walking fast in variable terrain. This is what you seriously need. This is what I am bringing to the market.
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« Reply #2 on: Monday January 28 2019 16:41:39 AEDT PM »

  
  
If we are serious about a VLF deep , mega  nugget detector!
This is the sort of detector that in my opinion is needed!
GEM-3&GEM-3 Array
  
  
  
  
doug smile

These systems are deep, but also ridiculously retarded and slow to use. For archaeology this is not a problem as the area searched would be rather limited. Fr mines too as those need to be detected slowly and removed slowly.
But in practical terms you need time to get over the big nuggets in the dessert and that space is vast.
My two box is far better as it allows to search huge areas in very short amount if time without detection of Iron, hot rocks or any junk smaller than 8" or so.

I have build to customer requests long time ago detectors with dual 40" coils (175cm x 100 cm) that were super deep, but also got all of the Iron on the planet. The name was Nexus Exselsior and the price was 15000 Euros. Never advertised those comersially as they were for tha mad men only.

Getting the super big nuggets, not detecting any trash and walking fast in variable terrain. This is what you seriously need. This is what I am bringing to the market.

Thanks.How do you process the inphase or quadrature  ground /target responses or does your processing ignore or remove the inphase response?
doug smile
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« Reply #3 on: Monday January 28 2019 16:49:32 AEDT PM »

  
My two box is far better as it allows to search huge areas in very short amount if time without detection of Iron, hot rocks or any junk smaller than 8" or so.

So what is the smallest nugget that your large coil nexus can detect at depth? An 8" nugget would be potentially be  many hundreds of ounces!!
doug smile
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« Reply #4 on: Monday January 28 2019 17:26:38 AEDT PM »

  
These systems are deep, but also ridiculously retarded and slow to use.
Their is a smaller portable version available but this one is TD not FD.
Man-Portable Vector EMI Sensor for Full UXO Characterization
MPV TECHNOLOGY DESCRIPTION
2.1.1 Electromagnetic sensor
The MPV is a man-portable, wide-band, time-domain, EMI sensor composed of a single
transmitter coil and an array of five receiver units that measure all three components of the EM
field (Figure 2). The sensor was specifically designed to (1) be man portable and therefore easy
to deploy, maneuver and adapt to a survey environment, and (2) acquire data that is suitable for
discriminating unexploded ordnance (UXO) from non-UXO targets. The MPV sensor head for
this demonstration comprises a 50-centimenter (cm) diameter circular loop transmitter coiled
around a disk that intermittently illuminates the subsurface, and five multi-component receiver
units (cubes) that measure the three orthogonal components of the transient secondary EM field
decay with three air-induction 8-cm square coils. One receiver cube is co-axial with the
transmitters while four receivers are placed off-axis around the transmitter loops in a cross
pattern. Gasperikova et al (2007) and others have shown that having multi-component receivers
placed at multiple locations can help reduce the ambiguity between the size and depth of a buried
target by more readily allowing recovery of the components of the polarizability tensor
associated with a buried metallic object, an indicator of the target shape.
The MPV is a programmable instrument. The duration of the excitation and time decay
recording can be adjusted to any given time to accommodate survey needs. The MPV features
distinct operating modes for detection and discrimination with a seamless switch between the
two. Detection mode consists of dynamic data collection for digital geophysical mapping
(DGM). It is based on fast EMI transmit-receive cycles so that the sensor can continuously move
(e.g., 1 millisecond [ms] time decay, similar to Geonics EM-61). Discrimination mode is tailored
for optimizing data quality and the ensuing target characterization. In this mode the sensor is
static so that signals can be stacked (averaged to reduce noise); longer EMI cycles are applied to
capture variations in time decay rates (e.g., 25 milliseconds (ms), similar to Geonics EM-63).
This late-time information has been shown to be very useful for distinguishing between intact
ordnance and thinner walled shrapnel and cultural debris (Billings et al., 2007). Other currently
available systems with multiple time channel measurement capabilities (e.g., Berkeley UXO
Discriminator [BUD], Geonics EM63, Time Domain EM Towed Array Detection System
[TEMTADS]) are required to be mounted on a cart platform due to the size and weight of the
multiple coils of wire required for the transmitters and receivers.
The MPV user interface has real-time monitoring and feedback capabilities on data quality,
spatial coverage and other key features (signal intensity, time decay, secondary targets, and
presence of magnetic soil). For example, the interface includes a target location tool obtained by
displaying the direction and amplitude of the measured EMI field at each receiver unit (the socalled
“dancing arrows” in top left corner of Figure 3). All these features assist the field operator
in efficient data collection, so that detection and discrimination data can be collected as part of
the same survey, thus limiting the need to revisit an anomaly for further characterization
  
The portable FD (hand held) is here:
  
  
you can get it with a 96 cm detecting head
doug smile
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« Reply #5 on: Monday January 28 2019 19:00:53 AEDT PM »

  
  
My two box is far better as it allows to search huge areas in very short amount if time without detection of Iron, hot rocks or any junk smaller than 8" or so.

So what is the smallest nugget that your large coil nexus can detect at depth? An 8" nugget would be potentially be  many hundreds of ounces!!
doug smile

The two box Nexus pathfinder will easily get my simulated nugget 600 grams at 1 meter depth. I have also done some tests with far smaller than that, but they are not a two box material, more for DD coils.
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« Reply #6 on: Monday January 28 2019 21:52:55 AEDT PM »

  


Thanks.How do you process the inphase or quadrature  ground /target responses or does your processing ignore or remove the inphase response?
doug smile
It's all analogue and true all metal mode at all times. My circuits do not discriminate/reject against remnants of ground interference instead they rely on proper tuning.
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« Reply #7 on: Monday January 28 2019 22:07:48 AEDT PM »

The GEM arrays emulate basic concentric coil design, no more no less. As such they would have to deal with the worse for the IB principal ground interference.
Also in the concentric coil design it does not matter if the TX loop is out side or inside, because the detection capabilities of concentric coils are determined by their total surface area and not solely by the size of TX.

I also have done probably hundreds of experiments with multipole RX loops in IB systems. They all turned out  a time waste as there was no real improvement in any aspect and there was a considerable loss of efficiency.

Loss of efficiency I find to be acceptable only if we can gain something else, like PI is not so efficient, but very stable on ground. Two box IB is not efficient at all, but it exhibits the best possible discrimination amongst all detectors and it is also super smooth and stable on grounds of any kind.

Now let see how deep is the understanding of IB detectors here.
Does anyone here knows for what reason the GEM systems are using that exact size wheels and not smaller or larger?
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« Reply #8 on: Monday January 28 2019 23:54:03 AEDT PM »

What are you proposing?
A 2 box vlf for prospecting or supplying Cc coils for Pi or both?

As I said in an earlier post, stability of build and stability of electronics ...is the most important thing.
Regardless of the technology used..
I would be very interested in your methods and hope to see one of your systems down here on the goldfields. Or perhaps someone who already owns one here could share their experience?




Cheers

Muntari

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« Reply #9 on: Tuesday January 29 2019 00:07:01 AEDT AM »

  
  


Thanks.How do you process the inphase or quadrature  ground /target responses or does your processing ignore or remove the inphase response?
doug smile
It's all analogue and true all metal mode at all times. My circuits do not discriminate/reject against remnants of ground interference instead they rely on proper tuning.

So are you saying that by proper "tuning" you  simultaneously eliminate  or ignore  the inphase and quadrature  effects of any  ground mineralization?
doug smile
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« Reply #10 on: Tuesday January 29 2019 00:16:13 AEDT AM »

  
Does anyone here knows for what reason the GEM systems are using that exact size wheels and not smaller or larger?

I think reading the  gem3 coil patent will provide the answer.
doug smile


* won patent.jpg (169.88 KB, 579x758 - viewed 80 times.)
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« Reply #11 on: Tuesday January 29 2019 03:33:43 AEDT AM »

  
  
Does anyone here knows for what reason the GEM systems are using that exact size wheels and not smaller or larger?

I think reading the  gem3 coil patent will provide the answer.
doug smile
I know the answer without reading the patent. I was curious if anyone else does, but no.
This patent only provides information of how the coil system operates and to tell you I wouldn't use this system not even under penalty of death.
The reason is the multipole audio responses such a system exhibits over every single target that may be close to the surface. Also in IB detectors concentric coils exhibits this very steep logarithmic response, which is far more difficult to manage that the more linear DD or figure of 8 coils. I have made measurements with such a system years ago in attempt to isolate the strong close proximity ground interference (the positive signal when IB coil is very close to the ground).
I found that by using more than one TX or RX loops in the concentric coils one can extend or shorten significantly this zone of positive signal from ground, but at the expense of Mad Max audio should should you go over some little bit of trash. Unless this system is used with proper digital processing to eliminate all near proximity signals it is useless except for very clean sites.

Now the answer to my question.
Every IB coil system will exhibit the mentioned above close proximity interference zone in front of the coil. For a coil with size of 1 x 1 meter (40"x40") this positive zone will be about from zero to 9". So if the coil is moved uniformly above the soil surface at that very distance 9"(or a little higher let say 10-12") the discrimination channel (or an analogue equivalent)  will work with highest stability and most reliable analysis, because in that area of space in front of the coil the ground interference input in the discrimination channel is at its minimum. This comment should give you a good idea how the creators of this detector came up with that specific size wheels.
Above that level the ground interference will tend to pull a negative signal in the detector, thus causing loss of depth to all non-ferrous targets by partially canceling their positive input signals.
Bellow that level the signal interference will be positive, which will result in false positive signals making it difficult to distinguish non-ferrous from false signals. However this condition would also result in increased  sensitivity to non-ferrous targets.
The major problem with big IB coils is that while they increase dramatically the over all amplification of the system they also bring more troubles with ground interference mainly of soil conductivity nature. Big coils are more difficult to use in wet soil conditions.
Here is a picture of my madness coil system for the Nexus Exselsior. 2 x 40" loops (175 cm x 100 cm), 4.5 kg, 9 full resonant frequencies from 1 to 10.5kHz. Fully collapsable construction for easy transport.



* Exselsior.JPG (250.46 KB, 1132x918 - viewed 77 times.)
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« Reply #12 on: Tuesday January 29 2019 03:45:50 AEDT AM »

  
What are you proposing?
A 2 box vlf for prospecting or supplying Cc coils for Pi or both?

As I said in an earlier post, stability of build and stability of electronics ...is the most important thing.
Regardless of the technology used..
I would be very interested in your methods and hope to see one of your systems down here on the goldfields. Or perhaps someone who already owns one here could share their experience?






Cheers

Muntari



I will offer both 2 box VLF and CC coils for PI. I could offer also DD coils for PI, but don't see the point since my max size is 20" and a pile of companies are doing it already.
I will also demonstrate later what the MP (VLF) with the big dual 30" coil can do. You will be surprised to say at the least.
The stability of electronics and coil design is quite evident from all of my videos on You Tube. You can check there or ask on Facebook   
or the UK MDF forum in the Nexus section.
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« Reply #13 on: Tuesday January 29 2019 09:44:13 AEDT AM »

  
  
  
Does anyone here knows for what reason the GEM systems are using that exact size wheels and not smaller or larger?

I think reading the  gem3 coil patent will provide the answer.
doug smile
I know the answer without reading the patent. I was curious if anyone else does, but no.
This patent only provides information of how the coil system operates and to tell you I wouldn't use this system not even under penalty of death.
The reason is the multipole audio responses such a system exhibits over every single target that may be close to the surface. Also in IB detectors concentric coils exhibits this very steep logarithmic response, which is far more difficult to manage that the more linear DD or figure of 8 coils. I have made measurements with such a system years ago in attempt to isolate the strong close proximity ground interference (the positive signal when IB coil is very close to the ground).
I found that by using more than one TX or RX loops in the concentric coils one can extend or shorten significantly this zone of positive signal from ground, but at the expense of Mad Max audio should should you go over some little bit of trash. Unless this system is used with proper digital processing to eliminate all near proximity signals it is useless except for very clean sites.

Now the answer to my question.
Every IB coil system will exhibit the mentioned above close proximity interference zone in front of the coil. For a coil with size of 1 x 1 meter (40"x40") this positive zone will be about from zero to 9". So if the coil is moved uniformly above the soil surface at that very distance 9"(or a little higher let say 10-12") the discrimination channel (or an analogue equivalent)  will work with highest stability and most reliable analysis, because in that area of space in front of the coil the ground interference input in the discrimination channel is at its minimum. This comment should give you a good idea how the creators of this detector came up with that specific size wheels.
Above that level the ground interference will tend to pull a negative signal in the detector, thus causing loss of depth to all non-ferrous targets by partially canceling their positive input signals.
Bellow that level the signal interference will be positive, which will result in false positive signals making it difficult to distinguish non-ferrous from false signals. However this condition would also result in increased  sensitivity to non-ferrous targets.
The major problem with big IB coils is that while they increase dramatically the over all amplification of the system they also bring more troubles with ground interference mainly of soil conductivity nature. Big coils are more difficult to use in wet soil conditions.
Here is a picture of my madness coil system for the Nexus Exselsior. 2 x 40" loops (175 cm x 100 cm), 4.5 kg, 9 full resonant frequencies from 1 to 10.5kHz. Fully collapsable construction for easy transport.



Their is another more important reason for the wheel size other than the ground proximity effects. The wheels may contain  some metal which will  be partially excited by the outer TX and thus  destroy the bucking or null (magnetic cavity) of the inner RX coil  perhaps more so when the cart is being wheeled. For a specific wheel size this effect can be  removed either electronically or by digital processing so the inner RX coil is still in a magnetic cavity and the only signal responses are from  the ground or ground+ target. In the GEM3 the quadrature phase is relatively insensitive to variations in coil height (ground proximity effects) and provides very reliable detection of targets even in magnetic /conductive soils
doug smile
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« Reply #14 on: Tuesday January 29 2019 10:09:14 AEDT AM »

  
  
  
Does anyone here knows for what reason the GEM systems are using that exact size wheels and not smaller or larger?

I think reading the  gem3 coil patent will provide the answer.
doug smile
I know the answer without reading the patent. I was curious if anyone else does, but no.
This patent only provides information of how the coil system operates and to tell you I wouldn't use this system not even under penalty of death.
The reason is the multipole audio responses such a system exhibits over every single target that may be close to the surface. Also in IB detectors concentric coils exhibits this very steep logarithmic response, which is far more difficult to manage that the more linear DD or figure of 8 coils. I have made measurements with such a system years ago in attempt to isolate the strong close proximity ground interference (the positive signal when IB coil is very close to the ground).
I found that by using more than one TX or RX loops in the concentric coils one can extend or shorten significantly this zone of positive signal from ground, but at the expense of Mad Max audio should should you go over some little bit of trash. Unless this system is used with proper digital processing to eliminate all near proximity signals it is useless except for very clean sites.

Now the answer to my question.
Every IB coil system will exhibit the mentioned above close proximity interference zone in front of the coil. For a coil with size of 1 x 1 meter (40"x40") this positive zone will be about from zero to 9". So if the coil is moved uniformly above the soil surface at that very distance 9"(or a little higher let say 10-12") the discrimination channel (or an analogue equivalent)  will work with highest stability and most reliable analysis, because in that area of space in front of the coil the ground interference input in the discrimination channel is at its minimum. This comment should give you a good idea how the creators of this detector came up with that specific size wheels.
Above that level the ground interference will tend to pull a negative signal in the detector, thus causing loss of depth to all non-ferrous targets by partially canceling their positive input signals.
Bellow that level the signal interference will be positive, which will result in false positive signals making it difficult to distinguish non-ferrous from false signals. However this condition would also result in increased  sensitivity to non-ferrous targets.
The major problem with big IB coils is that while they increase dramatically the over all amplification of the system they also bring more troubles with ground interference mainly of soil conductivity nature. Big coils are more difficult to use in wet soil conditions.
Here is a picture of my madness coil system for the Nexus Exselsior. 2 x 40" loops (175 cm x 100 cm), 4.5 kg, 9 full resonant frequencies from 1 to 10.5kHz. Fully collapsable construction for easy transport.




I would have thought the size of the wheels used was obvious...they could be larger or smaller , coils larger or smaller  but the thinking is flawed in real use on real ground...go over a small bump or rocky ground and response is compromised...unless the response is mute down by filtering and then its too slow....its all been done before.

Now to your detector, is there anyone here in Australia that you know of that would be willing to share their experience. I ask this because it will help you move forward quicker by gaining interest from seeing the real thing in action.

I don't doubt your detectors work but we need to be convinced with a real machine in working conditions

cheers

muntari
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« Reply #15 on: Tuesday January 29 2019 10:24:46 AEDT AM »

  

I don't doubt your detectors work but we need to be convinced with a real machine in working conditions
cheers

muntari

That is exactly right!We need to see it work in our GF and then do some depth testing using AL targets(closest conductivity to pure gold) at the various test sites.
doug smile
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« Reply #16 on: Tuesday January 29 2019 12:32:29 AEDT PM »

  
  
  
  
Does anyone here knows for what reason the GEM systems are using that exact size wheels and not smaller or larger?

I think reading the  gem3 coil patent will provide the answer.
doug smile
I know the answer without reading the patent. I was curious if anyone else does, but no.
This patent only provides information of how the coil system operates and to tell you I wouldn't use this system not even under penalty of death.
The reason is the multipole audio responses such a system exhibits over every single target that may be close to the surface. Also in IB detectors concentric coils exhibits this very steep logarithmic response, which is far more difficult to manage that the more linear DD or figure of 8 coils. I have made measurements with such a system years ago in attempt to isolate the strong close proximity ground interference (the positive signal when IB coil is very close to the ground).
I found that by using more than one TX or RX loops in the concentric coils one can extend or shorten significantly this zone of positive signal from ground, but at the expense of Mad Max audio should should you go over some little bit of trash. Unless this system is used with proper digital processing to eliminate all near proximity signals it is useless except for very clean sites.

Now the answer to my question.
Every IB coil system will exhibit the mentioned above close proximity interference zone in front of the coil. For a coil with size of 1 x 1 meter (40"x40") this positive zone will be about from zero to 9". So if the coil is moved uniformly above the soil surface at that very distance 9"(or a little higher let say 10-12") the discrimination channel (or an analogue equivalent)  will work with highest stability and most reliable analysis, because in that area of space in front of the coil the ground interference input in the discrimination channel is at its minimum. This comment should give you a good idea how the creators of this detector came up with that specific size wheels.
Above that level the ground interference will tend to pull a negative signal in the detector, thus causing loss of depth to all non-ferrous targets by partially canceling their positive input signals.
Bellow that level the signal interference will be positive, which will result in false positive signals making it difficult to distinguish non-ferrous from false signals. However this condition would also result in increased  sensitivity to non-ferrous targets.
The major problem with big IB coils is that while they increase dramatically the over all amplification of the system they also bring more troubles with ground interference mainly of soil conductivity nature. Big coils are more difficult to use in wet soil conditions.
Here is a picture of my madness coil system for the Nexus Exselsior. 2 x 40" loops (175 cm x 100 cm), 4.5 kg, 9 full resonant frequencies from 1 to 10.5kHz. Fully collapsable construction for easy transport.




I would have thought the size of the wheels used was obvious...they could be larger or smaller , coils larger or smaller  but the thinking is flawed in real use on real ground...go over a small bump or rocky ground and response is compromised...unless the response is mute down by filtering and then its too slow....its all been done before.

Now to your detector, is there anyone here in Australia that you know of that would be willing to share their experience. I ask this because it will help you move forward quicker by gaining interest from seeing the real thing in action.



cheers

muntari

The coil stand off distance and hence wheel diam  for the GEM3 will vary according to coil size and  soil mineralization level. Its a compromise  between  minimizing   changes in the in phase signal over  conductive/ magnetic soils and  the detection distance. Over mild mineralization the wheel diameters can be smaller(smaller standoff distance) and over high mineralization large diam wheels(bigger standoff  distance)  would be used.
doug  smile
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« Reply #17 on: Tuesday January 29 2019 12:51:09 AEDT PM »

  
  

I don't doubt your detectors work but we need to be convinced with a real machine in working conditions
cheers

muntari

That is exactly right!We need to see it work in our GF and then do some depth testing using AL targets(closest conductivity to pure gold) at the various test sites.
doug smile


I would also add, that any detector using just CC coils that tries to eliminate close proximity signals is throwing the baby out with the bath water..
Despite all the years of technical advances and a plethora of companies and individuals trying to rid the ground signal from detector responses, the ground is still winning..
The best detectors are the ones that have a good operator and know the ground they are searching and know the target they are looking for, the  detector is 30% of the picture, the rest is operator..
Having said that, there are only a handful of detectors that I am aware of that can handle OZ GF ground well enough for the operator to fill in the rest of the puzzle.
Most are PI and they don't all hog or require huge amounts of power to operate...
My design runs at 1600 or 3200 Hz and uses just 150mA on 7.2v....
I use tricks with coils too but I can't fool the ground all the time...but then I know when I'm being fooled by the ground... happy face

cheers

muntari
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« Reply #18 on: Tuesday January 29 2019 14:15:41 AEDT PM »

  
..My design runs at 1600 or 3200 Hz and uses just 150mA on 7.2v....
I use tricks with coils too but I can't fool the ground all the time...but then I know when I'm being fooled by the ground... happy face

cheers

muntari

I thought your design had been " lost"! SAD
doug smile
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When is 1halfgram4three (a proven forum hacker and  village idiot!) going to stop telling lies on his “forum”?
Muntari
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« Reply #19 on: Tuesday January 29 2019 14:28:52 AEDT PM »

  
  
..My design runs at 1600 or 3200 Hz and uses just 150mA on 7.2v....
I use tricks with coils too but I can't fool the ground all the time...but then I know when I'm being fooled by the ground... happy face

cheers

muntari

I thought your design had been " lost"! SAD
doug smile

Yes, that has been put to bed as I said .....this is a new PI design analog/digital, very light, minimal controls, good GB, a very vanilla...but extremely quiet  PI happy face
main point of difference..it is designed as a system..coil specific.

that's about as much as I can say.. don't feed the trolls

Ill share more on a separate thread when its appropriate...

cheers

muntari
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All posts submitted by myself to this forum are my opinion and are done so without prejudice
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