Interview, David Johnson and John Gardiner

[Monolith]

It's really a myth. Anyway, I'm a brave guy too.

Well, I made the proof some time ago (I think in the australian gold prospecting site). You can find somewhere (geotech as well) a formula how to calculate the power factor.

Aziz

Hi Aziz,

I greatly appreciate your calculations, simulations and great engineering skills in general. Yes, I have seen your formulas, but unfortunately your great knowledge is spread over so many different treads that it is very time consuming to find them.

Attached is one of your works.

Monolith

[Monolith]

No, because no-one are willing to dig ten 3.5m deep hole per day for rusty washers only.
Depth have to be accompanied with accurate target identification.
Depth alone mean nothing.
At the end we have devices that can go very deep, only hole diggers are missing.

I don't agree with the ten holes.
Few people are capable of digging a single hole 3.5m deep in a full day's work, even in soft soil.
I agree on the accurate target identification at the newly reachable depths. This is very important and is still a solid brick wall.

But if the Wall of Berlin could be brought down, any wall can be brought down. Interesting that we are talking of a somewhat similar time frame.

Ah, and we have one amazing tool that was not available 20 years ago. The Internet. We now have access to datasheets and multiple brain power, spread around the world.

Monolith

[Monolith]

I think there is a market for extra deep detector.
But how deep? Deep on what kind of buried objects?
Let's take one single gold or silver coin, 2cm diameter. How deep on such object?
So far we achieved 20-40cm depths on such and similar objects.
Depths are varying relating to soil conditions.
Is there any chance to locate such coin deeper?
How much deeper?
Target ID?
You gave a hint though - give here more details, please!

There is of course always a compromise to be found. hen we talk of the extreme range of traditional detectors and then want to double this extreme range, we will have to pay a price.
We can start looking at the coil size. The best detecting range is about 2 to 3r, r being the radius of the coil. At a distance further than that the signal amplitude really falls off very fast.
So if you have a detector that detects at a distance of 6r, try a larger coil. The cost is more weight and bulk.

Now we come to another Brick wall. A large coil looses sensitivity to small targets.
This is due to the reduced field density of the large coil. So we need to increase the power to compensate for the loss of field strength.
Look at the IMPULSE patent. What is different? A lot is different.

Take these ideas and develop them. I did.

Power today is not like power 25 years ago. We can pack a lot more power into a detector today and if you believe the deep advocates, they don't mind carrying 1kg of Li-Fe-ion battery if it gives the extreme depth.

There is a lot, I mean really a lot of power in such a battery.

But now we need to use this power wisely. Again, look at the IMPULSE patent.

The IMPULSE was a PI detector running on a 9V battery.

David Johnson, Eric Foster, George Payne and all the other great engineers, who were the pioneers of metal detecting design, all had many excellent ideas that never made it to commercial products, for some reason or other. This does not mean that the ideas were not good, it only means that the time was not right.

If you invent a product that is 20 years ahead of its time, it means that only 20 years later the time for marketing it is right.

Monolith

[ivconic]

I have always wondered if the way to break the depth barrier is to stop using coils (loop antennas) and start using straight antennas like radios -- where target signal falls off at different rate, maybe fourth power????

Don't know how to do that besides ground penetrating radar though!!!

But I think problem in general with straight antenna is the signal is too weak to start with, and it radiates causing EMI for others. Maybe a beer can reflector (like people use on wireless routers) would help??? Maybe beer would help (with an LRL)???

-SB

Anyway you put it - our skin is to closely!

[simonbaker]

I have always wondered if the way to break the depth barrier is to stop using coils (loop antennas) and start using straight antennas like radios -- where target signal falls off at different rate, maybe fourth power????

Don't know how to do that besides ground penetrating radar though!!!

But I think problem in general with straight antenna is the signal is too weak to start with, and it radiates causing EMI for others. Maybe a beer can reflector (like people use on wireless routers) would help??? Maybe beer would help (with an LRL)???

-SB

[ivconic]

It's really a myth. Anyway, I'm a brave guy too.

Well, I made the proof some time ago (I think in the australian gold prospecting site). You can find somewhere (geotech as well) a formula how to calculate the power factor.

Aziz

C'mon! Calculations are one thing - real life often can be quite another....
I would like to talk here only about feasible things.
DIY stuff we done so far are giving us right to think that there is chance to move least one step forward ....but "doubling" the depths without hard compromises... tough to understand!
I admit; am not that conversant...

[Aziz]

Aziz, with full respect, with all my good will to keep up an open mind, still ... that is a pretty brave claim!

It's really a myth. Anyway, I'm a brave guy too.

Well, I made the proof some time ago (I think in the australian gold prospecting site). You can find somewhere (geotech as well) a formula how to calculate the power factor.

Aziz

[ivconic]

....

BTW, the 64 times power requirement for doubling the detection depth is a myth.

....
Aziz

Aziz, with full respect, with all my good will to keep up an open mind, still ... that is a pretty brave claim!

[WM6]

Any orders for such a detector?

If Yes - contact China suppliers!

[Aziz]

"Can we break through this wall?"
yes

"Is there really a market for an extra deep detector?"
yes

BTW, the 64 times power requirement for doubling the detection depth is a myth.


Any orders for such a detector?

Aziz

[ivconic]

The old brick wall of extra depth.

Can we break through this wall? YES WE CAN! YES WE DID!

How? Can you blame me for keeping it secret?

I give you a hint though.

Interestingly, Dave Johnson did the first step with the IMPULSE. Sadly, corporate decisions had him abandon the path. 20 years later many things have changed. Many things are possible now, that were not then.

But, still it is the market that drives the industry.

Is there really a market for an extra deep detector?

Monolith

I think there is a market for extra deep detector.
But how deep? Deep on what kind of buried objects?
Let's take one single gold or silver coin, 2cm diameter. How deep on such object?
So far we achieved 20-40cm depths on such and similar objects.
Depths are varying relating to soil conditions.
Is there any chance to locate such coin deeper?
How much deeper?
Target ID?
You gave a hint though - give here more details, please!

[WM6]

Is there really a market for an extra deep detector?

No, because no-one are willing to dig ten 3.5m deep hole per day for rusty washers only.
Depth have to be accompanied with accurate target identification.
Depth alone mean nothing.
At the end we have devices that can go very deep, only hole diggers are missing.

[Monolith]

And this i found as MOST EDUCATIVE:
(very important to read, especially those "depth chasers" who will not stop annoying with depth demands!)


Dave: "Getting extra depth out of a VLF, multifrequency, or PI machine is very difficult, because these machines follow an inverse 6th power law relationship between signal voltage and depth. If everything else is maintained equal, doubling the depth requires 64 times as much signal. If this is done by increasing transmitter power, doubling depth requires 4,096 times as much battery drain. That’s the basic reason why depth increases come so slowly in this industry.

The biggest impediment to getting usable depth in the ground, is interference from magnetic and electrically conductive minerals in the ground, which can produce signals hundreds of times as strong as that of the metal target you’re trying to detect and hopefully identify. There are several approaches to extracting the metal signal from the ground mineral signal, but they all have their limitations. That’s why you see several different technologies coexisting in the market."

The old brick wall of extra depth.

Can we break through this wall? YES WE CAN! YES WE DID!

How? Can you blame me for keeping it secret?

I give you a hint though.

Interestingly, Dave Johnson did the first step with the IMPULSE. Sadly, corporate decisions had him abandon the path. 20 years later many things have changed. Many things are possible now, that were not then.

But, still it is the market that drives the industry.

Is there really a market for an extra deep detector?

Monolith

[ivconic]

Those are simple facts, usually we all do know about, but seems we need to refresh our memories about those from time to time.
Now, reading same facts, pronounced by somebody else, those, kind a carrying more weight.
It is always like that, good to hear it from somebody else.
Especially from somebody such experienced and conversant.
That's why i reposted those here; just as excellent reminder.
Between the lines there are few crucial facts we all must learn and remember...

[bernte_one]

thanks ivconic for posting this

read more than the half by flying over and it was all interesting