15" Deus Coil.

[Skippy]

"All kind off test is made and it isn't better than this largest Stock coil."

I think you are seeing the same problem that every other detectorist sees - they buy a big coil expecting it to be deeper, and are 'surprised' that it's not. Hence so many large coils for sale in the classified adverts. All the big coil does is increase pickup of the ground signal, and the target signal, and the end result is the detector still can't determine 'target' from 'ground signal'.

[Nupi]

@Skippy.
You're right. On the air tests they are much better than the smaller coils, but above ground only a little or evennot .
That's one of the reasons for the sense or nonsense of air tests. Air tests are often used as a sales pitch.
It is time that there is a standard for MD. Everywhere the same soil tests can be done.

[Henrikras]

But If a model / brand X dosn't make a good airtest, I can see how it could have any depth in soil !
A good airtest must be the first condition to be right, developing and building detectors and coils. Then comes all the must difficult part,
to make model / brand X working in a real environment.. All depending what kind of search you are doing.
To me a airtest makes sense, its just only one small step at a long Road.
Henrik.

[Nupi]

I think we are talking about two different criteria. To developing or buy a MD/coil.


"A good airtest must be the first condition to be right developing and building detectors and coils."
In some cases this is true, but certainly not all. It is not unusual that they have made a MD / adjusted
in the air one euro detects at 50cm but in the soil collapses to 23cm and an MD detects in the air 35 cm detects and in the soil 28 cm.
And I'm not have about heavily mineralized soil but an average.(but what is heavily/average?)
The must difficult part, I think, is to make a balanced MD.
Sometimes it is better to want to perform not a maximum in the air for better perform in soil.


The coil technolochie is complicated. That there is still no efective software programs made but
still needs to be experimenting/tested in practice.
Until now, no one can give me a good explanation why unshielded tx coil does better in mineralized soil than a shielded.
That's not the radiated power, I think, it's more the reactance component and more. Who really knows, I like to hear it.


I want to tell you that you've done an excellent job and I've learned a lot from you. Your thread is gain for Geotech and I mean that.
Thanks!

[Henrikras]

yeah... You so right, there is some brands with sales video's there never will go so deep. I did my mistakes, (more than one) buying a Detector after watching Utubes. (I was naive).
Thanks for your nice comments.
Henrik.

[golfnut]

I cant see why we need a Tx screen. We know the Rx screen dissipates any stored charge between the Rx coil and anything it comes into close proximity with.


As for air tests, the architecture of the machine may mean a poor air test.

for example if a PLL type of GEB system, this would not be running in lock in air - and may not give great air tests. But good in ground.

also

ML types dont air test real well, but the ground depth is the same as the air!


"unshielded tx coil does better in mineralized soil than a shielded."

It may be that you get a clearer more unified ground signal, and the user or the Auto Geb tracker can more reliably remove it, this would allow the sens to be cranked and find quieter signals?

[Nupi]

@ golfnut
"It may be that you get a clearer more unified ground signal, and the user or the Auto Geb tracker can more reliably remove it,
this would allow the sens to be cranked and find quieter signals?"

With an unshielded tx coil, I have more problems with wet grass also makes
it more difficult to adjust the ground balance but penetrates better in mineralized soil.
The Deeptech Smart, I do not think that had a schielt on the tx, is one of the better mineralization MD.

I think about a few points:

A shielded TX coil is actually a Magnetic Loop Antenna and radiates more magnetic field component.

A unshielded TX coil radiates more electric field component. The influence of coil capacity to soil is greater.

In electrical and electronic systems, reactance is the opposition of a circuit element to a change of electric current or voltage,
due to that element's inductance or capacitance. A built-up electric field resists the change of voltage on the element,
while a magnetic field resists the change of current. The notion of reactance is similar to electrical resistance, but they differ in several respects.
An ideal resistor has zero reactance, while ideal inductors and capacitors consist entirely of reactance.
The magnitude of the reactance of an inductor is proportional to frequency,
while the magnitude of the reactance of a capacitor is inversely proportional to frequency.

I hope you understand what I mean to say.

Today is not my best day to write down thoughts. Sorry.

[golfnut]

"With an unshielded tx coil, I have more problems with wet grass"
That suprises me !

"I think about a few points:

A shielded TX coil is actually a Magnetic Loop Antenna and radiates more magnetic field component.

A unshielded TX coil radiates more electric field component. The influence of coil capacity to soil is greater.

In electrical and electronic systems, reactance is the opposition of a circuit element to a change of electric current or voltage,
due to that element's inductance or capacitance. A built-up electric field resists the change of voltage on the element,
while a magnetic field resists the change of current. The notion of reactance is similar to electrical resistance, but they differ in several respects.
An ideal resistor has zero reactance, while ideal inductors and capacitors consist entirely of reactance.
The magnitude of the reactance of an inductor is proportional to frequency,
while the magnitude of the reactance of a capacitor is inversely proportional to frequency."

yes