Challenge Question

[reza vir]

Hi dear friends
In Metal Detector Coil
Low and high Henry and Ohm levels
How does each change in function?
Does it affect depth or distance?
Are there any different types of metals in Sense?
What is the best resistance and capacitance of coils in a pulse metal detector?
Thanks & Regards

[6666]

Not all the answers but somwhere for you to start
http://chemelec.com/Projects/Metal-1...I-Detector.htm

https://www.minelab.com/__files/f/11...S_&_THEORY.pdf

[Vadim18]

Thanks 6666, good articles, all basic information collected in one place.

Now i have my question too)
Is anywhere here handy formula for approximate calculation of signal attenuation with relation to coil diameter (mono coil), target distance and target diameter
I just want to understand a little bit this process, i exactly know what signal, at first integrator output, decaying not by linear law.

Regards.

[Carl-NC]

Hi dear friends
In Metal Detector Coil
Low and high Henry and Ohm levels
How does each change in function?
Does it affect depth or distance?
Are there any different types of metals in Sense?
What is the best resistance and capacitance of coils in a pulse metal detector?
Thanks & Regards

This is a challenge to write a book. There are no easy answers, it is all a matter of trade-offs.

For a given power supply, a lower L produces a stronger TX magnetic field.
But on the RX side, a lower L creates a weaker RX signal.
A lower R wastes less energy.
But a higher R can produce flat-topping which can increase sensitivity.
And so on...

[6666]

Thanks 6666, good articles, all basic information collected in one place.

Now i have my question too)
Is anywhere here handy formula for approximate calculation of signal attenuation with relation to coil diameter (mono coil), target distance and target diameter
I just want to understand a little bit this process, i exactly know what signal, at first integrator output, decaying not by linear law.

Regards.

Cannot help with that one, however Eric did publish a graph, which requires carefull study to understand it, but its sort of in the realm of describing something close to what you are asking

[green]

https://www.geotech1.com/forums/show...908#post241908

A chart that compares detection distance vs coil diameter using the same target. Targets move the curves up and down depending on size, slope stays the same. Assumes noise stays the same, I get noise proportional to coil diameter if inductance stays the same.

[Vadim18]

Thanks again 6666 and green, i still remember that chart, will try to learn.

I think what if measure maximum distance to target not by santimeters, inches, etc. but by relation to coil diameter, say distance 3coil diameters, 2coil diameters, 0.5coil diameters, if take care for coil and target proportion. Is it will be more practical? I may be wrong).

[green]

Thanks again 6666 and green, i still remember that chart, will try to learn.

I think what if measure maximum distance to target not by santimeters, inches, etc. but by relation to coil diameter, say distance 3coil diameters, 2coil diameters, 0.5coil diameters, if take care for coil and target proportion. Is it will be more practical? I may be wrong).

The coil diameters increase by 1.5 with the chart.

Wasn't thinking. You are suggesting X axis should be coil diameter maybe 3 diameters full scale? Have to think about that.

[green]

The coil diameters increase by 1.5 with the chart.

Wasn't thinking. You are suggesting X axis should be coil diameter maybe 3 diameters full scale? Have to think about that.

Think same data charted vs coil diameter

[Vadim18]

Think same data charted vs coil diameter

Thank green, i just thought like a beginner. Now i have doubts i feel i need to study the theory.

[Qiaozhi]

Does this help?
https://www.geotech1.com/forums/showthread.php?23946-test-targets&p=232423#post232423
https://www.geotech1.com/forums/show...429#post232429
https://www.geotech1.com/forums/show...708#post232708

[Vadim18]

Does this help?
https://www.geotech1.com/forums/showthread.php?23946-test-targets&p=232423#post232423
https://www.geotech1.com/forums/show...429#post232429
https://www.geotech1.com/forums/show...708#post232708

I think will help, not to fast but at least will help to understand better. Thank you Qiaozhi.

[maslivez2011]

[QUOTE = 6666; 266786] Не все ответы, но где-то для вас, чтобы начать
http://chemelec.com/Projects/Metal-1a/Understanding-the-PI-Detector.htm

https://www.minelab.com/ __files / f / 11043 / KBA_METAL_DETECTOR_BASICS _ & _ THEORY.pdf [/ QUOTE]
Thanks 6666, good information.