Help !!!

[AK48]

hello , can someone help me , i wanna teach a lot about geophysical
as i know , factory like OKM for exemple built their machine with a component called " fluxgate sensor " and i know that this electronic device detect all variations off the earth magnetism , this way , i can say : it's a sophisticaded magnétometer , but what i wanna know that: what components inside a real GPR , how it worked ? what is this technologie ? and are there manfacturers of real GPR ? what are the models in the market ? what can they detect ? also gold and silver or
just as magnétometer ? thank you , AK48 .

[Davor]

Fluxgate is a simple sensor that operates by means of a coil with core that easily goes to saturation. Such core materials are selected that have sharp transition to saturation, usually metglass. When such core is exposed simultaneously to AC field that partly saturates it, and a superimposed Earth (or some other) magnetic field, there will be some asymmetry in saturation. As saturation produces sharp glitches on the coil, there are a few means of detecting the difference, and fluxgate is a sensitive detector. It detects magnetic targets only.

GPR is literally a radar. A deciding element is its antenna. Almost all antennas are somewhat resonant, and when a train of sharp pulses is supplied to an antenna, it transmits a decaying oscillating field after each pulse. This field is coupled to the ground by means of proximity (therefore a GPR is dragged around in a cart) and it partly reflects against the objects in the ground. Those may be metallic, or insulators, voids, etc. Just about anything that disturbs either E or H field will produce some kind of reflection. There is a tradeoff between antenna complexity and target resolution, so the best resolution is obtained with the simplest antenna with no gain. For that reason you need continuous readouts over a length of terrain to establish the well-known GPR curves which reveal targets and their depth. A LOT is in the software.

[AK48]

thank you , now i can separate between magnetic sensor and GPR , i've seen some publicity about MALA GPR on the web , what do you think about this GPR unit ? is it a good GPR ? or it is cheapless on the market ? wich one do you recommeend to me ?thank you very much : AK48

[Davor]

IMHO all GPRs on the market are far too expensive for any amateur practical use.
There is a simple rule: will you shovel? It goes like this - your detector is a very deep one, yet you have no clue what exactly you are going to dig out, and you know it is 1m deep - will you shovel, or just go away?

[AK48]

Hello !!! yes , i shovel , i know that my detector is a deep one and i'm proud to own it but my clues says : in my area , almost of the targets but coins are
more that twos meters deep , very olds wooden chests full of gold money and everythings like this , thtat's why i wanna by the best and cheaper GPR on the market , this way , which one do you recommend to me ? AK48
best regards .

[Davor]

A half way decent PI detector can be fitted with a big coil and it will be sufficient for finding big targets at over 1m deep. A GPR requires anear constant distance to the ground, and therefore it is dragged around in a cart. For that reason GPRs are far better suited for urban utility detection.
If you still think GPR is the very thing you need, just hop to any of the GPR topics and ask a question. Someone will contact you for sure.