#26
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yes indeed... I think people never made such kind of MDs cause of power problems and weight issues... that requires a vehicle and cannot be good for handheld or any other man-carried thing. The fact we haven't already such kind of stuff around is also related to magnetometers that are widely used in THing for decades now... but limited to the ferrous stuff locating. But many THunters need iron and iron-alloys detection more than other stuff... like happens in ship-wreck search... where mandatory setup is in most of the cases having both a side scan sonar and a very sensitive and fast magnetometer... then , when wreck is located, they use rov or at small depth people go with waterproof MDs etc ... or simply cut the wreck and recover the valuable things on the expedition ship.... like happened about a gold bars payload inside a wreck some years ago. But... what about big natural gold nuggets ? Or large treasures mostly made of noble metals (gold/silver etc not iron) ? I think older methods have no usefulness with big, deep e.g. gold stuff... cause magnetometer will no see that stuff... and conventional MDs have too limited range for some places. I remember that I read many times of gold nuggets found in Australia at considerable depth... several at meters underground during excavation for roads/tunnels and similar stuff: no MD of what we know can detect such stuff in meters of Australian hi-mineralized soil. Same apply to some middle-east and central-asian treasure locations.... rooms at 10meters and more depth! Same for some US nuggets, very rare and very BIG... but covered by meters or tens meters of sand! So... the idea, though not exactly an MD for everyone... or everyday search have good applications in the right place I think. The capacitor bank idea is employed in some older german designs... and that's a good idea indeed cause in such hi power delivery at coil it's easy charge a capacitor bank to mantain energy levels between pulses... more easy than , instead, try to make a bank of mosfets to share the current and so the heat generated... maybe someone will made one of these monsters in the next future... who knows! Kind regards, Max
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"Kill for gain or shoot to maim... But we dont need a reason " someone said... |
#27
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very high current in the coil also means extreme high Flyback voltage. Insulation problems become dominant. Max, I have a question: You have mentioned in the past that fired clay shards are a problem when detecting with a PI. The ferrous content in fired clay indeed responds to the strong PI pulse. I have been working on a discriminating PI design for some time now. There are still some problems with certain FE targets that give about the same resistive response as reactive response and are therefore not well discriminated. But, MOST of the FE response is eliminated. The sensitivity to all FE is minimal, (see http://www.geotech1.com/forums/showthread.php?t=15441) the sensitivity to non magnetic metals is greatly enhanced. Would such a PI detector, that has a good depth penetration be useful in the areas that you mentioned? All the best Tinkerer |
#28
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Hi, indeed was real pain... more the power ...more the troubles... the concept I already know before making e.g. GSIV clone... but when tested that on such sites it become really apparent the device couldn't be productively employed in such scenario , if not in the depth variation... with a big coil suspended far from soil. I discussed with Alexis the problem and realized that , indeed, the real possible use was just that, depth version, coil far from soil. If your new PI is capable of discriminating fired clay, pottery and other ceramics ...well it's worth for sure in such kind places. That's cause using VLFs some deep targets are undetected at their depth and use of conventional, old PIs is simply impossible with small coils near soil (like for coinshooting and other small stuff search). I hope you'll go ahead with that project... will be very nice hear of complete immunity to ceramics and pottery with hi-iron-oxides content. Kind regards, Max
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"Kill for gain or shoot to maim... But we dont need a reason " someone said... |
#29
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Any help is welcome. Tinkerer |
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