smart metal detector (GOLD, PLATINUM)

I know there is a lot of build your own metal detector info out there. However, I would like some input on changing coil design. Typically, the depth of the EMF is near the diameter of the coil...the very bulky coil. I have had great success gold prospecting by looking where others don't. namely crevices well above current water levels, water laid gravel benches on the sides of bone dry hills etc. My quarry would be: can a substantial EMF be generated vertically? Say, creating a coil that is long and narrow that would direct the EMF to a point 1/4" - 3/8" in diameter? The purpose would be for probing deep cracks above and below water level. There was a detector on the market many years ago...it could pin point very small gold nuggets, however it had virtually no depth, you had to almost be touching the metal to get a reading. And if coils have to be bulky, is there a way to concentrate or direct the EMF in a vertical depth orientation? thanks, plumber.

To get that degree of directionality you ened to use high frequencies, high frequencies don't penetrate, so it's one or the other, you can't have both. Well unless you get into some advanced phased array transmitters, but that's more than major project.

Sceadwian said:

To get that degree of directionality you ened to use high frequencies, high frequencies don't penetrate, so it's one or the other, you can't have both. Well unless you get into some advanced phased array transmitters, but that's more than major project.

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Thanks for your reply, I should have known, the technology has gone no where in 3 decades. Assuming the signal grows weaker with increased density and depth...I don't know, maybe modern tech components can multiply or boost the resulting signal for a more sensitive reading. Like taking the human ear out of the equation, and converting the signal to something that can "sense" and indicate micro fluctuations in the magnetic field when passing over metal. Would this be more possible? Sonic leak locator's come to mind. They have both audio and digital graph indicators...the graph was always way more sensitive than the earphones. plumber

I just realized that perhaps the electromagnetic field is self limiting, and will only travel a relative distance...regardless of the media it travels through. But increasing or converting the signal would still help a little? no?

IMO, difficult or impossible. I've been looking at metal detector projects for ages, including some early ones with widely separated transmit and receive modules, operating at frequencies and power levels that aren't legal, and haven't seen anything with a narrow beam.

My need is searching for buried survey disks (benchmarks). Specifically I want to find a 3" diameter bronze disk, buried up to 4 foot down- without using a 4 foot diameter coil. My guess is we'd like something similar.

Hey, Sceadwian, we're neighbors- I'm over in Canandaigua.

Best,
Conrad

Waves from Hilton =)

Conrad Hoffman said:

IMO, difficult or impossible.

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Thanks for the reply, same boat, except my target is a lot smaller. Not to stir scientific waters, but a surveyors marker seems a very easy target for using properly used dowsing rods. I have experienced first hand the viability of certain forms of dowsing, a single point target like a brass disk would be easy. I believe scientific factors are involved with metallic rod type dowsing. Meaning the same result can be repeated consistently. plumber

The gold mining industry uses wand-type sensors in the mine shafts; they look like the ones to scan people by security personnel. No typical coils.
There has to be a supplier for commercial gold miners somewhere. Or get the "Pistol Probe"

If it were possible with current technology, Minelab (or Whites, etc.) would have done it. The best gold detector on the market is the Minelab GPX4500.

perhaps PM Chemelec on this forum who has submitted some designs of his own and who also lives in former gold country.

Roff said:

If it were possible with current technology, Minelab (or Whites, etc.) would have done it.

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yeah, gold prospecting has always been a conventional wisdom sort of thing ie. gold is where you find it etc. I have a old whites I refuse to throw away. I tried to break the mold with black sand separators; (using high viscosity liquid, agitation and alternating electromagnets to concentrate flour gold quickly.) Knowing one bead of sweat from your forehead can "float" fine gold right out of your pan gave me the idea to take a different direction instead of conventional gravity/centrifugal force processes and amalgamation. The hack prototype worked, soap resolving the final outcome. But alas, I moved out of gold country, and the flame died. I'm in WA. state now, but the older I get, the farther the mountains seem to get!
Conrad had posted about the"pistol probe" very interesting, maybe even for nugget shooting but I doubt it can discriminate black magnetic sand. But reviews swear it is directional and at the tip only...the direction I wish to go.
take care, plumber