give it metal detectors with a penetrathion depth of 1m

[Nightryder]

There is probably no way to detect a coin at 1m. I have seen a very high-powered PI detector with a 32cm coil detect a US nickel at roughly 50cm. The Garrett ATX will detect a US nickel at 43cm. I don't know that any of the projects posted here can do anywhere near that, probably more likely 30cm max. With some heavy mods they might get close to 40-50cm but you will need a really good understanding of PI to get there, and a big battery.

That's with the ATX 12 * 10" DD coil. With the 13 * 11" DD coil, I detected a US nickel at about same distance however sensitivity was at 9. I couldn't increase sensitivity due to EMI around me. Which makes me believe detection distance can be more than 45 cm. Even a lot more with a 13" mono coil which I don't have yet. Test was performed in my backyard, GB and Iron Disc were off. It's a straightforward machine when compared to GPX5000

[moodz]

I can pick up a nickel at 50 cm with GB on and 18 inch DD coil in the backyard .... its not a PI though ... its a single frequency VLF @ 19 Khz.

Pic below shows nickel detection in the latter part of the target level trace.

[Nightryder]

I can pick up a nickel at 50 cm with GB on and 18 inch DD coil in the backyard .... its not a PI though ... its a single frequency VLF @ 19 Khz.

Hey Moods,

Not too shabby man! I mean an IB machine, running at 19KHz, and against a nickel? I'd be detecting with it any time any day of the week. It might be a little heavy of a beast but still quite impressive. Please don't tell me it's a nexus standard mp, maybe with a special request for its coil. Because I have a crush on that beautiful thing .

Anyway, best of luck!

[moodz]

Hey Moods,

Not too shabby man! I mean an IB machine, running at 19KHz, and against a nickel? I'd be detecting with it any time any day of the week. It might be a little heavy of a beast but still quite impressive. Please don't tell me it's a nexus standard mp, maybe with a special request for its coil. Because I have a crush on that beautiful thing .

Anyway, best of luck!

Thanks .. its a custom job ...still working out some details like auto ground balance ... not a fan of manual GB.

[ivconic]

I always have problems with that measurement system... 18 inches is 45.72cm !!!
I always have to consult a calculator to understand what it is about.
In that case, it is no wonder to detect a coin at 50cm.
I remember a long time ago, many years ago, some smart man wrote in a patent that the maximum useful range on a coin is about the diameter of the coil.
In that case, Paul, you have not failed miserably!

[ivconic]

But these are old truths that we have known for a long time.
Some new "kids" only find out some things today.
I have one problem with that though.
I can't imagine how I would be able to pull such a coil through my terrain, very steep hills with lots of rocks and low bushes.
The only place where valuable ancient coins are found.
I always have in front of my eyes a rather comical picture of a Youtube advertisement for a detector that uses a huge... gigantic OO coil with which it finds a Roman "Sestertius" (a rather large coin) at about 45-50cm deep... in a fairly uniform and "clean" soil!
Whenever I want to laugh out loud, I look for that fiercely tragic YouTube video!
Even Benny Hill is no match for that kind of humor!

[pito]

47 cm gold ring
https://www.youtube.com/watch?v=LOreCtJLw8I

[moodz]

I always have problems with that measurement system... 18 inches is 45.72cm !!!
I always have to consult a calculator to understand what it is about.
In that case, it is no wonder to detect a coin at 50cm.
I remember a long time ago, many years ago, some smart man wrote in a patent that the maximum useful range on a coin is about the diameter of the coil.
In that case, Paul, you have not failed miserably!

Ivica not really ... the coil is an older DD type coil so the real RX aperture is only about 22 cm. I would expect the better or same performance on a 22 cm OO coil. ... ie still 50 cm. ( bit over 2 coil diameters )
Smaller coils are better at smaller targets and vice versa for larger coils are good for larger targets. For a particular detector scheme you can plot a graph of coil size vs range for a particular target size and there will be a sweet spot where the coil size and detection range is optimal for a particular target size. I have tested with a 6 inch coil and detected coin sized objects approaching 50 cm using a powerful PI.

This is a VLF detector that exceeds PI sensitivity ( but has discrim as well ).

One of the main advantage of a fully digital detector is that there is only 1 signal level that can be overloaded no matter how high the sensitivity is raised its just a question of how much sensitivity can be applied before the small target disappears in the noise.
The 45.72 cm coil ( even being a "old" DD type ) is easily good in my case for searching 1 meter depth gold nuggets .. which is what the detector is designed for.

The really big kicker though is the ground cancellation and EMI rejection .... no good having max sensitivity if you cant reject the ground and EMI also.

I would like to see everyone repeat their tests with a 4 inch ferrite next to the target also and see how you go.... LOL

I use the GPZ7000 as the benchmark and I can exceed it by about 10% in performance with the latest code.

[kt315]

I can pick up a nickel at 50 cm with GB on and 18 inch DD coil in the backyard .... its not a PI though ... its a single frequency VLF @ 19 Khz.

Pic below shows nickel detection in the latter part of the target level trace.

Moodz, why you are not able to continue of Carl's research thread??? why again? we call that CACHE TEST, 17 pages of posting.

Cache Test - Geotech Forums (geotech1.com)

[ivconic]

Hats off to your knowledge and your work so far.
Of course, you can't take all my posts too seriously, in gloomy days the only cure is a joke.
You have an advantage because you live in Australia, the biggest "pan" on the planet, everything is flat to the point of hopelessness and unprecedented monotony.
So you can work there with a coil 4 meters in diameter!
(I have yet to see anyone break Eric's record on that one)
But the statement that coil diameter is also the greatest useful range on a dime still stands.
BTW I think George Payne said that once upon a time... I could be wrong.
Certainly more will be achieved in the air, but in the soil it is still the rule.
Yes, it is interesting that when it comes to a DD coil, the "diameter" is not the same as the diameter of the entire coil, but the rule still applies, I don't know how to explain this.
Maybe Aziz with his "doughnut" drawings could explain it better?

[ivconic]

Once upon a time when I was still chasing air depths... on the TGSL I added one "monostable" (if I remember correctly) and the TGSL detected the coin at a fantastic 56cm with a 27cm coil... but in the air!
Of course, it was totally unusable on soil.

[kt315]

Once upon a time when I was still chasing air depths... on the TGSL I added one "monostable" (if I remember correctly) and the TGSL detected the coin at a fantastic 56cm with a 27cm coil... but in the air!
Of course, it was totally unusable on soil.

be cause you mean CLEAR coin. in the soil IN REAL CONDITIONS works HALLO effect and OLD coin has BIG ground volume of conductivity around - more much than coin size. some kinda the coin is increasing itself in volume -!
IN TIMES -! so you do not waste the depth and the depth is SURE SAME like you see the test in air.

Галло – Образующиеся втечение длительного времени проводимые соли в окружающем объект грунте.

[Nightryder]

47 cm gold ring
https://www.youtube.com/watch?v=LOreCtJLw8I

Hi Pito, looks sweet! What detector is this? And what are the coil specs?

Thanks for sharing the video!

[pito]

quasar arm metal detector
https://www.google.com/search?sca_es...ih=738&dpr=1.1

[GeoMax]

Hi Pito,

is it this project? GitHub - mrKuzmich/quasar_arm_pcb: Altium Designer project of metal detector "Quasar ARM"

Can someone who has Altium Designer export the schematics from this project as an image (jpg, gif, png or bmp etc.) and post it here in the forum?
Thanks...