give it metal detectors with a penetrathion depth of 1m

[ivconic]

And for the end there remains the last case; this is where the very correct position expressed by Riss comes into play.
And those are big forests. It rarely happens that there is a settlement in such a forest.
But lately, most detectorists are determined to go to such places and look for "accidental" finds, because the known sites have long been searched and emptied.
So today there is a greater chance of finding something valuable in such forests, as an "accidental" find.
There the soil is relatively "clean" and this is where a deep detector could come into play.
But... take my word for it; while walking through such a forest and searching with some "depth" detector;
inside you pray to God that such a detector does not find anything deep for you!
Because if it finds; the long, painfull and difficult agony of excavation follows!
The first 20 cm of the layer is loose soil with small veins from plants and small stones. Easy.
And then a much harder layer begins, with stones embedded in strong clay soil, as if someone was building an impenetrable wall with mortar and concrete.
And all this is made more difficult by thick and even thicker veins and tree roots.
Every 5cm deeper is more and more agony!
The worst part of the whole story is that there is no such thing as 100% reliable discrimination.
Discrimination with the detector is to a good extent accurate only up to 20-30... even 40 cm deep.
After that, the discrimination accuracy drops rapidly with each centimeter of depth.
So you're digging something you're not sure what you're actually digging.
It very often happens that the famous horseshoe is found at a depth of over 50 cm!
After two hours of hard physical work. In some incredible way it got there.
Often, at depths of over 50 cm and 1 m, some undefined rusty iron mass is found, which is worth nothing.
And while you dug it up; you are so broken and tired that that day of searching is over for you.
Who searched and has such experiences; he knows what those torments and agonies are.

[ivconic]

On the fields and plains (Vojvodina, Serbia), "ultra shallow" detectors like the Tesoro Silver Sabre, Golden Sabre and similar types performed very well.
Every year after the season of plowing the fields; such detectors pick up all the good finds from shallower surfaces.
They are particularly successful in finding the smallest silver coins.
And who has ever tried to search on such surfaces; knows that the smallest silver coins are the hardest "targets" in such conditions.
We can talk about "depths" seriously, only when it comes to very "clean" soils with a very uniform composition.
Sahara ... for example. That's where deep detectors are successful!

[ivconic]

In the USA, you don't have the remains of ancient Roman and late Roman as well as medieval fortresses, towers, and settlements.
And here in this part of Europe we have a lot of them.
Next to the main places, between the main places; there were numerous smaller towns, villages, rest stations and horse exchanges.
Some claim that along the route of the Roman road "Via Militiaris" (which passes 30 km from me) there was one such place every 6 Roman miles.
And in the mountains and hills there are also places where people retreated in times of wars, unrest and barbarian invasions from the east.
All listed are places of great interest.
In such places, finding a coin at a depth of more than 20-25 cm is an extraordinary success and does not happen often.
80% of coin finds in such places; does not exceed a depth of 10-15 cm.
And in the valleys of the rivers, next to the banks of the rivers, there are "peaceful" settlements.
There, the river flooded and deposited layers of soil, and the finds are very deep there. Sometimes over several meters.
I am more inclined towards mountainous and hilly terrains, I rarely visit river valleys.
But in both cases it is about surfaces that are very densely "seeded" with various metal pieces, sawdust, rust, as well as crushed ceramics.
In the valleys of the rivers, in the fields, to all of that, we need to add very aggressive chemistry left over from the regular annual fertilization of the fields.
In such described conditions, finding a coin is a challenge.
And finding it at greater depth is a very rare phenomenon.
Depth does not go along with other good features on the detector. Well, the rule of thumb is that a "deep" detector has no other good features.
Deep Detector is only good for Youtube video ads. In practice, it is mostly unusable on the mentioned surfaces.
In the described conditions; coins are not found by the "deep" detector. Coins are found by a detector that has a very good GEB, DISC and Recovery Speed.
And that is the harsh truth that 90% of detectorists today do not understand.
Now after this story, all those YouTube depth tests should seem totally pointless to you, right?
I don't know about you, but to me they are totally pointless.
Of course, in such conditions, as I have described and I have on my fields; an additional mm to cm of greater depth is always desirable.
But it is also the most difficult task to project such a detector, which will satisfy all these conditions.
Good PI detector BUT with perfect GEB&Discrimination; would be the closest thing to an ideal detector for such conditions.
But such a PI is an oxymoron, of course.
I don't need to mention that I already had the ML GP3000 for a long period of time and that I also carried the GPX 5000 there for shorter periods.
They proved to be almost unusable.
Explorer SE is very deep, but it is too "slow" for such conditions.
The Fisher CZ series and 12xx series performed relatively solid.
But the XP models performed best.
This story, I hope, well illustrates the reasons why "depth" by itself means nothing.

[Riss]

which of the detectors described in this forum has the greatest detection depth. can the PI detector with the 1m coil detect a coin at 1m?
Levin

Let's leave the technical part aside . I have come to the conclusion that you have no experience in digging holes. Get out your best shovel and dig a hole 50 cm (20 inches) deep and note how long it took you to dig it. Then a hole 71 cm (28 inches) - for how long, and one 1 meter deep - for how long. You must have dug 3 separate holes! -only with a spade and a pickaxe, otherwise the coin may be damaged during excavation . I hope you have great physical strength and endurance , because in real conditions the last 10 cm are dug very carefully, which takes extra time . What if the soil is heavy and dense (difficult to dig) ? Well - get and a special shovel for digging up the soil…what if the soil is wet and sticks to the shovel… We all look forward to your next post the results of this science experiment, nothing but the results of the experiment!

[MartinB]

Well Carl, the Garratt ATX looks like a great machine but carries a hefty price tag of just under 3,000 GBP. Way beyond my capabilities, but is there anyone out there up the challenge of replicating one? Even if it cost a couple of hundred dollars to construct, it would be worth it.

[Carl-NC]

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.

[Levin]

which of the detectors described in this forum has the greatest detection depth. can the PI detector with the 1m coil detect a coin at 1m?
Levin

[ivconic]

The best detectors will get a single coin at maybe 50cm. On a good day, in mild ground.

I've been in this since 1987.
I've been changing detectors, brands and models, ever since.
I've benn making detectors since 1994.
I've had appox. 100 to 110 my own metal detectors, originals, made by genuine manufacturers.
I've been visiting the ancient Roman sites also since 1987.
... and yet;
I have NEVER SEEN a detector detecting single coin at 50cm so far.
NEVER!
And accoridng to all my collected knowledge and experience so far; I stand here and claim; NO SUCH DETECTOR!
At least not yet.
...
Now additional explanation.
Me to accept that there is such a detector that can detect a coin 50cm deep in the ground:
The coin must be "normal", either one of the modern ones in circulation, or one of the antique ones.
Maximum size (diameter) up to 50 mm.
Placed at the bottom of a 50cm deep hole, laid down. The hole is well covered with the same soil.
The detector must give a clear and unequivocal response to that coin, in both cases with the probe crossing at a 90 degree angle.
Soil can be any type, from clean to heavily polluted, it doesn't matter to me.
The detector coil can be of any shape, composition and size, it doesn't matter to me.
And the test must be repeatable several times. Always in every moment.
The detector must be either VLF I/B or PI type. If the VLF is of type I/B; must be with discrimination and geb.
If it is of PI type; I do not care.
Show me what that detector is and I "might believe you".
I'm not saying that I haven't seen cases when some detector "detects" a coin, even a gold coin, up to 60 cm in the ground.
But these are rigged situations by either malicious people, or the detector's behavior has been misinterpreted by illiterate users,
who misinterpret the detector's rampage as responding to anything but that coin.
...
The deepest coin I personally found was a silver medieval Serbian coin with a diameter of just under 20mm,
at a depth of 32cm, with Deus and coil 34x28.
But that "was that day" that happened then and never again.
...
I'm sorry to jeopardize anyone's dreams with this story... but it's the harsh truth.
Accept it as soon as possible; and you will stop self-deception and that truth will save you many days in your life,
many nerves and a lot of money, above all a lot of health.
...

[GeoMax]

Hi Levin,

I would suggest to build one of the following detectors like Surf PI, Geotech Baraccuda, Hammer Head PI or MiniPulse PI, because these projects are well documented and if problems occoure you can find here in the forum support.

@others
Do you really want to dig 1 meter deep for a possible coin target? I believe that after the first few bottle caps at 1 meter you will be not keen to dig every target at 1 meter and will opt for a smaller coil.

[Levin]

what is the best detector you can build yourself and give it introductions for these one

[Carl-NC]

The best detectors will get a single coin at maybe 50cm. On a good day, in mild ground.

[Levin]

oh sorry I forgot to say that the piece of metal is about the size of a coin

[Carl-NC]

The metal detector should at best recognize a piece of metal that is about 1 m deep...

Is the piece of metal the size of a car, or the size of a coin?

[Levin]

The metal detector should at best recognize a piece of metal that is about 1 m deep, a depth recognition and metal differentiation would also be very helpful
Levin

[Qiaozhi]

Hello
I'm new to metal detector construction but have basic electronic skills. Can you also build metal detectors that have a penetration depth of 1 m, if so where can I find instructions for one?
thanks for answers
Levin

What type and size of target are you wanting to detect at 1m?