Speaker 1: Brought to you by the reinvented two thousand twelve Camray.
Speaker 1: It's ready. Are you get in touch with technology with
Speaker 1: tech Stuff from how stuff works dot com. Hello again, everyone,
Speaker 1: Welcome to tech stuff. My name is Chris Polett and
Speaker 1: I'm an editor at how stuff works dot com. I
Speaker 1: worked with a person across from me pretty often. Uh.
Speaker 1: He has a senior writer at how stuff works dot com. Also,
Speaker 1: his name is Jonathan Strickland. New Wave tried to kill
Speaker 1: the Metal but they failed as they were stricken down
Speaker 1: to the ground. The second time I've quoted this band. Really,
Speaker 1: at least it isn't from Tron, that's true. Not from Tron,
Speaker 1: not from war games. Um. So today we are going
Speaker 1: to talk about you know what, This was a topic,
Speaker 1: uh that I don't know that anyone has ever requested. Um.
Speaker 1: It came to me actually as I was looking through
Speaker 1: stuff in my basement and went metal detectors you should
Speaker 1: talk about We've never talked about metal detective Actually, we've
Speaker 1: sort of talked about metal detectors because metal detectors use
Speaker 1: a lot of the technology we talked about before, especially
Speaker 1: the relationship of magnetism to electricity. Yeah, um, but yeah,
Speaker 1: I mean it's something that we run into very often,
Speaker 1: especially if we travel and walk through the metal detectors
Speaker 1: at the airport. If we're not getting back scattered or
Speaker 1: uh you know, dropping stuff that you can't find, losing
Speaker 1: your wedding ring and the maltch outside. Yikes, that's good stuff.
Speaker 1: I've done that. I still have it, so there you go.
Speaker 1: I've never lost my wedding ring. Alright, Well it was
Speaker 1: only temporary. So anyway, metal detectors talk about what they are.
Speaker 1: We're mostly going to be talking about the kind that
Speaker 1: you would you would carry with you, you know, the
Speaker 1: portable metal detectors that you would use when looking for say,
Speaker 1: loose change on the beach, or you know, searching for
Speaker 1: that rare civil war uh bullet or a gun that
Speaker 1: might be part of you know, in an area that
Speaker 1: you knew the battle happened here, so there may very
Speaker 1: well be stuff here. Yeah, we we should definitely talk
Speaker 1: about some of the applications of the technology. UM and
Speaker 1: I would like to point out that we have an
Speaker 1: excellent article on how stuff works dot com if you're
Speaker 1: interested in learning more. UM it's called how metal Detectors Work. Yeah,
Speaker 1: it should be pretty easy for people to find, written
Speaker 1: by Jeff Tyson, and it is a very good article
Speaker 1: and very uh simple to follow, easy to understand. I
Speaker 1: would say this is this is one of those really
Speaker 1: great how stuff works articles. Yeah, by the time you
Speaker 1: get through it and you're like, oh, yeah, no, that
Speaker 1: totally makes sense, especially if you have a little bit
Speaker 1: of grounding in the way electromagnetism works and conductors and inducers.
Speaker 1: So we'll we'll cover that. I mean, we've talked about
Speaker 1: an in previous podcast, but we'll will will do a
Speaker 1: quick brush up so that we can explain it. Um,
Speaker 1: so you wanna, let's let's talk about the the Jeff
Speaker 1: does a great job at breaking down what the typical
Speaker 1: portable metal detector, the four main parts of one, what
Speaker 1: they would be. Yeah, I mean, if you've ever seen
Speaker 1: people walking around with a metal detector, you you sort
Speaker 1: of know what they look like. They have a round
Speaker 1: dish part that's used close to the ground, right, that's uh,
Speaker 1: that's called the coil. Yes, and then you have the stabilizer, um,
Speaker 1: which is the part that you actually hold onto, that
Speaker 1: holds onto your rope, that that you see on your
Speaker 1: arm because you know, frankly having used a metal detector,
Speaker 1: it's not the lightest thing, right, This this helps, This
Speaker 1: helps distribute the weight somewhat so that you're not you
Speaker 1: don't feel like you're carrying around a you know, ten
Speaker 1: pound brick the whole time, because without that then you
Speaker 1: would get very tired, very quickly. Yeah. And the the
Speaker 1: ten pound the aforementioned ten pound brick, which probably isn't
Speaker 1: ten pounds, but it's certainly can feel that way after
Speaker 1: a while. That's the control box, uh, And you've got
Speaker 1: all your your electronics in there. And and then the
Speaker 1: connect yes, the long skinny part that's the shaft. Yes,
Speaker 1: it connects the coil at the base to the part
Speaker 1: that you're holding. And the of course the control box.
Speaker 1: So those are your four basic parts of your basic
Speaker 1: metal detector. Yes. And then you know you have your
Speaker 1: headphones because this is one of our episodes of stuff
Speaker 1: that beeps and stuff what beat? Stuff? What beeps? And
Speaker 1: it it does in fact beep. Yeah, there's usually some
Speaker 1: sort of audible alert that you have in fact detected metal. Yeah. Now,
Speaker 1: more sophisticated uh, metal detectors will tell you a lot
Speaker 1: more often with uh, well, sometimes with with an audible tone,
Speaker 1: but also with a visual uh, some kind of visual analysis.
Speaker 1: We can get into that too in a minute. So
Speaker 1: there are three main types of metal detectors, the ones
Speaker 1: that work, the three three main approaches to to metal detection.
Speaker 1: Let's say, Uh, there's UM, there's the very low frequency,
Speaker 1: which is probably the most um, the most popular or
Speaker 1: the most common type of MEL detector, at least for
Speaker 1: the portable metal detectors. UM. Yeah. When we get into this,
Speaker 1: you'll you'll see that each of these different types has
Speaker 1: its own strengths and weaknesses. And you might say, well,
Speaker 1: the VLF detector sounds great, why would you use the others?
Speaker 1: We'll get into that. The other two are pulse induction
Speaker 1: and beat frequency oscillation. Yeah. I I knew a beat
Speaker 1: frequency oscillator once. He was awesome. Yeah, Anyway, I think
Speaker 1: something else, I guess. So that's the beat boxer frequency oscillator.
Speaker 1: That the uh, the VLF metal detector is the type
Speaker 1: that I have. UM and uh. The the basic differences
Speaker 1: uh and these as you'll see those really in the coils,
Speaker 1: to be honest, because the VLF has two different coils.
Speaker 1: One transmits UM and and the other is basically an
Speaker 1: antenna to pick up the signals, so they're shielded from
Speaker 1: one another so it doesn't pick up because otherwise you
Speaker 1: turn it on, you would just have the receiver saying,
Speaker 1: oh my gosh, there's metal everywhere. Holy crap, you're rich,
Speaker 1: even up in the air. It's it's literally everywhere. Yeah,
Speaker 1: that would that would not be very useful. And taking
Speaker 1: this back to the store where I bought it. It's
Speaker 1: a detector detector. This does not do me any good.
Speaker 1: It's a detector. It's a detected or where's perry? So
Speaker 1: the the the transmitter coil um it's it. Think of
Speaker 1: a circle, all right. It's a this circular part at
Speaker 1: the base of the metal detector. And if you were
Speaker 1: to take it apart, which I do not recommend you do,
Speaker 1: you would see that there is a warrant point warranty
Speaker 1: and it may not work anymore. You will have a
Speaker 1: there's a coil of wire that goes around the perimeter
Speaker 1: of this circle, like it's it's wrapped around. So the
Speaker 1: circle itself is let's say it's like a quarter of
Speaker 1: an inch thick, and you've got this coil of wire
Speaker 1: that's that's coiled around this quarter of an inch all
Speaker 1: the way around the perimeter of this circle. When you
Speaker 1: run electricity through this coil of wire, what happens besides
Speaker 1: the fact that electrons are moving through because of the
Speaker 1: nature of electricity and magnetism, Well, when you run electricity
Speaker 1: around a coil like that, it generates a magnetic field.
Speaker 1: That's right. It does generate a magnetic field, and it
Speaker 1: generates a magnetic field perpendicular to the direction of the electricity.
Speaker 1: It's just the nature of electromagnetism. It's amazing, it's awesome.
Speaker 1: That's what how electro magnets work. And uh dynamo's work
Speaker 1: in uh and sort of using this in reverse. Um.
Speaker 1: So you've got electricity flowing through these coils and that
Speaker 1: generates the magnetic field. Well, it doesn't just the electricity.
Speaker 1: Actricity doesn't just flow in one direction, no, it it
Speaker 1: goes back and forth. It alternates very very very fast,
Speaker 1: almost as fast as I waffle back and forth on
Speaker 1: what I want to eat for lunch. And that means
Speaker 1: that the magnetic field also alternates. The direction of the
Speaker 1: magnetic field changes. Uh. And if you think of it
Speaker 1: in terms of the disc, the coil disc being towards
Speaker 1: the ground, you can think of it as the magnetic
Speaker 1: field occasionally is pushing against or pulling the ground in general.
Speaker 1: That just think of it that way. That's the direction
Speaker 1: of the magnetic field while the electricity is going around
Speaker 1: and around in a circle, back and forth and in
Speaker 1: the various directions, and that alternation is happening hundreds of
Speaker 1: times per second. So you've got this magnetic field that's
Speaker 1: that's just oscillating essentially right there against the ground. When
Speaker 1: it comes to contact with something that is metal, well,
Speaker 1: the metal will start to that magnetic field will as
Speaker 1: a a weaker magnetic field to generate around the metal object. Yeah.
Speaker 1: Basically induces a magnetic field in a metal object in
Speaker 1: the ground. So let's say, uh, um, you drop a
Speaker 1: screw and when you're trying to build something outside and
Speaker 1: you're trying to find it with your metal detector so
Speaker 1: that you don't step on it with a bare foot
Speaker 1: and you know need a trip to the hospital and
Speaker 1: a technis shot. Um. So as soon as you run
Speaker 1: the coil of the field and you're not trying to
Speaker 1: touch the ground with it, you really just need it
Speaker 1: close to the ground. Um, it will find the screw.
Speaker 1: The screw will basically start inducing a it will end
Speaker 1: metal detected detector will generate a field, and that will
Speaker 1: cause the screw to generate its own a weaker magnetic
Speaker 1: Oh yeah, yeah, considerably weaker, but it will the metal detector, Uh,
Speaker 1: the antenna coil inside the transmitter coil will say, oh,
Speaker 1: look there's something right there that is generating a magnetic field.
Speaker 1: It's right here. And the way that the the that
Speaker 1: antenna works is the way I was talking about with
Speaker 1: a dynamo. So if you have a coil of wire
Speaker 1: and you introduce it into a fluctuating magnetic field, that
Speaker 1: will induce the flow of electricity within the wire. Just
Speaker 1: as electricity and the wire will create generate a magnetic field,
Speaker 1: a magnetic field will induce electricity to run through wire
Speaker 1: fluctuating magnetic field. It can't just be just a magnetic field.
Speaker 1: So when the weak magnetic field from the mental object
Speaker 1: hits that that the wire in the the the the
Speaker 1: receiver coil that generates the electricity, which then alerts the
Speaker 1: control box that that's what When the control box gets
Speaker 1: an electric signal from the receiver coil that says beep,
Speaker 1: something is here stuff? What beeps? Yeah? Stuff what beeps. So, yeah,
Speaker 1: that's the basic uh way that a VLF metal detector works.
Speaker 1: It shoots out this magnetic field. The polar polarization is
Speaker 1: alternating the same as the the flow of electricity around
Speaker 1: the the the transmitter coil and then the receiver coil
Speaker 1: picks up any magnetic fields generated by metal objects that
Speaker 1: are under the surface of the ground. It's pretty cool
Speaker 1: and generally it will go more or less about a foot. Yeah,
Speaker 1: you're not going to find you know, the Earth's core
Speaker 1: and the depth of what the depth of the The
Speaker 1: effectiveness of this metal detector is also going to be
Speaker 1: dependent on other factors, like the nature of the metal
Speaker 1: object itself, because some some metal objects are going to
Speaker 1: generate a stronger magnetic field than others, like iron. Uh.
Speaker 1: It will also depend on the composition of the soil.
Speaker 1: So the soil has a lot of elements in it
Speaker 1: that would create a magnetic field, you're gonna get a
Speaker 1: lot of interference, yeah, or or an environment where uh
Speaker 1: that that would conduct electricity more readily. Like if you're
Speaker 1: trying to look for something and say saltwater, you might
Speaker 1: have more difficulty than if you were looking you know,
Speaker 1: on on a different type of soil. UM. Now there
Speaker 1: is something to uh called phase shifting, and that's how
Speaker 1: it's able to tell what sort of metal, what sort
Speaker 1: of metal it is UM, And it really has to
Speaker 1: do with the the inductance and the resistance of the
Speaker 1: object that you're looking for. Now, the inductance is UM
Speaker 1: the objects ability to conduct electricity UM. And if it's inductive,
Speaker 1: it would be able to to conduct electricity easily, but
Speaker 1: it's slow to react to changes in the electrical current. UM.
Speaker 1: If it's resistive, it doesn't conduct electricity is easily, but
Speaker 1: it is quick to react to those those changes. And
Speaker 1: a sophisticated metal detector will be able to tell you, well,
Speaker 1: that's I think that's gold or based upon that phase shift.
Speaker 1: Because the face shift for a particular element is going
Speaker 1: to remain constant, you know. That's that's why if it
Speaker 1: didn't remain constant, then this wouldn't matter at all, because
Speaker 1: it wouldn't you know, we wouldn't know, you know, it's
Speaker 1: like we just know something is down there, we wouldn't
Speaker 1: know have any way of guessing what it is. But
Speaker 1: because it's an inherent property of this particular material, and
Speaker 1: it's really dependent upon the molecular composition of whatever that
Speaker 1: material is. UM, then we can make start making guesses
Speaker 1: based on that phase shift UM. And it's yeah, the
Speaker 1: face shift, you know, with it being that difference in
Speaker 1: timing between the transmitters frequency uh and the frequency of
Speaker 1: the magnetic wave that's generated by the object. Um. You know.
Speaker 1: It's these are sort of ranges, right like if it
Speaker 1: if it's a certain range there, then the male detector
Speaker 1: can give a best guess as to what that material maybe.
Speaker 1: So there's no ever necessarily a guarantee that whatever it
Speaker 1: is you've detected is specifically going to be you know,
Speaker 1: aluminum versus goal or whatever. But it's a it's an indicator,
Speaker 1: so that uh, it gives you at least the idea
Speaker 1: of you know, is that you measure risk versus reward, right,
Speaker 1: the risk of exhausting yourself digging up useless junk versus
Speaker 1: the reward of possibly finding something that is of true value. Yes,
Speaker 1: so that's really the whole purpose of this anyway. It's
Speaker 1: just you know, to kind of tune in on that
Speaker 1: beep and make it more meaningful so that you know,
Speaker 1: you don't waste your time digging up uh little poll
Speaker 1: tabs from soda cans. Yeah. Now, yeah, if you have
Speaker 1: a higher inductance, it's going to create a larger phase shift,
Speaker 1: and lower inductance has a smaller phase shift. Now, metal
Speaker 1: detectors use a phase demodulator to read this, and uh,
Speaker 1: what that creates is scrimination. Yeah, yeah, I know it's terrible,
Speaker 1: but within metal detectors, it's okay, yeah, because the thing is,
Speaker 1: a good metal detector will allow you to filter out
Speaker 1: stuff that you don't want because the metal detector, if
Speaker 1: you said it at a certain setting and say, you know,
Speaker 1: I'm really looking for metals that fall within this range, yeah,
Speaker 1: perhaps gold. I've actually seen uh, metal detector booths and
Speaker 1: they'll have like this giant jar of class rings that
Speaker 1: people have lost, which is sort of a you know,
Speaker 1: reminder that you know, hey, you you can find stuff
Speaker 1: if you just take your metal. Of course people look
Speaker 1: at you funny, but yeah, that way. That way. Let's
Speaker 1: say that you're out there looking for something specific, you
Speaker 1: can you know, some meld detectors have settings where you can, uh,
Speaker 1: you can tell the meld detector to ignore anything outside
Speaker 1: of a particular range of frequencies. So in other words,
Speaker 1: you're saying. You might say, I'm only interested in finding silver.
Speaker 1: Let's say, So what I'll do is I'll set my
Speaker 1: MELD detector so that it'll it'll only uh activate, it
Speaker 1: will only alert me if something that generates a magnetic
Speaker 1: frequency similar to that of silver is encountered by the
Speaker 1: metal detector. So in other words, what you might you
Speaker 1: might pass over a gold deposit and nothing happens. But
Speaker 1: as soon as you go over that that silver half
Speaker 1: dollar but ink, and then you dig it up and
Speaker 1: you're like, hey, look I'm rich. I Meanwhile, the gold
Speaker 1: guy behind you was like, sucker. Well that's that. That
Speaker 1: can be called notching. Basically, you set it for a
Speaker 1: if you imagine a scale, uh you know, one notch
Speaker 1: on that scale, or some of the more sophisticated metal
Speaker 1: detectors will allow you to set more than one notch r.
Speaker 1: So that way you could look for both silver and
Speaker 1: gold and you'd say, ha ha, Mr smarty gold pants. Um.
Speaker 1: Now that's that's the VLF. The post induction metal detector
Speaker 1: is a little bit different. Yeah, it uses only a
Speaker 1: single coil, or it can use multiple oils working at
Speaker 1: the same time. Yeah, but there these are these are
Speaker 1: coils that haven't that don't have that shielding. It's not
Speaker 1: like you have a transmitter coil and then a receiver coil,
Speaker 1: and all of these coils are generating very quick bursts
Speaker 1: of electricity, which of course creates a very sharp magnetic wave.
Speaker 1: And uh so it's just a really quick spike. And
Speaker 1: then what will happen is that magnetic wave if it
Speaker 1: encounters a metal object. Again, that metal object will have
Speaker 1: to will generate its own magnetic wave, and the metal
Speaker 1: detector will pick up on that, and it's all it's
Speaker 1: kind of like an echo, right, It's kind of like
Speaker 1: an echo, right, thank you. So if you think about
Speaker 1: it that way, it's it's like sending out a signal
Speaker 1: and waiting for something to bounce back. Yeah, but it's
Speaker 1: very fast. I mean the average is about a hundred
Speaker 1: pulses per second, which is yeah, fairly rapid, pretty quick.
Speaker 1: And then you're looking for the reflected pulse, yes, which
Speaker 1: is what the the object that is under the ground
Speaker 1: or wherever. Uh, that's the the the pulse that it
Speaker 1: generates in response to the one that came from the
Speaker 1: mel detector. Yeah, Now it uses a these these types
Speaker 1: of metal detectors use a sampling circuit, basically trying to
Speaker 1: determine whether it's actually metal that you're finding or something else,
Speaker 1: some other type of magnetic field that is interfering with
Speaker 1: this signal, and it's basically judging that based on the
Speaker 1: amount of time it takes UH two to reflect. Um. Yeah,
Speaker 1: that's another thing that we should point out is that
Speaker 1: MEL detectors can and encounter lots of different kinds of interference.
Speaker 1: Not just the composition of the soil. But let's say
Speaker 1: that you happen to cross over where an electrical cable
Speaker 1: has been buried. That could cause a problem. Your male
Speaker 1: detector might think that, hey, look there's gold in them
Speaker 1: the Oar hills, and truth, what you've hit is the
Speaker 1: power line, which you don't want to dig that up. No,
Speaker 1: it could result in everything from death, which UH is
Speaker 1: in the metal detection biz we call a bad thing,
Speaker 1: or it could result in or and or it could
Speaker 1: result in an entire region losing electricity. That's also a
Speaker 1: bad thing. That's that's a very good point. I mean,
Speaker 1: these these metal detectures are not only incredibly useful, they
Speaker 1: can be a lot of fun. A lot of hobbyists
Speaker 1: love them, but you do have to be very very careful. Um.
Speaker 1: And it's good to know your the territory to quote
Speaker 1: a certain musical, but yeah, I mean you need to
Speaker 1: know the territory. You gotta know where you're you're digging
Speaker 1: because you you really could get hurt. Honestly, I've got
Speaker 1: Rock Island going through my head. Now, cash for the merchandise,
Speaker 1: al right, sorry, all right. So we have an integrator
Speaker 1: on these, on these pulse induction metal detectives, uh, and
Speaker 1: that's reading the signals from the sampling circuit and converting
Speaker 1: them to D that's current Yeah, not the district of Columbia. Yeah,
Speaker 1: not not a comic book publisher either. And that's feeding
Speaker 1: into it the audio circuit and that is what beats. Yeah,
Speaker 1: that's the stuff what beats for the pulse indicator. The
Speaker 1: thing is, uh, these are very good at detecting metal,
Speaker 1: but they're not very good at discriminating between different types
Speaker 1: of metal. Um, So you're not going to get the
Speaker 1: level of precision that you would get with a VLF
Speaker 1: metal detector. But you know they also you've got to
Speaker 1: remember that these different types of detectors, while some of
Speaker 1: them may work in conditions that others do not. There's
Speaker 1: there's also a price range here as well. Oh yes, yes, now, yeah,
Speaker 1: the beat frequency oscillator metal detectors can be uh fairly affordable. Um.
Speaker 1: They also used two coils, but one is in the
Speaker 1: search head and the other one is actually in the
Speaker 1: control box. UM. They're connected to an oscillator that as
Speaker 1: pulsing UM many many times per second. That was in
Speaker 1: of times per second UM. And and the and the
Speaker 1: frequency of the one that's inside the control box and
Speaker 1: the one that's inside the actual detector are slightly offset.
Speaker 1: They're not in sync or backstreet boys. Oh you got
Speaker 1: the other one I was gonna do U. So yeah, well,
Speaker 1: ironically enough to our our current part of the conversation.
Speaker 1: They create radio waves um, and then the receiver in
Speaker 1: the control box uh picks that up and plays tones
Speaker 1: to let you know when you're you're coming into range
Speaker 1: of metal, right, Because what's happening is that when the
Speaker 1: metal encounters this uh, this this this electromagnetic field that
Speaker 1: is going to alter that radio wave. And so what's
Speaker 1: really listening for our changes in the sound that you're hearing.
Speaker 1: The change in the sound indicates that you have encountered
Speaker 1: something that is generating this man medic field because of
Speaker 1: the one you're generating, they know what they're going through. Um.
Speaker 1: So yeah, I mean detectors killed the radio star. But
Speaker 1: these these uh, Like I said, these are a lot
Speaker 1: cheaper to manufacture. And therefore, if you are uh interested
Speaker 1: in getting your feet wet, uh and the metal detector
Speaker 1: the thing is a hobby, you might consider this, but
Speaker 1: they're they're far less accurate in terms of um being
Speaker 1: able to give you any kind of discrimination or any
Speaker 1: really any real control. Um they actually use these are
Speaker 1: the types of metal detectors that you the handheld detectors
Speaker 1: that they use the airport. Um, you know, if you
Speaker 1: walk through the scanner and and then yeah, that's the
Speaker 1: type they use in the one because they don't really
Speaker 1: need to know whether it's gold or iron. They just
Speaker 1: want to know what it is that you've got now
Speaker 1: once once, once something beeps, then they can say, all right,
Speaker 1: well let's see what that is. They don't, you know,
Speaker 1: necessarily need to know immediately. Yeah. And the metal detectors
Speaker 1: the frames at the airport, they work on essentially the
Speaker 1: same principles we've talked about here. They're generating electromagnetic fields,
Speaker 1: which of course has brought up some concerns with people
Speaker 1: who may have UH devices like medical devices that could
Speaker 1: react to electromagnetic fields. That's why you'll occasionally hear about
Speaker 1: UH folks like that having to go through like a
Speaker 1: pat down security as opposed to a metal detector, just
Speaker 1: because of the concern that it could interfere with a
Speaker 1: medical device. Right right now, with with all of these um,
Speaker 1: what you're gonna find depends on the type of metal detector,
Speaker 1: the type of metal that you're looking for, about how
Speaker 1: big it is, the kind of makeup of the soil,
Speaker 1: um any kind of interference from other objects, and the halo,
Speaker 1: which is basically, you know, if you have a piece
Speaker 1: of metal in the soil, it's going to read a
Speaker 1: little bit differently, it's going to it's going to register
Speaker 1: is larger than it actually is. Yeah, because those interesting things, Yeah,
Speaker 1: they I could see your halo. I was I was waiting.
Speaker 1: I was trying so hard not to go into that.
Speaker 1: We've done so many songs references in this podcast. It's crazy.
Speaker 1: And this might be our like our most intense references
Speaker 1: per minute other than the first one. None of them
Speaker 1: have been metal. That's true. That's true. So, but yeah,
Speaker 1: now that it is, really the halo effect is really
Speaker 1: an interesting thing. It's just this the fact that certain
Speaker 1: kinds of metal objects can actually increase the conductivity of
Speaker 1: the soil that's around them. And the longer that object,
Speaker 1: those particular objects have been in the ground, the greater
Speaker 1: that conductivity change can be. So then yeah, you might
Speaker 1: be like, hey, there's a there's a Sherman tank down
Speaker 1: there or something, and it just turns out that there's
Speaker 1: another object that's been down there and has affected the
Speaker 1: conductivity of the soil. Um that's pretty phenomenal. If you
Speaker 1: have a Sherman tank buried in your backyard, please give
Speaker 1: me a call. I'm I'm interested to well, not anymore. Yeah,
Speaker 1: I mean, well, you think about it. It It makes sense
Speaker 1: if you have let's say, let's say the aforementioned screw
Speaker 1: and it's been there for a couple of years. It's
Speaker 1: let's say iron, and it's beginning to rust, it's beginning
Speaker 1: to disintegrate, and you can change the conduct conductivity depending
Speaker 1: on the Again, it also depends it's rain then, you know, yeah,
Speaker 1: it really depends upon the composition of the soil. Itself
Speaker 1: as well. So, yeah, if there's a lot of iron
Speaker 1: content in the soil, that's gonna cause some issues when
Speaker 1: you're when you're doing metal detection. You know, you're just
Speaker 1: you're gonna get a lot of interference and you just
Speaker 1: have to factor that in. Doesn't mean that the metal
Speaker 1: detector is going to be useless. It just means that
Speaker 1: you have to kind of adjust your expectations and listen
Speaker 1: for bigger changes in UH in the soil content and
Speaker 1: not and kind of kind of ignore the noise, separate
Speaker 1: the signal from the noise. Yeah, I would argue that
Speaker 1: it probably takes some personal discrimination too. You really need
Speaker 1: to get out there in practice if you're going to
Speaker 1: start using doing metal detecting as a hobby, um, and
Speaker 1: maybe even trying it with things that you what that
Speaker 1: you know what they are, you know, some coins, a ring,
Speaker 1: a screwdriver, you know, something that hammers, you know, Sherman tanks,
Speaker 1: the stuff that you do, you know, tend to run
Speaker 1: across in your general area. Well, you know, you never
Speaker 1: know what you're gonna find when you're out in the
Speaker 1: field somewhere, and if you can identify what they are,
Speaker 1: you can get a sense of what different metals sound like.
Speaker 1: How get a feel for how your metal detector works,
Speaker 1: how sensitive it is, and how sensitive it is. Um, yeah,
Speaker 1: it can be a lot of fun to uh, as
Speaker 1: you were talking about before, like going to uh battlefields.
Speaker 1: Of course, I imagine probably all the major battlefields have
Speaker 1: been picked pretty clean at this point, you think, But
Speaker 1: it's it's amazing once you can stumble across It's again,
Speaker 1: it's one of those things where it may be it
Speaker 1: may require a phenomenal amount of luck. Sure experience, there's
Speaker 1: no such thing as luck, but it may require a
Speaker 1: phenomenal a series of incidences in order for you to
Speaker 1: stumble across the right section to find something significant. But
Speaker 1: really you never know. You just it's it's amazing to
Speaker 1: me how something that you would think, oh, well, this
Speaker 1: has got so much traffic, there's no way there's anything
Speaker 1: of significance can be found there. And yet like five
Speaker 1: years later you'll find that the find of this injury.
Speaker 1: How did that happen? But yeah, and you don't know
Speaker 1: what's around in places that you know might be a value.
Speaker 1: I mean again, people find I'm still searching for black
Speaker 1: Beard's treasure. All kinds of stuff out in time, I
Speaker 1: go to the Carolinas out in normal places. Maybe I
Speaker 1: should actually go to the everyday beach instead of in London.
Speaker 1: That's probably part of the problem. Yeah, you know, Charleston
Speaker 1: is so nice. I just like to, you know, spend
Speaker 1: some time there enough. Yeah, people even use them for prospecting,
Speaker 1: you know, and uh and for coin shooting. Now, if
Speaker 1: you do want to use your mail detective for prospecting,
Speaker 1: there are some things you need to remember. First, you
Speaker 1: have to grow a fear of at least a foot
Speaker 1: in length. That needs to be gray and grizzly. He's
Speaker 1: gonna punchy ladies and gentlemen. Second, you need to be
Speaker 1: able to say things like consarnate with a straight face.
Speaker 1: And then third, the most important thing about being a
Speaker 1: prospector is you have to develop your crazy prospect or
Speaker 1: dance when you strike gold. Very important. Yeah. Coin shooting
Speaker 1: is uh the practice of looking for coins after an
Speaker 1: outdoor event like a wedding or or like stock you
Speaker 1: go to you go to some big outdoor conference and
Speaker 1: you take a male detector and you start looking for
Speaker 1: for change. The thing is that if you live in
Speaker 1: an area where this sort of stuff goes on in
Speaker 1: a regular basis, you could presumably pay off that mel
Speaker 1: detector after you know, a few visits to these these
Speaker 1: areas once the concert is over or a game or whatever. Um,
Speaker 1: you know. And and because we're usually talking about change,
Speaker 1: you know, some some nickels or dimes or quarters or whatever,
Speaker 1: but whatever money you use, because you know, it's not
Speaker 1: all just United States folks. Well, if you find euros,
Speaker 1: you're rich, because I think a euro is equivalent to
Speaker 1: like seventeen dollars at this point. Um, that's a gross exaggeration,
Speaker 1: but the point being that, you know, yeah, you could
Speaker 1: conceivably pay off your mail detectors costs after a few visits,
Speaker 1: you know. Um. But although a lot of people just
Speaker 1: enjoy the this as a hobby, like it's just it's
Speaker 1: a way to get outside. You're enjoying your joying time
Speaker 1: outdoors and you're finding stuff which just brings you a
Speaker 1: level of of of satisfaction, right. It means that whole
Speaker 1: treasure hunting aspect, you know, when I when we discover something,
Speaker 1: there's an element of satisfaction there that you can't put
Speaker 1: a monetary value on. Yeah, yeah, you're just like, hey,
Speaker 1: look I found some money woo, And yeah, there's there's
Speaker 1: an enjoyment level there that goes beyond. Oh and it's
Speaker 1: worth you know, seventy five cents. Yes, um, although the cents,
Speaker 1: it's always nice to have seventy five cents more than
Speaker 1: you had, but when you showed up at the field.
Speaker 1: So yeah, I keep wondering, actually, why the value of
Speaker 1: the giant jar of class rings. You'd figure they'd cash
Speaker 1: that in. Yeah, I mean for more than just selling
Speaker 1: metal detectors. Maybe that's more lucrative than selling off some
Speaker 1: of those classroom you have, prying out all the little
Speaker 1: jewels and melting that stuff down and then just hey,
Speaker 1: you know, how can yourself bar a gold? It's worth
Speaker 1: its weight in gold. Anyway, I need to go out
Speaker 1: and get a mel detector. Yeah they're fun, Yeah they
Speaker 1: could be. They could be a lot of fun. Yeah, definitely.
Speaker 1: So anyway, that that kind of sums up this podcast
Speaker 1: on how mel detectors work. Remember, we do have an
Speaker 1: article on the website that goes into more detail and
Speaker 1: kind of walks you through what we've talked about here.
Speaker 1: I highly recommend it. If you guys have any technology
Speaker 1: you would want us to talk about, please let us know.
Speaker 1: You can drop us a line on Facebook or Twitter,
Speaker 1: are handled there as tech Stuff hs W, or send
Speaker 1: us an email. That address is tech stuff at how
Speaker 1: stuff works dot com. Chris and I will talk to
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