Joe McCormick and Jonathan continue their discussion about radio waves, transmitters and radio direction finding. How can you locate a transmitter and what is fox hunting?
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Get in text with technology with tex Stuff from how stuff Works dot com. Hey there, and welcome to tech Stuff. I'm your host, Jonathan Strickland, senior writer for how stuff Works dot com and today in the studio, I am not by myself. It is so amazingly awesome. Only am I not by myself? But I didn't even have to pick the topic. My guest did it for me. And my guest, of course, is someone you all know and love, Joe McCormick. Beloved in our office. We sing his phrases when he's not around. Joe. Welcome back to the show. Thank you for having me. Jonathan, You're welcome, Joe. It's like a little it's like a two thirds forward thinking reunion right now. So I wanted to talk today a little bit about a subject that is recently near and dear to my heart. Not a long time fascination, a recent obsession, and that is the idea of radio direction finding. Yeah, this was something I knew. I mean really, I knew nothing about it when you brought this to my attention. And the more I learned about it, the more I realized, not only is it a fascinating subject, but it also in many ways. It's kind of a spiritual cousin to some other topics I've covered, like geo cashing. Just for one specific part of radio direction finding that we'll get into in this episode. Okay, so, uh to introduce you here, I want you to imagine you have a favorite radio station. You don't have to imagine, you really do it. What do they play on Power nine. Well, they don't play anything anymore because now it's but back in the nineties, Power ninety nine was the station that slowly introduced Atlanta to the wonderful world of alternative music. Okay, so R e M got a lot of play. In fact, the very first time I ever heard R e M Losing my religion was on Power ninety nine. Yeah. Do you listen now to point one the River? You know what? Not a big not a big fan of the River, but I do still listen to ninety nine X, which is not one seven anymore. I can't remember which station it's on, but I still listen to that. Okay, Well take yourself back in time, Jonathan, go back to the days of power and imagine. You know, Power ninety nine. It just gets you through the morning. You wake up every day, you know. Uh, it gets you through the t d M of peeling those thirty seven hard boiled eggs you're gonna eat for breakfast and accurate so far, and it's just it's your favorite part of the day. But one morning you switch on your radio to Power ninety nine. You think you're gonna hear some great new R E M singles, But instead, something is wrong. Instead of the regular programming of your of your regular favorite radio station, you are treated to an unending loop of Mick Jaggers solo love ballad hard Woman. Is this the one that has the terrible music video? Yeah, that was put together by a Ray supercomputer. Yeah, now I remember this. I remember you showing me that music video. And and the only thing worse than the music video was, in fact, the song itself. It's it's hard to know which is worse, but yeah, so it's looping. In fact, they don't even let the song finish. Each time it plays, the loop begins about ten to fifteen seconds before the song's over. Maddening. Yeah. Uh, so you call up the station, You call up Power nine and nine, say hey, what's up with hard Woman all the time? Where's my R E M? And they say, I don't know what you're talking about. We're running our regular programming. Somebody is jamming you. So what they're doing is they're using a transmitter, presumably one much closer to you than the radio station's transmitter, and had a power that overpowers the incoming signal for that radio station. Right, because they're closer to you than the radio station is. They can do this because the only other way they could do that is if they were actually putting in more power in their transmitter than the radio station is, which is not likely. But somebody in your neighborhood, somebody near your house with a with a vendetta against R. E. M or maybe just an unending, powerful, overflowing love for Mick Jagger's hard woman, or some sort of curmudgeon in between, is broadcasting this malicious interference on the same frequency as your beloved station. Now, obviously this is intolerable, but the station themselves, well, they probably can't do anything about it. So you contact the FCC. Right, this should be their job to deal with here in the US. That's exactly who I would have got them on speed dial. Right, Signal intrusion. Right, you're supposed to regulate the airwaves. So you call up the FCC, but they tell you to take a hike. They're busy undoing net neutrality too, So what are you gonna do? Are you just going to allow this radio freak to jagger up your mornings for the rest of your life. That doesn't sound like me, Joe. Uh, if you're If that's not your style, One thing you could do is try to take matters into your own hands. Now, how would you do that? You would have to track down the jagger jammer yourself and give this creep a piece of your mind. But how could you do that? Like the song loop doesn't say, hey, by the way, here's the address of my secret jamming transmitter, at least not explicitly, So then I'd have to figure out some way independent of the content of the signal to track the location of the transmitter. Yeah, and that's what today's episode is going to be about. If you know a few techniques, and if you have some special equipment on hand, you actually should be able to locate this jammer through the art of radio direction finding or r DF as I'm sure we'll refer to it throughout this episode. It's the act of hunting a radio broadcast to its physical source. UM So today we're gonna talk a little bit about r DF in general, a little bit about the history, about the science behind it. But we also wanted to focus somewhat on the sport of transmitter hunting, also known as t hunting or fox hunting, which turns this activity of radio direction finding into a recreational activity. And this this ties into a lot of those other subjects I was talking about, like from the aspect of geocashing, where we're using technology for some sort of recreational activity that it wasn't necessarily intended to be when we first started developing that tech, all the way to the story Chuck and I did about the infamous Max Headroom incident right where somebody another case of signal intrigues exactly, someone was able to do signal intrusion in the Chicago market and uh overpower television signals and present a an absurd, slightly disturbing and very surreal Max Headroom type of intrusion. Well, those those things, I mean, that's that's kind of why we're talking about this, is like, how would you detect where such an intrusion is coming from if you had enough time to do so. In the case of the Max Headgroom incident. Yeah, by the time anyone knew what was happening, it was too late to really figure out where's the signal coming from. They had general ideas just based upon the architecture of the city, because things like buildings and stuff can get in the way of radio signals, so that that limits where a signal can come from. But you need something more sophisticated in order to narrow down the actual direction and specifically the locality of a transmitter. So this has a really long history. It dates back pretty much shortly after we started sending radio signals. Uh. In fact, the very first person to kind of associate directionality with radio signals was Heinrich Hurts. And that name Hurts probably rings some bells. We're gonna be talking about a lot about Hurts, the unit of measurement, and not Hurts, the person in this episode. He discovered with an open loop of wire which was acting like an antenna, or it really wasn't antenna wasn't acting like one. Yeah, but this was a loop of wire that had a gap between the two ends of the loop. So it's not a closed loop. It's an open loop, it had some direction finding properties to it. He found that if he used this loop near a transmitter, and if the looper position so that it's ends faced the transmitter. In other words, if you're looking at the face of a transmitter and you're looking at a loop, the loop is at a ninety degree angle, it's it's the wire part is facing the ends of the wire parts facing the transmitter as opposed to the open face. UH, it would create a real big spark between those two ends. If he started to rotate the loop of wire so that the open face the o if you will, of the loop faced the transmitter, it didn't create that spark. So rotating it would create sparks. And the biggest spark would be if it was in this ninety degree alignment with the transmitter. And that showed that there was some directionality with radio waves and antenna Yeah, and that specifically you could put together an antenna receiver in certain ways that it would respond differently depending on how it's oriented exactly with respect to the source of transmission exactly. So the next one you would talk about the actual One of the earliest successful UH implementations of this idea would be the Balini Tosy apparatus. Uh not the only early direction finding antenna. Why am I imagining some kind of dessert making machine the Bellini tocy apparatus. Like it's like a large box out of which comes big blobs of icing, right, or gelato or something. I'm on a diet, Dude, you are killing me on diesel. I would eat diesel powered gelato right now in a heartbeat, but instead I'm going to stick to my Brussels sprouts. Uh So, two Italian officers named a Torre Bellini and Alessandro Tosi came up with this. Sometimes it's actually called the Marconi Balini Tosi because Marconi's name gets attached to everything that might be a little bitter tesla left over issues that I have about Marconi's name getting associated with stuff that certainly he was instrumental in the development of, but perhaps not the primary source of that technology the way his name would indicate. Yeah, the wireless telegraph. You'd want his name all over everything. Yeah, yeah, don't worry about people who worked on that stuff, you know, before him, or or had originally secured a patent before he had and then had their patents overturned. That's another episode. In fact, I've talked about it in previous episodes. So the way this worked is that they actually created uh, two loops of wire arranged at right angles with respect to one another. So you can think of these as kind of like a casing, these two big loops of wire at right angles in the middle of which they put a third coil of wire, but this one could rotate freely within those two fixed ninety degree angle loops. Okay, so it's like a wire globe and then another loop inside. Yeah, and that wire loop inside can freely rotate, and that's where they were able to create this directional antenna, this direction finding antenna. They the the rotating element is called a rotor or sense coil, and then the other two are called stators or field coils. And folks, I apologize, I'm still over getting over at cold, So you're gonna hear me be raspy throughout this episode, just like last time. Yea. So these original ones were big, big devices. Yeah. The first picture I saw it showed the operator sitting at a desk, and the actual TENNA was about twice the height of the desk he was sitting at. Now, what was this used for At the time, these were used as land stations around primarily Europe, and we're used mainly to help with navigation. So so how would that work. You would have this enormous UH antenna that was detecting transmissions coming from other vessels, let's say navy vessels or or maritime vessels, and they would be able to detect what direction the that transmissions coming from and send information back out via radio vessel. So the lost ship says where am I sends a transmission saying where am I southwest? It knows where it is, and if it knows the direction your transmission is coming from, then it can tell you where you are in general. Yes, And then eventually you actually saw these devices being placed on the craft themselves. So then you could have a stationary radio transmission center sending out a basic signal sometimes and frequently having the the location for that that transmission center encoded in the signal itself sent out to sea, and then the the vessels would have these type of antenna aboard them. They could then use the antenna to figure out what direction the transmissions coming from because they know the specific location of that center because it's in the signal itself, but inverse exactly. So early ones were land based, then later on they were actually based on the vehicles themselves, whether it was it started off with shops and eventually also incorporated aircraft. Now I know that the idea of finding the physical location of a radio transmitter, whether it's a vehicle or a station of some kind, must have played a big role once radio was used in warfare. Absolutely there were some instrumental battle in which UH one side or the other frequently actually was the Allies had determined the that a certain German group of units, typically U boats, was really effective naval warfare in World War One, world War two. Actually world War One there was some, but world War two it really came into play. World War One, certainly the U boat communications, which were using very low frequency radio waves, it was very important. By the World War Two you're talking about more high frequency and radio waves being put into use. It's where we get the huff duff because it's high frequency direction finder antenna's hf DFS or huff duff was the nickname. You get the huff duff antennas that would indicate the direction of a transmission and that would help be able to track like enemy movements, enemy troop movements, particularly in the in the Navy. And it can you imagine how disappointed these antennas are when they get sorted. Yeah, now right, like you know, they all want to be slythering because that's my house. I don't know what the house you belong to. I that's not for me to say. I've never been sorted. I got sorted into slythering. I mean, I'm just saying I didn't try to. It just happened. Um, you just put on the hat. I do what the hat tells me. Man, I live my life that way. So this type of antenna was originally meant not for military purposes. It was actually meant to help meteorologists learn more about lightning. Was developed by Robert Watson Watt back in nineteen six, and it was to help locate where a lightning strike occurs, because you know, lightning, it gives off electromagnetic rays just or waves, I should say, not raised, but waves, just as a radio antenna would. And so you would use these antenna to detect the location of lightning strikes. That also helped you track the pathway of electrical storms. So that's what it was intended for, but in World War Two it got put to other uses to try and track movements of enemy troops. Very important now. Uh. After World War Two, we started seeing more development in radio direction finding technology, not just in military but also commercial applications. Uh. In fact, we also saw a lot of amateur radio operators get interested in it, and particularly once ham radio in the United States was really starting to take off. Yeah, forties and fifties really were really post world War two, because during World War Two they were very very picky about who got a chance to actually broadcast radio. They were like, you know, guys, we need you, guys to to unless we're telling you to do it, don't do that thing, right. So, but once World War two was over, we saw a lot more develop them and go into that and there are a lot of a lot of purposes for our DF. We talked about navigation, it's not really used for navigation that much anymore because we have more sophisticated methods for navigation. Yeah, we've got we've got stuff beyond like a radio transmitter and a receiver. That being said, there's still some places that use radio beacons as a means for emergency backup, uh some around the UK, not really any in the United States at this point, um maritime vehicles held onto it longer than aircraft did. But even today you don't really see that as a as a even a tertiary method for navigation because we have so many other more sophisticated systems at play. But there are other reasons that we do still use them. I mean, well, one would be like the example hunting down illicit broadcasts and jammers. Absolutely, yeah, Now this was huge and World War two as well. The UK actually ended up getting a big volunteer force of interceptors about folks in the UK who were amateur radio operators and use them to help suss out any uh enemy transmissions that were coming from the UK. Because there a period piece movie about this year there should be, although it'd be kind of boring because I think they only found they found like two and one of them was one that they were doing on purpose. Well, that could be the angle. Maybe maybe there was a cover up, there's some big secret or like like there's the crowd of ham operators carrying pitchforks storming the transmitter room of this one perceived enemy of the state and it turns out that they're just following orders from the UK government to send out false UH commands, because that was a thing, right, Like, it wasn't just secret information, it was disinformation. There were a lot of different campaigns going on in the information and intelligence worlds in World War Two. So, but that's glorious the image of an army of hams radio hams coming at you to to VHF you up, yep, that's right. There's there's so much opportunity there for UH edge of your seat drama. But the the interesting thing to me was that the UK, they were using m I five to head this operation because that's their domestic intelligence agency, but they determined that really this was a bigger problem in Europe. They had a lot more clandestine operators in Europe on both sides, really sending out messages via radio transmission, and so they switched this operation over to m I six, which looked at UH intelligence coming from outside the UK rather than from within it. So it's kind of in the United States, the difference between our FBI and our c I a same sort of thing, and UH in Europe was a much different story. Like the r d F was incredibly important during World War Two, because there were so many different operators using radio transmission as a way of getting either spy reports or orders across various borders. It eventually got to the point actually where the access powers were, um, really shy about transmitting any information because they were still worried about it getting intercepted and caught. And this is the same era as the Enigma machine, right, and once the Allies were able to crack some of the Enigma codes, it was a it really became apparent that you had to be super careful with your intelligence otherwise you were handing the enemy all of your game plans. So really interesting story though. Um, then there's other methods, are other reasons to use r d F. There's search and rescue, Yeah, how about that, so coast guard or rescuing it down on plane. Either one. You might have a vehicle that is equipped with radio transmission capability, but is itself stranded. Yeah, there's a lot of civil aircraft that have this. There are a lot of like if you are if you're hiking in an area that is prone for two avalanches, you may even have a transmitter on you as a means for emergency signaling. In the case of an avalanche. So this is still a thing, right. It's it's something that can send out a steady signal with perhaps an encoded message, usually a unique identifier to whatever the transmitter is, so that once you tune into it, you know that you're actually listening for the right signal. You're not going to get distracted by a signal on a similar frequency that is not what you're looking for, and you can try and narrow down your search to find whatever it is that's lost. Now, one thing we mentioned earlier is hunting malicious interference, people who are intentionally jamming a radio station or broadcasting propaganda or something like that. But there's also unintentional interference, and this could be useful too for tracking down you know, uh something maybe uh radio frequencies are leaking out of some sort of device and they're interfering with the broadcast band around there. Yeah, I mean, it's uh, it's not necessarily something that's done with malicious intent. Really, anything that creates an electrical field is creating electromagnetic radiation, and that some form of that is in radio waves, and depending upon the power of the the device in question, it could be putting out radio waves strong enough to interfere with transmission of normal signals. You'll hear about this also, Like I remember hearing about this with um uh theaters, in fact, theaters that we're using wireless radios in order to have back of house talk to front of house for stuff like like stage managing and lighting changes and stuff, and then you would end up getting truckers talking over your system and it would just Peter Pan became an entirely different show at that point. Like, but but this is the sort of thing about the speed trap up there. Yeah, And it all has to do with with the frequency you're using in the power of the radios in question, right, or perhaps more problematically, having that transmission of a high school production of Peter Pan being transmitted out to people who are using radio for really important reasons. Uh. This is one of the reasons why most places around the world have very strict rules of what types of equipment can use which frequency bands so that it avoids that kind of cross contemning. You don't have the problem where officer Officer hurts tries to radio in for backup, but instead he's being jammed by Peter Pan, right, or suddenly Captain hook and a bunch of pirates show up, like, this is not the backup I was hoping for. That wasn't hoping for a chorus line, I really need physical people to help back me up for this dangerous situation. Another use that you have here that I didn't even think of, but very smart wildlife tracking. Yeah, yeah, and I get tagged exactly. These are transmitters that send out a study signal so that scientists can continue to monitor the movement of various wildlife. Usually you do this to track migration patterns and how those might change, particularly in light of things like human uh enter like humans moving into what used to be territory. For animals, how do their migration patterns change, or in the face of changing weather patterns, that kind of thing. And you need obviously to have a direction finder in order to know where the animals are actually going. Plus, if you ever want to go into a physical check, let's say that you are doing like a drawing blood from a specific animal every few months, then you need to be able to track where that animal is and and narrow down its range so that you can actually get to it and do that. So that is another use. And of course we've already kind of talked about. But spies, I mean not not just not just someone trying to transmit something. Sometimes it's like trying to find a bug. Like bugs that have been planted in places they're they're sending out little radio transmission. Typically, Uh, I mean, you could have one that's just recording natively to a device, but that means you have to go back into that place and retrieve the device in order to hear what's been recorded on it. Most bugs are transmitters, so that means that you have to have a radio direction finder to figure out where a transmission is coming from. Let's say it's a nice big embassy building. You might need to narrow down exactly where is this thing? Um and that. You know, we see those in spy movies, but it really does happen. At the Spy Museum in Washington, d C. Fascinating you can actually see some of the devices that were used to both plant bugs and to detect them. I want to go to that sometime. I've read a little bit about I remember seeing online a thing about their ex a bit on spy pigeons. Yeah, it's fun, it's it's weird in that I don't mean this to become like an ad for the Spy Museum in d C. It's weird because I feel like the presentation is really perfectly geared towards kids, but there's so much text involved in in the exhibits that I don't know that your average kid has the the tension span or desire to read that much while going through a museum. So my experience was that I was trying to read the same paragraph fifteen times while kids were running all over the place trying to play with stuff. So it's a little frustrating for me, but fascinating exhibits, really well laid out, and lots of fun stuff. They incorporate both real world spy gadgets and also movie stuff, so they had like an entire James Bond section that was really a lot of fun. Yeah, yeah, so that's cool. And then one of their modern use for radio direction finding is what we're really going to focus on towards the end of the show, which is using it recreationally for sport. So this idea of fox hunting trying to you know, competitively, you mean the sport itself, not like using radio direction finding to find a lost ball in golf. I mean, there's no reason you couldn't do that other than the fact that you would have to have a golf ball with a transmitter and have to build it in such a way that it could withstand enormous force being placed upon the ball and still not, you know, still continue to transmit. Probably would have keep going. Yeah, No, I'm thinking about all the this is the thing you're gonna put out a joking hypothetical, and I'm going to go through why it's going to be difficult to implement. Well, impossible, but difficult. Maybe we should stop you there and take a break. Yeah, let's do that. Let's take a quick break to thank our sponsor. All right, we're back now. Before we dive into the wonderful world of fox hunting, Uh, it would probably behoove us to understand a little bit more about radio waves, how they work, transmitters and antenna in order to get at what transmitter hunting is all about. So we're gonna start at basic like elementary level radio physics. We're gonna build from there. So radio waves are a subset of electromagnetic waves, so are also called E M waves or N waves. You have to put your finger up to your chin like you're thinking in waves now, e M. Waves come from stuff that generates an electric field. Doesn't have to be a particularly sophisticated setup. You can actually do this with something as simple as a nine volt battery and a coin. Yeah, if you put a coin across the the terminals of a nine volt battery, you are generating an electric field, because all you're doing is closing the circuit from the negative and positive terminals and allowing electricity to flow through. That creates an electric field, right, But I'm assuming you're saying this because doing that would generate some kind of radio signal that can be detected. Yes, it's a very weak radio signal. But if you were to do this very close to an AM radio first, you would you would want to tune the AM radio to uh something that's just static. You're not actually getting a signal like a strong signal in And if you were to place the coin against the terminals and listen closely to the radio, you should hear a crackle as the coin makes contact with those terminals because you're sending out this little radio signal and the radio is detecting it. Now, you're not sending out anything meaningful. You're just it's just noise. That's why you're just getting a crackle. You could send a signal in Morse code, so you could encode a signal by the sound and absence of sound of this crackle, but there's nothing meaningful in the crackle itself. Right. But that does show you that doesn't take very much for you to generate radio waves. Uh. The the electromagnetic waves that we talk about all have kind of common features, even though they may do very different things. There's certain things that we can use to describe them that's common across all of them. So when we plut those waves on a graph, you know it's a little up and down the crests and troughs that you would see usually across X and y axis. Uh. We would call the height of those waves the amplitude. This typically like in sound waves, this would be the volume of sound. Right. The higher the amplitude, the louder the sound is. The length of the wave is the wave length. That's really kind of tricky, right, Um, And the number of waves that pass through any given point on that graph within a second, that's the frequency. But because these waves always move at the same speed, which is the speed of light. Yes, if you know one, or if you know the wavelength or the frequency, you know the other exactly. You know how fast it's going, right, right, So when we talk about different frequencies, we're not talking about speed of the signal, because the signals still try like at the speed of light. No matter what. We're talking about the number of times a wave passes any given point within a second. Typically it's within a second. It's really any unit of time, but for the purposes of measurement, we talk about hurts and it hurts talks about the number of uh times a wave passes a point in a second. So one hurts would be once a second. That would need to be an extremely long wave because for it to take a full second for the wave to pass that point, and it's traveling at a speed of light, that's incredibly long. Right, So how far does light go in a second. Let's see, I don't know, like further than I've ever been. I can tell you that, Okay, Well, so how do you get to using radio though? Because we so, yes, we live in a universe of radio signals. They're they're electromagnetic waves all over the place around us, but that's humans use radio for specific purposes. They can take these waves and incode information with Yeah, and this this comes from manipulating either the amplitude or the frequency of those waves, modulating them in some way. Typically that's how we can encode information into them. So, uh, let's say that you build a circuit containing a capacitor and an inductor. These are two very basic circuit components. So you build your circuit, You've got a capacitor and an inductor involved in this that this will allow you to create a sign wave that's just a very smooth, continuously varying wave. It's you know that kind of smooth up and down like like your typical let's show, uh, ocean waves kind of viewpoint and just nice little hills and valleys. This saltwater crocodile and the saltwater crocodile would be carrying information. So without any saltwater crocodiles, you're still not you're still not transmitting anything meaningful. Right, It's just a sign wave. There's no information there. But if you modulate it, then you can encode information in it. One way to do that is with pulse modification. This is similar to what I was talking about with that nine volt mattery. This just involves turning a signal on and off so that when the signals on it might indicate a dot or dash in morse code, so you're not Again, nothing within the signal itself is necessarily meaningful. It's when you detect it versus when you don't detect it that gives you information. Then you have amplitude modification or our modulation I should say, or a M that's changes the peak to peak voltage of the sine wave UM And the way you do this with a M radio as you start with a basic SiGe wave. That's your that's your baseline. You take whatever you want to transmit, whether it's you know, the cool hits of the seventies or some talk show hosts or whatever. You take that that yeah, it could be hard woman. You take that signal and you overlay that signal on top of the baseline sine wave to modulate it. This changes the amplitude of that sign wave. You get kind of a uh, you know, a product from the modulation of these two. Like by adding the two together, you get a new frequency, a new wave. It's not really the same frequency, it's different amplitude, but you get a new wave with a different amplitude than both of your basic ones. This is what you transmit to a a radio tower. You actually have to amplify it by quite a lot. Obviously, the further you want this signal to go, the more you have to amplify it, the larger your antenna tends to be. And then the signal goes out over the air and then people with receivers tuned to that frequency can pick it up, and the signal gets converted uh, back into something that a radio can play, amplified again so that you can hear hard Woman. Uh. Frequency frequency modulation is similar, except instead of changing the amplitude like modulting the amplitude, you're moduling the frequency of the signal. So you again you start with a base sine wave for the radio station. This is what transmitting, whether any noise is coming out of it or not, it's just this base sine wave. Then you take on the the the wave created from whatever you're trying to transmit hard Woman, and it changes the frequency. Now, Jonathan, I wonder how exactly, if if you're not a radio expert, um, how does modulating the frequency not affect the uh you know, the station you're listening to, because the station you listen to the radio on is the frequency. When there's a number in front of a radio station power that's mega hurts right nine seven. Yeah. Well, part of it is that each radio station really has a range like there's it's you get a number that's the base frequency, but there's a range within o our surrounding that frequency that allows for this modulation. The modulation doesn't change the frequency so dramatically that it will bleed into another station. That's why we have stations that have very defined um uh frequencies, because if you didn't have that, if they were too close together, they would bleed over. Occasionally. You might have actually experienced this if you're listening, particularly to AM radio, because it travels much further. If you start traveling around, you might get two stations coming in simultaneously because you might you might move from the broadcast area of one station into the broadcast range of a station that's got a similar though not necessarily identical frequency, and then you're hearing both at the same time. That's really uh disconcerting. Um if you it could be like if you're if you're hearing r E M and hard woman, you might discover something interesting about yourself. I don't know, fire and brimstone sermon, and uh, I don't know some some good something about college sports here in the Southeast to be college sports and sermons. Yeah, But from my experience of listening to a M radio um SO receiving antenna, what they do, Like we just talked about you, you take your transmitter, you send a signality. It gets amplified a couple of times, usually before it hits the broadcast antenna and sends out over the airwaves. A receiver does the same sort of thing, but it does this in reverse. So antenna's are tuned to specific electromagnetic frequencies. Usually they have elements that are a certain size specified yep. And so what will happen is, uh, they resonate with a certain range of frequencies and if those frequencies are present, like if the antenna is present in the in the within those frequencies, then it can send it this get This creates an electrical current that it can then amplify and convert into sound so that we can hear it on our radios. Um the you know the purpose of the amplifiers just really to boost thatsnal. You're typically using like something along the lines of a transformer to do that, and I've talked about that in the past. So that means you can get your talk radio or your greatest Hits of the Ramones, which lasts twelve minutes, not because they're so few, but because Ramones songs are so short. Guys, we had a lot more to talk about when it comes to transmitter hunting. This is always the case Joe and I will end up having a conversation and we think at the beginning it's gonna take maybe forty minutes, and at the end it takes longer than an hour and a half. That's what happened this time. So we're splitting this episode up. That means next week you get to hear part two about transmitter hunting, where we really focus on the core aspects of the sport. So join us next week for the exciting conclusion. Remember, you can listen to Joe on Stuff to Blow your mind, and you can see a lot of his work at how stuff works dot com. And if you want to get in touch with me, maybe you've got a suggestion for an episode topic or someone I should have on the show. You can always write me The email address is tech stuff at how stuff works dot com, or drop me a line on Facebook or Twitter. To handle at both of those is text stuff hs W and I'll talk to you again really soon. For more on this and thousands of other topics, is it how stuff works dot com.