Speaker 1: Welcome to tech Stuff, a production from iHeartRadio.
Speaker 2: Hey there, and.
Speaker 1: Welcome to tech Stuff. I'm your host, Jonathan Strickland. I'm
Speaker 1: an executive producer with iHeartRadio and how the tech are you?
Speaker 1: It's time for another tech Stuff classic episode. This episode
Speaker 1: is titled tech Stuff Goes Transmitter Hunting, Part One that's
Speaker 1: published on March eighth, twenty seventeen, and Joe McCormick of Stuffed,
Speaker 1: Blow Your Mind joined me for this particular episode. I
Speaker 1: hope you enjoy. Joe McCormick beloved in our office. We
Speaker 1: sing his phrases when he's not around. Joe, welcome back.
Speaker 2: To the show. Thank you for having me.
Speaker 1: Jonathan, You're welcome, Joe. It's like a little it's like
Speaker 1: a two thirds forward thinking reunion right now.
Speaker 2: So I wanted to talk today a little bit about
Speaker 2: a subject that is recently near and dear to my heart. Yeah,
Speaker 2: not a long time fascination, a recent obsession. Yeah, and
Speaker 2: that is the idea of radio direction finding.
Speaker 1: Yeah. This was something I knew. I mean really, I
Speaker 1: knew nothing about it when you brought this to my attention.
Speaker 1: And the more I learned about it, the more I
Speaker 1: realized not only is it a fascinating subject, but it
Speaker 1: also in many ways is kind of a spiritual cousin
Speaker 1: to some other topics I've covered, like geo cashing. Just
Speaker 1: for one specific part of radio direction finding that we'll
Speaker 1: get into in this episode.
Speaker 2: Okay, So to introduce you here, I want you to
Speaker 2: imagine you have a favorite radio station, ninety nine. You
Speaker 2: don't have to imagine, you really do it. What do
Speaker 2: they play on Power.
Speaker 1: Ninety Well, they don't play anything anymore because now it's
Speaker 1: ninety nine X. But back in the nineties, Power ninety
Speaker 1: nine was the station that slowly introduced Atlanta to the
Speaker 1: wonderful world of alternative music.
Speaker 2: Okay, so r EM.
Speaker 1: Got a lot of play. In fact, the very first
Speaker 1: time I ever heard Ram's Losing My Religion was on
Speaker 1: Power ninety nine.
Speaker 2: Nice. Yeah, do you listen now to ninety seven point
Speaker 2: one the River? You know what?
Speaker 1: Not a big not a big fan of the River,
Speaker 1: But I do still listen to ninety nine X, which
Speaker 1: is not on ninety nine point seven anymore. I can't
Speaker 1: remember which station it's on, but I still listen to that.
Speaker 2: Okay, well take yourself back in time, Jonathan, Okay, go
Speaker 2: back to the days of Power ninety nine will do
Speaker 2: and imagine, you know, Power ninety nine. It just gets
Speaker 2: you through the morning. Yeah, you wake up every day,
Speaker 2: you know, it gets you through the TDM of peeling
Speaker 2: those thirty seven hard boiled eggs you're gonna eat for breakfast. Yeah,
Speaker 2: and it''s accurate so far, and it just it's your
Speaker 2: favorite part of the day. But one morning you switch
Speaker 2: on your radio to Power ninety nine. You think you're
Speaker 2: gonna hear some great new r EM singles, but instead
Speaker 2: something is wrong. Instead of the regular programming of your
Speaker 2: of your regular favorite radio station, you are treated to
Speaker 2: an unending loop of Mick Jagger's nineteen eighty five solo
Speaker 2: love ballad hard Woman.
Speaker 1: Is this the one that has the terrible music video?
Speaker 2: Yeah, that was put together by a crazy supercomputer.
Speaker 1: Yeah, now I remember this. I remember you showing me
Speaker 1: that music video. And the only thing worse than the
Speaker 1: music video was, in fact, the song itself.
Speaker 2: It's it's hard to know which is worse, but yeah,
Speaker 2: so it's looping. In fact, they don't even let the
Speaker 2: song finish. Each time it plays, the loop begins about
Speaker 2: ten to fifteen seconds before the song's over.
Speaker 1: It's just maddening.
Speaker 2: Yeah, So you call up the station, you call up
Speaker 2: Power ninety nine and say, hey, what's up with Hard
Speaker 2: Woman all the time? Where's myrim? And they say, I
Speaker 2: don't know what you're talking about. We're running our regular programming.
Speaker 2: Somebody is jamming you.
Speaker 1: So what they're doing is they're using a transmitter, presumably
Speaker 1: one much closer to you than the radio station's transmitter
Speaker 1: and at a power that overpowers the incoming signal for
Speaker 1: that radio station.
Speaker 2: Right, because they're closer to you than the radio station is.
Speaker 2: They can do this because the only.
Speaker 1: Other way they could do that is if they were
Speaker 1: actually putting in more power in the transmitter than the
Speaker 1: radio station is, which.
Speaker 2: Is not likely. But somebody in your neighborhood, somebody near
Speaker 2: your house with a with a vendetta against r em yeah,
Speaker 2: or maybe just an unending, powerful, overflowing love for Mick
Speaker 2: Jagger's Hard Woman.
Speaker 1: Or some sort of curmudgeon in between.
Speaker 2: Uh huh, yeah, is broadcasting this malicious interference on the
Speaker 2: same frequency as your beloved station. Now, obviously this is intolerable,
Speaker 2: but the station themselves, well they probably can't do anything
Speaker 2: about it. Sure, so you contact the FCC. Right, this
Speaker 2: should be their job to.
Speaker 1: Deal with here in the US. That's exactly who I
Speaker 1: would I've got them on speed dial.
Speaker 2: Right, Signal intrusion. Right, you're supposed to regulate the airwaves,
Speaker 2: so you call it the FCC. But ah, they tell
Speaker 2: you to take a hike. They're busy undoing net neutrality soon.
Speaker 2: So what are you going to do? Are you just
Speaker 2: going to allow this radio freak to jagger up your
Speaker 2: mornings for the rest of your life.
Speaker 1: That doesn't sound like me, Joe.
Speaker 2: If that's not your style. Yeah, one thing you could
Speaker 2: do is try to take matters into your own hands. Now,
Speaker 2: how would you do that? You would have to track
Speaker 2: down the jagger jammer yourself and give this creep a
Speaker 2: piece of your mind. But how could you do that?
Speaker 2: Like the song loop doesn't say, hey, by the way,
Speaker 2: here's the address of my secret jamming transmitter, right, at
Speaker 2: least not explicitly.
Speaker 1: So then I'd have to figure out some way independent
Speaker 1: of the content of the signal to track the location
Speaker 1: of the transmitter.
Speaker 2: Yeah, and that's what today's episode is going to be about.
Speaker 2: If you know a few techniques and if you have
Speaker 2: some special equipment on hand, you actually should be able
Speaker 2: to locate this jammer through the art of radio direction
Speaker 2: finding or RDF, as I'm sure we'll refer to it
Speaker 2: throughout this episode. It's the act of hunting or radio
Speaker 2: broadcast to its physical source. So today we're going to
Speaker 2: talk a little bit about RDF in general, a little
Speaker 2: bit about the history about the science behind it. But
Speaker 2: we also wanted to focus somewhat on the sport of
Speaker 2: transmitter hunting, also known as tea hunting or fox hunting,
Speaker 2: which turns this activity of radio direction finding into a
Speaker 2: recreational activity.
Speaker 1: And this ties into a lot of those other subjects
Speaker 1: I was talking about, like from the aspect of geocachhing,
Speaker 1: where we're using technology for some sort of recreational activity
Speaker 1: that wasn't necessarily intended to be when we first started
Speaker 1: developing that tech, all the way to the story Chuck
Speaker 1: and I did about the infamous Max Hedgroom incident right where.
Speaker 2: Somebody another case of signal intruthu exactly.
Speaker 1: Someone was able to do signal intrusion in the Chicago
Speaker 1: market and overpower television signals and present an absurd, slightly disturbing,
Speaker 1: and very surreal Max Headroom type of intrusion, Well those things,
Speaker 1: I mean, that's that's kind of why we're talking about this,
Speaker 1: is like, how would you detect where such an intrusion
Speaker 1: is coming from if you had enough time to do so.
Speaker 1: In the case of the Max Headroom incident, Yeah, by
Speaker 1: the time anyone knew what was happening, it was too
Speaker 1: late to really figure out where's the signal coming from.
Speaker 1: They had general ideas just based upon the architecture of
Speaker 1: the city, because things like buildings and stuff can get
Speaker 1: in the way of radio signals, so that that limits
Speaker 1: where a signal can come from. But you need something
Speaker 1: more sophisticated in order to narrow down the actual direction
Speaker 1: and specifically the locality of a transmitter. So this has
Speaker 1: a really long history. It dates back pretty much shortly
Speaker 1: after we started sending radio signals. In fact, the very
Speaker 1: first person to kind of associate directionality with radio signals
Speaker 1: was Heinrich Hertz. And that name Hurts probably rings some bells.
Speaker 1: We're gonna be talking about a lot about Hurts the
Speaker 1: unit of measurement and not Hurts the person in this episode.
Speaker 1: He discovered in eighteen eighty eight with an open loop
Speaker 1: of wire which was acting like an antenna, or it
Speaker 1: really was an antenna, wasn't acting like one, just a
Speaker 1: bent one. Yeah, But this was a loop of wire
Speaker 1: that had a gap between the two ends of the loop.
Speaker 1: So it's not a closed loop, it's an open loop.
Speaker 1: It had some direction finding properties to it. He found
Speaker 1: that if he used this loop near a transmitter and
Speaker 1: if the looper positions so that it's ends faced the transmitter.
Speaker 1: In other words, if you're looking at the face of
Speaker 1: a transmitter and you're looking at a loop, the loop
Speaker 1: is at a ninety degree angle. It's the wire part
Speaker 1: is facing the ends of the wire part is facing
Speaker 1: the transmitter as post to the open face.
Speaker 2: Okay, it would create real a.
Speaker 1: Big spark between those two ends. If you started to
Speaker 1: rotate the loop of wire so that the open face
Speaker 1: the o if you will, of the loop faced the transmitter,
Speaker 1: it didn't create that spark. So rotating it would create sparks,
Speaker 1: and the biggest spark would be if it was in
Speaker 1: this ninety degree alignment with the transmitter. And that showed
Speaker 1: that there was some directionality with radio waves and antenna.
Speaker 2: Yeah, and that specifically you could put together an antenna
Speaker 2: receiver in certain ways that it would respond differently depending
Speaker 2: on how it's oriented.
Speaker 1: Exactly with respect to the source of transmission exactly, So
Speaker 1: the next one you would talk about the actual One
Speaker 1: of the earliest successful implementations of this idea would be
Speaker 1: the Bellini Tosi apparatus, not the only early direction finding antenna.
Speaker 2: Why am I imagining some kind of dessert making machine
Speaker 2: the Billini Tosi apparatus. It's like a large box, out
Speaker 2: of which comes big blobs of icing.
Speaker 1: Right, or gelato or something. I'm on a diet, Dude,
Speaker 1: you are killing.
Speaker 2: The runs on diesel.
Speaker 1: I would eat diesel powered gelatto right now in a heartbeat,
Speaker 1: but instead I'm going to stick to my Brussels sprouts.
Speaker 1: So two Italian officers named Ettore Bellini and Alessandro Tossi
Speaker 1: came up with this. Sometimes it's actually called the Marconi
Speaker 1: Ballini tosi because Marconi's name gets attached to everything. Yeah,
Speaker 1: that might be a little bitter tesla left over issues
Speaker 1: that I have about Marconi's name getting associated with stuff
Speaker 1: that certainly he was instrumental in the development of, but
Speaker 1: perhaps not the primary source of that technology the way
Speaker 1: his name would indicate anyway.
Speaker 2: Yeah, the wireless telegraph you'd want his name all over everything. Yeah, yeah,
Speaker 2: don't worry.
Speaker 1: About people who worked on that stuff, you know, before him,
Speaker 1: or had originally secured a patent before he had and
Speaker 1: then had their patents overturned. Stop with your bitterness. That's
Speaker 1: another episode. In fact, I've talked about it in previous episodes.
Speaker 1: So the way this worked is that they actually created
Speaker 1: two loops of wire arranged at right angles with respect
Speaker 1: to one another. So you can think of these as
Speaker 1: kind of like a casing, these two big loops of
Speaker 1: wire at right angles in the middle of which they
Speaker 1: put a third coil of wire, but this one could
Speaker 1: rotate freely within those two fixed ninety degree angle loops.
Speaker 2: Okay, so it's like a wire globe and then another
Speaker 2: loop inside.
Speaker 1: Yeah, and that wire loop inside can freely rotate, and
Speaker 1: that's where they were able to create this directional antenna,
Speaker 1: this direction finding antenna. The rotating element is called a
Speaker 1: rotor or sense coil, and then the other two are
Speaker 1: called stators or field coils. And folks, I apologize, I'm
Speaker 1: still over getting over a cold, so you're gonna hear
Speaker 1: me be raspy throughout this episode, just like last time. Yay,
Speaker 1: So these original ones were big, big devices.
Speaker 2: Yeah.
Speaker 1: The first picture I saw it showed the operator sitting
Speaker 1: at a desk and the actual antenna was about twice
Speaker 1: the height of the desk he was sitting at.
Speaker 2: Now, what was this used for?
Speaker 1: At the time, These were used as land stations around
Speaker 1: primarily Europe, and were used mainly to help with navigation.
Speaker 2: So how would that work.
Speaker 1: You would have this enormous antenna that was detecting transmissions
Speaker 1: coming from other vessels, let's say navy vessels or maritime vessels,
Speaker 1: and they would be able to detect what direction the
Speaker 1: the that transmissions coming from and send information back out
Speaker 1: via radio to the vessel.
Speaker 2: So the lost ship says where am I sends a
Speaker 2: transmission saying where am I land based?
Speaker 1: Our southwest?
Speaker 2: It knows where it is, yes, and if it knows
Speaker 2: the direction you're transmission is coming from, then it can
Speaker 2: tell you where you.
Speaker 1: Are in general. Yes. And then eventually you actually saw
Speaker 1: these devices being placed on the craft themselves. So then
Speaker 1: you could have a stationary radio transmission center sending out
Speaker 1: a basic signal sometimes and frequently having the location for
Speaker 1: that transmission center encoded in the signal itself sent out
Speaker 1: to sea, and then the vessels would have these type
Speaker 1: of antenna aboard them. They could then use the antenna
Speaker 1: to figure out what direction the transmission's coming from because
Speaker 1: they know the specific location of that center because it's
Speaker 1: in the signal itself.
Speaker 2: So the same thing, but inverse exactly.
Speaker 1: So early ones were land based, then later on they
Speaker 1: were actually based on the vehicles themselves. Whether it was
Speaker 1: it started off with ships, it eventually also incorporated aircraft.
Speaker 2: Now I know that the idea of finding the physical
Speaker 2: location of a radio transmitter, whether it's a vehicle or
Speaker 2: a station of some kind, must have played a big
Speaker 2: role once radio was used in warfare.
Speaker 1: Absolutely there were some instrumental battles in which one side
Speaker 1: or the other frequently actually was the Allies had determined
Speaker 1: that a certain German group of units, typically U boats,
Speaker 1: was really effected in naval warfare thiss in World War One,
Speaker 1: world War two. Actually world War one there was some,
Speaker 1: but world War two it really came into play. World
Speaker 1: War one, certainly the U boat communications, which were using
Speaker 1: very low frequency radio waves, it was very important. By
Speaker 1: world War two, you're talking about more high frequency and
Speaker 1: radio ways being put into use. That's where we get
Speaker 1: the huff Duff because it's high frequency direction finder antennas
Speaker 1: hf DFS or huff Duff was the nickname. You get
Speaker 1: the huff Duff antennas that would indicate the direction of
Speaker 1: a trans and that would help be able to track
Speaker 1: like enemy movements, enemy troop movements, particularly in the in
Speaker 1: the Navy.
Speaker 2: And it can you imagine how disappointed these antennas are
Speaker 2: when they get sorted into huffleduff.
Speaker 1: Yeah, no, right, Like you know, they all want to
Speaker 1: be Slytherin because that's my house. I don't know what
Speaker 1: house you belong to.
Speaker 2: I I that's not for me to say.
Speaker 1: It never been sorted. I got sorted into Slytherin. I mean,
Speaker 1: I'm just saying I didn't try to. It just happened.
Speaker 1: You just put on the hat. I do what the
Speaker 1: hat tells me. Man. I live my life that way.
Speaker 1: So this type of antenna was originally meant not for
Speaker 1: military purposes. It was actually meant to help meteorologists learn
Speaker 1: more about lightning and was developed by Robert Watson Watt
Speaker 1: back in nineteen twenty six, and it was to help
Speaker 1: locate where a lightning strike occurs, because you know lightning.
Speaker 1: It gives off electromagnetic rays just or waves, I should
Speaker 1: say not rays, but waves, just as a radio antenna
Speaker 1: would sure, and so you would use these antenna to
Speaker 1: detect the location of lightning strikes. It also helped you
Speaker 1: track the pathway of electrical storms. So that's what it
Speaker 1: was intended for. But in World War Two it got
Speaker 1: put to other uses to try and track movements of
Speaker 1: enemy troops. Very important. Now, after World War Two, we
Speaker 1: started seeing more development in radio direction finding technology, not
Speaker 1: just in military but also commercial applications. In fact, we
Speaker 1: also saw a lot of amateur radio operators get interested
Speaker 1: in it, and particularly once ham radio in the United
Speaker 1: States was really starting to take off.
Speaker 2: I guess that was in the fifties sort of.
Speaker 1: Yeah, forties and fifties really really post world War two,
Speaker 1: because during World War Two they were very very picky
Speaker 1: about who got a chance to actually broad cast radio. Right, Yeah,
Speaker 1: they were like, you know, guys, we need you, guys
Speaker 1: to unless we're telling you to do it, don't do
Speaker 1: that thing, right. So, but once World War two was over,
Speaker 1: we saw a lot more development go into that and
Speaker 1: there are a lot of a lot of purposes for
Speaker 1: RDF we talked about navigation, it's not really used for
Speaker 1: navigation that much anymore because we have more sophisticated methods
Speaker 1: for navigation.
Speaker 2: Lots satellites, now, yeah, we've.
Speaker 1: Got we've got stuff beyond, like a radio transmitter and
Speaker 1: a receiver. That being said, there's still some places that
Speaker 1: use radio beacons as a means for emergency backup, some
Speaker 1: around the UK, not really any in the United States.
Speaker 1: At this point, maritime vehicles held onto it longer than
Speaker 1: aircraft did. But even today you don't really see that
Speaker 1: as a as a even a tertiary method for navigation
Speaker 1: because we have so many other more sophisticated systems at play.
Speaker 1: But there are other reasons that we do still use them.
Speaker 2: I mean, well, one would be like the example hunting
Speaker 2: down illicit broadcasts and jammers.
Speaker 1: Absolutely, yeah, Now this was huge in World War Two
Speaker 1: as well. The UK actually ended up getting a big
Speaker 1: volunteer force of interceptors about seventeen hundred folks in the
Speaker 1: UK who were amateur radio operators, and use them to
Speaker 1: help suss out any enemy transmissions that were coming from
Speaker 1: the UK.
Speaker 2: Because is there a period piece movie about this year?
Speaker 1: There should be, although it'd be kind of boring because
Speaker 1: I think they only find anything. They found like two
Speaker 1: and one of them was one that they were doing
Speaker 1: on purpose.
Speaker 2: Well, that could be the angle. Maybe there was a
Speaker 2: cover up, there's some big secret or like.
Speaker 1: There's the crowd of HAM operators carrying pitchforks storming the
Speaker 1: transmitter room of this one perceived enemy of the state,
Speaker 1: and it turns out that they're just following or from
Speaker 1: the UK government to send out false commands. Because that
Speaker 1: was a thing, right, Like, it wasn't just secret information,
Speaker 1: it was disinformation. There were a lot of different campaigns
Speaker 1: going on in the information and intelligence worlds in World
Speaker 1: War Two.
Speaker 2: So but that's glorious the image of an army of Hams. Yeah,
Speaker 2: radio Hams coming at you to vhfu up yep.
Speaker 1: That's right. There's so much opportunity there for edge of
Speaker 1: your seat drama. But the interesting thing to me was
Speaker 1: that the UK they were using I five to head
Speaker 1: this operation because that's their domestic intelligence agency, but they
Speaker 1: determined that really this was a bigger problem in Europe.
Speaker 1: They had a lot more clandestine operators in Europe on
Speaker 1: both sides, really sending out messages via radio transmission and
Speaker 1: so they switched this operation over to I six, which
Speaker 1: looked at intelligence coming from outside the UK rather than
Speaker 1: from within it. So it's kind of in the United
Speaker 1: States the difference between our FBI and our CIA, same
Speaker 1: sort of thing, and in Europe was a much different story. Like,
Speaker 1: the RDF was incredibly important during World War Two because
Speaker 1: there were so many different operators using radio transmission as
Speaker 1: a way of getting either spy reports or orders across
Speaker 1: various borders. It eventually got to the point actually where
Speaker 1: the access powers were really shy about transmitting any information
Speaker 1: because they were so worried about it getting intercepted and caught. Now,
Speaker 1: this is the same era as the Enigma machine, right,
Speaker 1: and once the Allies were able to crack some of
Speaker 1: the Enigma codes, was it really became apparent that you
Speaker 1: had to be super careful with your intelligence, otherwise you
Speaker 1: were handing the enemy all of your game plans. So
Speaker 1: really interesting story though. Then there's other methods or other
Speaker 1: reasons to use RDF.
Speaker 2: There's search and rescue, Yeah, how about that, So coast
Speaker 2: guard or rescuing a down plane. Either one. You might
Speaker 2: have a vehicle that is equipped with radio transmission capability
Speaker 2: but is it self stranded.
Speaker 1: Yeah, there's a lot of civil aircraft that have this.
Speaker 1: There are a lot of like if you are if
Speaker 1: you're hiking in an area that is prone to avalanches,
Speaker 1: you may even have a transmitter on you as a
Speaker 1: means for emergency signaling in the case of an avalanche.
Speaker 1: So this is still a thing, right. It's something that
Speaker 1: can send out a steady signal with perhaps an encoded message,
Speaker 1: usually a unique identifier to whatever the transmitter is, so
Speaker 1: that once you tune into it, you know that you're
Speaker 1: actually listening for the right signal. You're not going to
Speaker 1: get distracted by a signal on a similar frequency that
Speaker 1: is not what you're looking for, and you can try
Speaker 1: and narrow down your search to find whatever it is
Speaker 1: that's lost.
Speaker 2: Now, one thing we mentioned earlier is hunting malicious interference,
Speaker 2: people who are intentionally jamming a radio station or broadcasting
Speaker 2: propaganda or something like that. But there's also unintentional interference,
Speaker 2: and this could be useful too for tracking down you
Speaker 2: know something, maybe radio frequencies are leaking out of some
Speaker 2: sort of device and they're interfering with the broadcast band
Speaker 2: around there.
Speaker 1: Yeah, I mean, it's it's not necessarily something that's done
Speaker 1: with malicious intent. Really, anything that creates an electrical field
Speaker 1: is creating electromagnetic radiation, and that some form of that
Speaker 1: is in radio waves, and depending upon the power of
Speaker 1: the device in question, it could be putting out radio
Speaker 1: waves strong enough to interfere with transmission of normal signals.
Speaker 1: You'll hear about this also, like I remember hearing about
Speaker 1: this with theaters, in fact, theaters that were using wireless
Speaker 1: radios in order to have back of house talk to
Speaker 1: front of house for stuff like stage managing and lighting
Speaker 1: changes and stuff, and then you would end up getting
Speaker 1: truckers talking over your system and it would just Peter
Speaker 1: Pan became an entirely different show at that point.
Speaker 2: But this is the sort of thing tinker Bell about
Speaker 2: the speed trap up there.
Speaker 1: Yeah, And it all has to do with the frequency
Speaker 1: you're using in the power of the radios in question, right,
Speaker 1: or perhaps more problematically, having that transmission of a high
Speaker 1: school production of Peter Pan being transmitted out to people
Speaker 1: who are using radio for really important reasons. This is
Speaker 1: one of the reasons why most places around the world
Speaker 1: have very strict rules of what types of equipment can
Speaker 1: use which frequency bands, so that it avoids that kind
Speaker 1: of crost contamination.
Speaker 2: You don't have the problem where Officer Officer Hurtz tries
Speaker 2: to radio in for backup, but instead he's being jammed
Speaker 2: by Peter Pan.
Speaker 1: Right, or suddenly Captain Hook and a bunch of pirates
Speaker 1: show up, Like, this is not the backup I was
Speaker 1: hoping for. That wasn't hoping for a chorus line, I
Speaker 1: really need physical people to help back me up for
Speaker 1: this dangerous situation.
Speaker 2: Another use that you have here that I didn't even
Speaker 2: think of, but very smart wildlife tracking.
Speaker 1: Yeah, yeah, animals get tagged exactly. These are transmitters that
Speaker 1: send out a steady signal so that scientists can continue
Speaker 1: to monitor the movement of various wildlife. Usually you do
Speaker 1: this to track migration patterns and how those might change,
Speaker 1: particularly in light of things like human like humans moving
Speaker 1: into what used to be territory. For animals, how do
Speaker 1: their migration patterns change, or in the face of changing
Speaker 1: weather patterns, that kind of thing, And you need obviously
Speaker 1: to have a direction finder in order to know where
Speaker 1: the animals are actually going. Plus, if you ever want
Speaker 1: to go into a physical check, let's say that you
Speaker 1: are doing like a drawing blood from a specific animal
Speaker 1: every few months. Then you need to be able to
Speaker 1: track where that animal is and narrow down its range
Speaker 1: so that you can actually get to it and do that.
Speaker 1: So that is another use, and of course we've already
Speaker 1: kind of talked about it, but spies, I mean not
Speaker 1: just not just someone trying to transmit something. Sometimes it's
Speaker 1: like trying to find a bug. Like bugs that have
Speaker 1: been planted in places, they're sending out little radio transmission. Typically,
Speaker 1: I mean, you could have one that's just recording natively
Speaker 1: to a device, but that means you have to go
Speaker 1: back into that place and retrieve the device in order
Speaker 1: to hear what's been recorded on it. Most bugs are transmitters,
Speaker 1: so that means that you have to have a radio
Speaker 1: direction finder to figure out where a transmission is coming from.
Speaker 1: Let's say it's a nice big embassy building. You might
Speaker 1: need to narrow down exactly where is this thing and
Speaker 1: that you know, we see those in spy movies, but
Speaker 1: it really does happen. I Museum in Washington, DC fascinating.
Speaker 1: You can actually see some of the devices that were
Speaker 1: used to both plant bugs and to detect them.
Speaker 2: I want to go to that sometime. I've read a
Speaker 2: little bit about I remember seeing online a thing about
Speaker 2: their exhibit on spy pigeons.
Speaker 1: Yeah, it's fun. It's weird in that I don't mean
Speaker 1: this to become like an ad for the Spy Museum
Speaker 1: in DC. It's weird because I feel like the presentation
Speaker 1: is really perfectly geared towards kids. But there's so much
Speaker 1: text involved in the exhibits that I don't know that
Speaker 1: your average kid has the tension span or desire to
Speaker 1: read that much while going through a museum. So my
Speaker 1: experience was that I was trying to read the same
Speaker 1: paragraph fifteen times while kids were running all over the
Speaker 1: place trying to play with stuff. So it was a
Speaker 1: little frustrating for me, but fascinating exhibits, really well laid
Speaker 1: out and lots of fun stuff. They incorporate both real
Speaker 1: world spy gadgets and also movie stuff, so they had
Speaker 1: like an entire James Bond section that was really a
Speaker 1: lot of fun. Yeah, yeah, so that's cool. And then
Speaker 1: one other modern use for radio direction finding is what
Speaker 1: we're really going to focus on toward the end of
Speaker 1: the show, which is using it recreationally for sport. So
Speaker 1: this idea of fox hunting trying to.
Speaker 2: You know, competitively, you mean the sport itself, not like
Speaker 2: using radio direction finding to find a lost ball in golf.
Speaker 1: I mean, there's no reason you couldn't do that other
Speaker 1: than the fact that you would have to have a
Speaker 1: golf ball with a transmitter and have to build it
Speaker 1: in such a way that it could withstand enormous force
Speaker 1: being placed upon the ball and still not you know,
Speaker 1: still continue to transmit. Probably would have keep going on. Yeah, no,
Speaker 1: I'm thinking about all the different This is the thing
Speaker 1: you're gonna put out a joking hypothetical, and I'm going
Speaker 1: to go through why it's going to be difficult to implement, Well, impossible,
Speaker 1: but difficult.
Speaker 2: Maybe we should stop you there and take a break. Yeah,
Speaker 2: let's do that.
Speaker 1: Let's take a quick break that the think our sponsor
Speaker 1: all right, we're back now. Before we dive into the
Speaker 1: wonderful world of fox hunting, it would probably behoove us
Speaker 1: to understand a little bit more about radio waves, how
Speaker 1: they work, transmitters and antenna in order to get at
Speaker 1: what transmitter hunting is all about. So we're gonna start
Speaker 1: at basic, like elementary level radio physics, okay, and we're
Speaker 1: gonna build from there. So radio waves are a subset
Speaker 1: of electromagnetic waves, so are also called EM waves or
Speaker 1: N waves. You have to put your finger up to
Speaker 1: your chin like you're thinking N waves. Now, em waves
Speaker 1: come from stuff that generates an electric field.
Speaker 2: Doesn't have to.
Speaker 1: Be a particularly sophisticated setup. You can actually do this
Speaker 1: with something as simple as a nine volt battery and
Speaker 1: a coin. Really, yeah, if you put a coin across
Speaker 1: the terminals of a nine volt battery, you are generating
Speaker 1: an electric fil because all you're doing is closing the
Speaker 1: circuit from the negative and positive terminals and allowing electricity
Speaker 1: to flow through. That creates an electric field.
Speaker 2: Right, But I'm assuming you're saying this because doing that
Speaker 2: would generate some kind of radio signal that can be detected.
Speaker 1: Yes, it's a very weak radio signal. But if you
Speaker 1: were to do this very close to an AM radio first,
Speaker 1: you would you would want to tune the AM radio
Speaker 1: to something that's just static. You're not actually getting a
Speaker 1: signal like a strong signal. In and if you were
Speaker 1: to place the coin against the terminals and listen closely
Speaker 1: to the radio, you should hear a crackle as the
Speaker 1: coin makes contact with those terminals. Because you're sending out
Speaker 1: this little radio signal and the radio is detecting it. Now,
Speaker 1: you're not sending out anything meaningful. It's just noise. That's
Speaker 1: why you're just getting a crackle. You could send a
Speaker 1: signal in Morse code, so you could encode a signal
Speaker 1: by the sound and absence of sound of this crackle,
Speaker 1: But there's nothing meaningful in the crackle itself. Right, But
Speaker 1: that does show you that it doesn't take very much
Speaker 1: for you to generate radio waves. The electromagnetic waves that
Speaker 1: we talk about all have kind of common features, even
Speaker 1: though they may do very different things. There's certain things
Speaker 1: that we can use to describe them that's common across
Speaker 1: all of them. So when we plot those waves on
Speaker 1: a graph, you know, it's a little up and down
Speaker 1: the crests and troughs that you would see usually across
Speaker 1: an X and y axis. We would call the height
Speaker 1: of those waves the amplitude. This typically, like in sound waves,
Speaker 1: this would be the volume of sound, right, yea. The
Speaker 1: higher the amplitude, the louder the sound is. The length
Speaker 1: of the wave is the wave length.
Speaker 2: Okay, that's really kind.
Speaker 1: Of tricky, right, And the number of waves that pass
Speaker 1: through any given point on that graph within a second,
Speaker 1: that's the frequency.
Speaker 2: But because these waves always move at the same speed,
Speaker 2: which is the speed of light. Yes, if you know
Speaker 2: one or if you know the wavelength or the frequency,
Speaker 2: you know the other exactly. You know how fast it's going, right, right.
Speaker 1: So when we talk about different frequencies, we're not talking
Speaker 1: about speed of the signal, because the signal is still
Speaker 1: traveling at the speed of light no matter what. We're
Speaker 1: talking about the number of times a wave passes any
Speaker 1: given point within a second. Typically it's within a second.
Speaker 1: It's really any unit of time. But for the purposes
Speaker 1: of measurement, we talk about hurts, and a hurtz talks
Speaker 1: about the number of times a wave passes a point
Speaker 1: in a second. So one hurts would be once a second.
Speaker 1: That would need to be an extremely long wave because
Speaker 1: for it to take a full second for the wave
Speaker 1: to pass that point, and it's traveling at a speed
Speaker 1: of light, that's incredibly long.
Speaker 2: Right, So how far does light go in a second?
Speaker 2: Let's see, I don't know, like.
Speaker 1: Further than I've ever been.
Speaker 2: I can tell you that, Okay, Well, so how do
Speaker 2: you get to using though, because we so, Yes, we
Speaker 2: live in a universe of radio signals. They're electromagnetic waves
Speaker 2: all over the place around us. But that's humans use
Speaker 2: radio for specific purposes. They can take these waves and
Speaker 2: encode information with them.
Speaker 1: Yeah, and this this comes from manipulating either the amplitude
Speaker 1: or the frequency of those waves, modulating them in some way. Typically,
Speaker 1: that's all we can encode information into them. So let's
Speaker 1: say that you build a circuit containing a capacitor and
Speaker 1: an inductor. These are two very basic circuit components. So
Speaker 1: you build your circuit, you've got a capacitor and an
Speaker 1: inductor involved in this. This will allow you to create
Speaker 1: a sine wave that's just a very smooth, continuously varying wave.
Speaker 1: It's you know, that kind of smooth up and down
Speaker 1: like like your typical let's show ocean waves kind of
Speaker 1: viewpoint and just nice little hills and valleys. Little saltwater crocodile,
Speaker 1: yeah along in there, and the saltwater crocodile would be
Speaker 1: carrying information. So without any saltwater crocodiles, you're still not
Speaker 1: transmitting anything meaningful. Right, It's just a sine wave, but
Speaker 1: there's no information there. But if you modulate it, then
Speaker 1: you can encode information in it. One way to do
Speaker 1: that is with pulse modification. This is similar to what
Speaker 1: I was talking about with that nine volt battery. This
Speaker 1: just involves turning a signal on and off so that
Speaker 1: when the signal's on, it might indicate a dot or
Speaker 1: dash in morse code, so you're not Again, nothing within
Speaker 1: the signal itself is necessarily meaningful. It's when you detect
Speaker 1: it versus when you don't detect it that gives you information.
Speaker 1: Then you have amplitude modification or our modulation I should say,
Speaker 1: or AM That changes the peak to peak voltage of
Speaker 1: the sine wave. And the way you do this with
Speaker 1: AM radio is you start with a basic sin wave.
Speaker 1: That's your that's your baseline. You take whatever you want
Speaker 1: to transmit, whether it's you know, the cool hits of
Speaker 1: the seventies or or some talk show hosts or whatever.
Speaker 1: You take that that hard woman, yeah it could be
Speaker 1: a hard woman. You take that signal and you overlay
Speaker 1: that signal on top of the baseline sine wave to
Speaker 1: modulate it. This changes the amplitude of that sine wave.
Speaker 1: You get kind of a you know, a product from
Speaker 1: the modulation of these two. By adding the two together,
Speaker 1: you get a new frequency, a new wave. It's not
Speaker 1: really it's the same frequency, it's different amplitude, but you
Speaker 1: get a new wave with a different amplitude than both
Speaker 1: of your basic ones. This is what you transmit to
Speaker 1: a radio tower. You actually have to amplify it by
Speaker 1: quite a lot. Obviously, the further you want this signal
Speaker 1: to go, the more you have to amplify it, the
Speaker 1: larger your antenna tends to be. And then the signal
Speaker 1: goes out over the air and then people with the
Speaker 1: receivers tuned to that frequency can pick it up, and
Speaker 1: the signal gets converted back into something that a radio
Speaker 1: can play, amplified again so that you can hear uhcy.
Speaker 1: Frequency modulation is similar, except instead of changing the amplitude
Speaker 1: like moduling the amplitude, you're moduling the frequency of the signal.
Speaker 1: So again you start with a base sine wave for
Speaker 1: the radio station. This is what's transmitting, whether any noise
Speaker 1: is coming out of it or not, it's just this
Speaker 1: base sine wave. Then you take on the the the
Speaker 1: wave created from whatever you're trying to transmit hard woman,
Speaker 1: and it changes the frequency.
Speaker 2: Now, Jonathan, I wonder how exactly, if you're not a
Speaker 2: radio expert, how does modulating the frequency not affect the
Speaker 2: you know, the station you're listening to, because the station
Speaker 2: you listen to the radio on is the frequency. Sure,
Speaker 2: when there's a number in front of a radio station,
Speaker 2: power ninety nine, that's ninety nine megahertz, right.
Speaker 1: Right, nine nine point seven. Yeah. Well, part of it
Speaker 1: is that each radio station really has a range like
Speaker 1: there's it's you get a number that's the base frequency,
Speaker 1: but there's a range within are surrounding that frequency that
Speaker 1: allows for this modulation. The modulation doesn't change the frequency
Speaker 1: so dramatically that it will bleed into another station. That's
Speaker 1: why we have stations that have very defined frequencies, because
Speaker 1: if you didn't have that, if they were too close together,
Speaker 1: they would bleed over. Occasionally. You might have actually experienced
Speaker 1: this if you're listening pathleearly to AM radio, because it
Speaker 1: travels much further. If you start traveling around, you might
Speaker 1: get two stations coming in simultaneously, because you might you
Speaker 1: might move from the broadcast area of one station into
Speaker 1: the broadcast range of a station that's got a similar
Speaker 1: though not necessarily identical frequency, and then you're hearing both
Speaker 1: at the same time. That's really disconcerting. If you transcend,
Speaker 1: it could be like if you're if you're hearing are
Speaker 1: Em and hard Woman, you might discover something interesting about yourself.
Speaker 1: I don't think fire and brimstone sermon, and I don't
Speaker 1: know some some good something about college sports. Yeah here
Speaker 1: in the Southeast to be college sports and sermons. Yeah,
Speaker 1: But from my experience of listening to AM radio, so
Speaker 1: receiving antenna, what they do, Like we just talked about, you,
Speaker 1: you take your transmitter, you send a signal out, it
Speaker 1: gets amplified a couple of times, usually before it hits
Speaker 1: the broadcast antenna and sends out over the airwaves. A
Speaker 1: receiver does the same sort of thing, but it does
Speaker 1: this in reverse. So antennas are tuned to specific electromagnetic frequencies.
Speaker 2: Yeah. Usually they have elements that are a certain size, yes,
Speaker 2: specified yep.
Speaker 1: And so what will happen is they they resonate with
Speaker 1: a certain range of frequencies and if those frequencies are present,
Speaker 1: like if the antenna is present in the in the
Speaker 1: within those frequencies, then it can send it. This creates
Speaker 1: an electrical current that it can then amplify and convert
Speaker 1: into sound so that we can hear it on our radios.
Speaker 1: The the purpose of the amplifiers just really to boost
Speaker 1: that signal. You're typically using like something along the lines
Speaker 1: of a transformer to do that, and I've talked about
Speaker 1: that in the past. So that means you can get
Speaker 1: your talk radio or your grazed hits of the ramones
Speaker 1: which lasts twelve minutes, not because they're so few, but
Speaker 1: because romote songs are so short. Well, I hope you
Speaker 1: enjoyed that discussion Joe McCormick and I had about transmitter hunting.
Speaker 1: Remember that was just part one, So next week we
Speaker 1: will conclude with part two of transmitter hunting. I hope
Speaker 1: you're enjoying it. I also hope you are all well,
Speaker 1: and I will talk to you again really soon. Tech
Speaker 1: Stuff is an iHeart Radio production. For more podcasts from iHeartRadio,
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