 presentation would be, so there's gonna be a lot of flugs, a lot of hems, a lot of haws without further ado, let's get going. I can't even transition to slide all right. So a little bit about me in my background. I started off my professional life as a civil engineer. I went to college, got my bachelor's degree, master's degree in civil engineering, became a professional engineer and realized it really wasn't for me. I didn't really like it as much as I thought it was going to. I then got an opportunity to start security analyst position at Barracuda Networks. We started coming to DEFCON, DEFCON 22. So I've been here for what, six years now, seven years now. And I love doing anything wireless. I love wireless security. So I started playing in the wireless CTF and we won three years in a row, I believe. And now I'm a village member, so now I get to help make the challenges. And yeah, it's one of those things that the reason I started off with this is because I forever feel like a noob. I forever feel like the imposter syndrome is a real thing. And this talk is more of a, I'm not an expert in this, but it's something that I find really interesting and it definitely encapsulates that hacker mentality. So if this is your first DEFCON, you're going virtual, you're watching this talk, don't hesitate to get your feet wet to reach out to people because at the end of the day, I feel like everybody feels like a noob. And if they don't, then they definitely are a noob. So that I basically just wanted to give my background that I didn't have a computer science degree. I didn't have a formal background in computer security or really anything at all except for civil engineering. So don't hesitate to get yourself out there. So this talk, talking to satellites, why? Personally, I think it's cool. The International Space Station is specifically what we're going to be going to cover. But there's a lot of satellites that are floating up above us or orbiting above us that are capable of ham radio communication or just communication from the ground just by normal citizens that don't require any special permission other than ham radio license to transmit to. Well, it's cool about the International Space Station. I mean, it's orbiting 200 miles above us, which actually when I first started doing this, 200 miles didn't seem like a lot to me. It seemed like that it should be orbiting higher than that. But sooner miles up, it's going roughly 17,000 miles an hour. And that's 10 times faster than a bullet, just kind of put it in like rough perspective. And it is orbiting so quickly that it can go around the entire planet in about 90 minutes, which I think is incredible. And it's also the most expensive object ever built, which is kind of neat that just being a normal civilian, I can talk to the International Space Station and even to astronauts on the International Space Station with just general equipment and just a ham radio license. And even if you don't have a ham radio license, you can still listen to transmissions from the International Space Station, which is also, I think, pretty cool. So here's a quick overview. Basically, we're how to talk to ISS on the cheap, the hows and the whys of why you'd want to do it and how you do it, the gear that you're going to need, the software that you'll need, the rough skills that you might need to have or brush up on, timing when you're going to talk to the International Space Station because it's orbiting every 90 minutes and there's only very narrow windows that you can actually try and communicate with it on. And then basically just now that you have all this power, how not to be a jerk? I feel like hacker mentality is the, oh my gosh, we're going to do all these bad, terrible things, but at the end of the day, should you? This is something that's pretty cool and you want to give others the opportunity to do it as well. See, moving on. So the hows and whys. So there's AR ISS, which is Amateur Radio on the International Space Station. Basically, this is up there for educational purposes. It's community driven. It's one of these things that kind of inspire the heart of people of, hey, what are we going to do with space? Why is space important? So I think it's kind of cool that they have a couple amateur radio stations on board or not stations, but I guess transceivers on the International Space Station that are meant for amateur radio operators to interact with. Specifically, what we're going to be talking about is the two meter packet radio that's unattended on the International Space Station. There are definitely some attempts that you can have where crew members might be staffing the International Space Station and actually on the ham radio that you can talk to via voice. However, to try and get that to work is far more limited and you have to plan far more up in advance. Whereas the unattended packet radio basically is going to act as like a repeater for you and it's always up and always operational. And it's just one of those things that it's far easier to get a communication repeated from the International Space Station because it's done automatically. And there's a bunch of other operating modes that the International Space Station has and you can go online at any point in time and check that, but really what we're going to be focusing on is the two meter packet radio. And I also had no idea that a lot of ISS crew members are also ham radio operators, which I thought was kind of cool. Yeah, so we'll just break down the basics of it. To transmit and talk to the International Space Station, you're going to need a ham license and that's just to transmit and that's really because you're going to be operating on frequencies and with hardware that could cause issues for other people. So it's not just like a cell phone where your phone is going to take responsibility for talking back and forth to a cell tower. This is something that you're going to have transmit power and you want to be judicious with how you use it. However, that being said, if there's something that's interesting to you, you can listen without a ham license, no problem at all. You don't need anything just to listen. It's really just transmitting because that could affect other people. And if you want your ham radio license, the ham radio village is offering I believe $5 exams, which is, I mean, pretty cheap normally is I think $20, but everything's going to be virtual obviously because it's DEFCON and for $5 to, you know, make an attempt at your technician license. It's one of those things I think you have to renew it every 10 years. I definitely recommend checking it out. You know, it's definitely a great opportunity. All right, so there's a lot of things that I never quite understood when I was getting into all of this and I'm again, by no means an expert. So there's probably a ton of, you know, things in these slides that a seasoned, you know, extra ham operator is going to know that I'm going to completely flub up on. But I basically just, this is something that, you know, whenever I looked at this, I would always kind of say, oh my gosh, I don't even know what all of this garbage means. So when people always said two meter band, I had no idea what the heck is a two meter band, you know, FM, 1200 BPS packet radio, all that stuff just sounded like gibberish to me initially, and I really wish that somebody would have explained it to me in layman's terms, you know, just so I could at least get the basics and then kind of dig down from there, at least kind of get my feet wet. So if you look at that small little equation on the right hand side of your screen, you're going to see it's C equals, I think that's lambda and then whatever the new, I don't even know the Greek symbols, right? But at the end of the day, what happens to C is the speed of light. So if you divide that by your frequency, which is a megahertz, a megahertz is a million hertz, so a million cycles per second. So, you know, you can think of Wi-Fi as 2.4 gigahertz, you know, or 5.8 gigahertz, just kind of put that in perspective. So if you divide the speed of light by the megahertz of the frequency you're transmitting on, you divide those two and you get two meters. That's, you know, kind of how the math works out. And so when people say like, oh, it's on the two meter band, well, you know, that's the same thing as saying it's about 144 megahertz-ish. And I think the two meter bands anywhere from 144 to 148 megahertz, but that's what people are talking about. So 70 centimeters, you can do the same math and figure out that it's, you know, about 460 megahertz, I think of off the top of my head. And that's also considered VHF. So you'll hear VHF two meter and 144 megahertz, those are all kind of in the same ballpark. You know, and that's just one of those things. So here those terms thrown around a lot and I had no idea what they meant. So I figured it would be helpful to kind of throw out a slide and explain that briefly when somebody says I'm operating on the two meter band. Oh, okay, that means 144 megahertz-ish. You know, and that's also considered VHF, very high frequency. So the next part of that, what is FM? You know, you probably have heard of AM FM radio on in your car. AM is amplitude modulation. So you can see the little graphic on the bottom right of the screen. That's where the wave is actually modulated up and down. So you can kind of think of this waves in a pond. You know, if you throw a rock in and there's big splash, those waves are gonna be bigger and that's gonna be amplitude. You know, there's the varying amplitude there. Whereas FM is how close those waves are, you know, in a ring and a circle. Sorry, I'm using my hands a lot. I don't know, probably look like a magician. But basically you're stretching like a slinky, you know, FM waves. You're modulating the frequency how fast it goes. So, you know, there's AM FM. So we're looking at two meter band FM. So it's frequency modulated. And this is typically not something that you're gonna have to worry about. It's lower level stuff that the radio is gonna take care of, but it's just good to know because I didn't know it when I started out. Gosh, 1200 BPS. So it's BOD, not bits. If you mess this up, you know, the internet's gonna murder you because you're, you know, technically wrong. I always thought that BOD and bits were exactly the same. It wasn't until I dug into it that I actually realized, oh gosh, they're, you know, they can be different. So you can think of a BOD as like a signal interval or like a pulse. And in the early days, I guess, I don't know, I wasn't around during the early days. But early modems would do one bit per BOD. So it would basically just be one BOD and one bit were the same. So 1200 bits and 1200 BOD were the same exact thing. However, now there's craftiness in there that allows you to transmit at a higher bit rate with the same level of BOD rate. So if you can transmit eight bits in a single BOD pulse, that should come out to 9,600 bits per second, even though your BOD rate is only 1200. I don't really know. Again, it's one of these things that that's just what APRS or the packet radio service uses. The software takes care of it all for you. You don't have to worry about it, but it is helpful to know so that the internet doesn't murder you. And then the technique that is used for like, you know, packing things, you're packing eight bits per a single BOD is called quadrature amplitude modulation. Say that at a party and no one will want to talk to you. So it's one of those things, again, super nerdy stuff, but it kind of helps to know. For me, you can look at that and at least kind of digest it and understand maybe not why it's that way, but at least that that's what all of these things mean when somebody says, oh, two meter band FM at 1200 BOD, you kind of know what's going on there. And then packet radio, you know, I guess to me this wasn't any news, but it's packetized data, right? And so that's one of those things where instead of it just being a continuous flood of data, all the data comes in packets. And especially for, you know, for APRS, it uses the AX25, which includes your call sign. And I believe for FCC requirements, you need to transmit your call sign anytime that you're going to transmit, you know, power out into the, you know, to the atmosphere. And so this basically satisfies that. But yeah, data comes in in packets. And what happens is say you have like a small walkie-talkie or not walkie-talkie, but a small handheld radio. If you were to transmit on that small radio, what's going to happen there is it is going to get sent out, you know, at not a very far distance. And so the goal of the packet radio service, or I think it's packet radio, packet reporting system, I can read my slides, is basically to repeat that information out farther. So your handheld, you know, radio is going to only make a certain distance, hopefully gets far enough away that, you know, that it can reach a larger repeater that's then going to take your message and repeat it. And the way that APRS works, I think I have this on my next slide, maybe not, but the way that essentially works is you can select how far out you want that message to be repeated. So if you're, say, you know, out in the sticks and there's not a whole lot of, you know, there's not a whole lot of repeaters out there, you might want to set a wider setting or, you know, like a time to live if you're familiar with, you know, internet lingo. That basically says, hey, you know, repeat this out this many hops. And the whole goal of this is essentially to reach what's called an eye gate. And an eye gate will take your packet radio, your take, take your transmission and put it on the public internet. So that way, you know, anybody in the world then can now look at it or, you know, any other, if you have a program written or something like that, you can digest that information and see where it's coming from anywhere in the world. So APRS was created by somebody. His name is Bob Roon. I don't know how to say his last name is Bob. Bob created it, I believe in 1973-ish. And if you look at this image of the world, every continent-ish or every, you know, region of the world has a different, slightly different frequency that it transmits APRS on. And those are all in megahertz. So you can see anywhere in the United States, if you're, you know, which is where I am at least, it's going to be transmitted on 144.390 megahertz is the frequency that everything is going to share. The kind of bummer part about that is that because we're all using, you know, and say we ham operator, ham operators, if we're all transmitting 144.390 megahertz, well, your transmission will interrupt somebody else's transmission. So there's a lot of room for collision, especially when you figure that every time you transmit a message, what's going to happen is that's going to be repeated by any number of other larger repeaters. So there's a lot of, you know, potential congestion in there. So it's one of those things that you don't always want to transmit your message as far as it will possibly go. You just want to get it as far as you need to go to kind of be respectful of the space. And again, I'm breaking all this down because you'll see why it's important when it comes to the ISS later on. So automatic packet reporting system, that's what APRS stands for. A lot of times what people will do is ham operators will have, you know, a little tracking device, beacon devices that have a GPS unit on there and they will beacon out, you know, a location at a set interval, you know, it could be 10 minutes, it could be one minute, whatever their specified interval is. And they will beacon from the small transmitter to, you know, larger repeaters with the intent of getting online. And this is useful if, you know, you're somewhere where there's not cell coverage or, you know, this was invented before cell phones ever existed. Like, I guess like as ubiquitous as they are now. And so it was a great way to track things. You know, it's a great way to track, you know, you can put them in your car or put them in a boat, put them in a plane. You know, people have used them for hot air balloons, you know, and just all sorts of things where maybe cell coverage isn't gonna fit. This is a great way to track assets really. So you can see from this little image there, you know, this is kind of like the traditional what people think of when they hear APRS or, you know, packet radio. They think of a radio that actually transmits the signal. They think of, there's a little device, I think it's called a terminal node controller, yeah, TNC, which basically takes your GPS data and any message data or any other additional data. And it basically makes that into an audio format, you know, it encodes into an audio format that then is transmitted out by your radio. So that's kind of the traditional way that this looks. However, things have changed now since everybody has cell phones. So you could do a couple of things here. So instead of having, you know, a device that has to have onboard GPS and you already has to have an additional piece of GPS information and additional computer and additional encoder and all this different stuff. Instead of what you're going to have here is you can have a Raspberry Pi that does it or you could just have a phone that, you know, automatically has GPS on board, automatically has the audio cable on board. And basically you hook up an audio cable or a sound card if you're using a Raspberry Pi to a radio. I chose about thing. People love and hate these types of radios, but I like mine personally. And basically what you do is you use them, these devices to encode your message, you know, as an audio file that is then transmitted out your radio. And the whole purpose of that is essentially, you know, you could take what used to be a giant apparatus that would fill, you know, like an entire desk and now it's something that can easily go in your pocket and the batteries last for a pretty decent amount of time. And so that's kind of how this, how like the hardware wise, at least what you need or what that looks like. The next part, at least when I was starting out looking at this, I thought that, man, I must need a ton of power in order to transmit to the International Space Station. Like it must just be crazy amounts of power. I'm probably gonna dim the lights in my house trying to get the signal that far away. But really it's incredibly low. I've heard that people have done it on as low as a single watt, but a five watts that comes on your standard Baufang radio is more than enough to transmit to International Space Station. And really when you think about it, that's less power than what your, you know, your phone charger puts out, which I thought was pretty interesting that you could transmit up to something orbiting up in upper atmosphere or low earth orbit for just five watts. Just seems kind of crazy that I can get that far, I guess. So this kind of is a better way to show what I was trying to explain is that there's a little tracker. You can see that I think that I've, I forget what the name of that tracker is, but basically it's super small tracker. I think it's about $100 that, you know, will beacon out, I believe one watt at a pre-described interval with GPS and everything on board. And the whole goal of it is that, that little transmitter may not be able to get very far. But the whole point of it is that you're trying to reach a single digipeter and these digipeters set up by their ham radio operators. And if there's not one in your area, you know, it's one of those things that'd be kind of cool to set one up just to spread the net of APRS far and wide. But essentially the whole goal is for that little tracking device or, you know, any other, and know that you may be having your pocket or whatever to transmit to a higher power digipeter, you know, repeater that digitally repeats it with the express purpose of really trying to get it to a larger gateway. And the gateway, you know, in this case is an eye gate and eye gate can then connect it to the internet. Nice part about that is once it's connected to the internet there are websites like aprs.fi which will aggregate all of this data globally. So you can look around and see all the devices that are transmitting out and about in the world. And, you know, you can look at the other side of the world and just see all the devices that are out there. And there's weather stations, there's, you know, hot air balloons, a lot of cars, boats, planes, you name it. There's a lot of devices that are tracked, you know, on APRS and it's kind of neat to be able to see where all these devices are out on the internet. So that was a full big explanation of APRS. And what matters is that the ISS has one of these digipeters on board, which at the end of the day is kind of neat because you figure normally you would try and, you know, reach a digipeter that is going to be, say, on a mountaintop nearby. But really if you can transmit to the International Space Station and have it repeat your signal, so did you repeat your message? Well, now you can be received on a huge far and wide area down below because the International Space Station has a great vantage point on the rest of the planet. So what's kind of neat is I think I've gotten up to 800 or 1,000 miles from how far I've heard somebody else transmit from. And likewise, normally to transmit a message that far to 1,000 miles, you would need a decent amount of power, a great vantage point, and everything would need to be kind of go right to transmit on, especially VHF or the two meter band that far. Whereas now with the International Space Station because of its vantage point in space and clear line of sight down on the earth, you can transmit your message really far, which I, again, I just think is really cool that the most expensive object that any, it's ever been built that we have the capability as amateurs to be able to transmit and relay a message off of it. I just think it's kind of neat. Yeah, so this is a website. If you go to ariss.net, it looks like what a website would look like if I made it. The graphics aren't crazy, but at the end of the day, it's really cool in that it aggregates all of the stations that heard the ISS and have transmitted the International Space Station. So again, you don't need any hardware at all if you have a phone, you can pull up ariss.net and basically just see, oh, what stations around me have heard the International Space Station? Where is the International Space Station? What messages are coming off the International Space Station? Again, because the whole point of it, or maybe not the whole point of APRS, but at least a, I don't know, a takeaway of APRS is that if that information all gets aggregated online, you can see it from anywhere in the world, which I think, again, is kind of neat. So let's talk about the hardware. I have made the horrific mistake in the past of trying to post links to hardware on my slides and then I find a better price somewhere or I find, oh, it's not there anymore. So what I'm gonna try and do this time is if you wanna look at the hardware, I'm gonna try and keep an up-to-date list at github.com. Again, you can see the link right there and the whole purpose of that is so that I can update this list and find better prices or whatever, because things change and there are better spots to potentially get some stuff at. So again, this is kind of my go-to hardware, which again, if you look at it, it's pretty darn cheap. You're looking at $35, $20, $10, $8. You're looking at under $100 to be able to transmit a signal to the hand radio, to the International Space Station, which again, for that price and the skill requirement and just be an amateur and a civilian, I think it's pretty cool. Balfang radio, this is a cheap Chinese radio. I personally really like them. I know a lot of people on the internet have hate for them, but it works well for me and I find that for $35, it's a great way to just not break the bank but really figure out a hand radio just in general is gonna be a good hobby for you and has a lot of other capabilities. You can listen to normal FM radio, can be a police scanner. There's just a lot of other stuff that it can do. And so I really like it for $35 on Amazon. You can't really beat it. So let's see. So it comes with what's, a little stick antenna, like what you would see on a walkie-talkie. That's what if you were by this Balfang radio, it would come with, but you can build a directional antenna, which is what you're going to want if you're gonna talk to satellites or the International Space Station because a traditional stick antenna is going to radiate its signal out, kind of like a donut. So if you were to hold it, like thumbs up, so the antenna's sticking up, it's gonna radiate out like a donut. I should probably have a slide in there that has these radiation patterns. But really what you want is a directional antenna that kind of focuses that being more like a flashlight into the general spot in the sky where you're trying to focus all of your energy. And so for $10, $20, you can really build your own antenna, which I think is even cooler. And then you need an audio cable and audio card if you're gonna use the Raspberry Pi or if you don't want to use a Raspberry Pi at all and you're just gonna use your cell phone, typically most people have cell phones. And so just an audio cord for that, under $100, you can no problem transmit the International Space Station. And again, all I'm gonna try and keep this updated if there's something missing from it, I hope to shoot me a message and I can update it or see if there's really anything else out there. And again, it's one of those things, for the amount of money, what you get out of it, especially because I'm sure a lot of you have kids that are home from school or maybe you're a kid that is learning remotely now. What an awesome project for under $100 to learn about physics, space, orbits, math, all these things that are super nerdy, because I'm a super nerd, but really there's a lot of other applicable lessons to other stuff out there. The other thing that you're gonna wanna do is turn on Vox. Again, this is one of those things that I'm probably getting internet hate mail for. Vox's voice operated switch. So basically you can think of it as when you start talking, the radio is gonna detect that you're talking already and it will then start transmitting right away. That's nice because that means if you plug an audio cable in from your phone or from a Raspberry Pi, the second that it starts playing audio over that jack, it's gonna start transmitting. Why this isn't ideal is because there's always a little bit of space, a little bit of transmit time after you're done talking where the radio is still on and that can mess up some communications. So it's not ideal, you really want push talk, but if you're just getting started, it doesn't hurt just to use Vox just to get your feet wet. That's my personal opinion. Again, I'm gonna get hate mail, I'm sure, but whatever. So I own an arrow directional antenna from, it's very similar to the one that's in that image right there, it's like $150, which is more than the entire cost of the project. And if hand radio is potentially something you're not gonna get into, you're gonna wanna buy some giant antenna. I don't really know. Personally, I have one because it's something that I really enjoy. However, it's $150 and it's pretty steep. Or you could build your own. And this is one of those things that I was just, checking stuff out online. And I saw that somebody had built their own directional Yagi antenna for like $10 in like PVC parts and like a measuring tape, which is like perfect because I build everything with raspberry pies in PVC anyway. So I had a lot of that basically just flying around. And a measuring tape, which funnily enough, I didn't even think about it, measuring tapes are steel. And so if you, as long as you basically sand off the tips of your antenna to solder your cables to, it's one of those things that, oh, wow, that's kind of neat. Like you can make an antenna out of a steel measuring tape and it folds up nicely too, which is the added benefit. I'll have a link to this on that GitHub page that I mentioned, but if you just wanna Google it right now while you're watching this, if you just do legios, I don't know how you say it. That's how you say it, but that's how I say it. And then Yagi, all the instructions, the build list, everything, I'm not gonna go over all the super details or my time lapse of me building mine because not really necessary at all. Just go online, look at it. Plenty of other people have done a lot of work to make that pretty nice. So it's one of those things too that like, I personally think that this is a nerd merit badge to build your own antenna. That's one of those things. As a student, if this is interesting to you, it kind of gives you a little bit more stake in it, not just to like, oh, I bought all this stuff off the internet, put it together and I can talk to International Space Station. There's a little bit of that like hacker spirit, hacker mentality just to like, I built this antenna out of raw parts and kind of cobbled it together to get it to work. And to me personally, I think that's kind of neat just to kind of have this project of like, yeah, this is something I built in my hands and I'm talking to the most expensive object, like humanity's ever built, you know, arguably, right? And it's just kind of cool to me that you can talk to International Space Station with PVC and a measuring tape and like a radio that you bought off Amazon. And it takes about an hour to build. If you have kids and you want to all get them interested in space and engineering and STEM stuff, you know, or just to get their hands dirty. I think this is personally a really cool project and it's not going to break the bank to try it. And let's see, I don't know why I can't change sides. So there it goes. So this is my antenna up on top of my patio. It's all on top of my patio, obviously. So I can get a better line of sight and I keep everything in my little ammo box and I use a tripod. But again, you can just hold your hand out there with an extra piece of PVC and it works just as well. It's one of those things that it looks homemade and that's what it is, but you're talking to a satellite with a homemade antenna. I think that's pretty cool. So obviously, if you build your own antenna, you're going to have to tune it a little bit. Luckily, if you follow the instructions online of the antenna that at least I made when I went to tune it and from what I've heard from others when they go to tune it, everything is pretty spot on it if you measure things carefully. But the way that you tune your antenna is by looking at the standing wave ratio or SWR. And this really just measures the performance. I like to think of it as, say you have a tube of like, you know, gift wrap, right? And you shout down that tube, how much of your sound that's leaving your mouth going through the tube is actually making its way out the tube. And that's kind of how you can think of SWR working with your antenna of, hey, if I'm going to put five watts of power into my antenna, how much of that power is actually going to be coming out my antenna or how much of it's going to be wasted, you know, kind of just banging around the, you know, just kind of radiating off of it. So there's one of those things that, you know, if you know a ham radio operator, I'm sure they have, you know, a SWR meter, you can buy a cheap one online for $20. I don't have one of those. I don't know how well it works. I personally have a nano-VNA. It was like 50 or something dollars online and does a bunch more stuff other than just looking at SWR, but it's really small and has a battery. I personally really like it. But again, if you're trying to not break the bank, you know, maybe a $20 one online is worth it or you find a ham radio operator that you just say, hey, can I plug this in real quick and test it? You know, there are plenty of older ham radio operators that would love nothing more than to talk radio and talk shop. And it's a great way to, you know, build a community, build a hobby because ham radio operating is an aging hobby, you know, just go to any ham radio operator meeting, you know, in your city, in your state, in your wherever you're from. And it's definitely an older person's hobby, but I don't think it has to be that way at all. The next thing is, it's really just one of those things that if you follow the instructions, you can probably have a pretty good SWR. And again, I think mine, when I did it was 1.3 to one, which I think perfect SWR is one to one. To me, this is just magic. I don't really understand how it works. I just know that you want your numbers to be as close to one to one as possible. Again, if I'm wrong, shoot me a message and let me know and I'll update the slides. So next piece of this is the software. Again, I have lots of Raspberry Pi's lying around from a bunch of other projects. I personally like to use Raspberry Pi. I use the software called DireWolf. It's just an app to get install. Again, if you check out the GitHub page, you'll have the instructions on how to set it up perfectly, as well as like my configuration files to kind of mess with. So you can look at them and not have to recreate it from scratch. And then when you install DireWolf, it'll also install KissUtil, which is what I use to be able to transmit messages into DireWolf. And then the next thing is there's a tool called Zaster. I don't know how you actually say that because it has an X and a Stur in it. So I don't know, I assume that's how you say it. And this is a more of a GUI tool that you can have on the Raspberry Pi, which is kind of neat because you can see, it'll automatically plot where radio transmissions are coming from as they come in through APRS. So if you were to be receiving information and you had Zaster up and running and you're receiving it with DireWolf, you could potentially see all of the beaconing devices or all the other APRS transmitters that are out and about, which is kind of cool when the ISS goes over and all of a sudden you have to zoom far out to see, wow, look, there's all these people transmitting from all over the world. The last time that I did this, I got a contact from Canada, which I'm in Central California, right? So it's crossing over at least two states just to get there in a good part of California as well. So I thought that was kind of neat. And those are all applications that you want to look at if this is something you're interested in. There's also a lot of APRS applications for phones. I personally, like I said, I use the Raspberry Pi, so that's not something that I'm, I've checked out a couple of them for iOS, but I haven't played with any of the Android applications. So it's one of those things that, I would just recommend checking out an app. You can get trials, I'm sure, of all of these applications and just try to hook up an audio jack to your phone and just plug it in your bow thing and you're off to the races. And it's one of those things that, your phone is kind of the perfect device. It has a battery, it has a GPS, it has a nice touch screen and it can encode audio like nobody's business. So it's one of those things that before, like I said, you'd have a desk full of equipment and now it's a phone and a radio and that's all that's really required of if so long as you have the audio cable in between. Let's see. So the next part of this is planning your pass of like when the ISS is gonna be over. This is a screenshot from my app when I was doing the slides. I use this application called GoSatWatch. It's for iOS. It gives you a little bit of augmented reality which I really like. So what you can see at least from this screen is you can see that this is like currently where the international space station is and you can see like what it's orbit is. It's kind of cool. It gives you statistics of how high it is. So you can see it's like 264 miles orbiting like that's it's altitude elevation. I don't know if the technical satellite turn is for that. It's also going 17,000 miles an hour and then you can kind of see how far it is relative to where you are. And what's nice is that if you are trying to make some communication, if you're trying to digipede off of the ISS, what this app allows you to do is if you hit the sky button down below, you can actually hold up your phone. And since it has the compass and everything in there it'll kind of like orient as to like where you want to point your antenna up in the sky to be able to get your best transmission or your best point of contact. And it gives you live stats. It'll notify you on good passes and then you can, you know, based upon where you are you can see all the different times of day or night when the ISS is going to come. And it also does a ton of other satellites. And that's another thing that I probably neglected to mention is that this is just talking to, or this talk is just going over talking to the ISS. But there are tons of other satellites out there that also perform basically the same operations. All right, let's see, sorry, I had to resume it. But yeah, so this application is great. I think it was like $7 in the app store but there are plenty of other applications that probably do similar things to just check out. It's worthwhile at least. And the other thing too that, again, I really like about this is that it'll notify you and you can point this app up and you can see like where in the sky it is and that matters for a couple of reasons which I'll go over here in a second. So when you're planning your pass you also have to take into effect the Doppler effect. I really like the, I'm not sure if anybody's seeing Big Bang for theory, I'm sure plenty of you have Sheldon's costume of the Doppler effect I just had to throw it in there. But you've all heard the Doppler effect before. It's an ambulance or police cars going by as you can see the little graphic down below. If it's going away from you, the sound will appear slower because it's a lower, longer wavelength. And as the cars approaching you, it'll be higher pitch because it's a smaller wavelength relative to the object that's traveling. And because the International Space Station is traveling at 17,000 miles an hour relative to where you are on the planet it's actually having the frequency, its frequency that's on board is Doppler shifting. So when it's coming by you, it's going to be at a higher frequency. So it's gonna be 145.825 megahertz plus 3.5 kilohertz. And then as it's leaving, so as it's going away from you it's gonna be a longer wavelength. I hope I did that right, if not again, whatever you understand that depending on where you are situated on the planet and where the International Space Station is either approaching or leaving you, it's going to change slightly the frequency that you're gonna tune your radio to. Personally, what I do for this is I try and find a pass when the International Space Station is as far overhead as possible or as close to overhead as possible because then there'll be no Doppler shift that I really have to take into account. And again, a single pass is about five minutes so you don't have a lot of time to really fiddle with your radio and try and readjust or do anything like that. So this is one of those things taking into account to try and find a pass where the International Space Station is coming as close to overhead as possible. And you can go Google this online, you don't even need an app for it. But I personally found that having the app makes it easier to make more longer distance communications because if the International Space Station is directly above you and you're sending a signal to it well it's gonna radiate that or it's gonna digit be that signal right below you. So you're not gonna get a contact that's gonna be far away necessarily or at least as far as you can possibly get it. The optimal kind of thing if you're looking to try and transmit your signal as far as possible would be to kind of hit the edge of the International Space Station and then have it transmit at a farther area away from you. Again, it's one of those things, you can see it, I'll go back a couple slides. You can see the size of the area that International Space Station covers. So at any given point you can hit, that's a large portion of whatever that LMS is, Asia and Europe and then if that were to fly over the United States, it covers a good portion and when it flies over California, you can hit Idaho, Colorado, again, depending on whatever its orbit is. Okay, so this was the hardest part for me is finding out how to actually send a message. I didn't think it would be as difficult as it was. But again, I was using a Raspberry Pi and I was trying to do everything on command line and maybe I was making it more difficult for myself than I really needed to. But again, I could use my phone and have it been easier but again, with some of the plans that I have going forward, I'd rather do this kind of more in an automated fashion. So I use screen, you can use team-ups, you can use multiple putty sessions or whatever you want to connect to your Raspberry Pi. But essentially I had three separate screens for my Raspberry Pi. I had DireWolf that ran my DireWolf configuration. That's what dash C is, dash T is to not do any color on the output of when DireWolf runs. I have the KissUtil, which is installed when you install DireWolf. And basically I have the folder RX and the folder TX that if anything I receive will go into the RX folder, anything that I transmit will go into the TX folder. And so that's kind of nice because I can just drop text files in there and then the KissUtil and DireWolf will take care of converting that to audio and then transmitting it out, which is awesome. Because then at that point you can script up whatever you want, you can do things in an automated manner or manually. But again, you only have five minutes or so that you're trying to communicate with the International Space Station and then even more of a narrow window when it's directly above your one, it's kind of prime time. And you don't want to necessarily, you want to have everything set up in such a way to where you can send out a single message per pass or maybe just a handful of messages per pass because there are other people also trying to communicate with it. And if you remember the International Space Station is operating on a single frequency. It's operating on 145.825 megahertz, which again, I don't know if I put that in notes, but it'll be, you Google it, right? Like it's out there. But only one person can talk to International Space Station at a time. So you don't want to be constantly transmitting because then you'll prevent other people from also communicating with it. So basically what I had is on a, I believe every minute interval I would have it copy my message.txt into the transmit folder and they would shoot that message off or transmit that message off, I guess I should say. And so what's kind of neat about this is that you can script it up in such a way that if you have a program that you want to have automatically beacon something out, you can, or anything like that. Personally, I like that, but if this is just, you're just trying to make a contact or you're trying to, if you want to be digiputed off the International Space Station, that's your only goal. Just with your phone, you can just send the message out that way manually. You don't have to go through all this dire wolf craziness. Most phone applications should be able to do it pretty darn easily. All right, so this is a sample message and I'm going to decipher it here real quick. So if you see the KJ60HH, that's my call sign followed by APRS, and then AR ISS, that indicates basically that I want to be digiputed by the International Space Station. Then you'll see my call sign again, followed by a dash seven. That's because this is coming from my mobile unit, which is just my Balfang radio. After that, you'll see my GPS coordinates. They're kind of in a funny format, not a format that I'm used to seeing, but it's not hard to kind of decipher what those mean. And then followed by a dash, and then after that dash is just whatever message you'd like to send to the International Space Station. So it's not super difficult to decipher, but if it's your first time looking at APRS messages, it might be a little bit more difficult than you would have anticipated. This is the folder structure. So when I run dire wolf, I run it from my home directory, dire wolf config is right there. And then I have a TX and an RX folder for the messages that I'm going to send, going to the TX folder and messages that I'm going to receive come from, or get placed in the RX folder. Let's see if I can take this. All right, so some of the things going forward, I think that are important to cover. So my goal with this is I want to automate it. I want to make some rotors and rotors, if you're not familiar, are basically rotors would allow me to change the elevation up and down. So like if you're looking like a tripods, a great example, right? I could change the orientation 360 degrees, like a compass and then the elevation up and down. Cause it'd be really cool if on the Raspberry Pi, you had some software that basically tracked for the international space station was, and anytime it was up overhead to transmit a message automatically. So that's kind of my idea of what I think would be kind of neat. So we'll see how that goes. And then I would also like to see, how far away can I hear from? How far could I be digipeted by the international space station? And if you kind of think about it out onto the horizon, so if you were out basically to the horizon, that would be zero degrees, but obviously there are trees, there are houses, there are all those things in the way. And so there's a point at which you can hit the international space station with a signal, maybe is that 20 degrees? Is it 30 degrees? Is it 40 degrees? The higher the elevation is relative to where you were on the ground, the easier it will be to communicate with it. So it's one of those things that automating it, I think would be kind of neat. And I also like to investigate, looking at other satellites. Yeah, and basically just seeing what else is out there. A huge thank you to AMSAT and ARISS.net, just because checking out that website inspired me to try and get on the board. It's anything with AMSAT, there's tons of great information there on how other people have had successful communications. And really at the end of the day, I think this is just something that's kind of cool. The hacker mindset here of just kind of scraping and cobbling together all these things to really do something that's kind of neat to be able to transmit to the international space station. Not to mention too, that this is how you can transmit to a lot of other satellites. And it's really kind of covers the basics in terms of what's required to talk to a satellite. There's a whole bunch of different satellite orbits, a whole bunch of different satellite communication protocols, frequencies, modulations, and this is just dipping your toe in the water of what's available and what's out there. And it's for honestly a pretty small budget, right? For $100, $200, you could get a really solid setup to communicate with the international space station with other satellites with just a ham license, just being amateur radio operator. And if you just want to hear, if you just want to listen to what gets transmitted, you can do that without a license. And really, you can just get a Baufang radio, your phone, and it doesn't even have to be a directional antenna at that point. If you just want to listen, you can have an omnidirectional antenna, which is basically just a longer version of the normal stick antenna that would come with the Baufang. Again, I'll post links to everything on that GitHub page. But yeah, at the end of the day, this is a great way just to get started if it's something that you're interested in. And then from there, who knows how much farther you can level up and what other satellite communications you can do. You can spend thousands and thousands of dollars and sink a full-time work week into all of this stuff, especially as an amateur. So it definitely helps to have a good starting point and to have a good point in time of like, this is something that I can measurably check off a list and do, and especially, again, I know that I've said it a bunch of times, but if you have kids at home, if you're a kid at home, this is a great project to really get your feet wet and you learn a ton of different principles from physics to radio to computers to protocols. So there's so many small lessons intertwined that I just think it's kind of one of those perfect projects to basically figure out if it's for you, ham radio operating is for you to find out if chasing satellites across the skies for you. So again, I encourage you to take a look at it. Feel free to check out the GitHub page. I'll post some of my contact information on there along with the links to all the hardware and all the apps and all the things that I've mentioned. And yeah, hope you enjoy the talk. See how do I pause this thing. All right, thank you for that great talk. We have Eric here, take some Q and A. I think one of the ones that came up in the Twitch chat first was the person actually hit by that police car. They were a little worried about that. Can you hear me, Eric? I don't know if Eric can hear us here. We can't hear you, are you talking, Eric? Hello, Eric. Yeah, I can hear you fine. I think our speaker's having some technical difficulties. So what we'll do is he'll just hang around and chat in the village on the channels there. And if you have any questions, he'll follow up certainly in text and maybe on one of the voice channels in there. Alrighty, thanks everybody for attending and hope you all enjoy the talk. I thought it was pretty awesome and we'll go from there.