 Hey everyone, my name is Eric Escobar and today my presentation is going to be on talking to satellites and this is really a one-on-one You've never tried it before you don't even know where to begin This is also gonna be a one-cut take like a normal DEFCON presentation would be so there's gonna be a lot of flugs a lot of hens a lot of That's about it. I know he's without further ado. Let's get going. I can't even transition a 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 in security analyst position at Barrick to 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 a plan 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 start 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 and you're watching this talk Don't 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 that I basically just want to give my background that I didn't have a you know 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 don't hesitate to get your get yourself out there. So this talk talking to satellites Why? Personally, I think it's cool 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 that are capable of you know ham radio communication or just communication from the ground just by my normal citizens that don't require You know 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 when I first started doing this 200 miles didn't seem like a lot to me It seemed like that that 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 it is going it's 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 you know 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 But basically we're how to talk to ISS on the cheap the how's and the why's You know 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 you know 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 You know try and communicate with it on and then basically just now that you have all this power I'm not to be a jerk. I feel like hacker mentality is the you know like oh my gosh We're gonna do all these bad terrible things, but at the end of the day, you know, should you this is 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 house and wise so there's 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 you know 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, you know amateur radio Stations on board the Internet or not stations, but I guess Transceivers on the International Space Station that are 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 is You know, it's a far more limited and you have to plan far more, you know up in advance Whereas the unattended packet radio basically is going to act as like a repeater for you And that's it's always up and always operational And it's just one of those things that it's far easier to get a communication You know 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 know, you can go online at any point in time and check that but but really what we're going to be focusing on is the two meter packet radio It's also I also had no idea that you know a lot of ISS crew members are also ham radio operators, which I thought was kind of cool Yeah, so we'll just you know 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 You know, cause issues for other people. So it's not just like a cell phone where you know your your phone is going to take responsibility for talking back and forth to a cell tower. This is something that you know, 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 know, 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 a believe $5 exams, which is, I mean, pretty cheap. Normally, 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 this. And again, by all 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, 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 see is the speed of light. So if you divide that by your frequency, which is a megahertz a megahertz is a million hertz so 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 is saying it's about, you know, 144 megahertz ish and I think the two meter bands anywhere from 144 to 148 megahertz. But, but that's what people are talking about. So 70 centimeters. You can do the same, you know, 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 to hear 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 going to be bigger and that's going to be amplitude. You know, there's a 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 magician. But, but basically you're, 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 going to have to worry about. It's lower level stuff that the radio is going to 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 going to 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 basically just be one BOD and one bit were the same. 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 9600 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 that is used for like, you know, packing things you're packing eight bits per 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. I mean, 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 those would or 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, 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 AX 25, 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 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. And so if you transmit on that small radio what's going to happen there is it is going to get sent out, you know, and 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 to repeat that information out farther because if 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 then I 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 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 created it. I believe in 1973 ish. And if you look at this, this image of the world, every, 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 bomber 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 the 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 APR stands for. A lot of times what people will do is a ham ham operators will have, you know, a little tracking device beacon devices that have a GPS unit on there, and they will be now, you know, a location at a set interval, you know, it could be 10 minutes 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 on online. So if you know you're somewhere where there's not cell coverage or 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 going to 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 a PRS 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 and 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 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 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. So basically what you do is you use then 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 out something that can easily go in your pocket and the batteries last for a pretty decent amount of time. So that's kind of how this, how, like, like the hardware wise at least what you need or what that looks like. The next part at least what I 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 and probably in the lights in my house, trying to get the signal that far away. And actually, it's incredibly low. I, I've heard that people have done it on as low as a single lot, but a five watts that comes on your standard bowfang radio is more than enough to to transmit to International Space Station. And really when you think about it that's less power than what your, what your, you know, your phone charger puts out which I thought was pretty, pretty interesting that you could transmit up to something orbiting up, up in, you know, upper atmosphere, you know, low Earth orbit for just five just seems kind of crazy that that there, you know, that I can get that far I guess. So this kind of is a better way to, to show what I was trying to explain is that there's a little tracker you can see that I think that I've figured with the name of that tracker is but basically it's super small tracker I think it's about $100 that, you know, will will beacon out I believe one watt at a predescribed 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. It's kind of cool to set one up just to spread the net of a PRS far and wide. But essentially the whole goal is for that little tracking device or you know any other any other and know that you may be having your pocket or whatever to transmit to a higher powered digipeter or you know repeater that digitally repeats it. So what the express purpose of really trying to get it to a larger gateway and the gateway, you know, in this case is an I gate and I gate can then connect it to the internet. Nice part about that is once it's connected to the internet, there are websites like a PRS dot 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 internet 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 a PRS 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 a PRS and why it 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. So if you're trying, you know, reach a digipeter that is going to be say on a mountain top nearby, or really if you can transmit to the International Space Station and have it repeat your signal so did you beat your message. Well now you can be received on a huge far and wide area down below because international space station has a great vantage point on the rest of the planet. I think I've gotten up to 800 or 1000 miles from how far I've heard somebody else transmit from and likewise normally to to you know transmit a message that far to you know 1000 miles. You would need a decent amount of power great vantage point and you know everything would need to be kind of kind of go right to transmit on you know especially VHF or the two meter band that far whereas now with International Space Station because of its vantage point and clear line of sight, you know down to the earth, you can transmit your message really far which I, again, I just think it's really cool that, you know, the most expensive object that any, you know, it's ever been built that we have the capability is, you know, is amateurs to be able to transmit relay message off of it. I just think it's kind of neat. Yeah, so this is a website if you go to our is s.net, you know, it looks like what a website would look like if I made it. You know the graphics aren't crazy, but at the end of the day, it's really cool and that it aggregates all of the stations that heard the International Space Station. So again, you don't need any, any hardware at all if you have a phone you can pull up a rss.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 a PRS but you know at least, at least a, I don't know, a takeaway of a PRS is that if that information all gets aggregated online. You know, 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 you know my slides and then you know I find a better price somewhere or I find oh it's not there anymore. So what I'm going to try and do this time is if you want to look at the hardware I'm going to 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 you know there there are better spots, you know potentially get some stuff at. So again, this is kind of my like 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 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. This is a cheap Chinese radio. I personally really like them. I know a lot of people on the internet have have hate for them, but it works well for me and I find that it, you know, for $35. It's a great way to just you know not break the bank, but really figure out of hand radio just in general is going to be a good hobby for you and has a lot of other capabilities you can listen to normal FM radio. You 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 you know a little stick antenna like what you would see on a walkie talkie that's what if you were by this baffing radio. It would come with, but you can build a directional antenna which is what you're going to want. If you're going to 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're to hold it like thumbs up, you know, so the radio so the antenna sticking up, it's going to radiate out like a donut and I should probably have a slide in there that has, you know, these radiation patterns. But really what we want is a directional antenna that kind of focuses that being more like a flashlight, you know, into the general spot in the sky where you're trying to focus all of your energy. And so for $1020 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 going to use the Raspberry Pi, or if you're if you don't use Raspberry Pi at all, and you just can use your cell phone. You know, typically most people have cell phones. And so just an audio cord for that, you know, under $100 you can no problem transmit the International Space Station. And again, I'm going to try and keep this updated. If there's something, you know, 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, you know, 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, you know, is learning remotely now. It's not an awesome project for under $100 to learn about physics, space, orbits, math, you know, all these things that are super nerdy, because I'm super nerd, but but really there's a lot of other applicable lessons to other stuff out there. The other thing that you're going to want to do is turn on Vox. Again, this is one of those things that I'm probably going to internet hate mail for Vox is voice operated switch. So if you think of it as when you start talking, the radio is going to detect that you're 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 it's going to start transmitting. Why this isn't ideal is because there's always a little bit of space of, you know, a little bit of transmit time after you're done talking where the radio is still on and that can mess up some 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 just to get your feet wet. That's my personal opinion. Again, I'm going to 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 it's like $150 which is more than the entire cost of the project. And if hand radio is potentially something you're not going to get into, you know, you're going to want to 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, you know, I live out online and I saw that somebody had built a their own directional Yagi antenna for like $10 and like PVC parts and like a measuring tape, which is like perfect because I build everything with raspberry pies and PVC anyway so I had a lot of that basically just lying around and measuring tape, which, funnily enough, I didn't even think about it but I guess it's you know measuring tapes are steel. And so if you as long as you, you know, basically sand off the tips of your antenna to solder your, your, your cables to it's one of those things that are kind of neat like you can make an antenna out of a steel measuring tape and it folds up nicely too, which is the out of benefit. I'll have a link to this on that GitHub page that I mentioned but if you just want to Google it right now while you're watching this. If you just do legios, I don't know how you say 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 going to go over all the the super details or my time lapse of me building mine, because not really necessary at all just 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 this is a nerd merit badge to build your own to build your own antenna. That's one of the things if you're a student if this is interesting to you it. It kind of gives you a little bit more stake in it not just 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, you know I built this antenna out of raw parts you know and kind of cobbled it together to get it to work and to me personally I think that's kind of neat just to you know, kind of have this project of like yeah this is something I built my hands and you know I'm talking to the most expensive, expensive object, you know the humanities ever built you know arguably right. And, and it's just kind of cool to me that you can talk to international space station 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 at 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 the things that it looks, it looks homemade and that's what it is but you're talking to 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, you know, 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, a like a tube of like, you know, gift wrap right. And you shout down that tube how much of your sound that's from 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 and 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 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 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 the talk radio and talk shop and it's great way to build the community build a hobby, because ham radio operating is an aging hobby. So just go go to any ham radio operator meeting. You know, in your city and your state and 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, you, 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 pies lying around from a bunch of other projects. I personally like to use raspberry pie. I use the software called dire wolf. It's just an apt get install. Again, if you check out the GitHub page will have the instructions on how to like set it up perfectly. As long as well as like my configuration files to kind of to kind of mess with so you can look at them and not have to recreate it from from scratch. And then when you install dire wolf, it'll also install kiss util, which is what I use to be able to transmit messages into dire wolf. 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 stern it so I don't assume that's how you say it. And this, 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, you know, it'll automatically plot where radio transmissions are coming from as they come in through a PRS. So if you were to be receiving information, and you had zaster up and running, and you're receiving it with dire wolf, you could potentially see all of the beaconing devices or all the other APRS, you know, 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 how look at there's all these people. You know, transmitting from all over the world. The last time that I did this. I got a contact from, from Canada, which, you know, I'm in, I'm in central California right so it's, you know, crossing over at least two states just to get there, and 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. So I would just recommend checking out an app. You can get trials, I'm sure of all of these applications and just, and just try to hook up an audio jack to your phone and, you know, 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 has a battery has a GPS has a nice touch screen, and it can encode audio like nobody's business so it's 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 passive like when I assess is going to be over. This is a screenshot from my app. When I was doing the slides I use this this application called go sat watch. 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, as you can see that this is like currently where the International Space Station is and you can see like, you know what it's orbit is. It's kind of cool gives you statistics of, you know, how high you know how high it is so you can see it's like 264 miles, you know, orbiting like that's it's altitude elevation I don't know the technical satellite service 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, you know, some communication if you're trying to did you feed 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 as the compass and everything in there at all kind of like orient as to like where you want to point your antenna up in the sky to be able to get your, you know, best transmission or you know your best, you know, 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 when the ISS is going to come and 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 I 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. 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 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 reasons which I'll go over here in a second. So when you're planning your past you also have to take into effect the Doppler effect. I really like the, I'm not sure if anybody seen 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 you know an ambulance or police cars going by using see the little graphic down below. You know if it's going away from you the sound will appear, you know, slower because it's a lower, you know longer wavelength, and as the cars approaching you, it'll be higher pitch because it's a smaller wavelength relative to you know, the, 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 you know its frequency that that's on board is Doppler shifting so when it's coming by you it's going to be at a higher frequency you know so it's going to be 145.825 megahertz plus 3.5 kilohertz and then as it's leaving you know so as it's going away from you, it's going to be a longer wavelength. I hope I did that right if not again whatever you understand that 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 going to tune your radio to personally what I do for this is I try and find a password when the International Space Station is as far overhead as possible, or as close to overhead as possible, because there will 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 the things to take 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 going to radiate that or it's going to be that signal right below you so you're not going to get a contact that's going to 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 a farther area away from you. Again, it's one of those things, you know you can see I'll go back double slides, you can see the size of the area that International Space Station covers so at any given point you can hit. And that's a large portion, you know, of whatever that landmess is Asia and Europe, and then if that were to fly over the United States, you know it covers a good portion and when it flies over California, you can hit Idaho, Colorado, you know, again depending on whatever it is. Okay, so this was the hardest part for me is finding out how to actually send a message. I didn't think it was be as difficult as it was. But again, I was using Raspberry Pi and I was trying to do everything on command line. And maybe I was making it more difficult for myself. Then I really needed to but again I could use my phone have been easier but I, but again with some of the plans that I have going forward I'd rather do this kind of more in an automated fashion. I use screen you can use team up so you can use multiple putty sessions or you know whatever you want to connect to your Raspberry Pi but essentially I had three separate screens for for my Raspberry Pi. I had dire wolf that ran my dire wolf configuration that's a dash C is dash T is to not do any color on the output of when dire wolf runs. I have the kiss you till which is installed when you solve dire wolf and basically I have the folder RX in the folder TX that you know 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 kiss you till and dire wolf will take care of converting that to audio and then transmitting it out. Which is, which is awesome because then at that point you can script up whatever you want you can do things on in an automated manner or manually. But again, you only have five minutes or so that you're trying to, you know, communicate with international space station, and then even more of an arrow window when it's directly above your one it's kind of prime time, and you don't want to necessarily want to have everything set up in such a way to where you can send out a single message per pass, you know, 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, you know it's operating on 145.825 megahertz which again I don't know if I put that in notes but again it'll be you Google it right like it's out there. But, 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, you know, copy my message txt into the transmit folder, and they would shoot that message off, or you know 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 you know if you have a program that you want to have automatically begin 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 know you're trying to, you know, begin some or did you be did you pitted off of the internationals. It's my gosh can't talk. If you want to be did you pitted off the international space station that's your only goal. You know just with your phone you just send the message out that way manually you don't have to go through all this dire wolf craziness. Most most phone applications should be able to do it pretty darn easily. So if you have a stable message so if you have a. You know a client on here this is this is one of those things that like this is what I use. Basically I transmit this text in that message txt again that's my call sign. When you see my call sign or so then you see AR ISS essentially all that means is they want to be did you pitted by the international space station that's its call sign. You basically are just saying hey, I want you to did you beat this message the international space station. And then what you have is you have my call sign again, followed by dash seven that's because it's my mobile unit. Again, not getting too deep into a PRS, having that designation there that dash seven just showing that your mobile, and then the next, you know, digits and numbers right there it's kind of a weirdly encoded way that I had to like Google how to do of what different GPS coordinates are and then after that, you can see, you know your message so did you pitting, you know, Defcon 28 aerospace village out to the international space station which then gets relayed, you know, down down to ground stations that receive that message and then off to the the greater internet. This is the folder structure so when I run dire wolf I run it for 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 go into the tx folder and messages that I'm going to receive come from or you know get placed in the rx folder. Let's see if I can get this. Alright, so, so some of the things going forward I think that are important to cover. You know, 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 what it would allow, you know, rotors would allow me to change the elevation, you know, up and down so like if you're looking like a tripod is a great example right. I could, you know, change the orientation 360 degrees like a compass and then the elevation up and down. Because it'd be really cool if on the Raspberry Pi you had some software that basically track for the international space station was, and anytime it was up overhead to transmit a message, message automatically so that's that's kind of my idea of what I think would be kind of So we'll see how that goes. And then I would also like to see, you know, how far away can I hear from, you know, or how far could I try to be digiputed by the international space station. And if you kind of think about it, you know, out onto the horizon so if you were, if you were out, you know, basically to the to the horizon that would be zero degrees but obviously there are trees their houses are all those things in the way. And so there's a, there's a point at which you know you you can hit the international space station. We know with a signal maybe is that 20 degrees is it 30 degrees is it 40 degrees the higher the higher the elevation is relative to where you were on the ground. The easier 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, you know, investigate looking at other satellites. Yeah, and basically just just seeing what else is out there. A huge thank you to AMSET and and ira a RISS net just because checking out that website inspired me to, you know, try and get on the board. It's anything AMSET there's tons of great information there on how other people have, you know, had successful communications. And really at the end of the day, I think this is just something that's kind of cool. You know, 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 to 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 right there's a whole bunch of different satellite orbits a whole bunch of different satellite 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, you know, to communicate with the national space station with other satellites with just a ham license you know just be an amateur radio operator. So if you just want to hear if you just want to listen to what gets transmitted, you know, you can do that without a license and really you can just get about fame radio, your phone and you know it doesn't even have to be a directional antenna at that point you know if you just want to listen you can have an omnidirectional antenna which is basically just, you know, a longer version of the normal stick antenna that would come with about thing. And again, I'll post links to everything on that GitHub page but yeah at the end of the day this is 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 you know what other satellite communications you can do, you can spend thousands and thousands of dollars and, you know, sink the full time work week into all of this stuff, so 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 know you're a kid at home. This is a great project to really get your feet when you learn a ton of different principles from physics to, you know, radio to computers to, you know, protocols to just just there's so many small things intertwined that I just think it's kind of one of those perfect projects to, you know, 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 I pause this thing.