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5780	10020	Hey everyone, my name is Eric Escobar and today my presentation is going to be on talking
10020	14900	to satellites. And this is really a 101. You've never tried it before and you don't even know
14900	19420	where to begin. This is also going to be a one cut take like a normal DEF CON presentation
19420	24480	would be. So there's going to be a lot of flubs, a lot of hems, a lot of haws. That's
24480	29260	about it. Anyways, without further ado, let's get going. I can't even transition a slide
29260	34860	alright. So a little bit about me and my background. I started off my professional life as a civil
34860	39820	engineer. I went to college, got my bachelor's degree, master's degree in civil engineering,
39820	44440	became a professional engineer and realized it really wasn't for me. I didn't really like
44440	49840	it as much as I thought it was going to. I then got an opportunity to start a security
49840	54900	analyst position at Barracuda Networks. We started coming to DEF CON, DEF CON 22. So
54900	60780	I've been here for what, six years now, seven years now. And I love doing anything wireless.
60780	66180	I love wireless security. So I started playing in the wireless CTF and we won three years
66180	70580	in a row, I believe. And now I'm a village member. So now I get to help make the challenges.
71400	74260	And yeah, it's one of those things that the reason I started off with this is because
74260	80260	I forever feel like a noob. I forever feel like the imposter syndrome is a real thing.
80600	85120	And this talk is more of a, I'm not an expert in this, but it's something that I find really
85120	90560	interesting and it definitely encapsulates that hacker mentality. So if this is your
90560	95560	first DEF CON, you're going virtual, you're watching this talk, don't, don't hesitate
95560	99700	to get your feet wet to reach out to people. Because at the end of the day, I feel like
99700	104660	everybody feels like a noob. And if they don't, then they definitely are a noob. So that,
104660	108880	that I basically just want to give my background that I didn't have a, you know, computer science
108880	115800	degree. I didn't have a formal background in computer security or really anything at
115800	121240	all except for civil engineering. So don't, don't hesitate to get your, get yourself out
121240	128440	there. So this talk, talking to satellites, why? Personally, I think it's cool. The International
128440	132460	Space Station is specifically what we're going to be going to cover. But there's a lot of
132460	138080	satellites that are floating up above us or orbiting above us that, that are capable of,
138080	142080	you know, ham radio communication, or just communication from the ground, just by, by
142080	146440	normal citizens that don't require, you know, any special permission other than ham radio
146440	151340	license to transmit to. What's cool about the International Space Station, I mean, it's
151340	155220	orbiting 200 miles above us, which actually, when I, when I first started doing this, 200
155220	159460	miles didn't seem like a lot to me, it seemed like that, that should be orbiting higher
159460	166200	than that. But 200 miles up, it's going roughly 17,000 miles an hour. And that's 10 times
166200	171220	faster than a bullet, just kind of put it in like rough perspective. And it, it, it is
171220	176040	going, it's orbiting so quickly that it can go around the entire planet in about 90 minutes,
176040	180360	which I think is incredible. And it's also the most expensive object ever built, which
180360	184980	is kind of neat that just being a normal civilian, I can talk to the International Space
184980	191320	Station, even to astronauts on the International Space Station, with just, you know,
191320	195440	general equipment and just a ham radio license. And even if you don't have a ham radio
195440	198780	license, you can still listen to transmissions from the International Space Station, which
198780	205000	is also I think, pretty cool. So here's a quick overview. But basically, we're how to
205000	208800	talk to ISS on the cheap, the hows and the whys of, you know, why you'd want to do it
208800	212860	and how you do it, the gear that you're going to need, the software that you'll need, the
212860	217140	rough skills that you might need to have or, you know, brush up on timing when you're
217140	220520	going to talk to the International Space Station, because it's orbiting every 90 minutes.
220520	225660	And there's only very narrow windows that you can actually, you know, try and communicate
225660	229420	with it on. And then basically, just now that you have all this power, how not to be a jerk,
229420	233020	I feel like hacker mentality is the, you know, like, Oh, my gosh, we're gonna do all these
233020	236820	bad, terrible things. But at the end of the day, you know, should you, this is this is
236820	240500	something that's pretty cool. And you want to give others the opportunity to do it as
240500	247940	well. See, moving on. So the hows and whys. So there's AR-ISS, which is amateur radio
247940	252640	on the International Space Station. Basically, this is up there for educational purposes.
252640	256860	It's community driven. It's one of these things that kind of inspire the, you know, the heart
256860	260880	of people of, hey, what are we going to do with space? Why is space important? So I think
260880	265780	it's kind of cool that they have a couple, you know, amateur radio stations on board
265780	270600	in or not stations, but I guess transceivers on the International Space Station that are
270600	274960	that are meant for amateur radio operators to interact with. Specifically, what we're
274960	279000	going to be talking about is the two meter packet radio that's unattended on the International
279000	284120	Space Station. There are definitely some attempts that you can have where crew members might
284120	287520	be staffing the International Space Station and actually on the ham radio that you can
287520	294500	talk to via voice. However, to try and get that to work is is, you know, it's a far more
294500	299480	limited and you have to plan far more, you know, up in advance, whereas the unattended
299480	303480	packet radio basically is going to act as like a repeater for you. And it's always up
303480	308520	and always operational. And it's just one of those things that it's far easier to get
308900	312060	a communication, you know, repeated from the International Space Station because it's done
312060	316500	automatically. And there's a bunch of other operating modes that the International Space
316500	321300	Station has. And, you know, you can go online at any point in time and check that. But really
321300	325220	what we're going to be focusing on is the two meter packet radio. And it's also I also
325220	329500	had no idea that, you know, a lot of ISS crew members are also ham radio operators, which
329500	335120	I thought was kind of cool. Um, yeah, so we'll just, you know, break down the basics of it
335120	338180	to transmit and talk to the International Space Station, you're going to need a ham
338180	341060	license. And that's just a transmit. And that's really because you're going to be operating
341060	345240	on frequencies and with hardware that could, you know, cause issues for other people. So
345240	348460	it's not just like a cell phone where, you know, your phone is going to take responsibility
348460	352080	for talking back and forth to a cell tower. This is something that, you know, you're going
352080	356660	to have transmit power, and you want to be judicious with how you use it. However, that
356660	360540	being said, if there's something that's interesting to you, you can listen without a ham
360540	364920	license, no problem at all. You know, you don't need anything just to listen. It's really
364920	368520	just transmitting because that could affect other people. And if you want your ham radio
368520	373680	license, the ham radio village is offering a bleep $5 exams, which is, I mean, pretty
373680	377660	cheap, normally, I think $20. But everything's gonna be virtual, obviously, because it's
377660	382660	DEF CON and for $5 to, you know, make an attempt at your technician license. It's one of
382660	386700	those things, I think you have to renew it every 10 years. I definitely recommend checking
386700	393200	it out. You know, it's definitely a great opportunity. All right, so there's a lot of
393200	397280	things that I never quite understood when I was getting into all this. And I'm, again,
397280	401400	by all by no means an expert. So there's probably a ton of, you know, things in these slides
401400	406440	that a seasoned, you know, extra ham operator is going to know that I'm going to completely
406440	412580	flub up on. But I basically just this is something that, you know, I whenever I looked at this,
412580	415400	I would always kind of say, Oh, my gosh, I don't even know what all of this garbage
415400	419740	means. So when people always said two meter band, I had no idea what the heck is a two
419740	425000	meter band, you know, FM 1200 BPS packet radio, all that stuff just sounded like gibberish
425000	429200	to me, initially. And I really wish that somebody would have explained it to me in layman's
429200	432760	terms, you know, just so I could at least get the basics and then kind of dig down from
432760	437540	there at least, at least kind of get my feet wet. So if you look at that small little equation
437540	442100	on the right hand side of your screen, you're going to see it's C equals I think that's
442100	447580	lambda and then whatever the new I don't even know the Greek symbols, right. But at the
447580	451040	end of the day, what happens to C is the speed of light. So if you divide that by your frequency,
451040	457960	which is a megahertz, a megahertz is a million hertz, so million cycles per second. So, you
457960	464120	know, you can think of Wi Fi as 2.4 gigahertz, you know, or 5.8 gigahertz, just kind of put
464120	468740	that in perspective. So if you divide the speed of light by the megahertz of the frequency
468740	473240	you're transmitting on, you divide those two and you get two meters. That's, you know, kind of how
473240	476860	the math works out. And so when people say like, oh, it's only two meter band, well, you know,
476860	481260	that's the same thing as saying it's about, you know, 144 megahertz ish. And I think the two meter
481260	486400	bands anywhere from 144 to 148 megahertz. But but that's what people are talking about. So 70
486400	490020	centimeters, you can do the same, you know, the same math and figure out that it's, you know,
490020	496180	about 460 megahertz, I think of off the top of my head. And that's also considered VHF. So you'll
496180	503040	hear VHF, two meter and 144 megahertz. Those are all kind of in the same ballpark. You know, and
503040	506200	that's just one of those things to hear those terms thrown around a lot. And I had no idea what
506200	510200	they meant. So I figured it would be helpful to kind of throw out a slide and explain that briefly
510200	517180	when somebody says I'm operating on the two meter band. Oh, okay, that means 144 megahertz ish. You
517180	522740	know, and that's also considered VHF, very high frequency. So the next part of that, what is FM?
522740	528720	You probably have heard of AM FM radio on in your car. AM is amplitude modulation. So you can see
528720	532920	the little graphic on the bottom right of the screen. That's where the wave is actually
532920	538500	modulated up and down. So you can kind of think of this waves in a pond. You know, if you throw a
538500	541480	rock in and there's big splash, those waves are going to be bigger. And that's going to be
541480	547360	amplitude, you know, there's a varying amplitude there. Whereas FM is how close those waves are,
547360	552720	you know, in a ring and a circle. So I'm using my hands a lot. I don't probably look like a
552720	558200	you're stretching like a slinky. You know, FM waves, you're modulating the frequency how fast
558200	563720	it goes. So you know, there's AM FM. So we're looking at two meter band FM. So it's frequency
563720	567820	modulated. And this is typically not something that you're gonna have to worry about. It's lower
567820	571500	level stuff that the radio is going to take care of. But it's just good to know because I didn't
571500	579720	know it when I started out. Um, gosh, 1200 BPS. So it's BOD not BITS. If you mess this up, you know,
579720	584440	internet's gonna murder you because you're, you know, technically wrong. I always thought that
584440	588600	BOD and BITS were exactly the same. It wasn't until I dug into it that I actually realized,
588600	594000	oh, gosh, they're, you know, they can be different. So you can think of a BOD as like a signal
594000	599320	interval or like a pulse. And in the early days, I guess, I don't know, I wasn't around during the
599320	605000	early days. But early modems would do one BIT per BOD. So basically just be one BOD and one BIT
605000	610760	were the same. So 1200 BITS and 1200 BOD were the same exact thing. However, now there's craftiness
610760	616280	in there that allows you to transmit at a higher BIT rate with the same level of BOD rate. So if
616280	622740	you can transmit eight BITS in a single BOD pulse, that should come out to 9600 BITS per second,
622740	626740	even though your BOD rate is only 1200. I don't really know. Again, it's one of these things that
626740	632840	that's just what APRS or the packet radio service uses. The software takes care of it all for you.
632840	636300	You don't have to worry about it, but it is helpful to know so that the internet doesn't
636300	641600	murder you. And then the technique that is used for like, you know, packing things, you're
641600	646240	packing eight BITS per single BOD is called quadrature amplitude modulation. Say that at a
646240	651840	party and no one will want to talk to you. So it's one of those things, again, super nerdy stuff, but
651840	656140	it kind of helps to know. For me, you can look at that and at least kind of digest it and understand
656140	660900	maybe not why it's that way, but at least that that's what all of these things mean.
660900	665940	Somebody says, oh, two meter band FM at 1200 BOD, you kind of know what's going on there.
666580	674040	And then packet radio, you know, I guess to me this wasn't any news, but it's packetized data,
674040	677840	right? And so that's one of those things where instead of it just being a continuous flood of
677840	685900	data, all the data comes in packets. And especially for, you know, for APRS, it uses the AX25,
685900	690140	which includes your call sign. And I believe for FCC requirements, you need to transmit your call
690140	697060	sign anytime that you're going to transmit, you know, power out into the atmosphere. And so this
697060	703280	basically satisfies that. But yeah, data comes in in packets. And what happens is say you have
703280	709060	like a small walkie talkie, or not walkie talkie, but a small handheld radio. If you were to
709060	713940	transmit on that small radio, what's going to happen there is it is going to get sent out,
713940	717420	you know, and not a very far distance. And so the goal of the packet radio service,
717420	726040	packet reporting system, I can read my slides, is basically to repeat that information out
726040	731180	farther. So your handheld, you know, radio is going to only make a certain distance, hopefully
731180	737840	gets far enough away that, you know, that it can reach a larger repeater that's then going to take
737840	742840	your message and repeat it. And the way that APRS works, I think I have this in my next slide,
742840	749300	but the way that essentially works is you can select how far out you want that message to be
749300	754360	repeated. So if you're say, you know, out in the sticks, and there's not a whole lot of,
754900	760100	you know, there's not a whole lot of repeaters out there, you might want to set a wider setting,
760100	763620	or, you know, like a time to live, if you're familiar with, you know, internet lingo,
763620	768200	that basically says, hey, you know, repeat this out this many hops. And the whole goal of this
768200	773720	is essentially to reach what's called an IGate. And an IGate will take your packet radio, your
773720	778820	take, take your transmission, and put it on the public internet. So that way, you know,
778820	783320	anybody in the world then can now look at it or, you know, any other, if you have a program written
783320	786300	or something like that, you can digest that information and see where it's coming from,
786300	795600	from anywhere in the world. So APRS was created by somebody, his name is Bob Brun... I don't know
795600	802500	his last name. Bob created it, I believe, in 1973-ish. And if you look at this, this image
802500	808860	of the world, every, every continent-ish or every, you know, region of the world has a different,
808860	814260	slightly different frequency that it transmits APRS on. And those are all in megahertz. So you
814260	818800	can see anywhere in the United States, if you're, you know, which is where I am, at least, it's
818800	825380	going to be transmitted on 144.390 megahertz is the frequency that everything's going to share.
825600	829440	The kind of bummer part about that is that because we're all using, you know, and say we
829440	837280	ham operators, if we're all transmitting 144.390 megahertz, well, your transmission will interrupt
837280	841420	somebody else's transmission. So there's a lot of room for collision, especially when you figure
841420	846120	that every time you transmit a message, what's going to happen is that's going to be repeated
846120	853160	by any number of other larger repeaters. So there's a lot of, you know, potential congestion
853160	857260	in there. So it's one of those things that you don't always want to transmit your message as far
857260	861240	as it will possibly go. You just want to get it as far as you need to go to kind of be respectful
861240	865880	of the space. And again, I'm breaking all this down because you'll see why it's important when
865880	874320	it comes to the ISS later on. So automatic packet reporting system, that's what APRS stands for.
874400	880740	A lot of times what people will do is ham operators will have, you know, little tracking
880740	887140	beacon devices that have a GPS unit on there and they will beacon out, you know, a location at a
887140	890520	set interval, you know, it could be 10 minutes, could be one minute, whatever their specified
890520	896820	interval is. And they will beacon from the small transmitter to, you know, larger repeaters with
896820	901080	the intent of getting online. And this is useful if, you know, you're somewhere where there's not
901080	906220	cell coverage or, you know, this was invented before cell phones ever existed, like, I guess,
906220	910720	like as ubiquitous as they are now. And so it was a great way to track things, you know,
911700	916400	you can put them in your car, put them in a boat, put them in a plane, you know, people have used
916400	921340	them for hot air balloons, you know, and just all sorts of things where maybe cell coverage isn't
921340	926520	going to fit. This is a great way to track assets really. So you can see from this little image
926520	929920	there, you know, this is kind of like the traditional what people think of when they hear
929920	935340	APRS or, you know, packet radio. They think of a radio that actually transmits the signal.
935520	940380	They think of, there's a little device, I think it's called a terminal node controller. Yeah,
940380	946440	TNC, which basically takes your GPS data and any message data or any other additional data.
946880	952280	And it basically makes that into an audio format. You know, it encodes into an audio format that
952280	956700	then is transmitted out by your radio. So that's kind of the traditional way that this looks.
956980	960960	However, things have changed now since everybody has cell phones. So you can do a couple things
960960	967340	here. So instead of having, you know, a device that has to have onboard GPS, and you already
967340	971340	have to have an additional piece of GPS information and additional computer and additional
971340	975980	encoder and all this different stuff. Instead of what you're going to have here is you can have a
975980	980780	Raspberry Pi that does it. Or you could just have a phone that, you know, automatically has GPS on
980780	985760	board, automatically has the audio cable on board. And basically you hook up an audio cable or sound
985760	991840	card if you're using a Raspberry Pi to a radio. I chose Baofeng. People love and hate these types
991840	998320	of radios, but I like mine personally. And basically what you do is you use then these
998320	1004840	devices to encode your message, you know, as an audio file that is then transmitted out your radio.
1005480	1009880	And the whole purpose of that is essentially, you know, you could take what used to be a giant
1009880	1013320	apparatus that would fill, you know, like an entire desk, and now it's something that can
1013320	1017220	easily go in your pocket and the batteries last for a pretty decent amount of time.
1017780	1023160	And so that's kind of how this, how like the hardware-wise, at least what you need or what
1023160	1027340	that looks like. The next part, at least what I, when I was starting out looking at this,
1027340	1032260	I thought that, man, I must need a ton of power in order to transmit to the International Space
1032260	1035360	Station. Like it must just be crazy amounts of power. I'm probably going to dim the lights in
1035360	1041020	my house trying to get the signal that far away. But really it's incredibly low. I've heard that
1041020	1046540	people have done it on as low as a single watt, but five watts that comes on your standard
1047080	1051740	Baofeng radio is more than enough to transmit to International Space Station.
1052000	1054880	And really, when you think about it, that's less power than what your,
1054880	1059160	what your, you know, your phone charger puts out, which I thought was pretty, pretty interesting
1059160	1064320	that you could transmit up to something orbiting up, up in, you know, upper atmosphere, you know,
1064320	1069860	low Earth orbit for just five watts. It just seems kind of crazy that, that there, you know,
1069860	1076000	that it can get that far, I guess. So this kind of is a better way to, to show what I was trying
1076000	1080520	to explain is that there's a little tracker. You can see that. I think that I've, I forget what
1080520	1083820	the name of that tracker is, but basically it's super small tracker. I think it's about a hundred
1083820	1088880	dollars that, you know, we'll, we'll beacon out, I believe one watt at a pre-described interval
1088880	1093660	with GPS and everything on board. And the whole goal of it is that that little transmitter may
1093660	1097680	not be able to get very far, but the whole point of it is that you're trying to reach a single
1097680	1101880	digipeter and these digipeters are set up by their ham radio operators. And if there's not one in your
1101880	1105900	area, you know, it's one of those things that'd be kind of cool to set one up just to spread the net
1105900	1112180	of APRS far and wide. But essentially the whole goal is for that little tracking device or, you
1112180	1118700	know, any other, any other end node that you maybe have in your pocket or whatever to transmit to a
1118700	1125220	higher power digipeter, you know, repeater that digitally repeats it with the express purpose
1125220	1130220	of really trying to get it to a larger gateway. And the gateway, you know, in this case is an
1130220	1134660	iGate and an iGate can then connect it to the internet. A nice part about that is once it's
1134660	1140400	connected to the internet, there are websites like APRS.fi, which will aggregate all of this data
1140400	1145200	globally. So you can look around and see all the devices that are transmitting out and about in
1145200	1149360	the world. And, you know, you can look at the other side of the world and just see all the devices
1149360	1154100	that are out there. And there's weather stations, there's, you know, hot air balloons, a lot of cars, boats,
1154100	1157860	planes, you name it. There's a lot of devices that are tracked, you know, on APRS. And it's kind of
1157860	1163240	neat to be able to see where all these devices are out on the internet. So that was a full big
1163240	1170160	explanation of APRS. And why it matters is that the ISS has one of these DigiPeters on board,
1170160	1175120	which at the end of the day is kind of neat because you figure normally you would try and, you know,
1175120	1179680	reach a DigiPeter that is going to be, say, on a mountaintop nearby. But really, if you can transmit
1179680	1185140	to the International Space Station and have it repeat your signal, so DigiPete your message,
1185140	1190020	well now you can be received on a huge far and wide area down below because the International
1190020	1194640	Space Station has a great vantage point on the rest of the planet. So what's kind of neat is I
1194640	1199800	think I've gotten up to 800 or 1,000 miles from how far I've heard somebody else transmit from.
1200080	1205480	And likewise, normally to, you know, transmit a message that far to, you know, 1,000 miles,
1205480	1208980	you would need a decent amount of power, a great vantage point, and, you know, everything would need
1208980	1216160	to be kind of go right to transmit on, you know, especially VHF or the two meter band that far.
1216160	1219700	Whereas now with the International Space Station, because of its vantage point in space and clear
1219700	1224420	line of sight, you know, down to the earth, you can transmit your message really far, which I,
1224420	1229720	again, I just think is really cool that, you know, the most expensive object that any, you know,
1229720	1234660	that's ever been built that we have the capability as, you know, as amateurs to be able to transmit
1234660	1241480	and relay a message off of it. I just think it's kind of neat. Yeah, so this is a website. If you
1241480	1247820	go to ariss.net, you know, it looks like what a website would look like if I made it. You know,
1247820	1253220	the graphics aren't crazy, but at the end of the day, it's really cool in that it aggregates all of
1253220	1257740	the stations that heard the ISS and have transmitted to the International Space Station. So again,
1257740	1262180	you don't need any hardware at all. If you have a phone, you can pull up ariss.net
1262180	1266800	and basically just see, oh, what stations around me have heard the International Space Station?
1266800	1270800	Where is the International Space Station? What messages are coming off the International Space
1270800	1275800	Station? Again, because the whole point of it, or maybe not the whole point of APRS, but, you know,
1275800	1282580	at least, at least a, I don't know, a takeaway of APRS is that if that information all gets
1282580	1287400	aggregated online, you know, you can see it from anywhere in the world, which I think, again, is
1287400	1293900	kind of neat. So let's talk about the hardware. I have made the horrific mistake in the past of
1293900	1298600	trying to post links to hardware on, you know, my slides and then, you know, I find a better price
1298600	1303220	somewhere or I find, oh, it's not there anymore. So what I'm going to try and do this time is,
1303220	1307520	if you want to look at the hardware, I'm going to try and keep an up-to-date list at github.com.
1307580	1311240	Again, you can see the link right there. And the whole purpose of that is so that I can update this
1311240	1315380	list and find better prices or whatever, because things change and, you know, there are better
1315380	1321420	spots, you know, to potentially get some stuff at. So again, this is kind of my like go-to hardware,
1321420	1328180	which again, if you look at it, it's pretty darn cheap. You're looking at $35, $20, $10, $8. You're
1328180	1335720	looking at under $100 to be able to transmit a signal to the international space station, which
1335720	1340160	again, for that price and the skill requirement and just being an amateur and a civilian,
1340160	1346000	I think is pretty cool. Baofeng Radio, this is a cheap Chinese radio. I personally really like
1346000	1350820	them. I know a lot of people on the internet have hate for them, but it works well for me.
1350820	1355320	And I find that it, you know, for $35, it's a great way to just, you know, not break the bank,
1355320	1359140	but really figure out if ham radio just in general is going to be a good hobby for you.
1359140	1364000	It has a lot of other capabilities. You can listen to normal FM radio, you know, can be a police
1364000	1369420	scanner. There's just a lot of other stuff that it can do. And so I really like it for $35 on Amazon.
1369480	1375020	You can't really beat it. So let's see. So it comes with what's, you know, a little stick antenna,
1375020	1379420	like what you'd see on a walkie talkie. That's what if you were to buy this Baofeng Radio,
1379420	1384060	it would come with, but you can build a directional antenna, which is what you're going to want
1384060	1387440	if you're going to talk to satellites or the International Space Station, because
1389020	1395560	a traditional stick antenna is going to radiate its signal out kind of like a donut. So if you're
1395560	1399620	to hold it like thumbs up, you know, so the radios, so the antenna sticking up, it's going to
1399620	1402920	radiate out like a donut. And I should probably have a slide in there that has, you know, these
1402920	1407720	radiation patterns. But really what we want is a directional antenna that kind of focuses that
1407720	1412780	beam more like a flashlight, you know, into the general spot in the sky where you're trying to
1412780	1417960	focus all of your energy. And so for $10, $20, you can really build your own antenna, which I
1417960	1422480	think is even cooler. And then you need an audio cable, an audio card, if you're going to use the
1422480	1427160	Raspberry Pi, or if you're, if you don't use Raspberry Pi at all, and you're just going to
1427160	1431460	use your cell phone, you know, typically most people have cell phones. And so just an audio
1431460	1436580	cord for that, you know, under $100, you can no problem transmit the International Space Station.
1436580	1442240	And again, I'm going to try and keep this updated. If there's something, you know,
1443580	1448420	missing from it, I'll shoot me a message and I can update it or see if there's
1449540	1454760	really anything else out there. And again, it's one of those things, you know, for the amount
1454760	1458560	of money, what you get out of it, especially because I'm sure a lot of you have kids that
1458560	1462600	are home from school, or maybe you're a kid that, you know, is learning remotely now.
1463020	1469480	What an awesome project for under $100 to learn about physics, space, orbits, math, you know,
1469480	1475080	all these things that are super nerdy, because I'm super nerd, but really, there's a lot of other
1475080	1480300	applicable lessons to other stuff out there. The other thing that you're going to want to do is
1480300	1484640	turn on Vox. Again, this is one of those things that I'm probably getting internet hate mail for.
1484900	1489960	Vox is voice operated switch. So basically, you can think of it as when you start talking,
1489960	1493580	radio is going to detect that you're that you're talking already, and it will then start
1493580	1498380	transmitting right away. That's nice, because that means if you plug an audio cable in from
1498380	1503380	your phone or from a Raspberry Pi, the second that it starts playing audio over that jack,
1503380	1507720	it's going to start transmitting. Why this isn't ideal is because there's always a little bit of
1507720	1515140	space of, you know, a little bit of transmit time after you're done talking where the radio is still
1515140	1520820	on and that can mess up some some communications. So it's not ideal, you really want push to talk.
1520820	1525860	But if you're just getting started, it doesn't hurt just to use Vox just to just to get your
1525860	1530560	feet wet. That's my personal opinion. Again, going to get hate mail, I'm sure. But whatever.
1531240	1535820	So I own an aero directional antenna from it's very similar to the one that's in that image
1535820	1541020	right there. It's like $150, which is more than the entire cost of the project. And if hand radio
1541020	1544460	is potentially something you're not going to get into, you know, you're going to want to buy some
1544460	1549060	giant antenna. I don't really know. Personally, I have one because it's something that I really
1549060	1556380	enjoy. However, it's $150 and it's pretty steep. Or you could build your own. And this is one of
1556380	1561340	those things that I was just, you know, checking stuff out online and I saw that somebody had built
1562300	1568040	a their own directional Yagi antenna for like $10 in like PVC parts and like a measuring tape,
1568040	1572260	which is like perfect because I build everything with Raspberry Pis in PVC anyway. So I had a lot
1572260	1578120	of that basically just lying around. And a measuring tape, which funnily enough, I didn't
1578120	1581840	even think about it, but I guess it's, you know, measuring tapes are steel. And so if you, as long
1581840	1590380	as you, you know, basically sand off the tips of your antenna to solder your cables to, it's one
1590380	1594460	of those things that, oh, wow, that's kind of neat. Like you can make an antenna out of a steel
1594460	1599540	measuring tape and it folds up nicely too, which is the added benefit. I'll have a link to this on
1599540	1603280	that GitHub page that I mentioned, but if you just want to Google it right now while you're
1603280	1608200	watching this, if you just do Legios, I don't know how you say it, that's how you say it, but that's
1608200	1614200	how I say it. And then Yagi, all the instructions, the build list, everything. I'm not going to go
1614200	1619100	over all the super details or my time-lapse of me building mine, because it's not really necessary
1619100	1625720	at all. Just go online, look at it. Plenty of other people have done a lot of work to make that
1625720	1632060	pretty nice. So it's one of those things too that like, I personally think this is a nerd merit badge
1632060	1636340	to build your own antenna. That's one of those things, if you're a student, if this is
1636340	1641200	interesting to you, it kind of gives you a little bit more stake in it, not just to like, oh, I
1641200	1644160	bought all this stuff off the internet, put it together, and I can talk to International Space
1644160	1648940	Station. There's a little bit of that like hacker spirit, hacker mentality, just to like, you know,
1648940	1654200	I built this antenna out of raw parts, you know, and kind of cobbled it together to get it to work.
1654200	1658200	To me personally, I think that's kind of neat, just to, you know, kind of have this project of
1658200	1661220	like, yeah, this is something I built with my hands, and you know, I'm talking to the most
1661220	1666480	expensive object, you know, that humanity's ever built, you know, arguably, right?
1667820	1671280	And it's just kind of cool to me that you can talk to International Space Station with PVC
1671280	1675100	and a measuring tape and like a radio that you bought off Amazon. And it takes about an hour
1675100	1680280	to build. If you have kids and you want to at all get them interested in space and engineering and
1680840	1685400	STEM stuff, you know, or just to get their hands dirty. I think this is personally a really cool
1685400	1691500	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
1691500	1695560	change sides. Oh, there it goes. So this is my antenna up on top of my patio. It's on top of my
1695560	1699720	patio, obviously, so I can get a better line of sight. And I keep everything in my little ammo
1699720	1705120	box. And I use a tripod. But again, you can just hold your hand out there with an extra piece of
1705120	1711100	PVC and it works just as well. It's one of those things that it looks, it looks homemade. And
1711100	1714220	that's what it is. But you're talking to a satellite with a homemade antenna. I think
1714220	1720080	that's pretty cool. Um, so obviously, if you build your own antenna, you're gonna have to tune it a
1720080	1725720	little bit. Luckily, if you follow the instructions online of the, you know, of the antenna that at
1725720	1729560	least I made, when I went to tune it, and from what I've heard from others, when they go to tune
1729560	1734280	it, everything is pretty spot on it if you measure things carefully. But the way that you tune your
1734280	1739660	antenna is by looking at the standing wave ratio or SWR. And this really just measures the
1739660	1746200	performance. I like to think of it as say you have a, a like a tube of like, you know, gift wrap,
1746200	1752020	right? And you shout down that tube, how much of your sound that's from leaving your mouth going
1752020	1755960	through the tube is actually making its way out the tube. And that's kind of how you can think of
1756600	1762280	SWR working with your antenna of, hey, if I'm going to put five watts of power into my antenna,
1762280	1766840	how much of that power is actually going to be coming out my antenna, or how much of it's going
1766840	1771540	to be wasted, you know, kind of just banging around the, you know, just kind of radiating
1771540	1775720	off of it. So there's one of those things that that, you know, if you know, a ham radio operator,
1775720	1783440	I'm sure they have, you know, a SWR meter, you can buy a cheap one online for $20. I don't have
1783440	1788840	one of those. I don't know how well it works. I personally have a nano VNA. It was like 50 or
1788840	1793520	something dollars online and does a bunch more stuff other than just looking at SWR, but it's
1793520	1797700	really small, has a battery. I personally really like it. But again, if you're trying to not break
1797700	1802280	the bank, you know, maybe a $20 one online is worth it. Or you find a ham radio operator that
1802280	1806720	you just say, hey, can I plug this in real quick and test it? You know, there are plenty of older
1806720	1810840	ham radio operators that would love nothing more than the talk radio and talk shop. And it's a
1810840	1816100	great way to, you know, build a community, build a hobby, because ham radio operating is an aging
1816100	1823540	hobby. You know, just go to any ham radio operator meeting, you know, in your city, in your state,
1823540	1829040	in your wherever you're from. And it's definitely an older person's hobby. But I don't think it has
1829040	1833660	to be that way at all. The next thing is, it's really just one of those things that if you follow
1833660	1840080	the instructions, you can probably have a pretty good SWR. And again, I think mine when I did it
1840080	1846320	was 1.3 to 1, which I think perfect SWR is 1 to 1. To me, this is just magic. I don't really
1846320	1851120	understand how it works. I just know that you want your numbers to be as close to 1 to 1 as possible.
1851120	1855100	Again, if I'm wrong, shoot me a message and let me know and I'll update the slides.
1856420	1861820	So the next piece of this is the software. Again, I have lots of Raspberry Pis lying around
1861820	1866780	from a bunch of other projects. I personally like to use Raspberry Pi. I use the software called
1866780	1871160	Direwolf. It's just an apt-get install. Again, if you check out the GitHub page, I'll have the
1871160	1877980	instructions on how to set it up perfectly, as well as my configuration files to kind of mess
1877980	1883240	with so you can look at them and not have to recreate it from scratch. And then when you
1883240	1890200	install Direwolf, it'll also install Kissutil, which is what I use to be able to transmit messages
1891140	1895940	into Direwolf. And then the next thing is there's a tool called Zaster. I don't know how you actually
1895940	1900100	say that because it has an X and a str in it. So I don't know. I assume that's how you say it.
1900100	1903880	And this is more of a GUI tool that you can have on the Raspberry Pi, which is kind of neat
1903880	1909240	because you can see, you know, it'll automatically plot where radio transmissions are coming from
1909240	1915880	as they come in through APRS. So if you were to be receiving information and you had Zaster up and
1915880	1921200	running and you're receiving it with Direwolf, you could potentially see all of the beaconing devices
1921200	1926040	or all the other APRS, you know, transmitters that are out and about, which is kind of cool when
1926040	1929740	the ISS goes over and all of a sudden you have to zoom far out to see, wow, look, there's all these
1929740	1937280	people, you know, transmitting from all over the world. The last time that I did this, I got a
1938380	1943020	contact from Canada, which, you know, I'm in central California, right? So it's, you know,
1943020	1947540	crossing over at least two states just to get there and a good part of California as well. So
1947540	1951100	I thought that was kind of neat. And those are all applications that you want to look at if this
1951100	1956260	is something you're interested in. There's also a lot of APRS applications for phones. I personally,
1956260	1961040	like I said, I use the, you know, I use the Raspberry Pi. So that's not something that I'm,
1961040	1964100	you know, I've checked out a couple of them for iOS, but I haven't played with any of the Android
1964420	1968720	applications. So it's one of those things that I would just recommend checking out an app. You can
1968720	1972740	get trials, I'm sure, of all of these applications and just try it out. Hook up an audio jack to your
1972740	1977980	phone and, you know, just plug it in your Baofeng and you're off to the races. And it's one of those
1977980	1981960	things that your phone is kind of the perfect device. It has a battery, has a GPS, has a nice
1981960	1987120	touchscreen, and it can encode audio like nobody's business. So it's one of those things that before,
1987120	1991520	like I said, you'd have a desk full of equipment, and now it's a phone and a radio. And that's all
1991520	1998880	that's really required, as long as you have the audio cable in between. Let's see. So the next
1998880	2002820	part of this is planning your path of like when the ISS is going to be over. This is a screenshot
2002820	2009760	from my app when I was doing the slides. I use this application called GoSatWatch. It's for iOS.
2009920	2014820	It gives you a little bit of augmented reality, which I really like. So what you can see, at least
2014820	2019280	from this screen, is you can see that this is like currently where the International Space Station is
2019280	2024000	and you can see like, you know, what its orbit is. It's kind of cool. It gives you statistics of,
2024000	2028180	you know, how high, you know, how high it is. So you can see it's like 264 miles,
2028180	2032980	you know, orbiting like that's its altitude elevation. I don't know the technical satellite
2032980	2037860	terms for that. It's also going 17,000 miles an hour. And then you can kind of see how far it is
2037860	2042140	relative to where you are. And what's nice is that if you are trying to make, you know, some
2042140	2047720	communication, if you're trying to digipede off of the ISS, what this app allows you to do is if
2047720	2053660	you hit the sky button down below, you can actually hold up your phone. And since it has the compass
2053660	2057520	and everything in there, it'll kind of like orient as to like where do you want to point your
2057520	2062920	antenna up in the sky to be able to get your, you know, best transmission or, you know, your best,
2062920	2068080	you know, point of contact. And it gives you live stats. It'll notify you on good passes. And then
2068080	2073040	you can, you know, based upon where you are, you can see all the different times of day or night
2073040	2077840	when the ISS is going to come. And it also does a ton of other satellites. And that's another thing
2077840	2081780	that I probably neglected to mention is that this is just talking to, or this talk is just going
2081780	2085880	over talking to the ISS. But there are tons of other satellites out there that also perform
2085880	2096840	basically the same operations. All right, let's see. Sorry, I had to resume it. But yeah, so this
2096840	2100780	application is great. I think it was like $7 in the App Store. But there are plenty of other
2100780	2105460	applications that probably do similar things to just check out. It's worthwhile, at least.
2106280	2111700	And the other thing too, that again, I really like about this is that it'll notify you and you can
2111700	2115880	point this app up and you can see like where in the sky it is. And that matters for a couple of
2115880	2120200	reasons, which we'll go over here in a second. So when you're planning your pass, you also have to
2120200	2125060	take into effect the Doppler effect. I really like the, I'm not sure if anybody's seen Big Bang
2125060	2129240	Theory. I'm sure plenty of you have Sheldon's costume of the Doppler effect. I just had to
2129240	2133220	throw it in there. But you've all heard the Doppler effect before. It's, you know, if an
2133220	2137520	ambulance or police car is going by, as you can see the little graphic down below, you know, if
2137520	2141140	it's going away from you, the sound will appear, you know, slower because it's a lower, you know,
2141140	2145740	longer wavelength. And as the car's approaching you, it'll be higher pitch because it's a smaller
2146260	2153560	wavelength relative to, you know, the object that's traveling. And because the International
2153560	2158100	Space Station is traveling at 17,000 miles an hour relative to where you are on the planet,
2158740	2163860	it's actually having the frequency, you know, its frequency that that's on board is Doppler
2163860	2167820	shifting. So when it's coming by you, it's going to be at a higher frequency, you know, so it's
2167820	2176660	going to be 145.825 megahertz plus 3.5 kilohertz. And then as it's leaving, you know, so as it's
2176660	2182440	going away from you, it's going to be a longer wavelength. I hope I did that right. If not, again,
2182440	2189100	whatever you understand, that depending on where you are situated on the planet and where
2189100	2193200	the International Space Station is either approaching or leaving you, it's going to change
2193200	2197120	slightly the frequency that you're going to tune your radio to. Personally, what I do for this is
2197120	2202700	I try and find a pass when the International Space Station is as far overhead as possible,
2202700	2207060	or as close to overhead as possible, because then there will be no Doppler shift that I really have
2207060	2213500	to take into account. And again, a single pass is about five minutes, so you don't have a lot of time
2213500	2218240	to really fiddle with your radio and try and readjust or do anything like that. So this is
2218240	2222020	one of those things to take into account to try and find a pass where the International Space
2222020	2226000	Station is coming as close to overhead as possible. And you can go Google this online, you don't even
2226000	2230860	need an app for it. But I personally found that having the app makes it easier to make more longer
2230860	2235840	distance communications, because if the International Space Station is directly above you, and you're
2235840	2239360	sending a signal to it, well, it's going to radiate that, or it's going to digitally beat that signal
2239360	2244300	right below you. So you're not going to get a contact that's going to be far away necessarily,
2244300	2249680	or at least as far as you can possibly get it. The optimal kind of thing, if you're looking to try
2249680	2254040	and transmit your signal as far as possible, would be to kind of hit the edge of the International
2254040	2258540	Space Station and then have it transmit at a farther area away from you. Again, it's one of
2258540	2263140	those things, you know, you can see, I'll go back a couple slides, you can see the size of the area
2263140	2268020	that International Space Station covers. So at any given point, you can hit, you know, that's a large
2268020	2274580	portion, you know, of whatever that land mass is, Asia and Europe. And then if that were to fly over
2274580	2278520	the United States, you know, it covers a good portion. And when it flies over California,
2278520	2283940	you can hit Idaho, Colorado, you know, again, depending on whatever its orbit is.
2285520	2290440	Okay, so this was the hardest part for me, is finding out how to actually send a message. I
2290440	2295160	didn't think it would be as difficult as it was. But again, I was using Raspberry Pi, and I was
2295160	2299060	trying to do everything on command line. And maybe I was making it more difficult for myself
2299560	2304980	than I really needed to. But again, I could use my phone had it been easier. But again,
2304980	2308180	with some of the plans that I have going forward, I'd rather do this kind of more in an automated
2308180	2314620	fashion. So I use screen, you can use tmux, you can use multiple putty sessions, or you know,
2314620	2319180	whatever you want to connect to your Raspberry Pi. But essentially, I had three separate screens
2319180	2325220	for my Raspberry Pi. I had direwolf that ran my direwolf configuration. That's what dash c is,
2325220	2331500	dash t is to not do any color on the output of when direwolf runs. I have the kissutil,
2331500	2337420	which is installed when you install direwolf. And basically, I have the folder rx and the folder tx
2337420	2341720	that you know, if anything I receive will go into the rx folder, anything that I transmit will go
2341720	2346020	into the tx folder. And so that's kind of nice, because I can just drop text files in there.
2346240	2351240	And then the kissutil and direwolf will take care of converting that to audio and then transmitting
2351240	2356000	it out, which is which is awesome, because then at that point, you can script up whatever you
2356000	2362020	want, you can do things on in an automated manner or manually. But again, you only have five minutes
2362020	2366520	or so that you're trying to, you know, communicate with International Space Station. And then even
2366520	2371040	more of a narrow window when it's directly above your when it's kind of primetime. And you don't
2371040	2375340	want to necessarily, you know, you want to have everything set up in such a way to where you can
2375340	2379800	send out a single message per pass, you know, or maybe just a handful of messages per pass,
2379800	2383500	because there are other people also trying to communicate with it. And if you remember,
2384220	2388940	the International Space Station is operating on a single frequency, you know, it's operating on
2390640	2395140	145.825 megahertz, which again, I don't know if I put that in notes, but again, it'll be,
2395140	2399460	you Google it, right? Like it's out there. But, but only one person can talk to International
2399460	2403840	Space Station at a time. So you don't want to be constantly transmitting, because then you'll
2403840	2408300	prevent other people from also communicating with it. So basically, what I had is on a I believe
2408300	2413380	every minute interval, I would have it, you know, copy my message.txt into the transmit folder,
2413380	2417100	and they would shoot that message off, or you know, transmit that message off, I guess I should
2417100	2421680	say. And so what's kind of neat about this is that you can script it up in such a way that you know,
2421680	2425620	if you have a program that you want to have automatically begin something out, you can,
2426140	2430280	or anything like that. Personally, I like that. But if this is just you're just trying to make
2430780	2436080	a contact, or you know, you're trying to, you know, begin some or did you be digipeded off of
2436080	2440120	the International Space Station? Oh my gosh, I can't talk. If you want to be digipeded off the
2440120	2443700	International Space Station, that's your only goal. You know, just with your phone, you can
2443700	2447080	just send the message out that way manually, you don't have to go through all this direwolf
2447080	2451100	craziness. Most most phone applications should be able to do it pretty darn easily.
2451880	2458040	This is a simple message. So if you have a, you know, a client on here, this is this is one of
2458040	2463640	those things that like this is what I use. Basically, I transmit this text in that message
2463640	2470000	dot txt. Again, that's my call sign. When you see my call sign, or so then you see AR ISS,
2470000	2474000	essentially, all that means is that you want to be digipeded by the International Space Station,
2474000	2478820	that's its call sign. And when you do that, you basically are just saying, Hey, I want you to
2478820	2482800	digipede this message to the International Space Station. And then what you have is you have my
2482800	2488020	call sign again, followed by dash seven, that's because it's my mobile unit. Again, not getting
2488020	2492880	too deep into APRS, having that designation there, that dash seven is just showing that you're
2492880	2497720	mobile. And then the next, you know, digits and numbers right there, it's kind of a weirdly
2497720	2502920	encoded way that I had to like Google how to do of what your current GPS coordinates are. And then
2502920	2508300	after that, you can see, you know, your message. So digipeding, you know, DEFCON 28, Aerospace
2508300	2513420	Village out to the International Space Station, which then gets relayed, you know, down to
2513420	2519400	ground stations that receive that message and then off to the greater internet. This is the folder
2519400	2523980	structure. So when I run direwolf, I run it from my home directory, direwolf config is right there.
2523980	2528760	And then I have a tx and an rx folder for the messages that I'm going to send go into the tx
2528760	2533160	folder and messages that I'm going to receive come from or, you know, get placed in the rx folder.
2533620	2541720	Um, let's see, let's see if I can get this. All right, so some of the things going forward,
2541720	2546540	I think that are important to cover, you know, so my goal of this is I want to automate it,
2546540	2552540	I want to make some rotors and rotors, if you're not familiar, are basically what it would allow,
2552540	2558380	you know, rotors would allow me to change the elevation, you know, up and down. So like,
2558380	2562480	if you're looking like a tripod is a great example, right? I could, you know, change the
2562480	2568080	orientation 360 degrees, like a compass, and then the elevation up and down. Because it'd be really
2568080	2571280	cool if on the Raspberry Pi you had some software that basically tracked where the International
2571280	2576740	Space Station was, and anytime it was up overhead to transmit a message automatically. So that's
2576740	2581660	kind of my idea of what I think would be kind of neat. So we'll see how that goes. And then I would
2581660	2587600	also like to see, you know, how far away can I hear from, you know, or how far could I be
2587600	2593280	digipeded by the International Space Station? And if you kind of think about it, you know,
2593280	2598340	out onto the horizon. So if you were, if you were out, you know, basically to the horizon,
2598340	2601480	that would be zero degrees. But obviously there are trees, there are houses, there are all those
2601480	2607700	things in the way. And so there's a point at which, you know, you can hit the International
2607700	2612940	Space Station, you know, with a signal, maybe is that 20 degrees? Is it 30 degrees? Is it 40 degrees?
2612940	2617660	The higher the elevation is, relative to where you are on the ground,
2617660	2621080	the easier it will be to communicate with it. So it's one of those things that automating it,
2621080	2626460	I think would be kind of neat. And then I also like to, you know, investigate looking at other
2626460	2632140	satellites. Yeah, and basically just just seeing what else is out there. A huge thank you to AMSAT
2632140	2639060	and ARISS.net just because checking out that website inspired me to, you know, try and get
2639060	2643980	on the board. It's in the AMSAT. There's tons of great information there on how other people have,
2643980	2648040	you know, had successful communications. And really at the end of the day, I think this is
2648040	2652220	just something that's kind of cool. You know, the hacker mindset here of just kind of scraping and
2652220	2656640	cobbling together all these things to really do something that's kind of neat to be able to
2656640	2662260	transmit to the International Space Station. Not to mention too, that this is how you can transmit
2662260	2668240	to a lot of other satellites. And it's really kind of covers the basics in terms of what's
2668240	2672680	required to talk to a satellite, right? There's a whole bunch of different satellite orbits, a whole
2672680	2678700	bunch of different satellite communication protocols, frequencies, modulations, and this is
2678700	2684040	just dipping your toe in the water of what's available and what's out there. And it's for
2684040	2690940	honestly a pretty small budget, right? For $100, $200 you could get a really solid setup to, you
2690940	2694960	know, to communicate with the International Space Station with other satellites with just a HAM
2694960	2698660	license, you know, just be an amateur radio operator. And if you just want to hear, if you
2698660	2703320	just want to listen to what gets transmitted, you know, you can do that without a license. And
2703320	2708660	really, you can just get a Baofeng radio, your phone, and, you know, it doesn't even have to be a
2708660	2711740	directional antenna at that point. You know, if you just want to listen, you can have an omni-directional
2711740	2715580	antenna, which is basically just, you know, a longer version of the normal stick antenna that would
2715580	2720920	come with the Baofeng. Again, I'll post links to everything on that GitHub page. But yeah, at the
2720920	2724140	end of the day, this is a great way just to get started if it's something that you're
2724140	2729400	interested in. And then from there, who knows how much farther you can level up and, you know, what
2729400	2733960	other satellite communications you can do. You can spend thousands and thousands of dollars and,
2733960	2740860	you know, sink a full-time work week into all of this stuff, especially as an amateur. So it
2740860	2745700	definitely helps to have a good starting point and to have a good point in time of, like, this is
2745700	2750280	something that I can measurably check off a list and do. And especially, again, I know that I've
2750280	2755300	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
2755300	2761080	great project to really get your feet wet and you learn a ton of different principles from physics
2761080	2767780	to, you know, radio to computers to, you know, protocols to just... there's so many small
2769760	2774620	lessons intertwined that I just think it's kind of one of those perfect projects to, you know,
2775020	2779700	to basically figure out if it's for you, if ham radio operating is for you, to find out if chasing
2779700	2784280	satellites across the sky is for you. So again, I encourage you to take a look at it. Feel free
2784280	2789260	to check out the GitHub page. I'll post some of my contact information on there along with the
2789260	2793580	links to all the hardware and all the apps and all the things that I've mentioned. And yeah,
2793580	2796680	hope you enjoyed the talk. Let's see, how do I pause this thing?