[00:05.780 --> 00:10.020]  Hey everyone, my name is Eric Escobar and today my presentation is going to be on talking
[00:10.020 --> 00:14.900]  to satellites. And this is really a 101. You've never tried it before and you don't even know
[00:14.900 --> 00:19.420]  where to begin. This is also going to be a one cut take like a normal DEF CON presentation
[00:19.420 --> 00:24.480]  would be. So there's going to be a lot of flubs, a lot of hems, a lot of haws. That's
[00:24.480 --> 00:29.260]  about it. Anyways, without further ado, let's get going. I can't even transition a slide
[00:29.260 --> 00:34.860]  alright. So a little bit about me and my background. I started off my professional life as a civil
[00:34.860 --> 00:39.820]  engineer. I went to college, got my bachelor's degree, master's degree in civil engineering,
[00:39.820 --> 00:44.440]  became a professional engineer and realized it really wasn't for me. I didn't really like
[00:44.440 --> 00:49.840]  it as much as I thought it was going to. I then got an opportunity to start a security
[00:49.840 --> 00:54.900]  analyst position at Barracuda Networks. We started coming to DEF CON, DEF CON 22. So
[00:54.900 --> 01:00.780]  I've been here for what, six years now, seven years now. And I love doing anything wireless.
[01:00.780 --> 01:06.180]  I love wireless security. So I started playing in the wireless CTF and we won three years
[01:06.180 --> 01:10.580]  in a row, I believe. And now I'm a village member. So now I get to help make the challenges.
[01:11.400 --> 01:14.260]  And yeah, it's one of those things that the reason I started off with this is because
[01:14.260 --> 01:20.260]  I forever feel like a noob. I forever feel like the imposter syndrome is a real thing.
[01:20.600 --> 01:25.120]  And this talk is more of a, I'm not an expert in this, but it's something that I find really
[01:25.120 --> 01:30.560]  interesting and it definitely encapsulates that hacker mentality. So if this is your
[01:30.560 --> 01:35.560]  first DEF CON, you're going virtual, you're watching this talk, don't, don't hesitate
[01:35.560 --> 01:39.700]  to get your feet wet to reach out to people. Because at the end of the day, I feel like
[01:39.700 --> 01:44.660]  everybody feels like a noob. And if they don't, then they definitely are a noob. So that,
[01:44.660 --> 01:48.880]  that I basically just want to give my background that I didn't have a, you know, computer science
[01:48.880 --> 01:55.800]  degree. I didn't have a formal background in computer security or really anything at
[01:55.800 --> 02:01.240]  all except for civil engineering. So don't, don't hesitate to get your, get yourself out
[02:01.240 --> 02:08.440]  there. So this talk, talking to satellites, why? Personally, I think it's cool. The International
[02:08.440 --> 02:12.460]  Space Station is specifically what we're going to be going to cover. But there's a lot of
[02:12.460 --> 02:18.080]  satellites that are floating up above us or orbiting above us that, that are capable of,
[02:18.080 --> 02:22.080]  you know, ham radio communication, or just communication from the ground, just by, by
[02:22.080 --> 02:26.440]  normal citizens that don't require, you know, any special permission other than ham radio
[02:26.440 --> 02:31.340]  license to transmit to. What's cool about the International Space Station, I mean, it's
[02:31.340 --> 02:35.220]  orbiting 200 miles above us, which actually, when I, when I first started doing this, 200
[02:35.220 --> 02:39.460]  miles didn't seem like a lot to me, it seemed like that, that should be orbiting higher
[02:39.460 --> 02:46.200]  than that. But 200 miles up, it's going roughly 17,000 miles an hour. And that's 10 times
[02:46.200 --> 02:51.220]  faster than a bullet, just kind of put it in like rough perspective. And it, it, it is
[02:51.220 --> 02:56.040]  going, it's orbiting so quickly that it can go around the entire planet in about 90 minutes,
[02:56.040 --> 03:00.360]  which I think is incredible. And it's also the most expensive object ever built, which
[03:00.360 --> 03:04.980]  is kind of neat that just being a normal civilian, I can talk to the International Space
[03:04.980 --> 03:11.320]  Station, even to astronauts on the International Space Station, with just, you know,
[03:11.320 --> 03:15.440]  general equipment and just a ham radio license. And even if you don't have a ham radio
[03:15.440 --> 03:18.780]  license, you can still listen to transmissions from the International Space Station, which
[03:18.780 --> 03:25.000]  is also I think, pretty cool. So here's a quick overview. But basically, we're how to
[03:25.000 --> 03:28.800]  talk to ISS on the cheap, the hows and the whys of, you know, why you'd want to do it
[03:28.800 --> 03:32.860]  and how you do it, the gear that you're going to need, the software that you'll need, the
[03:32.860 --> 03:37.140]  rough skills that you might need to have or, you know, brush up on timing when you're
[03:37.140 --> 03:40.520]  going to talk to the International Space Station, because it's orbiting every 90 minutes.
[03:40.520 --> 03:45.660]  And there's only very narrow windows that you can actually, you know, try and communicate
[03:45.660 --> 03:49.420]  with it on. And then basically, just now that you have all this power, how not to be a jerk,
[03:49.420 --> 03:53.020]  I feel like hacker mentality is the, you know, like, Oh, my gosh, we're gonna do all these
[03:53.020 --> 03:56.820]  bad, terrible things. But at the end of the day, you know, should you, this is this is
[03:56.820 --> 04:00.500]  something that's pretty cool. And you want to give others the opportunity to do it as
[04:00.500 --> 04:07.940]  well. See, moving on. So the hows and whys. So there's AR-ISS, which is amateur radio
[04:07.940 --> 04:12.640]  on the International Space Station. Basically, this is up there for educational purposes.
[04:12.640 --> 04:16.860]  It's community driven. It's one of these things that kind of inspire the, you know, the heart
[04:16.860 --> 04:20.880]  of people of, hey, what are we going to do with space? Why is space important? So I think
[04:20.880 --> 04:25.780]  it's kind of cool that they have a couple, you know, amateur radio stations on board
[04:25.780 --> 04:30.600]  in or not stations, but I guess transceivers on the International Space Station that are
[04:30.600 --> 04:34.960]  that are meant for amateur radio operators to interact with. Specifically, what we're
[04:34.960 --> 04:39.000]  going to be talking about is the two meter packet radio that's unattended on the International
[04:39.000 --> 04:44.120]  Space Station. There are definitely some attempts that you can have where crew members might
[04:44.120 --> 04:47.520]  be staffing the International Space Station and actually on the ham radio that you can
[04:47.520 --> 04:54.500]  talk to via voice. However, to try and get that to work is is, you know, it's a far more
[04:54.500 --> 04:59.480]  limited and you have to plan far more, you know, up in advance, whereas the unattended
[04:59.480 --> 05:03.480]  packet radio basically is going to act as like a repeater for you. And it's always up
[05:03.480 --> 05:08.520]  and always operational. And it's just one of those things that it's far easier to get
[05:08.900 --> 05:12.060]  a communication, you know, repeated from the International Space Station because it's done
[05:12.060 --> 05:16.500]  automatically. And there's a bunch of other operating modes that the International Space
[05:16.500 --> 05:21.300]  Station has. And, you know, you can go online at any point in time and check that. But really
[05:21.300 --> 05:25.220]  what we're going to be focusing on is the two meter packet radio. And it's also I also
[05:25.220 --> 05:29.500]  had no idea that, you know, a lot of ISS crew members are also ham radio operators, which
[05:29.500 --> 05:35.120]  I thought was kind of cool. Um, yeah, so we'll just, you know, break down the basics of it
[05:35.120 --> 05:38.180]  to transmit and talk to the International Space Station, you're going to need a ham
[05:38.180 --> 05:41.060]  license. And that's just a transmit. And that's really because you're going to be operating
[05:41.060 --> 05:45.240]  on frequencies and with hardware that could, you know, cause issues for other people. So
[05:45.240 --> 05:48.460]  it's not just like a cell phone where, you know, your phone is going to take responsibility
[05:48.460 --> 05:52.080]  for talking back and forth to a cell tower. This is something that, you know, you're going
[05:52.080 --> 05:56.660]  to have transmit power, and you want to be judicious with how you use it. However, that
[05:56.660 --> 06:00.540]  being said, if there's something that's interesting to you, you can listen without a ham
[06:00.540 --> 06:04.920]  license, no problem at all. You know, you don't need anything just to listen. It's really
[06:04.920 --> 06:08.520]  just transmitting because that could affect other people. And if you want your ham radio
[06:08.520 --> 06:13.680]  license, the ham radio village is offering a bleep $5 exams, which is, I mean, pretty
[06:13.680 --> 06:17.660]  cheap, normally, I think $20. But everything's gonna be virtual, obviously, because it's
[06:17.660 --> 06:22.660]  DEF CON and for $5 to, you know, make an attempt at your technician license. It's one of
[06:22.660 --> 06:26.700]  those things, I think you have to renew it every 10 years. I definitely recommend checking
[06:26.700 --> 06:33.200]  it out. You know, it's definitely a great opportunity. All right, so there's a lot of
[06:33.200 --> 06:37.280]  things that I never quite understood when I was getting into all this. And I'm, again,
[06:37.280 --> 06:41.400]  by all by no means an expert. So there's probably a ton of, you know, things in these slides
[06:41.400 --> 06:46.440]  that a seasoned, you know, extra ham operator is going to know that I'm going to completely
[06:46.440 --> 06:52.580]  flub up on. But I basically just this is something that, you know, I whenever I looked at this,
[06:52.580 --> 06:55.400]  I would always kind of say, Oh, my gosh, I don't even know what all of this garbage
[06:55.400 --> 06:59.740]  means. So when people always said two meter band, I had no idea what the heck is a two
[06:59.740 --> 07:05.000]  meter band, you know, FM 1200 BPS packet radio, all that stuff just sounded like gibberish
[07:05.000 --> 07:09.200]  to me, initially. And I really wish that somebody would have explained it to me in layman's
[07:09.200 --> 07:12.760]  terms, you know, just so I could at least get the basics and then kind of dig down from
[07:12.760 --> 07:17.540]  there at least, at least kind of get my feet wet. So if you look at that small little equation
[07:17.540 --> 07:22.100]  on the right hand side of your screen, you're going to see it's C equals I think that's
[07:22.100 --> 07:27.580]  lambda and then whatever the new I don't even know the Greek symbols, right. But at the
[07:27.580 --> 07:31.040]  end of the day, what happens to C is the speed of light. So if you divide that by your frequency,
[07:31.040 --> 07:37.960]  which is a megahertz, a megahertz is a million hertz, so million cycles per second. So, you
[07:37.960 --> 07:44.120]  know, you can think of Wi Fi as 2.4 gigahertz, you know, or 5.8 gigahertz, just kind of put
[07:44.120 --> 07:48.740]  that in perspective. So if you divide the speed of light by the megahertz of the frequency
[07:48.740 --> 07:53.240]  you're transmitting on, you divide those two and you get two meters. That's, you know, kind of how
[07:53.240 --> 07:56.860]  the math works out. And so when people say like, oh, it's only two meter band, well, you know,
[07:56.860 --> 08:01.260]  that's the same thing as saying it's about, you know, 144 megahertz ish. And I think the two meter
[08:01.260 --> 08:06.400]  bands anywhere from 144 to 148 megahertz. But but that's what people are talking about. So 70
[08:06.400 --> 08:10.020]  centimeters, you can do the same, you know, the same math and figure out that it's, you know,
[08:10.020 --> 08:16.180]  about 460 megahertz, I think of off the top of my head. And that's also considered VHF. So you'll
[08:16.180 --> 08:23.040]  hear VHF, two meter and 144 megahertz. Those are all kind of in the same ballpark. You know, and
[08:23.040 --> 08:26.200]  that's just one of those things to hear those terms thrown around a lot. And I had no idea what
[08:26.200 --> 08:30.200]  they meant. So I figured it would be helpful to kind of throw out a slide and explain that briefly
[08:30.200 --> 08:37.180]  when somebody says I'm operating on the two meter band. Oh, okay, that means 144 megahertz ish. You
[08:37.180 --> 08:42.740]  know, and that's also considered VHF, very high frequency. So the next part of that, what is FM?
[08:42.740 --> 08:48.720]  You probably have heard of AM FM radio on in your car. AM is amplitude modulation. So you can see
[08:48.720 --> 08:52.920]  the little graphic on the bottom right of the screen. That's where the wave is actually
[08:52.920 --> 08:58.500]  modulated up and down. So you can kind of think of this waves in a pond. You know, if you throw a
[08:58.500 --> 09:01.480]  rock in and there's big splash, those waves are going to be bigger. And that's going to be
[09:01.480 --> 09:07.360]  amplitude, you know, there's a varying amplitude there. Whereas FM is how close those waves are,
[09:07.360 --> 09:12.720]  you know, in a ring and a circle. So I'm using my hands a lot. I don't probably look like a
[09:12.720 --> 09:18.200]  you're stretching like a slinky. You know, FM waves, you're modulating the frequency how fast
[09:18.200 --> 09:23.720]  it goes. So you know, there's AM FM. So we're looking at two meter band FM. So it's frequency
[09:23.720 --> 09:27.820]  modulated. And this is typically not something that you're gonna have to worry about. It's lower
[09:27.820 --> 09:31.500]  level stuff that the radio is going to take care of. But it's just good to know because I didn't
[09:31.500 --> 09:39.720]  know it when I started out. Um, gosh, 1200 BPS. So it's BOD not BITS. If you mess this up, you know,
[09:39.720 --> 09:44.440]  internet's gonna murder you because you're, you know, technically wrong. I always thought that
[09:44.440 --> 09:48.600]  BOD and BITS were exactly the same. It wasn't until I dug into it that I actually realized,
[09:48.600 --> 09:54.000]  oh, gosh, they're, you know, they can be different. So you can think of a BOD as like a signal
[09:54.000 --> 09:59.320]  interval or like a pulse. And in the early days, I guess, I don't know, I wasn't around during the
[09:59.320 --> 10:05.000]  early days. But early modems would do one BIT per BOD. So basically just be one BOD and one BIT
[10:05.000 --> 10:10.760]  were the same. So 1200 BITS and 1200 BOD were the same exact thing. However, now there's craftiness
[10:10.760 --> 10:16.280]  in there that allows you to transmit at a higher BIT rate with the same level of BOD rate. So if
[10:16.280 --> 10:22.740]  you can transmit eight BITS in a single BOD pulse, that should come out to 9600 BITS per second,
[10:22.740 --> 10:26.740]  even though your BOD rate is only 1200. I don't really know. Again, it's one of these things that
[10:26.740 --> 10:32.840]  that's just what APRS or the packet radio service uses. The software takes care of it all for you.
[10:32.840 --> 10:36.300]  You don't have to worry about it, but it is helpful to know so that the internet doesn't
[10:36.300 --> 10:41.600]  murder you. And then the technique that is used for like, you know, packing things, you're
[10:41.600 --> 10:46.240]  packing eight BITS per single BOD is called quadrature amplitude modulation. Say that at a
[10:46.240 --> 10:51.840]  party and no one will want to talk to you. So it's one of those things, again, super nerdy stuff, but
[10:51.840 --> 10:56.140]  it kind of helps to know. For me, you can look at that and at least kind of digest it and understand
[10:56.140 --> 11:00.900]  maybe not why it's that way, but at least that that's what all of these things mean.
[11:00.900 --> 11:05.940]  Somebody says, oh, two meter band FM at 1200 BOD, you kind of know what's going on there.
[11:06.580 --> 11:14.040]  And then packet radio, you know, I guess to me this wasn't any news, but it's packetized data,
[11:14.040 --> 11:17.840]  right? And so that's one of those things where instead of it just being a continuous flood of
[11:17.840 --> 11:25.900]  data, all the data comes in packets. And especially for, you know, for APRS, it uses the AX25,
[11:25.900 --> 11:30.140]  which includes your call sign. And I believe for FCC requirements, you need to transmit your call
[11:30.140 --> 11:37.060]  sign anytime that you're going to transmit, you know, power out into the atmosphere. And so this
[11:37.060 --> 11:43.280]  basically satisfies that. But yeah, data comes in in packets. And what happens is say you have
[11:43.280 --> 11:49.060]  like a small walkie talkie, or not walkie talkie, but a small handheld radio. If you were to
[11:49.060 --> 11:53.940]  transmit on that small radio, what's going to happen there is it is going to get sent out,
[11:53.940 --> 11:57.420]  you know, and not a very far distance. And so the goal of the packet radio service,
[11:57.420 --> 12:06.040]  packet reporting system, I can read my slides, is basically to repeat that information out
[12:06.040 --> 12:11.180]  farther. So your handheld, you know, radio is going to only make a certain distance, hopefully
[12:11.180 --> 12:17.840]  gets far enough away that, you know, that it can reach a larger repeater that's then going to take
[12:17.840 --> 12:22.840]  your message and repeat it. And the way that APRS works, I think I have this in my next slide,
[12:22.840 --> 12:29.300]  but the way that essentially works is you can select how far out you want that message to be
[12:29.300 --> 12:34.360]  repeated. So if you're say, you know, out in the sticks, and there's not a whole lot of,
[12:34.900 --> 12:40.100]  you know, there's not a whole lot of repeaters out there, you might want to set a wider setting,
[12:40.100 --> 12:43.620]  or, you know, like a time to live, if you're familiar with, you know, internet lingo,
[12:43.620 --> 12:48.200]  that basically says, hey, you know, repeat this out this many hops. And the whole goal of this
[12:48.200 --> 12:53.720]  is essentially to reach what's called an IGate. And an IGate will take your packet radio, your
[12:53.720 --> 12:58.820]  take, take your transmission, and put it on the public internet. So that way, you know,
[12:58.820 --> 13:03.320]  anybody in the world then can now look at it or, you know, any other, if you have a program written
[13:03.320 --> 13:06.300]  or something like that, you can digest that information and see where it's coming from,
[13:06.300 --> 13:15.600]  from anywhere in the world. So APRS was created by somebody, his name is Bob Brun... I don't know
[13:15.600 --> 13:22.500]  his last name. Bob created it, I believe, in 1973-ish. And if you look at this, this image
[13:22.500 --> 13:28.860]  of the world, every, every continent-ish or every, you know, region of the world has a different,
[13:28.860 --> 13:34.260]  slightly different frequency that it transmits APRS on. And those are all in megahertz. So you
[13:34.260 --> 13:38.800]  can see anywhere in the United States, if you're, you know, which is where I am, at least, it's
[13:38.800 --> 13:45.380]  going to be transmitted on 144.390 megahertz is the frequency that everything's going to share.
[13:45.600 --> 13:49.440]  The kind of bummer part about that is that because we're all using, you know, and say we
[13:49.440 --> 13:57.280]  ham operators, if we're all transmitting 144.390 megahertz, well, your transmission will interrupt
[13:57.280 --> 14:01.420]  somebody else's transmission. So there's a lot of room for collision, especially when you figure
[14:01.420 --> 14:06.120]  that every time you transmit a message, what's going to happen is that's going to be repeated
[14:06.120 --> 14:13.160]  by any number of other larger repeaters. So there's a lot of, you know, potential congestion
[14:13.160 --> 14:17.260]  in there. So it's one of those things that you don't always want to transmit your message as far
[14:17.260 --> 14:21.240]  as it will possibly go. You just want to get it as far as you need to go to kind of be respectful
[14:21.240 --> 14:25.880]  of the space. And again, I'm breaking all this down because you'll see why it's important when
[14:25.880 --> 14:34.320]  it comes to the ISS later on. So automatic packet reporting system, that's what APRS stands for.
[14:34.400 --> 14:40.740]  A lot of times what people will do is ham operators will have, you know, little tracking
[14:40.740 --> 14:47.140]  beacon devices that have a GPS unit on there and they will beacon out, you know, a location at a
[14:47.140 --> 14:50.520]  set interval, you know, it could be 10 minutes, could be one minute, whatever their specified
[14:50.520 --> 14:56.820]  interval is. And they will beacon from the small transmitter to, you know, larger repeaters with
[14:56.820 --> 15:01.080]  the intent of getting online. And this is useful if, you know, you're somewhere where there's not
[15:01.080 --> 15:06.220]  cell coverage or, you know, this was invented before cell phones ever existed, like, I guess,
[15:06.220 --> 15:10.720]  like as ubiquitous as they are now. And so it was a great way to track things, you know,
[15:11.700 --> 15:16.400]  you can put them in your car, put them in a boat, put them in a plane, you know, people have used
[15:16.400 --> 15:21.340]  them for hot air balloons, you know, and just all sorts of things where maybe cell coverage isn't
[15:21.340 --> 15:26.520]  going to fit. This is a great way to track assets really. So you can see from this little image
[15:26.520 --> 15:29.920]  there, you know, this is kind of like the traditional what people think of when they hear
[15:29.920 --> 15:35.340]  APRS or, you know, packet radio. They think of a radio that actually transmits the signal.
[15:35.520 --> 15:40.380]  They think of, there's a little device, I think it's called a terminal node controller. Yeah,
[15:40.380 --> 15:46.440]  TNC, which basically takes your GPS data and any message data or any other additional data.
[15:46.880 --> 15:52.280]  And it basically makes that into an audio format. You know, it encodes into an audio format that
[15:52.280 --> 15:56.700]  then is transmitted out by your radio. So that's kind of the traditional way that this looks.
[15:56.980 --> 16:00.960]  However, things have changed now since everybody has cell phones. So you can do a couple things
[16:00.960 --> 16:07.340]  here. So instead of having, you know, a device that has to have onboard GPS, and you already
[16:07.340 --> 16:11.340]  have to have an additional piece of GPS information and additional computer and additional
[16:11.340 --> 16:15.980]  encoder and all this different stuff. Instead of what you're going to have here is you can have a
[16:15.980 --> 16:20.780]  Raspberry Pi that does it. Or you could just have a phone that, you know, automatically has GPS on
[16:20.780 --> 16:25.760]  board, automatically has the audio cable on board. And basically you hook up an audio cable or sound
[16:25.760 --> 16:31.840]  card if you're using a Raspberry Pi to a radio. I chose Baofeng. People love and hate these types
[16:31.840 --> 16:38.320]  of radios, but I like mine personally. And basically what you do is you use then these
[16:38.320 --> 16:44.840]  devices to encode your message, you know, as an audio file that is then transmitted out your radio.
[16:45.480 --> 16:49.880]  And the whole purpose of that is essentially, you know, you could take what used to be a giant
[16:49.880 --> 16:53.320]  apparatus that would fill, you know, like an entire desk, and now it's something that can
[16:53.320 --> 16:57.220]  easily go in your pocket and the batteries last for a pretty decent amount of time.
[16:57.780 --> 17:03.160]  And so that's kind of how this, how like the hardware-wise, at least what you need or what
[17:03.160 --> 17:07.340]  that looks like. The next part, at least what I, when I was starting out looking at this,
[17:07.340 --> 17:12.260]  I thought that, man, I must need a ton of power in order to transmit to the International Space
[17:12.260 --> 17:15.360]  Station. Like it must just be crazy amounts of power. I'm probably going to dim the lights in
[17:15.360 --> 17:21.020]  my house trying to get the signal that far away. But really it's incredibly low. I've heard that
[17:21.020 --> 17:26.540]  people have done it on as low as a single watt, but five watts that comes on your standard
[17:27.080 --> 17:31.740]  Baofeng radio is more than enough to transmit to International Space Station.
[17:32.000 --> 17:34.880]  And really, when you think about it, that's less power than what your,
[17:34.880 --> 17:39.160]  what your, you know, your phone charger puts out, which I thought was pretty, pretty interesting
[17:39.160 --> 17:44.320]  that you could transmit up to something orbiting up, up in, you know, upper atmosphere, you know,
[17:44.320 --> 17:49.860]  low Earth orbit for just five watts. It just seems kind of crazy that, that there, you know,
[17:49.860 --> 17:56.000]  that it can get that far, I guess. So this kind of is a better way to, to show what I was trying
[17:56.000 --> 18:00.520]  to explain is that there's a little tracker. You can see that. I think that I've, I forget what
[18:00.520 --> 18:03.820]  the name of that tracker is, but basically it's super small tracker. I think it's about a hundred
[18:03.820 --> 18:08.880]  dollars that, you know, we'll, we'll beacon out, I believe one watt at a pre-described interval
[18:08.880 --> 18:13.660]  with GPS and everything on board. And the whole goal of it is that that little transmitter may
[18:13.660 --> 18:17.680]  not be able to get very far, but the whole point of it is that you're trying to reach a single
[18:17.680 --> 18:21.880]  digipeter and these digipeters are set up by their ham radio operators. And if there's not one in your
[18:21.880 --> 18:25.900]  area, you know, it's one of those things that'd be kind of cool to set one up just to spread the net
[18:25.900 --> 18:32.180]  of APRS far and wide. But essentially the whole goal is for that little tracking device or, you
[18:32.180 --> 18:38.700]  know, any other, any other end node that you maybe have in your pocket or whatever to transmit to a
[18:38.700 --> 18:45.220]  higher power digipeter, you know, repeater that digitally repeats it with the express purpose
[18:45.220 --> 18:50.220]  of really trying to get it to a larger gateway. And the gateway, you know, in this case is an
[18:50.220 --> 18:54.660]  iGate and an iGate can then connect it to the internet. A nice part about that is once it's
[18:54.660 --> 19:00.400]  connected to the internet, there are websites like APRS.fi, which will aggregate all of this data
[19:00.400 --> 19:05.200]  globally. So you can look around and see all the devices that are transmitting out and about in
[19:05.200 --> 19:09.360]  the world. And, you know, you can look at the other side of the world and just see all the devices
[19:09.360 --> 19:14.100]  that are out there. And there's weather stations, there's, you know, hot air balloons, a lot of cars, boats,
[19:14.100 --> 19:17.860]  planes, you name it. There's a lot of devices that are tracked, you know, on APRS. And it's kind of
[19:17.860 --> 19:23.240]  neat to be able to see where all these devices are out on the internet. So that was a full big
[19:23.240 --> 19:30.160]  explanation of APRS. And why it matters is that the ISS has one of these DigiPeters on board,
[19:30.160 --> 19:35.120]  which at the end of the day is kind of neat because you figure normally you would try and, you know,
[19:35.120 --> 19:39.680]  reach a DigiPeter that is going to be, say, on a mountaintop nearby. But really, if you can transmit
[19:39.680 --> 19:45.140]  to the International Space Station and have it repeat your signal, so DigiPete your message,
[19:45.140 --> 19:50.020]  well now you can be received on a huge far and wide area down below because the International
[19:50.020 --> 19:54.640]  Space Station has a great vantage point on the rest of the planet. So what's kind of neat is I
[19:54.640 --> 19:59.800]  think I've gotten up to 800 or 1,000 miles from how far I've heard somebody else transmit from.
[20:00.080 --> 20:05.480]  And likewise, normally to, you know, transmit a message that far to, you know, 1,000 miles,
[20:05.480 --> 20:08.980]  you would need a decent amount of power, a great vantage point, and, you know, everything would need
[20:08.980 --> 20:16.160]  to be kind of go right to transmit on, you know, especially VHF or the two meter band that far.
[20:16.160 --> 20:19.700]  Whereas now with the International Space Station, because of its vantage point in space and clear
[20:19.700 --> 20:24.420]  line of sight, you know, down to the earth, you can transmit your message really far, which I,
[20:24.420 --> 20:29.720]  again, I just think is really cool that, you know, the most expensive object that any, you know,
[20:29.720 --> 20:34.660]  that's ever been built that we have the capability as, you know, as amateurs to be able to transmit
[20:34.660 --> 20:41.480]  and relay a message off of it. I just think it's kind of neat. Yeah, so this is a website. If you
[20:41.480 --> 20:47.820]  go to ariss.net, you know, it looks like what a website would look like if I made it. You know,
[20:47.820 --> 20:53.220]  the graphics aren't crazy, but at the end of the day, it's really cool in that it aggregates all of
[20:53.220 --> 20:57.740]  the stations that heard the ISS and have transmitted to the International Space Station. So again,
[20:57.740 --> 21:02.180]  you don't need any hardware at all. If you have a phone, you can pull up ariss.net
[21:02.180 --> 21:06.800]  and basically just see, oh, what stations around me have heard the International Space Station?
[21:06.800 --> 21:10.800]  Where is the International Space Station? What messages are coming off the International Space
[21:10.800 --> 21:15.800]  Station? Again, because the whole point of it, or maybe not the whole point of APRS, but, you know,
[21:15.800 --> 21:22.580]  at least, at least a, I don't know, a takeaway of APRS is that if that information all gets
[21:22.580 --> 21:27.400]  aggregated online, you know, you can see it from anywhere in the world, which I think, again, is
[21:27.400 --> 21:33.900]  kind of neat. So let's talk about the hardware. I have made the horrific mistake in the past of
[21:33.900 --> 21:38.600]  trying to post links to hardware on, you know, my slides and then, you know, I find a better price
[21:38.600 --> 21:43.220]  somewhere or I find, oh, it's not there anymore. So what I'm going to try and do this time is,
[21:43.220 --> 21:47.520]  if you want to look at the hardware, I'm going to try and keep an up-to-date list at github.com.
[21:47.580 --> 21:51.240]  Again, you can see the link right there. And the whole purpose of that is so that I can update this
[21:51.240 --> 21:55.380]  list and find better prices or whatever, because things change and, you know, there are better
[21:55.380 --> 22:01.420]  spots, you know, to potentially get some stuff at. So again, this is kind of my like go-to hardware,
[22:01.420 --> 22:08.180]  which again, if you look at it, it's pretty darn cheap. You're looking at $35, $20, $10, $8. You're
[22:08.180 --> 22:15.720]  looking at under $100 to be able to transmit a signal to the international space station, which
[22:15.720 --> 22:20.160]  again, for that price and the skill requirement and just being an amateur and a civilian,
[22:20.160 --> 22:26.000]  I think is pretty cool. Baofeng Radio, this is a cheap Chinese radio. I personally really like
[22:26.000 --> 22:30.820]  them. I know a lot of people on the internet have hate for them, but it works well for me.
[22:30.820 --> 22:35.320]  And I find that it, you know, for $35, it's a great way to just, you know, not break the bank,
[22:35.320 --> 22:39.140]  but really figure out if ham radio just in general is going to be a good hobby for you.
[22:39.140 --> 22:44.000]  It has a lot of other capabilities. You can listen to normal FM radio, you know, can be a police
[22:44.000 --> 22:49.420]  scanner. There's just a lot of other stuff that it can do. And so I really like it for $35 on Amazon.
[22:49.480 --> 22:55.020]  You can't really beat it. So let's see. So it comes with what's, you know, a little stick antenna,
[22:55.020 --> 22:59.420]  like what you'd see on a walkie talkie. That's what if you were to buy this Baofeng Radio,
[22:59.420 --> 23:04.060]  it would come with, but you can build a directional antenna, which is what you're going to want
[23:04.060 --> 23:07.440]  if you're going to talk to satellites or the International Space Station, because
[23:09.020 --> 23:15.560]  a traditional stick antenna is going to radiate its signal out kind of like a donut. So if you're
[23:15.560 --> 23:19.620]  to hold it like thumbs up, you know, so the radios, so the antenna sticking up, it's going to
[23:19.620 --> 23:22.920]  radiate out like a donut. And I should probably have a slide in there that has, you know, these
[23:22.920 --> 23:27.720]  radiation patterns. But really what we want is a directional antenna that kind of focuses that
[23:27.720 --> 23:32.780]  beam more like a flashlight, you know, into the general spot in the sky where you're trying to
[23:32.780 --> 23:37.960]  focus all of your energy. And so for $10, $20, you can really build your own antenna, which I
[23:37.960 --> 23:42.480]  think is even cooler. And then you need an audio cable, an audio card, if you're going to use the
[23:42.480 --> 23:47.160]  Raspberry Pi, or if you're, if you don't use Raspberry Pi at all, and you're just going to
[23:47.160 --> 23:51.460]  use your cell phone, you know, typically most people have cell phones. And so just an audio
[23:51.460 --> 23:56.580]  cord for that, you know, under $100, you can no problem transmit the International Space Station.
[23:56.580 --> 24:02.240]  And again, I'm going to try and keep this updated. If there's something, you know,
[24:03.580 --> 24:08.420]  missing from it, I'll shoot me a message and I can update it or see if there's
[24:09.540 --> 24:14.760]  really anything else out there. And again, it's one of those things, you know, for the amount
[24:14.760 --> 24:18.560]  of money, what you get out of it, especially because I'm sure a lot of you have kids that
[24:18.560 --> 24:22.600]  are home from school, or maybe you're a kid that, you know, is learning remotely now.
[24:23.020 --> 24:29.480]  What an awesome project for under $100 to learn about physics, space, orbits, math, you know,
[24:29.480 --> 24:35.080]  all these things that are super nerdy, because I'm super nerd, but really, there's a lot of other
[24:35.080 --> 24:40.300]  applicable lessons to other stuff out there. The other thing that you're going to want to do is
[24:40.300 --> 24:44.640]  turn on Vox. Again, this is one of those things that I'm probably getting internet hate mail for.
[24:44.900 --> 24:49.960]  Vox is voice operated switch. So basically, you can think of it as when you start talking,
[24:49.960 --> 24:53.580]  radio is going to detect that you're that you're talking already, and it will then start
[24:53.580 --> 24:58.380]  transmitting right away. That's nice, because that means if you plug an audio cable in from
[24:58.380 --> 25:03.380]  your phone or from a Raspberry Pi, the second that it starts playing audio over that jack,
[25:03.380 --> 25:07.720]  it's going to start transmitting. Why this isn't ideal is because there's always a little bit of
[25:07.720 --> 25:15.140]  space of, you know, a little bit of transmit time after you're done talking where the radio is still
[25:15.140 --> 25:20.820]  on and that can mess up some some communications. So it's not ideal, you really want push to talk.
[25:20.820 --> 25:25.860]  But if you're just getting started, it doesn't hurt just to use Vox just to just to get your
[25:25.860 --> 25:30.560]  feet wet. That's my personal opinion. Again, going to get hate mail, I'm sure. But whatever.
[25:31.240 --> 25:35.820]  So I own an aero directional antenna from it's very similar to the one that's in that image
[25:35.820 --> 25:41.020]  right there. It's like $150, which is more than the entire cost of the project. And if hand radio
[25:41.020 --> 25:44.460]  is potentially something you're not going to get into, you know, you're going to want to buy some
[25:44.460 --> 25:49.060]  giant antenna. I don't really know. Personally, I have one because it's something that I really
[25:49.060 --> 25:56.380]  enjoy. However, it's $150 and it's pretty steep. Or you could build your own. And this is one of
[25:56.380 --> 26:01.340]  those things that I was just, you know, checking stuff out online and I saw that somebody had built
[26:02.300 --> 26:08.040]  a their own directional Yagi antenna for like $10 in like PVC parts and like a measuring tape,
[26:08.040 --> 26:12.260]  which is like perfect because I build everything with Raspberry Pis in PVC anyway. So I had a lot
[26:12.260 --> 26:18.120]  of that basically just lying around. And a measuring tape, which funnily enough, I didn't
[26:18.120 --> 26:21.840]  even think about it, but I guess it's, you know, measuring tapes are steel. And so if you, as long
[26:21.840 --> 26:30.380]  as you, you know, basically sand off the tips of your antenna to solder your cables to, it's one
[26:30.380 --> 26:34.460]  of those things that, oh, wow, that's kind of neat. Like you can make an antenna out of a steel
[26:34.460 --> 26:39.540]  measuring tape and it folds up nicely too, which is the added benefit. I'll have a link to this on
[26:39.540 --> 26:43.280]  that GitHub page that I mentioned, but if you just want to Google it right now while you're
[26:43.280 --> 26:48.200]  watching this, if you just do Legios, I don't know how you say it, that's how you say it, but that's
[26:48.200 --> 26:54.200]  how I say it. And then Yagi, all the instructions, the build list, everything. I'm not going to go
[26:54.200 --> 26:59.100]  over all the super details or my time-lapse of me building mine, because it's not really necessary
[26:59.100 --> 27:05.720]  at all. Just go online, look at it. Plenty of other people have done a lot of work to make that
[27:05.720 --> 27:12.060]  pretty nice. So it's one of those things too that like, I personally think this is a nerd merit badge
[27:12.060 --> 27:16.340]  to build your own antenna. That's one of those things, if you're a student, if this is
[27:16.340 --> 27:21.200]  interesting to you, it kind of gives you a little bit more stake in it, not just to like, oh, I
[27:21.200 --> 27:24.160]  bought all this stuff off the internet, put it together, and I can talk to International Space
[27:24.160 --> 27:28.940]  Station. There's a little bit of that like hacker spirit, hacker mentality, just to like, you know,
[27:28.940 --> 27:34.200]  I built this antenna out of raw parts, you know, and kind of cobbled it together to get it to work.
[27:34.200 --> 27:38.200]  To me personally, I think that's kind of neat, just to, you know, kind of have this project of
[27:38.200 --> 27:41.220]  like, yeah, this is something I built with my hands, and you know, I'm talking to the most
[27:41.220 --> 27:46.480]  expensive object, you know, that humanity's ever built, you know, arguably, right?
[27:47.820 --> 27:51.280]  And it's just kind of cool to me that you can talk to International Space Station with PVC
[27:51.280 --> 27:55.100]  and a measuring tape and like a radio that you bought off Amazon. And it takes about an hour
[27:55.100 --> 28:00.280]  to build. If you have kids and you want to at all get them interested in space and engineering and
[28:00.840 --> 28:05.400]  STEM stuff, you know, or just to get their hands dirty. I think this is personally a really cool
[28:05.400 --> 28:11.500]  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
[28:11.500 --> 28:15.560]  change sides. Oh, there it goes. So this is my antenna up on top of my patio. It's on top of my
[28:15.560 --> 28:19.720]  patio, obviously, so I can get a better line of sight. And I keep everything in my little ammo
[28:19.720 --> 28:25.120]  box. And I use a tripod. But again, you can just hold your hand out there with an extra piece of
[28:25.120 --> 28:31.100]  PVC and it works just as well. It's one of those things that it looks, it looks homemade. And
[28:31.100 --> 28:34.220]  that's what it is. But you're talking to a satellite with a homemade antenna. I think
[28:34.220 --> 28:40.080]  that's pretty cool. Um, so obviously, if you build your own antenna, you're gonna have to tune it a
[28:40.080 --> 28:45.720]  little bit. Luckily, if you follow the instructions online of the, you know, of the antenna that at
[28:45.720 --> 28:49.560]  least I made, when I went to tune it, and from what I've heard from others, when they go to tune
[28:49.560 --> 28:54.280]  it, everything is pretty spot on it if you measure things carefully. But the way that you tune your
[28:54.280 --> 28:59.660]  antenna is by looking at the standing wave ratio or SWR. And this really just measures the
[28:59.660 --> 29:06.200]  performance. I like to think of it as say you have a, a like a tube of like, you know, gift wrap,
[29:06.200 --> 29:12.020]  right? And you shout down that tube, how much of your sound that's from leaving your mouth going
[29:12.020 --> 29:15.960]  through the tube is actually making its way out the tube. And that's kind of how you can think of
[29:16.600 --> 29:22.280]  SWR working with your antenna of, hey, if I'm going to put five watts of power into my antenna,
[29:22.280 --> 29:26.840]  how much of that power is actually going to be coming out my antenna, or how much of it's going
[29:26.840 --> 29:31.540]  to be wasted, you know, kind of just banging around the, you know, just kind of radiating
[29:31.540 --> 29:35.720]  off of it. So there's one of those things that that, you know, if you know, a ham radio operator,
[29:35.720 --> 29:43.440]  I'm sure they have, you know, a SWR meter, you can buy a cheap one online for $20. I don't have
[29:43.440 --> 29:48.840]  one of those. I don't know how well it works. I personally have a nano VNA. It was like 50 or
[29:48.840 --> 29:53.520]  something dollars online and does a bunch more stuff other than just looking at SWR, but it's
[29:53.520 --> 29:57.700]  really small, has a battery. I personally really like it. But again, if you're trying to not break
[29:57.700 --> 30:02.280]  the bank, you know, maybe a $20 one online is worth it. Or you find a ham radio operator that
[30:02.280 --> 30:06.720]  you just say, hey, can I plug this in real quick and test it? You know, there are plenty of older
[30:06.720 --> 30:10.840]  ham radio operators that would love nothing more than the talk radio and talk shop. And it's a
[30:10.840 --> 30:16.100]  great way to, you know, build a community, build a hobby, because ham radio operating is an aging
[30:16.100 --> 30:23.540]  hobby. You know, just go to any ham radio operator meeting, you know, in your city, in your state,
[30:23.540 --> 30:29.040]  in your wherever you're from. And it's definitely an older person's hobby. But I don't think it has
[30:29.040 --> 30:33.660]  to be that way at all. The next thing is, it's really just one of those things that if you follow
[30:33.660 --> 30:40.080]  the instructions, you can probably have a pretty good SWR. And again, I think mine when I did it
[30:40.080 --> 30:46.320]  was 1.3 to 1, which I think perfect SWR is 1 to 1. To me, this is just magic. I don't really
[30:46.320 --> 30:51.120]  understand how it works. I just know that you want your numbers to be as close to 1 to 1 as possible.
[30:51.120 --> 30:55.100]  Again, if I'm wrong, shoot me a message and let me know and I'll update the slides.
[30:56.420 --> 31:01.820]  So the next piece of this is the software. Again, I have lots of Raspberry Pis lying around
[31:01.820 --> 31:06.780]  from a bunch of other projects. I personally like to use Raspberry Pi. I use the software called
[31:06.780 --> 31:11.160]  Direwolf. It's just an apt-get install. Again, if you check out the GitHub page, I'll have the
[31:11.160 --> 31:17.980]  instructions on how to set it up perfectly, as well as my configuration files to kind of mess
[31:17.980 --> 31:23.240]  with so you can look at them and not have to recreate it from scratch. And then when you
[31:23.240 --> 31:30.200]  install Direwolf, it'll also install Kissutil, which is what I use to be able to transmit messages
[31:31.140 --> 31:35.940]  into Direwolf. And then the next thing is there's a tool called Zaster. I don't know how you actually
[31:35.940 --> 31:40.100]  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.
[31:40.100 --> 31:43.880]  And this is more of a GUI tool that you can have on the Raspberry Pi, which is kind of neat
[31:43.880 --> 31:49.240]  because you can see, you know, it'll automatically plot where radio transmissions are coming from
[31:49.240 --> 31:55.880]  as they come in through APRS. So if you were to be receiving information and you had Zaster up and
[31:55.880 --> 32:01.200]  running and you're receiving it with Direwolf, you could potentially see all of the beaconing devices
[32:01.200 --> 32:06.040]  or all the other APRS, you know, transmitters that are out and about, which is kind of cool when
[32:06.040 --> 32:09.740]  the ISS goes over and all of a sudden you have to zoom far out to see, wow, look, there's all these
[32:09.740 --> 32:17.280]  people, you know, transmitting from all over the world. The last time that I did this, I got a
[32:18.380 --> 32:23.020]  contact from Canada, which, you know, I'm in central California, right? So it's, you know,
[32:23.020 --> 32:27.540]  crossing over at least two states just to get there and a good part of California as well. So
[32:27.540 --> 32:31.100]  I thought that was kind of neat. And those are all applications that you want to look at if this
[32:31.100 --> 32:36.260]  is something you're interested in. There's also a lot of APRS applications for phones. I personally,
[32:36.260 --> 32:41.040]  like I said, I use the, you know, I use the Raspberry Pi. So that's not something that I'm,
[32:41.040 --> 32:44.100]  you know, I've checked out a couple of them for iOS, but I haven't played with any of the Android
[32:44.420 --> 32:48.720]  applications. So it's one of those things that I would just recommend checking out an app. You can
[32:48.720 --> 32:52.740]  get trials, I'm sure, of all of these applications and just try it out. Hook up an audio jack to your
[32:52.740 --> 32:57.980]  phone and, you know, just plug it in your Baofeng and you're off to the races. And it's one of those
[32:57.980 --> 33:01.960]  things that your phone is kind of the perfect device. It has a battery, has a GPS, has a nice
[33:01.960 --> 33:07.120]  touchscreen, and it can encode audio like nobody's business. So it's one of those things that before,
[33:07.120 --> 33:11.520]  like I said, you'd have a desk full of equipment, and now it's a phone and a radio. And that's all
[33:11.520 --> 33:18.880]  that's really required, as long as you have the audio cable in between. Let's see. So the next
[33:18.880 --> 33:22.820]  part of this is planning your path of like when the ISS is going to be over. This is a screenshot
[33:22.820 --> 33:29.760]  from my app when I was doing the slides. I use this application called GoSatWatch. It's for iOS.
[33:29.920 --> 33:34.820]  It gives you a little bit of augmented reality, which I really like. So what you can see, at least
[33:34.820 --> 33:39.280]  from this screen, is you can see that this is like currently where the International Space Station is
[33:39.280 --> 33:44.000]  and you can see like, you know, what its orbit is. It's kind of cool. It gives you statistics of,
[33:44.000 --> 33:48.180]  you know, how high, you know, how high it is. So you can see it's like 264 miles,
[33:48.180 --> 33:52.980]  you know, orbiting like that's its altitude elevation. I don't know the technical satellite
[33:52.980 --> 33:57.860]  terms for that. It's also going 17,000 miles an hour. And then you can kind of see how far it is
[33:57.860 --> 34:02.140]  relative to where you are. And what's nice is that if you are trying to make, you know, some
[34:02.140 --> 34:07.720]  communication, if you're trying to digipede off of the ISS, what this app allows you to do is if
[34:07.720 --> 34:13.660]  you hit the sky button down below, you can actually hold up your phone. And since it has the compass
[34:13.660 --> 34:17.520]  and everything in there, it'll kind of like orient as to like where do you want to point your
[34:17.520 --> 34:22.920]  antenna up in the sky to be able to get your, you know, best transmission or, you know, your best,
[34:22.920 --> 34:28.080]  you know, point of contact. And it gives you live stats. It'll notify you on good passes. And then
[34:28.080 --> 34:33.040]  you can, you know, based upon where you are, you can see all the different times of day or night
[34:33.040 --> 34:37.840]  when the ISS is going to come. And it also does a ton of other satellites. And that's another thing
[34:37.840 --> 34:41.780]  that I probably neglected to mention is that this is just talking to, or this talk is just going
[34:41.780 --> 34:45.880]  over talking to the ISS. But there are tons of other satellites out there that also perform
[34:45.880 --> 34:56.840]  basically the same operations. All right, let's see. Sorry, I had to resume it. But yeah, so this
[34:56.840 --> 35:00.780]  application is great. I think it was like $7 in the App Store. But there are plenty of other
[35:00.780 --> 35:05.460]  applications that probably do similar things to just check out. It's worthwhile, at least.
[35:06.280 --> 35:11.700]  And the other thing too, that again, I really like about this is that it'll notify you and you can
[35:11.700 --> 35:15.880]  point this app up and you can see like where in the sky it is. And that matters for a couple of
[35:15.880 --> 35:20.200]  reasons, which we'll go over here in a second. So when you're planning your pass, you also have to
[35:20.200 --> 35:25.060]  take into effect the Doppler effect. I really like the, I'm not sure if anybody's seen Big Bang
[35:25.060 --> 35:29.240]  Theory. I'm sure plenty of you have Sheldon's costume of the Doppler effect. I just had to
[35:29.240 --> 35:33.220]  throw it in there. But you've all heard the Doppler effect before. It's, you know, if an
[35:33.220 --> 35:37.520]  ambulance or police car is going by, as you can see the little graphic down below, you know, if
[35:37.520 --> 35:41.140]  it's going away from you, the sound will appear, you know, slower because it's a lower, you know,
[35:41.140 --> 35:45.740]  longer wavelength. And as the car's approaching you, it'll be higher pitch because it's a smaller
[35:46.260 --> 35:53.560]  wavelength relative to, you know, the object that's traveling. And because the International
[35:53.560 --> 35:58.100]  Space Station is traveling at 17,000 miles an hour relative to where you are on the planet,
[35:58.740 --> 36:03.860]  it's actually having the frequency, you know, its frequency that that's on board is Doppler
[36:03.860 --> 36:07.820]  shifting. So when it's coming by you, it's going to be at a higher frequency, you know, so it's
[36:07.820 --> 36:16.660]  going to be 145.825 megahertz plus 3.5 kilohertz. And then as it's leaving, you know, so as it's
[36:16.660 --> 36:22.440]  going away from you, it's going to be a longer wavelength. I hope I did that right. If not, again,
[36:22.440 --> 36:29.100]  whatever you understand, that depending on where you are situated on the planet and where
[36:29.100 --> 36:33.200]  the International Space Station is either approaching or leaving you, it's going to change
[36:33.200 --> 36:37.120]  slightly the frequency that you're going to tune your radio to. Personally, what I do for this is
[36:37.120 --> 36:42.700]  I try and find a pass when the International Space Station is as far overhead as possible,
[36:42.700 --> 36:47.060]  or as close to overhead as possible, because then there will be no Doppler shift that I really have
[36:47.060 --> 36:53.500]  to take into account. And again, a single pass is about five minutes, so you don't have a lot of time
[36:53.500 --> 36:58.240]  to really fiddle with your radio and try and readjust or do anything like that. So this is
[36:58.240 --> 37:02.020]  one of those things to take into account to try and find a pass where the International Space
[37:02.020 --> 37:06.000]  Station is coming as close to overhead as possible. And you can go Google this online, you don't even
[37:06.000 --> 37:10.860]  need an app for it. But I personally found that having the app makes it easier to make more longer
[37:10.860 --> 37:15.840]  distance communications, because if the International Space Station is directly above you, and you're
[37:15.840 --> 37:19.360]  sending a signal to it, well, it's going to radiate that, or it's going to digitally beat that signal
[37:19.360 --> 37:24.300]  right below you. So you're not going to get a contact that's going to be far away necessarily,
[37:24.300 --> 37:29.680]  or at least as far as you can possibly get it. The optimal kind of thing, if you're looking to try
[37:29.680 --> 37:34.040]  and transmit your signal as far as possible, would be to kind of hit the edge of the International
[37:34.040 --> 37:38.540]  Space Station and then have it transmit at a farther area away from you. Again, it's one of
[37:38.540 --> 37:43.140]  those things, you know, you can see, I'll go back a couple slides, you can see the size of the area
[37:43.140 --> 37:48.020]  that International Space Station covers. So at any given point, you can hit, you know, that's a large
[37:48.020 --> 37:54.580]  portion, you know, of whatever that land mass is, Asia and Europe. And then if that were to fly over
[37:54.580 --> 37:58.520]  the United States, you know, it covers a good portion. And when it flies over California,
[37:58.520 --> 38:03.940]  you can hit Idaho, Colorado, you know, again, depending on whatever its orbit is.
[38:05.520 --> 38:10.440]  Okay, so this was the hardest part for me, is finding out how to actually send a message. I
[38:10.440 --> 38:15.160]  didn't think it would be as difficult as it was. But again, I was using Raspberry Pi, and I was
[38:15.160 --> 38:19.060]  trying to do everything on command line. And maybe I was making it more difficult for myself
[38:19.560 --> 38:24.980]  than I really needed to. But again, I could use my phone had it been easier. But again,
[38:24.980 --> 38:28.180]  with some of the plans that I have going forward, I'd rather do this kind of more in an automated
[38:28.180 --> 38:34.620]  fashion. So I use screen, you can use tmux, you can use multiple putty sessions, or you know,
[38:34.620 --> 38:39.180]  whatever you want to connect to your Raspberry Pi. But essentially, I had three separate screens
[38:39.180 --> 38:45.220]  for my Raspberry Pi. I had direwolf that ran my direwolf configuration. That's what dash c is,
[38:45.220 --> 38:51.500]  dash t is to not do any color on the output of when direwolf runs. I have the kissutil,
[38:51.500 --> 38:57.420]  which is installed when you install direwolf. And basically, I have the folder rx and the folder tx
[38:57.420 --> 39:01.720]  that you know, if anything I receive will go into the rx folder, anything that I transmit will go
[39:01.720 --> 39:06.020]  into the tx folder. And so that's kind of nice, because I can just drop text files in there.
[39:06.240 --> 39:11.240]  And then the kissutil and direwolf will take care of converting that to audio and then transmitting
[39:11.240 --> 39:16.000]  it out, which is which is awesome, because then at that point, you can script up whatever you
[39:16.000 --> 39:22.020]  want, you can do things on in an automated manner or manually. But again, you only have five minutes
[39:22.020 --> 39:26.520]  or so that you're trying to, you know, communicate with International Space Station. And then even
[39:26.520 --> 39:31.040]  more of a narrow window when it's directly above your when it's kind of primetime. And you don't
[39:31.040 --> 39:35.340]  want to necessarily, you know, you want to have everything set up in such a way to where you can
[39:35.340 --> 39:39.800]  send out a single message per pass, you know, or maybe just a handful of messages per pass,
[39:39.800 --> 39:43.500]  because there are other people also trying to communicate with it. And if you remember,
[39:44.220 --> 39:48.940]  the International Space Station is operating on a single frequency, you know, it's operating on
[39:50.640 --> 39:55.140]  145.825 megahertz, which again, I don't know if I put that in notes, but again, it'll be,
[39:55.140 --> 39:59.460]  you Google it, right? Like it's out there. But, but only one person can talk to International
[39:59.460 --> 40:03.840]  Space Station at a time. So you don't want to be constantly transmitting, because then you'll
[40:03.840 --> 40:08.300]  prevent other people from also communicating with it. So basically, what I had is on a I believe
[40:08.300 --> 40:13.380]  every minute interval, I would have it, you know, copy my message.txt into the transmit folder,
[40:13.380 --> 40:17.100]  and they would shoot that message off, or you know, transmit that message off, I guess I should
[40:17.100 --> 40:21.680]  say. And so what's kind of neat about this is that you can script it up in such a way that you know,
[40:21.680 --> 40:25.620]  if you have a program that you want to have automatically begin something out, you can,
[40:26.140 --> 40:30.280]  or anything like that. Personally, I like that. But if this is just you're just trying to make
[40:30.780 --> 40:36.080]  a contact, or you know, you're trying to, you know, begin some or did you be digipeded off of
[40:36.080 --> 40:40.120]  the International Space Station? Oh my gosh, I can't talk. If you want to be digipeded off the
[40:40.120 --> 40:43.700]  International Space Station, that's your only goal. You know, just with your phone, you can
[40:43.700 --> 40:47.080]  just send the message out that way manually, you don't have to go through all this direwolf
[40:47.080 --> 40:51.100]  craziness. Most most phone applications should be able to do it pretty darn easily.
[40:51.880 --> 40:58.040]  This is a simple message. So if you have a, you know, a client on here, this is this is one of
[40:58.040 --> 41:03.640]  those things that like this is what I use. Basically, I transmit this text in that message
[41:03.640 --> 41:10.000]  dot txt. Again, that's my call sign. When you see my call sign, or so then you see AR ISS,
[41:10.000 --> 41:14.000]  essentially, all that means is that you want to be digipeded by the International Space Station,
[41:14.000 --> 41:18.820]  that's its call sign. And when you do that, you basically are just saying, Hey, I want you to
[41:18.820 --> 41:22.800]  digipede this message to the International Space Station. And then what you have is you have my
[41:22.800 --> 41:28.020]  call sign again, followed by dash seven, that's because it's my mobile unit. Again, not getting
[41:28.020 --> 41:32.880]  too deep into APRS, having that designation there, that dash seven is just showing that you're
[41:32.880 --> 41:37.720]  mobile. And then the next, you know, digits and numbers right there, it's kind of a weirdly
[41:37.720 --> 41:42.920]  encoded way that I had to like Google how to do of what your current GPS coordinates are. And then
[41:42.920 --> 41:48.300]  after that, you can see, you know, your message. So digipeding, you know, DEFCON 28, Aerospace
[41:48.300 --> 41:53.420]  Village out to the International Space Station, which then gets relayed, you know, down to
[41:53.420 --> 41:59.400]  ground stations that receive that message and then off to the greater internet. This is the folder
[41:59.400 --> 42:03.980]  structure. So when I run direwolf, I run it from my home directory, direwolf config is right there.
[42:03.980 --> 42:08.760]  And then I have a tx and an rx folder for the messages that I'm going to send go into the tx
[42:08.760 --> 42:13.160]  folder and messages that I'm going to receive come from or, you know, get placed in the rx folder.
[42:13.620 --> 42:21.720]  Um, let's see, let's see if I can get this. All right, so some of the things going forward,
[42:21.720 --> 42:26.540]  I think that are important to cover, you know, so my goal of this is I want to automate it,
[42:26.540 --> 42:32.540]  I want to make some rotors and rotors, if you're not familiar, are basically what it would allow,
[42:32.540 --> 42:38.380]  you know, rotors would allow me to change the elevation, you know, up and down. So like,
[42:38.380 --> 42:42.480]  if you're looking like a tripod is a great example, right? I could, you know, change the
[42:42.480 --> 42:48.080]  orientation 360 degrees, like a compass, and then the elevation up and down. Because it'd be really
[42:48.080 --> 42:51.280]  cool if on the Raspberry Pi you had some software that basically tracked where the International
[42:51.280 --> 42:56.740]  Space Station was, and anytime it was up overhead to transmit a message automatically. So that's
[42:56.740 --> 43:01.660]  kind of my idea of what I think would be kind of neat. So we'll see how that goes. And then I would
[43:01.660 --> 43:07.600]  also like to see, you know, how far away can I hear from, you know, or how far could I be
[43:07.600 --> 43:13.280]  digipeded by the International Space Station? And if you kind of think about it, you know,
[43:13.280 --> 43:18.340]  out onto the horizon. So if you were, if you were out, you know, basically to the horizon,
[43:18.340 --> 43:21.480]  that would be zero degrees. But obviously there are trees, there are houses, there are all those
[43:21.480 --> 43:27.700]  things in the way. And so there's a point at which, you know, you can hit the International
[43:27.700 --> 43:32.940]  Space Station, you know, with a signal, maybe is that 20 degrees? Is it 30 degrees? Is it 40 degrees?
[43:32.940 --> 43:37.660]  The higher the elevation is, relative to where you are on the ground,
[43:37.660 --> 43:41.080]  the easier it will be to communicate with it. So it's one of those things that automating it,
[43:41.080 --> 43:46.460]  I think would be kind of neat. And then I also like to, you know, investigate looking at other
[43:46.460 --> 43:52.140]  satellites. Yeah, and basically just just seeing what else is out there. A huge thank you to AMSAT
[43:52.140 --> 43:59.060]  and ARISS.net just because checking out that website inspired me to, you know, try and get
[43:59.060 --> 44:03.980]  on the board. It's in the AMSAT. There's tons of great information there on how other people have,
[44:03.980 --> 44:08.040]  you know, had successful communications. And really at the end of the day, I think this is
[44:08.040 --> 44:12.220]  just something that's kind of cool. You know, the hacker mindset here of just kind of scraping and
[44:12.220 --> 44:16.640]  cobbling together all these things to really do something that's kind of neat to be able to
[44:16.640 --> 44:22.260]  transmit to the International Space Station. Not to mention too, that this is how you can transmit
[44:22.260 --> 44:28.240]  to a lot of other satellites. And it's really kind of covers the basics in terms of what's
[44:28.240 --> 44:32.680]  required to talk to a satellite, right? There's a whole bunch of different satellite orbits, a whole
[44:32.680 --> 44:38.700]  bunch of different satellite communication protocols, frequencies, modulations, and this is
[44:38.700 --> 44:44.040]  just dipping your toe in the water of what's available and what's out there. And it's for
[44:44.040 --> 44:50.940]  honestly a pretty small budget, right? For $100, $200 you could get a really solid setup to, you
[44:50.940 --> 44:54.960]  know, to communicate with the International Space Station with other satellites with just a HAM
[44:54.960 --> 44:58.660]  license, you know, just be an amateur radio operator. And if you just want to hear, if you
[44:58.660 --> 45:03.320]  just want to listen to what gets transmitted, you know, you can do that without a license. And
[45:03.320 --> 45:08.660]  really, you can just get a Baofeng radio, your phone, and, you know, it doesn't even have to be a
[45:08.660 --> 45:11.740]  directional antenna at that point. You know, if you just want to listen, you can have an omni-directional
[45:11.740 --> 45:15.580]  antenna, which is basically just, you know, a longer version of the normal stick antenna that would
[45:15.580 --> 45:20.920]  come with the Baofeng. Again, I'll post links to everything on that GitHub page. But yeah, at the
[45:20.920 --> 45:24.140]  end of the day, this is a great way just to get started if it's something that you're
[45:24.140 --> 45:29.400]  interested in. And then from there, who knows how much farther you can level up and, you know, what
[45:29.400 --> 45:33.960]  other satellite communications you can do. You can spend thousands and thousands of dollars and,
[45:33.960 --> 45:40.860]  you know, sink a full-time work week into all of this stuff, especially as an amateur. So it
[45:40.860 --> 45:45.700]  definitely helps to have a good starting point and to have a good point in time of, like, this is
[45:45.700 --> 45:50.280]  something that I can measurably check off a list and do. And especially, again, I know that I've
[45:50.280 --> 45:55.300]  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
[45:55.300 --> 46:01.080]  great project to really get your feet wet and you learn a ton of different principles from physics
[46:01.080 --> 46:07.780]  to, you know, radio to computers to, you know, protocols to just... there's so many small
[46:09.760 --> 46:14.620]  lessons intertwined that I just think it's kind of one of those perfect projects to, you know,
[46:15.020 --> 46:19.700]  to basically figure out if it's for you, if ham radio operating is for you, to find out if chasing
[46:19.700 --> 46:24.280]  satellites across the sky is for you. So again, I encourage you to take a look at it. Feel free
[46:24.280 --> 46:29.260]  to check out the GitHub page. I'll post some of my contact information on there along with the
[46:29.260 --> 46:33.580]  links to all the hardware and all the apps and all the things that I've mentioned. And yeah,
[46:33.580 --> 46:36.680]  hope you enjoyed the talk. Let's see, how do I pause this thing?