 Welcome to the afternoon session here. I'm in fact not the moderator, but as I'm standing here, I will say hello, the moderator is this gentleman over here. My name is Roland. In between Helping Organize Fossage in the last six weeks, I've been working on building a satellite rotator or satellite tracker. And my talk today is why this is interesting and then actually only a little bit at the end about the device itself. So this all begs the question, how, what is it that an individual could do to talk to a satellite if you're not a telco? If you're a telco, you've got dishes and so forth. Almost since the beginning of radio, there's been a hobby, if you like, and a licensing arrangement for amateurs to use radio spectrum by themselves rather than in the context of a broadcast or a mobile network. This service, astonishingly, is still existing even here in Singapore. There are currently fewer than 100 licensees, but it has never died out completely. To understand where it sits, there are a few ways to lawfully transmit radio signals. The most common is what are called industrial scientific and medical devices. The example we're all familiar with is Wi-Fi. But Bluetooth and garage door controllers and wireless microphones and almost every other thing that you've got that transmits a signal and is not connected to a mobile network is an ISM-band device. The difficulty with ISM-band devices is that the power limits are extremely low. Whereas for some things you want to do, like talk to satellites, you need more than the amount of power that's permissible for ISM. For the licensed transmits, so this doesn't need a license, you just go and buy a Wi-Fi device and use it all. For license holders, really there are four groups. Broadcasters, TV, radio, mobile network operators, telcos, maritime, aeronautical and land mobile. There's a whole lot of people who like security guards who walk around with radios, not unlike this one, Walkie-talkies effectively, they have a distinct license to use that set of radios in that area for that application. And then finally, amateurs. The amateur service looks a bit like the land mobile service, except that amateurs are required to pass a theory exam on electronics and radio as part of the licensing because we get to make our own decisions about, to some extent, about what we transmit and how we transmit it. There are rules, and you've got to pass an exam on those rules, which means you have to know what the rules mean, which means you need to know the theory. So, there's kind of a question about why bother with amateur radio anymore. So back when there was broadcast radio in 1905 and amateur radio 1915, there was a whole vista of unexplored territory that amateurs got involved in. But bit by bit, communications has gotten easier for everybody. So, the internet in 1969, cellular mobile in 1979, mobile internet in 1996, and then ubiquitous smartphones and broadband in the last decade, depending which year you count. And so people ask sort of why bother. Before I get to that, I'll talk about evidence that there is a change. About half the world's amateur licenses are in the US. This is the number of licenses issued every year in the last decade. Something's happened in the last six years. No one is quite sure what, but we think it's the maker movement. So over time, everyone getting hypnotized with their smartphones became less and less and less and less interested in using amateur radio to communicate long distance. But quite suddenly, in 2008, something changed. And the guess is it's the maker movement. If you look at the definition of amateur radio, and you take out that third point, sorry, the second point about intercommunication, this almost defines the maker movement. This is the language that's been used to define amateur radio for more than half a century. And I would suggest that the alignment between people who are amateurs for most of the last century and people who are now makers is very, very close. So again, that doesn't have the question. Why bother? So there's some things that mobile phones can't do. If you're in a place where the mobile network isn't, then your mobile is completely useless. I mean, it's a smartphone that can play a little game of something, but it can't do any communication. So if you're in wilderness areas, if you're communicating in space, if you're bouncing stuff off the moon, which I'm aiming to do, maybe this year, maybe next, this is stuff you just can't do with mobile phones. Also, there's two different points. Where it doesn't exist or when it's down. So in both Haiti and Tibet in the last 12 months, there have been natural disasters which took out phone networks. At that point, emergency responders couldn't move around, except to the extent that they had their own radios. So amateurs got involved and began providing communications while commercial networks were rebuilt. But amateurs can set up even hours. Commercial networks take weeks to rebuild. DIY electronics. If you're making your own radios, then the only way to get those on air is to use an animal assets. So if the electronics itself is of interest. And finally, although I don't do it, high power operation. So it's fairly common around the world to use amateur radio to communicate via the ionosphere directly. So in theory, someone can communicate from here to someone in, say, New York without infrastructure, just using the Earth's ionosphere as a communication duct, despite the fact that it's on the opposite side of the planet. That requires a lot of... In fact, amateurs do a whole lot of stuff. Public service and competition are a big deal here. Long distances common. Repeaters satellite, my interest, which is basically a repeater that happens to be in orbit. Moonbounds which are working towards tracking high altitude balloons. If you release a high altitude balloon to take photographs at the edge of space, how are you going to work out where your balloon landed to get your camera back? If you're in an area with good mobile coverage but no expensive buildings like desert areas in Australia or the US, that's fine. Sometime as your climate comes plummeting to Earth, it'll be in mobile range for about 30 seconds. That's just long enough to get one message to tell you where your device is. But if that fails, or if it comes down an area where you don't have mobile coverage, then you will not find your balloon. If you won't find your camera. So there are people who do putting cameras on the edge of space who depend upon amateurs or parameters to track their balloons. So they're putting a transmitter on board the balloon that's more powerful than an ISM band transmitter and then using an ISM band and tracking the balloon as it goes up and comes down so they can find the camera and recover it after it lands. Some really extraordinary people wait for meteors to enter the ionosphere. As a meteor passes through the ionosphere, it leaves behind a trail of ionized gas which will reflect radio waves. It's only there for about 15 seconds, but that's just enough time for really determined people to bounce signals off it and have a very short conversation. I'm not making this up. This is perfectly clear. I'm not yet at the point where I'm willing to try that, but there are people doing it. Less ambitious there are guys in Sydney and Melbourne who actually use jumbots. They know where the 747s are. They are on predictable flight schedules. And a plane is much slower moving in much larger objects than a meteor trail, and so they just bounce signals off aircraft fuselage. It's fine. By the time the signal hits the plane, it's way below the noise threshold. There's not much power left. The guys receiving have a hard time picking up the signal, but the plane is. So it's doable. Direction funding for Fox Hunting is a sort of field game for playing, which we might do at Maker Faire this year. We'll see. And mountain topping, if you happen to like walking in mountains, it's actually fun to operate when you've got a huge amount of visibility. But my talk is normally about satellite. This introduces a whole lot of complexity. The first thing is, where is the satellite, or where are the satellites? There are... Oops, wrong screen. Right. This is live. There are about half a dozen, eight, I think, satellites capable of carrying amateur traffic. One of them, whose name I can't read them now, will actually come into signal range for us in 1346. Six minutes. So that circle we can see with its lower edge near Singapore is a satellite that's going northwest. That way. So we'll rise there in about six minutes. It will cross the sky in about 10 or 12. I thought it's all satellites. Do you know how much they are? These are... These are the only... these are the satellites that are currently in service and carrying amateur traffic. I believe so, yes. There might be a couple more. I thought there were about 12 or 15. This only knows about eight. I can't explain that. I suspect a few more. The number isn't huge, but it's enough to play. Australia's carpet, I assume, that might be geostationary, right? No, no. Every one of these is low-off. At the present moment, there are no geostationary amateur transmitters. There will be next year, and you will not believe which country's radio club is doing it. Qatar. What? Qtel is putting a new phone... a TV and phone geostationary satellite up next year. And apparently the Qatar Amateur Radio Club has managed to get itself space on that satellite. Space and power. So, in theory, in about 10 months' time, it can be possible for amateurs to, over most of Asia, including Singapore, to communicate via a repeater that's 35,000 kilometres up, and apparently stationary. Watch this space. That's actually fairly exciting, and it's quite difficult. The signal, while it's not moving, which is half the problems I'm about to talk about, is that the 30,000 kilometres each way is just a long, long way. The signal attenuation that occurs over that range is significant. For satellites that are moving, however, which all of these are, there's a whole range of problems. The first one... Hello? Switch back. Right. The first one is where they are. You've got predictions off where they are and can therefore tell you when a thing is about to rise over your horizon and where it'll sit. The next problem is that amateurs' satellites are, to put it politely, a bit cheap, up until QTELS. But generally, they're at a thing the size of a shoebox, they're just tumbling in space. They don't bother with attitude control because that requires fuel and extra mass and extra power. So, if you've got a pair of antennas talking, they need to be roughly parallel. So, if you've got a satellite that's tumbling at random in three dimensions, then you have a problem. The solution to that problem, the reason my antenna has a nice soft foam handle, is not only do you point your antenna at the satellite, you twist it so that your antenna matches the orientation of the satellite's one, and it will change continuously, very slowly, but it will change continuously. So, free-handing is the way to do it. The other thing you can do is take advantage of the fact that the two signals don't interfere with each other. So, instead, use two. This is not something you can do with a free-hand if you've got a dual-band antenna, but if you notice the steel box there and there's a steel box there, you might have to guess that they are similar. In fact, it's the same device. I haven't yet done the two antenna loop. This is the device I'm building, and what I intend to get to is this position where it has two antennas at right angles, so that the orientation problem no longer applies. As long as the thing is pointing in the right direction, it will get enough signal between the two antennas to operate, except for the one case where the antenna is oriented that way. At which point? But that's, no, okay, one over 100, you won't be able to talk about it. That's the easier problem. The next one is something called Doppler. This is the, you know, trained pitch changes from you. The effective ground speed of a low-earth orbit satellite is about 20,000 km an hour, horizon to horizon in 15 minutes. And so, that's fast enough that even for radio speed of light communication there's a measurable Doppler impact of several percent, and that means that you've got to adjust the frequency of both your transmitting and receiving radios to compensate for Doppler. Now, if you can transmit them, let us suppose that B is the satellite. I'm here in position A in Singapore and someone else is, let's say Tokyo. The whole point of wanting to talk through a satellite is that we can't see each other directly with this particular band. So there might be other people using it that I can't hear. So the deal is that when you're doing satellite, because of all the other problems, orientation, attitude and Doppler shift, and then when there's a gap you then transmit, but you continue listening. So you're transmitting and receiving at the same time. So that requires two things. One is a radio capable full-duplex operation. There are six models of the hundred models of a radio in wide use of the world today. There are about six that can do it, none that are legal in Singapore. Fine. So fine, I'll just use two radios. It's perfectly fine. You listen with one and you're transferred to the other. You're at risk. If you have a PA system where the microphone gets too close to the speaker, you get this howling sound while the same is true for radio. And so the solution to that problem is for the transmitting or the uplink frequency and the downlink frequency to be not only two different frequencies, but on two different bands because the satellite can't afford the weight to carry good filters for frequencies that are close together. So put them so far apart that they don't interfere with each other at all. Meet along elements in one direction and 35cm long elements in the other direction. The two separate bands, one's used to transmit, one's used to receive and get right angles to each other to make it even less likely that they want to fear. Right. That's the list of problems. And so why build a tracking device? So the conventional amateur radio operation is listening and talking and making entries in a logbook. Mine's in here somewhere. To do what I've just described with a satellite without a tracker you have to point the antenna of the satellite forward across the sky, rotate the antenna to match the orientation antenna, perform Doppler correction by hand and sneak and listen and make entries in a logbook. I don't have that many hands. So make life a bit easier. Use a device like this which has a 2-axis mount so it will both tilt and rotate. So it's capable of tracking a device with a satellite across the sky. If you use the two antennas to solve the orientation problem then we don't care about the orientation of the satellite. There's a small loss in signal for doing that but it's easier than trying to rotate the antenna. And although I can't do it yet having to use a computer software perform Doppler correction on your radio's frequency. The computer won't transmit but it will tell the radio what frequency to operate. So second by second make little changes. And they're predictable. We know where the satellite is and it's uploaded onto a computer and everything is going to do it. It's back to listen and talk and maintain entries in a logbook which is what Amit has been doing for decades. So I've got a couple, I'm looking at two designs. I started with a sort of an old faithful by a guy named Mark Spencer which I now regret. Firstly it's a recipe rather than a complete design. Secondly the control has been antiquated so reprogramming requires certainly it's by metal robotic parts and machine it's been a while since I was in high school. My metal working skills have declined. So if you look at it closely it's a bit rough. The other thing is all U.S. parts are U.S. robotic parts and they're all imperial measures. So I'm sitting in a hacker space and I'm like oh I need a screw which does this. Nope. Everything we have even in a hacker space so there are no loose parts available for the solving problems. And finally it's not weatherproof. It's really only intended for tripod mounting for portable use. The one that I rather wish I had picked up is a thing called Sat-Mods. It's a much more modern design. It's really printable, it's parametric. You can take the designs and scale them up or down if you wish. It's not just a fixed design. They use a BeagleBone to control it which means the software is actually accessible and easy to modify and complete and importantly they're running a global tracking network. So they currently run about half a dozen ground stations. I'll add one if I can find a site in Singapore. It's a bit tricky. Which then allows satellites that don't have like a coverage to be tracked wherever they are subject to other demands on the network. But yeah it's this sort of aluminum and nice gears generative area spreader and tracking software. It's a much more contemporary approach to the problem not as tried and true as this one but no need to work still. So I wish I had done this one first. Habitatek questions what I will attempt depending upon what Gepodik tells us. I've now lost my predictions of what it says. After the talk Right, that one is too much marginal. I'll look at it upwards. Sometime this afternoon I will go outside and actually do a demonstration of at least the received site. I have two radios but I'm not yet set up to try and do it properly. Not using the tracker just pre-handling. Those who are looking backwards when the photo is being taken might as well be playing. And it is all working. That's all I want to talk about at this point. Did this make any sense? Does anyone have questions? It's done so well. It's all and all of them. Not digital. You're actually transmitting. What are you actually transmitting? So right now it's just voice, yes. Are there any rules or anything against digital? That's a bit of a landmine but a bit of a minefield. Broadly it's okay. IDA's rules are a little outdated and so there's a bit of give and take there. Nothing. Once you get beyond a certain degree of precision, yes. Getting to that point is quite difficult because you've got to have quite precise placement of your equipment. You've got to know which way north is. Yeah. Once you get to a certain degree of precision, yes. And there are packet modes. The more common one is Morse. But there are also custom modes that are digital but not automatic communication systems. So things like what's called JT65, which I tend to use for the moon bounce, because each set of six bits or you end up with a group of six bits being sent as one of 64 tones. You can hear it if you listen to it. It's a mode that you can't decode by listening to it. But it's also a mode that you, a computer is listening to a decoding that still expects an operator to be dealing with antenna and transmitter. When you're ready you say, yes, send this message. You type it and you press enter and it does. But you're still controlling the radio and decode signals rather than a full sort of Wi-Fi type computer. Why isn't there a full Wi-Fi type set up by now? There's not much reason for it. If you want to do that sort of stuff you can use Wi-Fi. There's little reason to do it for satellite Wi-Fi type operation with all the problems that satellite has. It is really tough. It's a bit fiddly. It's possible but it's sort of getting outside what is typical for amateurs. Am I sorry? I thought I had another 10 minutes. I voted. Thank you, Roland for sharing all this information.