 The next presentation of what I plugged this in, I'm going to, is a bit of a bit of an outlier. So there's a group called the open source radio telescopes. I was in, I mean, frequent contact with them, but I'm not actually a core member. And I asked them to, you know, come to foster them and talk about their work, because I think it's just really good, good stuff that they do. And like, it just fits it perfectly to foster them. But they couldn't, they couldn't get funding for like sending anyone out. So I said, okay, well, I'm not an expert on what you do, but if you, you know, we can come up with a good presentation together and I will just do it on your behalf, because I just want to get the word out there. Yeah, what's happening? So the, like my name is on here because I'm giving the presentation, but Evan, Ellie and Richard were the people who actually put this together, sort of as part of their initiative, you know, marketing material, I don't know, whatever you want to call it. Okay, so that's that. Now, open source radio telescopes, what is this actually about? So it's a bit of a different group than the other people that we've seen here. So the idea is to provide, you know, designs and instructions for doing radio astronomy with the intention of introducing them into sort of the education system, like making this become an easily accessible teaching tool. And now the idea is not necessarily to train, like, you know, like hundreds and hundreds of thousands of people to become radio or radio astronomers, but rather to get people interested in engineering and, you know, DSP and all those things in general, just happens that the people who started this project, they're all astronomers or like some are professional, some are hobby astronomers, and they're all interested in sort of education. And it's a good, what do you say, like field to both like build a simple experiments that are still very, very impressive, but also, you know, to do some actual engineering work. So that's sort of the general idea. And the express intent is not to sort of reinvent the wheel, but rather use radio, for example, where possible, just use cheap and easy things wherever available, and then focus on actually making it available to educators, for example. Okay, so this is some of the things that radio telescopes are currently doing. So there's this 21-centimeter horn antenna project. You can map out hydrogen lines that way and actually like draw a map of the galaxy, I'm gonna show some pictures later on. A small loop antenna, which has a different application. So those are sort of two sort of practical things that sort of came out of this project as like something you can do, and you know, has instructions and all of that. So these are sort of projects, and this is sort of the process. So there'll be, you know, more and more instruction manuals, and, you know, kits and all of those things made available. Yeah. And like I said earlier, so RTLSTR dongles can radio are sort of some of the main tools. Okay, let's take a look at those two projects that I just mentioned and, yeah, talk a lot about them. And yeah, this one is what they call the small loop antenna. So you can see it there on the left. You can see this isn't, I mean, this is a pretty capable piece of hardware, but it doesn't look like it's very difficult to make, and it's not, that's the whole point. So if you take all the parts together, you end up with about $100, it's a bit of an estimate. I, you know, it took a couple of iterations to sort of figure out an easy way how to do that. So yeah, the actual antenna is, I think I might actually have some more information here. The actual antenna is basically a, you know, long wire. There is a tuning part, so hammer it up effectively and amplifiers. So yeah, so you start up with just basically a frame and so the geometry matters, but like the exact carpentry doesn't really not, so you wind a wire around it and that's pretty much all you have to do. And then you need some electronics and that's where the fun starts, I guess. So this is an amplifier and some filtering and a hammered up is used to then, oh, sorry, okay. Hammered up is then used to move the signal into a frequency range that is receivable by the RTLSTR, so why do you need to hammer it up? Because the idea is to track VLF signals. So VLF is used by the Navy for communicating with submarines. So you can think what you want about the world's armed forces, but they give us a lot of high-powered transmitters to play with, like with the passive radar. So VLF is pretty high-power. I mean, so the point is that you have this one big transmitter like somewhere and you don't give away the location of your submarines because it's just basically available everywhere. It even penetrates water to a degree. And one thing it does is, so VLF goes everywhere and one thing that radio astronomers do, I don't know if they do it all the time, but in this experiment it's a nice, neat effect is when there are solar flares, the ionosphere changes its charge level, I don't know if that's the correct physical term, which has the effect that VLF signals sort of bounce off the ionosphere earlier than they usually do. So for those who've taken like ham exams, you are familiar with these terms, but these are layers in the ionosphere. So for reference, if you do HF bouncing off the ionosphere, they usually do happen in this area, F1, F2, Derrick is that correct? And VLF bounces off a little earlier and when you have solar flares, even more so. That means if you have a solar flare, the received power to your monitoring site is higher. And using that small loop antenna, you can measure that. So when it actually, the kit includes all the software as well, so just quickly. So starting from the antenna, which is just the wire, the amplifying circuit, which you have to assemble, the hammered up, putting it into an RTL-STR, you end up now in software, doing radio for some pre-processing and then there's another Python program that is sort of part of the OSRT kit that will then produce your graphs. And the graphs look, what? Where's my graph? No, I think I just miss something. I think I just, I was reordering the slides and I think I did something wrong there. So actually, I'm just gonna stick to the order, improvise a little and I apologize for misrepresenting the open source radio telescope project. So we'll see some results about that. The tools that were chosen, like I said, radio, RTL-STR were evaluated. So STR-SHARP, for example, is another one that was evaluated. So I don't know if you've used it, it's one of those tools that you just like fire up and then it immediately gives you nice guis, whereas GNU Radio is more on the sort of reconfiguration side. But then, like I showed earlier, for the actual final project, then GNU Radio came into play. But this is an interesting thing because it shows like the steps people have to go through for starting GNU Radio. And if you wanna make a tool that is very easily accessible we're not even talking undergraduate students, we're talking like middle school students here. You have to make sure that you don't put in any pitfalls. So as someone who's representing the GNU Radio project, that's a good sign for us to make sure that we keep things simple. Okay, so the DSP is very simple. It's just FFTs basically. I don't really wanna go into it because in the end we just plot everything into a waterfall. This is the flow graph, so nothing crazy in there. Like FFT is like the craziest, most DSP intensive block in the entire flow graph and that's saying a lot. So yeah, and now finally we come to the results that I promised to you earlier. So this is just a very long recording. Using the small loop antenna. This is like 24 hours or one full day. And I think it's, I don't think you can read it at the back, but these are sort of annotations where the signal power went up and it did coincide with solar flares. So yeah, so I didn't know this either, but as you have sunrise and sunset, like the reflection actually goes down, which are these dips here. So, but this is nice. I know, like you can, it's not like those just randomly happen, right, there's like forecasts for this kind of thing. So you, so if you're like into the whole radio, sorry, radio, I have radio scene and you will, you will know that in, so that's a good, good time to set up an experiment like that. So more elaborate is the, how much time do I have, Marcus? I think, oh, okay. I've got plenty of that. I thought it was like one minute for a minute. Sorry. Okay, the horn antenna is a more elaborate project. So it's also a little bigger. You can see like, you know, a laptop for scale here. This is involves a little bit more carpentry. The sort of electronics part of it is, it's a little bit more evolved at this point. So the, what basically what you have to do is you have, you have to like, I have another picture showing from the front, but you have sort of wave guide here. So you need to make sure that this, this gets appropriately captured. So you don't have to do the, the ham it up stage in this case, because this is will, I'll show you in a minute will be for detecting the hydrogen lines, but you have to make sure that you have the signal properly amplified and you know, matching all those things. But in the end, you end back in the SDR dongle, go to GNU radio, run a Python program over it and take a look at the results. So in that respect, it's very similar. Okay, but why, like what's the difference? Like, why do this project, not the other one? So this is something you can use to measure the hydrogen line. So this, if there's like, if you look into the galaxy and there are areas with more hydrogen, like some nebula or something like that, they will emit energy and you can just figure out where they are by pointing the horn in different directions. Fortunately, the planet we're on turns around. So that gives you a good view. Also, you know, this is just a, you know, more elaborate project can also mean, you know, more satisfaction for people. Maybe people do this more loop-intended first and then they want to build something a little bit more interesting. Yeah, and then, you know, this is a more, you know, just a slightly more elaborate project, yeah. It's also a bit more expensive. So Evan, who's one of the authors, like commented there, sort of trying to sort of improve the kit to make it a little cheaper. So with $250, it's like, you know, maybe slightly outside of the budget like some kid who just wants to buy the kit themselves, but it's still a very reasonable price. Plus, you get to keep the antenna. It's not like this is something you can country use or anything. So slightly more difficult, but also more interesting. So yeah, here are some pictures from the actual construction. So you have to sort of build a scaffolding frame, whatnot. This is, you know, some boards and drywall. I'm not quite sure what it is. Like obviously with reflective material and yeah, so waveguide, low-noise amplifier. Just put it all together. Following the schematic I showed on the first slide. And there you go. So this is an FFT plot of the actual signal. And you can like here, I don't know if you can see it, it's a peak, like just above the noise. At 1.4 something gigahertz and that's where the hydrogen line is. So this is pretty cool. You're basically looking at the galaxy at this point. And I can totally understand how that would, you know, fascinate people. Like even if it's just this line, it's like, this is, you know, like space and everything. And so really, really fantastic. Now if you align this with some information about where you're looking, you get pictures like this. So, you know, we don't have a measurement for every single spot on this graph which is why you have these curves. But, so I don't know how familiar you are with the galactic, what's it like, coordinate system. I actually had to look it up myself. But basically, you know, the galaxy is mostly flat. So you have one dimension which is basically the angle between the sun and the center of the galaxy. So you'd expect, and the other one is like going upwards from the galaxy. So you'd expect as you increase the latitude to see less stuff, because there's just no hydrogen there and that's exactly what we get here. So as you sort of sweep around, you can sort of correlate this with position of celestial objects that like emit hydrogen lines. So yeah. Personally, I find this pretty cool result. And I can, you know, this is just very nice to be able to do, like on a smaller scale, things that, you know, radio astronomy labs are doing around the world. Okay, so that's the two projects. So I'll talk a little bit about the, sorry, I mean that's like the actual project that you can build it. I wanna talk about the project, the open source radio telescopes just for a little bit. So they have a website and they have like instructions there and pictures and you can follow this. And so they're actively like creating better instructions and manuals and kits, but they're also very responsive. And in particular, like people who ask questions where they show that they're interested but they have very little experience are very welcome on this mailing list. So like if you go on that mailing list and right, you know, I wanna do this, it's awesome. I have no idea what you, like promise you you'll be well received and help through all the, you know all the way through to completion. So kudos to, you know, to the team for focusing, you know, primarily on like beginners at the very, very lowest level. And here's a couple of people that you can contact directly if you wanna get involved in the project. But they're also all on the mailing list. Okay, so, you know, I say lessons learned because now again, like these are not lessons I learned there's lessons they learned, but I wanna sort of I do wanna bring this forward here because I just love people getting involved in the educational sector. Yeah, so these projects might look simple, you know, at first glance, but it is a lot of work to come up with a sort of a kit and a whole project and a, you know, description of how to build something, you know, from scratch. So, but I'm glad they like, you know, took that all the way to completion and now we have this to, you know, to spread the word and there's something we can use as projects ourselves if we are in the, you know, teaching sector. Yeah, and there's a lot of radio astronomy things you can do without like having, you know, access to the Arecibo, you know, dish or something like that. So, if you, maybe you're already interested in astronomy, I mean, like not radio, but your regular astronomy or telescopes and this is sort of a very nice extension to that and plus you sort of trick people into learning all these engineering concepts which is, you know, the whole point of this exercise. Okay, there's a couple of people who were all involved in building these things. I might actually put it up again. I do have a couple more pictures here. So, this is Ellie who I worked with on this presentation. You can see here, Eve Claude from Oregon Institute of Technology, I think so, with her students, you know, building one of those dishes and they seem very happy. So, okay, I'm gonna go back to this guy and I'm gonna ask you guys to give them a round of applause for putting this all together. So, we have some time for questions and I will actually try and answer them as best. And Derek, thankfully, who knows a lot more about actual radio astronomy than I do has agreed to help me with any questions. So, yeah, oh, cool. Then, which meets that with criterion that gives you 16 more bits on the detection. So, why that converts to 24 kilohertz and even 48 kilohertz on the card will do the trick. So, you mean for the VLF signal, right? Yeah, that's a good question. I mean, so I can say for, I mean, this is a bit of a, for one, it'll make the whole thing simpler because it's the same solution for one way or the other. Plus, the RTLSR doesn't actually drive the price a lot. I think the Hamidap might not question how expensive they are. 30 bucks. Yeah. So, I mean, it does add some cost. Like, I don't know about matching and everything. Like, how do you get the antenna signal into your sound card, like, well enough? Do you know? So, we need an amplifier. Yeah, we need to, like, you'd need a different amplification circuit, that's for sure. I think it's just much easier to match a, I, you know, I'm just completely, like, guessing here, but it's probably easy to match your antenna to an RTLSR than it is. Yeah, you're right. Yeah, it's... Yeah. See, that's what I get for making stuff up on this one. I think another part of the consideration was that it was an interchangeable component with the Hydrogen-1 antenna. And also, it's general purpose at that point. So, you can show spectrum at other areas and it's an extensible tool at that point. So, if you have a student coming out of this thing, oh, this is awesome, what else can I do? It was like, oh, you can also run some other software and boom, you do AIS or whatnot. So, I think that's the main advantage. Okay, and I'm glad you got in touch with those guys. Any other questions? I'm just looking for a signal in that building. Just give them an SDR dongle and you hide somewhere a signal and you'll discover about what's happening in there. So, like a scavenger hunt? Yeah. Did you have like a blog post or something? Like you can... Of course, the blog post could be nice for this. So, cool experiments don't have to be complicated. I don't know how many people we've shown like FM demodulators with Gino Radio. And it's like, every $20 radio can has better FM reception than Gino Radio does if I don't tweak the software. But it's just way more tangible and people get excited about it. So, from my own personal experience, I can say like have people do simple experiments with SDR and many more people will enjoy it than you might expect. I think you had a question? No? Okay. Any others? So, I don't know that they're doing that project. Yeah, I'm trying to speak into the microphone a little bit to the recording. I don't know that they've done that. Actually, can you repeat the question? Their question is, are they considering doing a synthetic aperture or multi-antenna setup? And I don't know that they are. I kind of doubt it, simply because the RTL-SDR needs a lot of work before you can do that effectively. And the hardware that can do it effectively is more expensive. But there are certainly many other people, myself included, who have done things like that. Marcus Leach is an excellent resource if you look him up. And the general term is interferometry when you tend to speak about it with radio astronomy. And you can very effectively create a four-antenna interferometry receiver and get very good results with all the kind of classic benefits that you get of improved narrower beam width and physical resolution. And it's certainly something that you see with like the square kilometer array and many of the professional radio astronomy setups. So there are existing tools in GNU Radio and outside to do it. And there's an entire radio astronomy GNU Radio out-of-tree module to handle that. And it's targeted interferometry. And just to give you a final thought, without having spoken to these guys, like a synthetic aperture radar and interferometry, I would probably rate more like an undergraduate project, whereas they're really aiming at putting getting the bar down low. We have time for one or two more questions. Okay, well then, yeah? I'll throw out one comment. If you are looking for something to look in the sky, pulsars are a very easy target, 408 megahertz. And one of the interesting things about them is because there are so many, most are not observed all the time. And so some very notable astronomy conferences include works from just random people who have stared at a pulsar for a year and said, look at the data. And so that is a very interesting topic that can be done with like a tape measure Yagi and a very basic SDR. Okay, well, thanks to these guys.