 operate a station to spy on the way as far as you're going, which is roughly that direction. Okay, so another part of the hobby is to make your radios. In turn, homebrew is used by analogy to homebrew beer. That's to say, a licensed operator can certainly make a radio to their own use, but can't sell it. And the moment you're ready to market, you end up with a bunch of technical deals. The method for testing radios historically is used by an expensive instrument which has an inspection analysis method with the usual antenna ports plus control ports and audio ports. However, hey, expensive and neither are necessarily optimized for what Canada's care done. So, in principle, if you're going homebrew radio, get some parts, install them together, you'll already know that everything is awesome. Okay, you know I'm lying. So, there are a number of problems that are even worse for radio. The first is that some regulators are getting a notice about this and increasing their zone. IMDA in Singapore at the moment is unable to say yes to this. They haven't quite seen it in a long time, but they've got an idea. Four months in the hand of one announcer. That's quite... So, the next and the really big issue, and we're going to be sure that concerns... Sorry, the concerns are there is interference. It's really easy to bend interference, and it's particularly hard to attempt. A major area is harmonics, spirit stones that are multiple at the carrier. Example, for a hand-pasted antenna lens and a bunch of lab gear and did free testing for any radio contestant, the guy turns up with his proudly modified HD orthodoxy to increase the carrier power. So, they hooked it up and created it, and not only had he reduced the carrier power, he created a third harmonic that was larger. Now, this is a 2 meter VHF, so the 70 centimeter harmonic was in an amber band, but it's an amber-secret band where there was an auto-pulsing line. Of course, if you don't know your friend's meeting on the band, you can't listen. So, he was, in fact, breaking the blue line in the picture. So, it's a very large part of the risk is that you're doing harm that you don't even know you're doing. So, that's that problem that I'm looking to help to provide. It's not the whole issue, but that's something useful. And the same with the previous management, that's a really issue when you're on a sudden company. The next is a broad issue with making your own videos. Lesser, perhaps, of HDF, but it becomes a minor issue in your app. There's a lot of things to test. Yes, nowadays, you can get a $50 tonne USA and verify that your radio is not a peak. It's not what it's supposed to be. Or just own more expensive instruments than you would want to. But actually, it's a bunch of other stuff that you might not care about. These are also the good things that you're using. There's a bunch of modulation and evasions you're allowed to do, because that makes it simple and quick. Are you operating inside a warped bandwidth? Is your bass noise visible? This matters for weak signal work, whether the bass noise in the legosa, the canyon factor of the worm, the signal that you're trying to detect. How sensitive is your radio? Is it clever? Is it appropriate? Is it good for receiving close to legitimate, very powerful signals? Are we close to the weak signal? Again, this is a piece of puzzle. All of this stuff is non-consuming, but okay, maybe we can automate it. It all requires costly equipment. At least a principle. But it could be a while ago. Quite a lot of time. Watching a YouTube channel called The Second Class, which videos a lot of time going through the architecture of the test. Almost all of them are low-end PC. I'm going to screen, I'm not going to tell you about the keyboard. There's a bunch of... What we might think of as an HDR. A HDAC, a HDACC, and an FPGA or some other assets, to process them in a higher subway. And then there's a lot of women talking about this, talking about this, talking about this. Maybe I can make one, please. So the context is, what I want is a box, but you don't want to put it in a screen. People who are mainly into that, like using my laptop, because we don't want to, I'd rather just use a web interface, talk to the internet port, than not providing any interface on the front of the box at all. Power speech, power line, and a bunch of science. And then have your antenna, to the device and the test. So then you sort of talk to it using the music I've got. Inside the box, the design is relatively simple. Something like a Raspberry Pi, a USB sound card, a USB SDR, looking for the line 702, the line SDR. Another candidate, perhaps it's a tech point of the internet, which has the linear line 6000 chip in it. Sadly, not using Raychef. That has a lot of frequency of 300 megabits. Have a good room, and I'll be there in a few minutes. I'm a couple. So, plenty of room and a lot of use here, which included an SDR chip. But, okay, that sounds like it. The rest of the design is really straightforward. I'll put a couple of those to isolate the Duo pins, like pushing the transmit button, because you otherwise end up, because it can't make more effect to your test device and the laptop. If you're lucky, you just call this thing, especially if you've got 10s or 100s of watts coming out of your computer. So, that gives an issue, but it doesn't rise in small IoT devices. Speaking of micro-simple isolation, the one area that perhaps needs a little bit of explanation is the radio in itself. You need at least two different, at least two different cables. One has to cope with whatever the output power is from the transmitter. So, you have a few watts that are, okay, but anyway, if you have a radio that puts out a few hundred watts, you need a 10-watt, which is quite large, to get it down to something you can then put through the position of the transmitter and then into the input of your SDR. The other big issue is calibration. This applies to all of its limitations, but certainly if you're sort of covering together cheap, obvious bits and presuming to measure the performance of the radio in a way that might be easy to regulate, calibration becomes a really important question. We'll come back to that. So, certainly for any transmitter test, since we have much more time to talk as well, I think question is power. How do you measure power? So, here's a beautifully simple way of doing it. This is the radio. You already can pan it, which is the reason for the radio. We take the source, we do some high-pattern. You have a power issue. No, I haven't read that. It was measuring power. It's heard me. It's like, okay. I'm going to turn the power off. No, no, no, no, sorry. Okay, so this is what we're going to do for the rubbish. This is one of the things we built into the radio, through conflicts and acts with conversions. It samples this bar up IMQ. It's sampling at some frequency, and then you have something again called a cycle delay. It's the same frequency as the delay for a cycle. And so what you have, conceptually, are two samples that run into each other. To compute the magnitude, you just multiply them to take the square root. Good radio, which implies this complex domain squared, which we get from ballooning complex and arms, the wheel. What's important about it is that so far you're looking at voltage. Here, however, if you just multiply them together, you're now looking at something, there is a power. There are various reports of square root bits. Now, so you've got a series of speed samples here. There are linear and portable reports. It is great. You need to multiply by a constant. What constant? That's the calibration problem. It's going to outrun why what's coming up here is not and can't be directly at the kind of radio. But over a short range, you can say, a 10% change in the radius of our power is a corresponding 10% change here. And so as long as you're going to want to calibrate, you've got enough basis for saying, here's a number. It's probably going to be a better one. And for the purposes that we're trying to solve, that's enough. So again, this is like, how do we do this cheaper? Let's do it with an average. You have to be able to respond with linear measurements and add average materials. Then take a little bit of the decimals. This gives us how much power is coming on the entire surface with a bunch of water. That's not enough. It's important information, but it's not enough. The reason is you need to know about how much of that power is present in the harmonic and how much is present in the harmonics. If you already looked like this, earlier there was going to be an antenna. This is approximately a square wave. One can give you an example, but one can't. The fundamental is that it's really what's expected. The third harmonic is only 10 dB below it. Even in the simplest of the regulatory phases, this is the worst permissible quality is that it's 43 dB or 20,000 volt to be able to load and carry that. This is a thousand times the simplest possible compliance case, and actually we've got to work so that compliance requirements get tighter. What I'm saying is it's not enough to know how much power can be done in storage. The harmonics are relatively easy because the filters are not terribly difficult. Whatever the problem it is, you can really build a filter that goes 10% of your size, and then you can move that up to that, and so you can get your spent weight down pretty cheaply without any complicated maneuvering. That's a really important test and it's a regulatory one, and unfortunately that's relatively straightforward. Another one is Space Noise and this is a particular instance because of the habit of listening to stuff that's come to life beyond the sphere and therefore it's a reality. So, start with a presumed near cure tone at the end of this, and then a nearby signal that is 90 dB down, that begins. It seems like a very small signal, so that's huge for office operators to be able to follow that. However, if the oscillator in the radio is in parallel, to keep the average frequency right on the line where it's supposed to be, the operator to be able to considerably step the control volume down or the counter-racial volume down causes noises as you go through Space Noise and you can very quickly have more phase noise than the signal difference. And so, regardless of state numbers, they don't much care, but you certainly as a builder, it's an interest to know that you've made a mistake that's drastically worsened in terms of the design there. So, there's a whole lot to do with it. Unfortunately, the professional is not showing the devices, there's been much too much time understanding this problem and don't get her running cover. So, this is where I'm going, not what I've got. I'll come back to that. Oh, I'm sorry, here it is. So, the issue with Space Noise is you've worked major closely. In a spectrum analysis, and I have felt that it's really narrow. Typically, they're electronically they're expensive and they're idyllic, they're electronic. You look computationally, you need to pass period transformers, you have a whole range of new sources of error each one of which has to be correctly called. Which is not only idyllic, but computationally expensive. And thanks to my friends who run this one around 100 by 0, I suspect they'll be around for a problem. The interesting news is, of course, for the ones who use the others, not sure. The other big issue is the calibration. This I was concerned about until someone drew my attention to and I thought, this stupid way of solving problems. Start with a reasonably clean oscillator on average between these that I've worked so for a sense. All you need is a reasonably clean oscillator. So there won't be a lot of this result. General pair of back-to-back diodes across it. It's revolting procedure has two effects. One is, you now have a substantial engine component of the frequency. The other is that the peak is not going in the way. So the diodes don't tend to change their current voltage adding time over a period of time. So if you take the other component to not change, there's nothing to add up on anywhere. It might be a thermal problem. I haven't looked carefully at the thermal characteristics of a forward voltage, but there are the ones that are relatively stable. So what you then need to do is remove the second one. Which is what this thing is doing. This becomes conducted at a frequency you basically choose to do the second one. You've got back to your design way. But it now has the level of fixed power. What works in thermal power is not important. What's important is equilibrium. At that point you walk into your authentic tertiary institution of the lab and say hi. And I've had one of the important evidence that you can do a calibration run on this. That then becomes basis for the subsequent results. Because this then solves a whole of those certainties. What works around whole of those certainties in other ways is simple design. The other thing that I missed in my earlier design is the other obvious fact that I'm not currently working with this. So in fact it's likely that there are more switches at the cut-in. This also comes up when you get cut-in by yourself. So considering there's a whole design there's a bit too soon. So what's next? What's the cut-in? Again, I apologize. The phase-wise thing does concern me as well to be able to see HF statements that have been propagated by the others here. And this seems to be a you can spend as much money as you like. We wrote an earlier leak that actually publishes its test procedures. They state specific possibility from when it's all over. Approach the individual that has them and you can do useful phase-wise measurements by having your test instruments and also that is only slightly better than the other that is in the radio. You take whatever's up in the radio and you go double price and that is the reason also for this. What do you think was a serious mistake? Not an approach. I'll just stand very, very soon. So the Yeah, so this is a it's going to be a trade-off and having it going here what I have discovered is that the economy is also going to be expensive but the competition will be competition and that gets into the course of it. If you're doing FFT you've got to have buckets and if it's a time you're measuring between two buckets then the two measurements come together. Okay, it fixes together. Is this it? The ratio with PCM noise for some of the measurements I think it's okay but I haven't yet convinced myself that it is. Analyzing in a time-lose way of course doesn't particularly use this way at all and the risk is that if you have enough noise to exceed at least the 3RI and possibly the IP performance of the device in the test not sure probably no problem but I haven't yet convinced myself either way. The really big one is that this result, this provides a control channel. So we go back to that we'll go for 900 mA with PCM. There is a variable resistance of power and a variable capacitor for tuning, neither of which this device can control through a serial port. And so there is this gigantic call-up diagram that says that for this to be meaningful, the very existing has to have at least a market control through a serial port and still using various methods of editing the control rather than actual ones of the user terms and for a lot of home that's actually a problem. That with the build of traditional designs that fit out to the teams they can have a market control which will be on for sure for you. Another issue is the this is sort of an issue in the cinema actually synchronizing the sound card and the SD card. So in the cinema you look at the cut-off work. In the cinema you look at the video of the sound the cut-off work which makes a sharp, awesome sound and there is more than one video that's enough to live up. So what would weigh yet to do the same thing with a cheap sound card that you have to work on but get the mother's answer or call. And finally there's some regulars all over the world are doing this Singapore Advertisement, the MRO GeoSpec about two years ago and that's the EOC stuff. They're more concerned about emissions than about acceptance of course though that they do worry about both and very early but there's also an approach to do that and we're looking for ideas for benchtop EOC and fine metal boxes sometimes for tell-tales sometimes for real chamber metal but few of them are there's few of them why to do it that's far more ambitious but that IMDA is already asking and in the context of how respect they want to be like you're not going to respect what you expect they're actually stating expressly that it does not apply to license standards making ready for better use but actually the name doesn't be the only use of that it's named in the standard because there's stuff that's not coming to mind or don't use it you might be saying use that standard or 100 so maybe hopefully we just afford that all together because it could be worse if you're making a review of the device a small problem with interference if you're making one not so much that's what I am questions, comments how do you not break the normal test again this is a even more difficult question so at least with respect to IMDA what they're looking for is the devices that appear in the license they're formally authorized that we look up to on that channel they have to yes it's a near certainty that there's an amount of mission occurring during the testing it's not expecting a house on a bench yes for sure there's some amount of leverage to go into the hands of on the test frequency it will go into providing unscripted that's not a concern that's almost we've authorized to connect this radio transmitter and transmit power that we've given permission to is not there more generally low power if you don't put single-digit watts that are in tens of hundreds into a test environment that's who you can certain that a million-wide work range that everything is looking for and only then there's power access the whole thing is a compliance question so we can't avoid getting ourselves into the millions didn't really get a bit of an answer to the emissions emissions and the examples so a device if you're looking for a bench for the emcee one of them is tens of years for torture testing you put a device in a tensile and then you put a kilowatt of power and the device has to not malfunction so for example if it contains a transmitter and a multimeter the multimeter must not no, no, the ion is actually okay what it must not do is select an intermissible frequency and begin transmitting just because of the presence of some of it so this is that's a bit consumer protection to do but for now it's like my radio's not working I don't know why but this is an approach to me but it means that because the same thing happens about the safety otherwise testing at 16,000 volts A, I don't do that in my heart and B, you test it as part of the test, you test and try it if you do a lab, you send two