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To the moon and back. Software Defiened Radio and High Power transmissions

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OK thank you well this welcome to my talk here the part of the talk is to the moon and back softer defined radiant high-powered transmissions and the subtitles how to do cool things and stay of my markers and the obvious that my call sign and we were having a little stand on their own and their we noticed many people with a call center that 1st ask you how many people do have a call sign while at the top of the wall OK and tested can on expect about 5 10 but so many OK so that most of you have at least that kind of an insights from their own practical all being formed from your own doing this in well let's start from and the call sign is actually something that's important exactly here there because this wonderful little device transmits about 10 really wants and OK the lies people among you know how far you can get potentially what's but but the question to the others who don't have a license how far do you get with 10 really words that same short wave what you think Jimmy guesses some numbers kilometres thousands the that's what play a very important point is this so the next topic that will be from from Asia and the major will presented little device little raspberry but with a just a wire attached it's and through the wire out of the window down there and he was able to bridge um funiculars over to England's just with this little wire attached to a respirator so respirators stimuli was so it's worth thinking about how far you can get with small power next actually what's so interesting about them on balance is that all those aspects high power and low power comes very close together even though there completely different and they require completely different approaches so now let's start I it's a nice area it's not
mine no what is it take it takes a very very good intended to go to the moon very good antenna the moon is somewhere between 400 and 5 thousand 330 thousand kilometers away it's quite a distance that's kind just take 400 thousand kilometers in that case and the other way back so that's 800 thousand kilometers and a that also brought me to the idea well was Apollo really on the moon and from from while thinking about what is possible is not clearly it was possible and it is possible and the guys to do that's my friends that over that action you can send the moon with the 20 what's transmitter and transferred to the Earth and somebody on the Earth will hear you that is possible this was a problematic about will bounce is that the moon is a very bad reflector the moon has a very uneven surface it and it is around which means the waves come up here maybe there's a little mountain and the way it will be deflected away and the even if even if the moonies even here yeah the wave comes here but it will be deflected somewhere else so just a very small portion of the power that really hits the moon I mean I don't put all the power on the moon because intent is usually not so so narrow you go beyond the moon and just a very small portion of the power will be reflected and the science about it is 1st of all how to put as much power as you can see on on the moon and how to pick up as much power as you can see from the little amount of power it's going back that's also somebody the was quite an
error in his garden um there's also something about antennas because antennas have a certain game and the funny thing about amateur radios that's we are can Limited's the the amount of power that comes out here but the limitation is candor relative because and depending on the country given put out here a power of 1 thousand watts the and that's a funny thing about it is but it's gets even funnier because everybody few has been playing around with magnifying glasses you can of course magnet you can of of course concentrate all the power to certain spots and this is what a good intended does so if you have the continent and the focus everything into 1 direction and produces a very very small beam you can make sure that all of the power really goes we when I have it and this is kind of device with the
good but this is also possible so that's kind of that's mobile operation little room the intent is 2 mutant and that's about 10 meters long and that also works the I've been talking quite a lot about
antennas obviously antennas play an important very crucial very very very important role and I'd take the jump from the internet 2 filters because but in the morning Tom told us that's an antenna is eventually a filter when you have power distributed over spectrum the that's the frequency that's the power of the if it's evenly distributed amounts the high Apollo evenly distributed and the government and 10 as a resonance and it will only pick up what's in this resonance a all well this is the resonance and this is what it picks up this and of course you wanna make sure that it picks up as much as it can but there is something else that's important about softer defined radio and reality that's the question about the dynamics off the and look at analog digital converter which means if you have backgrounds all sort of can all kinds of transmitters from LTE base stations broadcast transmitters everything all of that energy will come into your receiver every day and all of that energy will go in and the ADC c is OK there's there is an amplitude so that samples the amplitude at a certain point of time but no matter what kind of frequency that is 1st of all later on then you can tell OK you can calculate that out but it's there on that on that that's the reason why it's very important through well for example this is the this is the this what antenna picks up and this is the frequency which you really want to hear the and if there is a transverse strong signal about here the intent of also think up but that what comes in into the line will be the energy of all signals so and the big signal that's up here will eventually and reduce the sensitivity of your receiver so that you cannot pick up the very very weak signal which you really want to hear and that's the reason why it's very reasonable to to put the filter and narrow filter here so that you a blank out all the rest which you don't want a year and this is what you put into your ATC good now let's have a look at the uh let's have a look at the link budget how to calculate the 1 really wants 0 dBm it's a logarithmic scale as we several times as they 1 what is start 1 kilowatt to succeeded in in Germany we have a maximum legal limits of of 750 which is few deviance less but after all the events to I mean since intent of focuses said if you can't really tell us 1 thousand what signal from a 750 what's that's just a little weaker or stronger but that's not really the point the let's calculate the round the stick around for years because it's easier to calculate it on if you have the goods Yagi antenna on 2 meters on the 244 megahertz you will have to balance the 14 14 dB for BI DBI is referring to the uh to to um radiation and to to a ball that radiates in all directions but that doesn't exist in reality because uh um an oscillation always happens between 2 points in the disturbs the idea of the the were crashes your idea that uh the transmitted the trends sent into all directions so after all of the in the eyes trophic uh um a body does not exist in reality it's just a theoretical matter so anyway the if you have a 14 dB and 10 dB I intend on things and if you if you take 2 of these antennas you gain 3 visible and if you take 4 antennas again another 3 dB laughter all you will end up at 20 dB gain so this is the game which again adds to your transmission power because it's um it is practically your the concentration of the signal into the direction which you want to have so what comes out in front of your antenna this 80 dB which is 100 kilowatts and others moralist legal I mean if if we have 750 what's in Germany so you have to do that a little bit but that's not the big portion the In America learned the limits are I think 1 and a half kilowatts so even a little more this is thing so 1 a kilowatts is completely legal but but this example refers to the to meet band and not to the antenna here because this antenna very very likely has a gain of 40 to 50 dB so you have to add
50 visible instead of 20 dB and it's only my experimentation side we have a dish of 3 meters dying and 3 meters diameter and we have said we have a crazy idea it's called the chicken is so that's the idea of roasting a chicken at 100 meters distance and how we haven't tried it out yet but the and this OK but that's what the calculation in front of the antenna let's see you can the API you come out with 100 kilowatts and then you send your energy to the moon the way to the moon is quite easy still but the reflection is the problem so the path attenuation overall at about a hundred megahertz this 250 decibels this is what you have to direct that's why I have minus and this is what comes out and and 70 this is the signal strength the comes back to the is the signal strength in front of your antenna the and now the Internet helps you again because since it is 20 dB has an accord focusing power it's so it gives you 20 dB the but this antenna again and then you In this case in this applications usually of a preamplifier so wonderful devices with with a pH you them a the um a transistor the the a very low noise transistor the fantastic things for the fantasy devices and after all you end up at 100 minus 130 yen and then you have a trick because it always depends on the on the on the breadth of the signal if you have a very broad signal over a narrow signal that helps also quite a lot here in this case I'm talking about 10 decibel but this this varies very much according to the kind of about how you use how use how you decodes the signal which you want to hear afterward in this case when that minus 1 in 20 Mrs. 1 what's really what's microwatts not a lot of people and 1 Pico what's this detectable that is possible and this is how you can hear a signal from from the your own signal and if the computer or if the presentation doesn't crash because it that didn't several times because his father such a so big that's a reflection from the moon and the this to event and now I'm here very close in this more skilled In the game should be sufficient to demonstrate what what the effect is Morse code is a binary transmission because the power goes out and that's it there's no modulation the so the energy level of the signal arises instantly and it terminates instantly but since signals come here at the the at the nearest point of the moon and they're reflect a little further there is a time delay and even further down here maybe there's a mountain it will also be reflected this means that those sharp edges come out in the end well there's a 3 3 seconds delay anyway but it's projected onto like the like this and at the end but it's it's like effect from from our capacitor it will be delayed a little and the the signal is not so well detectable anymore there are people who do um voice transmissions also the Moon and that's kind of the problem why they're very very hard to understand and it's also the reason why many people prefer telegraphy of the all because the signals are much easier to detect as you as you could hear you could very clearly distinguish OK there's a tone and there is no modal and if you can do that old are older amateurs but in Germany it's no longer required to pass the telegraph you tests I did it's and I can just read that's like and it's like somebody's talking to me I can just listen to that it's just a matter of training OK hooked up with my presentation and we're office kind of weird sometimes the the and so I mean the the captain continue this way of work in Will you can see this guy
who did the more skilled there's something that you can make a lot of fun but if you if you have learned how to how to ride right didn't listen to it but there are better ways to do it and the other person who is depicted here that's the Joe teller a Nobel Prize winner of the radio astronomers use to work on at the MIT and you need a lot of research on Paul stars and when he retired so the at the age of 65 they decided what he was an iterator operator OK 1 we decided that he wanted to do something in amateur radio was the background knowledge of his profession and the he wrote a program the W S J T in the WSJ to program was designed for 1 bounce transmissions called weak signal communications by k 1 T K. 1 j the WSJ team has a number of terrorists for all sorts of applications not just from will bonds but also for a short where transmissions uh 1 of those applications will be presented afterwards by it and it's also but a way to use uh overweight to analyze very low energy signals in here the signal in this case consists of a 65 tones but there's 1 liter 1 synchronization tone and 64 tones for transporting information and 1 the way how to do that is you connect the receiver to the computer through the sound card in this case it's not like this but I'm I'm not going to talk depictive ively about this because this is really a fantastic device but take not technologically after all this is something like a sound card very very far some card and in this case but the obvious treaty does that something similar it takes the input from the sound card and there's a lot of transformations particularly of the fast Fourier transformation but which they can analyze signals and way but much weaker than the background noise and that's interesting part about and it also the the the transmission also relies on a fixed formats but depending on the on the modes there different modes but here in this case the 1st of the the 1st version relies on the fixed formats and it also has a very very slow abort rates just to board and you'll see that in the next slide 1 of the next slides I a more or less precise PC clock is also required and 1 transmission can can transfer 13 characters it's not very much but given that the transmitted over 800 thousand kilometers this is quite interesting nevertheless what's in the in the standard transmission you call with the call of the center it the reports In DBM's of GP-UCB and how strong the signal is so when I'm sending out I'd tell all the others OK my signal 10 really what's and my locator so where I'm located and the receiver can then say OK the signal goes from here over the moon to their there is a rieger apologies like I maybe it's no
it has not really recovered in the meantime what a moment please so the harbor this 1
minus 1 of the rest of the
class strong if 1 of those pressure there's
some technical problems ahead the and
of you in the yeah while the mistake was to embed the sound file in the presentation this is probably something you shouldn't do if it's a very big I but I tend to area land jumped and just jumping to the slide here and how to make a little bigger and you can read that then these figures are very small here but they're the most interesting ones the so this image 1865 here as board rate of 2 . 69 and the essence of the um as an R is minus 25 and that's interesting thing you can detect a signal that is as weak as 25 dB below noise that's really really fantastic and no unfortunate have not yet seen a reimplementation of WSJ 2 years and radio which should be possible because it's open source now you can download and and compile it yourself and on that would be something something really fantastic and if someone a you can implement that's I would be very very happy the so here are those of you already have a call sign you don't need to worry about that but for the others I I have good news because there are lots of frequencies which you can use an amateur radio frequencies start from 135 kilohertz and go up to doesn't start here no way beyond 250 gigahertz so you can you can play in all of those the frequency ranges and goes from from kilometre waves to 2 millimeter waves and you you know you have all sorts of of funny things which you can play a role with which you can play around these you don't you probably don't leave what's there that reflects everything reflects but it's incredible just recently I heard of an example that somebody is doing but rain reflections I mean of course you you all all if you know there is rain radar the internet so range reflects radio signals and you can send a signal into a rain clouds which is 10 thousand meters high and it will reflect far beyond the rise in you can talk to other people through encounter it's possible and this is that had happened that's a real cloud applications and and something else that's very funny of course you can use airplanes to talk over them you send a signal to an airplane and the airplane will reflect its far beyond arise because they're playing a source is also 10 hours in kilometres up and that you can talk to other people through a reflection on an airplane there are applications had to that people do that and this is why as I tell you that amateur radio is a lot of fun it's a playground for curers people and I if you have questions how to do that there are people who know how to do it's uh almost in almost every country there is a uh rated topic in Germany we have to the other seed detriment of about above globe and the about any of that will be our the and I'm contact them they will tell you how to get a license and it's not so difficult since you're sitting here and you're interested in radio should be easy for you to pass the license exempts not so difficult I didn't when I was 14 years old so everybody and you can do that right thank you very much the implicit it any questions the in the company to kind birds I haven't but why not should be possible they do reflect for sure but and again thank you
Call Center
Punkt
Sender
Datentransfer
Systemaufruf
Zahlenbereich
Bridge <Kommunikationstechnik>
Summengleichung
Reduktionsverfahren
Software
Flächeninhalt
Vorzeichen <Mathematik>
Bildschirmfenster
Mereologie
Statistische Analyse
Leistung <Physik>
Wort <Informatik>
Leistung <Physik>
Spiegelung <Mathematik>
Wellenlehre
Gruppenoperation
Transmissionskoeffizient
Fokalpunkt
Data Mining
Richtung
Reduktionsverfahren
Konzentrizität
Software
Flächentheorie
Spieltheorie
Statistische Analyse
Leistung <Physik>
Inverser Limes
Abstand
Leistung <Physik>
Fehlermeldung
Bit
Sensitivitätsanalyse
Resonanz
Umsetzung <Informatik>
Punkt
Systemzusammenbruch
Unrundheit
Punktspektrum
Internetworking
Richtung
Reduktionsverfahren
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Wechselsprung
Spieltheorie
Gruppe <Mathematik>
Stichprobenumfang
Statistische Analyse
Meter
Inverser Limes
Gerade
Analogieschluss
Leistung <Physik>
Zentrische Streckung
Nichtlinearer Operator
Diskretes System
Mobiles Internet
Güte der Anpassung
Datentransfer
Transmissionskoeffizient
Binder <Informatik>
Frequenz
Ereignishorizont
Quick-Sort
Transversalschwingung
Energiedichte
Konzentrizität
Software
Twitter <Softwareplattform>
Verschlingung
Digitalisierer
Leistung <Physik>
Pendelschwingung
Punkt
Spiegelung <Mathematik>
Versionsverwaltung
Iteration
Kartesische Koordinaten
Soundkarte
Synchronisierung
Übergang
Internetworking
Reduktionsverfahren
Statistische Analyse
Meter
Nichtlinearer Operator
ATM
Dicke
Systemaufruf
Rechnen
Ein-Ausgabe
Bitrate
Ereignishorizont
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Verschlingung
Datenverarbeitungssystem
Dateiformat
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URL
Lesen <Datenverarbeitung>
Telekommunikation
Wellenpaket
Geräusch
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Zahlenbereich
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Kombinatorische Gruppentheorie
Code
Whiteboard
Spieltheorie
Abstand
Optimierung
Leistung <Physik>
Soundverarbeitung
Durchmesser
Zwei
Datentransfer
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Office-Paket
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Mereologie
Leistung <Physik>
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Reduktionsverfahren
Software
Diskrete-Elemente-Methode
Momentenproblem
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Leistung <Physik>
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Druckverlauf
Verschlingung
Statistische Analyse
Leistung <Physik>
Spiegelung <Mathematik>
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Kartesische Koordinaten
Kombinatorische Gruppentheorie
Whiteboard
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Spannweite <Stochastik>
Vorzeichen <Mathematik>
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Statistische Analyse
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Bildgebendes Verfahren
Open Source
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Frequenz
Cloud Computing
Quick-Sort
Codec
Rechenschieber
Software
Flächeninhalt
Leistung <Physik>
Streuungsdiagramm

Metadaten

Formale Metadaten

Titel To the moon and back. Software Defiened Radio and High Power transmissions
Untertitel How to do cool things and stay legal
Alternativer Titel Software Defined Radio - sdr and High Power transmissions
Serientitel FOSDEM 2015
Autor Heller, Markus
Lizenz CC-Namensnennung 2.0 Belgien:
Sie dürfen das Werk bzw. den Inhalt zu jedem legalen Zweck nutzen, verändern und in unveränderter oder veränderter Form vervielfältigen, verbreiten und öffentlich zugänglich machen, sofern Sie den Namen des Autors/Rechteinhabers in der von ihm festgelegten Weise nennen.
DOI 10.5446/34478
Herausgeber FOSDEM VZW
Erscheinungsjahr 2016
Sprache Englisch
Produktionsjahr 2015

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