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posted by janrinok on Sunday April 15, @12:27AM   Printer-friendly
from the one-for-the-true-hackers-among-us dept.

We’ve become used to software-defined radio as the future of radio experimentation, and many of us will have some form of SDR hardware. From the $10 RTL USB sticks through to all-singing, all-dancing models at eye-watering prices, there is an SDR for everyone.

What about the idea of an SDR without any external hardware? Instead of plugging something into your Raspberry Pi, how about using the Pi itself, unmodified? That’s just what the Nexmon SDR project has achieved, and this has been made possible through clever use of the on-board Broadcom 802.11ac WiFi chip. The result is a TX-capable SDR, albeit one only capable of operating within the 2.4 GHz and 5 GHz spectrum used by WiFi.


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  • (Score: 0, Disagree) by Anonymous Coward on Sunday April 15, @01:12AM (5 children)

    by Anonymous Coward on Sunday April 15, @01:12AM (#667110)

    ...and you can tune into other frequency bands.

    • (Score: 4, Interesting) by Ethanol-fueled on Sunday April 15, @01:58AM (4 children)

      by Ethanol-fueled (2792) Subscriber Badge on Sunday April 15, @01:58AM (#667119) Homepage

      There goes your gimmick. But it's not that easy, mixers themselves introduce artifacts(2OIP, 3OIP, etc.) which is why they're used in conjunction with filters and other shit. And if you're going to get that involved for any reason other than the sake of learning, you might as well just buy a more full-featured SDR hardware.

      The device in TFA would probably be fun if you could configure it to jam and hope you don't have any hams or ARRL people closeby, who get hardons for tracking down spectrum abusers.

      • (Score: -1, Flamebait) by Anonymous Coward on Sunday April 15, @03:01AM (3 children)

        by Anonymous Coward on Sunday April 15, @03:01AM (#667141)

        Why aren't you bitching about how this fucking bullshit SDR project hasn't even produced an SDR. The stupid shitbrained nigger jew cunts only used a fucking wifi chip to (guess what!) transmit wifi frequencies. Fucking bullshit!

        • (Score: 0) by Ethanol-fueled on Sunday April 15, @03:10AM (2 children)

          by Ethanol-fueled (2792) Subscriber Badge on Sunday April 15, @03:10AM (#667145) Homepage

          Never underestimate the capacity for humans to nigger-rig. Thinking down to a lower level can shoot down stealth fighters and otherwise provide an avenue to give untermensch a level playing-field to the most advanced warmongering societies.

          • (Score: -1, Flamebait) by Anonymous Coward on Sunday April 15, @03:16AM (1 child)

            by Anonymous Coward on Sunday April 15, @03:16AM (#667147)

            Yeah that's rite. And next up for our soylednews series on nigger rigging, how to nigger rig your wifi chip into monitor mode. Keepin it real nigga. Real dumb.

            • (Score: 0) by Ethanol-fueled on Sunday April 15, @03:38AM

              by Ethanol-fueled (2792) Subscriber Badge on Sunday April 15, @03:38AM (#667150) Homepage

              I never claimed to be intelligent. But you are a smart guy, my fiend. When South California is fighting for its independence, I will come back to you for some smart answers. Let's hope you have some by then.

  • (Score: 0, Disagree) by Anonymous Coward on Sunday April 15, @04:01AM (4 children)

    by Anonymous Coward on Sunday April 15, @04:01AM (#667154)

    Modulation types require different types of antennae, filter, etc. You can't simply replace the software and expect to get the desired/required performance - you actually need different hardware to accommodate different transmission/reception methods.

    And what the fuck is its application anyways? I still have AM/FM radio on my cars.

       

    • (Score: 1, Interesting) by Anonymous Coward on Sunday April 15, @04:16AM

      by Anonymous Coward on Sunday April 15, @04:16AM (#667155)

      Dude, what if we made an antenna out of like, plasma. And had the software define its shape dynamically.

      Oops, I made that shit up but it was real [wikipedia.org].

    • (Score: -1, Troll) by Anonymous Coward on Sunday April 15, @04:42AM

      by Anonymous Coward on Sunday April 15, @04:42AM (#667161)

      I shit my pants

    • (Score: 2) by fyngyrz on Sunday April 15, @06:01PM (1 child)

      by fyngyrz (6567) Subscriber Badge on Sunday April 15, @06:01PM (#667333) Homepage Journal

      Modulation types require different types of antennae, filter, etc.

      An antenna system should ideally be wideband enough to accommodate the max modulation bandwidth of the widest used modulation scheme across the RX/TX range, plus 1/2 the bandwidth of the widest symmetrical modulation scheme, or 1x the bandwidth of asymmetrical modulation schemes at one end, if you want to be able to transmit with the reference frequency right at the edge of the frequency range.

      But other than that, no, you don't need different types of antennas, and you don't need filters.

      For RX, what you need is enough dynamic range on the A/D system so that the sampled signal coming in from the antenna never clips. Everything else - demodulation, filtering, etc. - that can all be software.

      For TX, you need a D/A with enough dynamic range to create a quality signal, and, generally speaking, you probably need an amplifier, as high-power D/As aren't exactly off-the-shelf items.

      Now, it may be that the subject hardware - the wifi hardware - has built-in filtering and etc., and that could possibly interfere with some non-wifi uses of the hardware. I don't know, I've not looked at the hardware in question. But in the general case, SDR software is what handles the demodulation and modulation task.

      I develop SDR software [fyngyrz.com] and have written quite a few SDR demodulators from scratch. So you can take me at my word here.

      --
      The eyes are the windows to the soul.
      Sunglasses are the window shades.
      • (Score: 0) by Anonymous Coward on Sunday April 15, @07:12PM

        by Anonymous Coward on Sunday April 15, @07:12PM (#667365)

        You would definitely want filters at hardware level in order to focus on a particular band, otherwise your a/d converter would be overwhelmed to cover the wide spectrum the radio is supposed to be operate on.

        In the end, software is limited by the hardware capacity, in this case the wifi hardware. "Software-defined" doesn't magically turn a wifi radio into something else.

  • (Score: 0) by Anonymous Coward on Sunday April 15, @05:36AM (2 children)

    by Anonymous Coward on Sunday April 15, @05:36AM (#667167)

    It seems I don't need to open Hackaday anymore as its articles are starting to appear here.

    • (Score: 2) by realDonaldTrump on Sunday April 15, @05:57AM (1 child)

      by realDonaldTrump (6614) Subscriber Badge on Sunday April 15, @05:57AM (#667169) Homepage Journal

      The tweets on this site are much easier to understand.

      --
      Text TRUMP to 88022 to join the #TrumpTrain [facebook.com]!
      • (Score: 1, Touché) by Anonymous Coward on Sunday April 15, @05:11PM

        by Anonymous Coward on Sunday April 15, @05:11PM (#667314)

        TBH, it would have been nice if the summary specified what SDR is, I know what SDR is and it took me a minute to figure out that they meant software defined radio as the context isn't really good enough to quickly bring that up.

  • (Score: 1, Redundant) by nitehawk214 on Sunday April 15, @06:22PM (4 children)

    by nitehawk214 (1304) on Sunday April 15, @06:22PM (#667349)

    Oh it's maybe going to have a SDR, cool.

    What the actual fuck is a SDR?

    --
    "Don't you ever miss the days when you used to be nostalgic?" -Loiosh
    • (Score: 1, Funny) by Anonymous Coward on Sunday April 15, @08:43PM

      by Anonymous Coward on Sunday April 15, @08:43PM (#667384)

      SDR= SystemD Replacement... it's Poettering's next project.

    • (Score: 0) by Anonymous Coward on Sunday April 15, @09:52PM (2 children)

      by Anonymous Coward on Sunday April 15, @09:52PM (#667394)

      We are lucky to live in an age where we have a wealth of information at our fingertips. Try learning to make use of it. If you made the effort then you would know what an SDR is and an intelligent person can infer which definition of SDR is appropriate from context.

      You could have found the answer in the amount of time it took you to ask the question.

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