6 comments

  • mallets 2 hours ago
    So many $1 wireless ICs have a powerful "SDR", but will never be documented due to certification/compiliance/export-control reasons. The projects listed here rightly limited the scope to RX-only but Espressif might be forced to "patch" this away if arbitrary TX too is possible (or starts making headlines). Hope it doesn't come to that, more cheap options for RF-to-bits is always welcome.

    On a technical note, not much I can find about the signal quality. Phase noise, images, DC Offset, etc. Have to get my hands on one, ESP32-S31 seems promising.

    • BlackRabbit1 2 hours ago
      I'm pretty sure that that WiFi-7 modems/routers have a similar modes up to 320MHz bandwidth.

      The modems could be quite interesting as they are connected via PCIe which can eat a lot of bandwidth.

      But they are very difficult (to almost impossible) to find if there isn't anything left in the firmware blob or device driver.

    • ErroneousBosh 2 hours ago
      > The projects listed here rightly limited the scope to RX-only but Espressif might be forced to "patch" this away if arbitrary TX too is possible

      Why would they? It's perfectly legal to operate radio transmitters on any frequency you like, if you hold a suitable licence.

      • ssl-3 1 hour ago
        It is legal for a person with an appropriate license, yes. But laws (in the US) about RF transmission differ from how many other laws are structured: We're only allowed to transmit what we have permission to transmit -- and by default, we're forbidden.

        But right now, I've got an ESP32 WROOM module on a dev board sitting in my windowsill reporting some sensor values over wifi.

        The WROOM itself is registered with the FCC[1]. If I stick to using the documented operation, then I have permission to use it in those documented ways. As a practical concept, I don't need a unique license to use it in the way that I am; I'm granted the ability to use it by Part 15 of the FCC rules.

        And that's pretty great: The hardware was inexpensive to buy and very easy to find. I was able to spin this sensor up very quickly and get moving on the software side that deals with those readings. It has been a very rewarding little project with a fantastic cost:benefit ratio.

        The fear being expressed here (which I don't necessarily subscribe to) is that things like this WROOM module will become less-available when/if methods to use it in undocumented ways are published and start becoming used.

        [1]: https://fccid.io/2AC7Z-ESPWROOM32

        • ErroneousBosh 12 minutes ago
          The FCC is relevant in exactly one country in the world.
          • ssl-3 5 minutes ago
            Thank you. I had no idea! Holy smokes!

            (Up next, will you tell all of us that world isn't flat?)

      • mallets 1 hour ago
        Legal for end-user, sure. But Espressif might run into trouble with regulators like FCC.
        • ErroneousBosh 11 minutes ago
          Then sell them in the UK, where the FCC is entirely irrelevant.

          We treat RF like your lot treat Mexican fireworks.

  • BlackRabbit1 2 hours ago
    As far as I follow the research process it's currently quite difficult to get all data (like the 80MSPS@10-Bit showcase on Reddit) to a computer without a FPGA+USB3.

    With the new ESP32-S31 we most likely can extract the I/Q data over its new 1 GBit/s interface. Guessing something around 20-40MSPS should work.

    These hack will most likely will be a revolution for 13cm ham radio. With the new 5GHz ESP32 modules most likely also for 5cm. As all Espressif components are WiFi-qualified we can expect a very very stable and robust radio.

    I ordered a few and waiting for Ali to deliver them to my lab.

  • xd1936 1 hour ago
    Very exciting!

    > However, the current prototype uses the FPGA to clock the ESP32, which results in poor phase noise.

    Looks like this was solved five days ago:

    https://github.com/h0m3us3r/eSpDR/commit/41a0ffe279119df942e...

  • drtz 1 hour ago
    Since I'm a little slow and it took me a minute:

    SDR in this context is software defined radio.

  • ErroneousBosh 2 hours ago
    > undocumented feature that lets the firmware bypass the fixed WiFi and Bluetooth functionality and instead capture raw IQ baseband samples

    So kind of like those TV USB sticks that you can adapt into proper SDRs?

    • wiml 14 minutes ago
      The ones that the website hosting this article is named after?
    • brcmthrowaway 2 hours ago
      Yep, Matt Ettus converted that to hundreds of millions of dollars
      • BlackRabbit1 1 hour ago
        RTLSDRs only have a 8-Bit ADC that easily drown next to strong transmitters.

        I remember the Ettus devices to be much much much more powerful.

      • CamperBob2 11 minutes ago
        Not with RTL-SDR specifically but by introducing one of the first open-architecture SDRs, the USRP.

        RTL-SDR is the cheapest imaginable commodity implementation of SDR technology, while USRP was... well, pricy enough to bring in some solid revenue and get his company bought. More power to him, it was (and is) an incredibly useful platform.

      • jcrawfordor 45 minutes ago
        the Ettus USRP SDRs predate RTL-SDR by almost (not quite) a decade.
        • ErroneousBosh 6 minutes ago
          I was always into the soundcard HF SDRs, they were so simple and elegant. An oscillator, a ring counter, a 4052 MUX and one really fast dual opamp.
  • iamtheamerican 39 minutes ago
    [dead]