DCC 2011: FUNCube project development


The FUNcube Dongle is a SDR receiver on a USB dongle which currently sells for $125 GPB. It uses the same E4000 tuner found in the $20 RTL-SDR dongle we’ve posted about previously.

The developer is Howard Long, G6VLB, who chronicled the FUNCube’s development in the above video from the 2011 Digital Communications Conference hosted by the ARRL and TAPR in September, 2011 in Baltimore, MD.


A primary goal of the project is to provide a platform for students to monitor the FUNcube satellite. (Contrary to the photo above, the actual FUNCube dongle is small enough to plug into a USB drive.)

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13 Comments

  1. Very instructive video, showing the odds of starting a mass production from a hobby project!

    I t also explains the reasons why a closed hardware solution was eventually chosen.

  2. The FUNcube does not use the RTL2832U for analog to digital conversion and USB interface. It does use the E4000 tuner IC which is also on the DVB-T USB receivers.

    1. You are absolutely right! I just read the legend after watching the video.

      The FunCube Dongle (FCD) is using a much better ADC (102-dBA SNR, 96 kHz SR, up to 32 bit data) from TI and a PIC microcontroller to drive the ADC/audo codec and interface to USB, rather than the 8-bit-only ADC in the all-integrated RTL2832U chip used in the cheap DVB-T USB receivers.

      But the FCD is only one part of the story: it is purposed to be a cheap affordable receiver for the FunCube Satellite!!!

      So, beside its superior receiving characteristics, the FCD Pro is priced higher so the benefits will be used both to finance a cheaper educational model and to launch a few experimental satellites to play with.

      Although it is not an open hardware project for the reasons explained in the video, it is still a respectable non-profit/educational goal.

  3. I’d prefer the Realtek ADC because it has a much higher sample rate meaning it may cover a broader piece of the spectrum. You could for example record multiple transmissions in a frequency multiplex system at once. With only 96 kHz you could only receive one or two immediately adjacent narrowband fm channels.

    Jan

    1. The Realtek has a faster ADC, but only with a 7-bit resolution. I can’t find its bandwidth, but you are right, it is probably larger than FCD.

      This means that the Realtek will be more appropriate for wide band and/or FM, and the FCD for narrow band and/or AM, so YMMV.

  4. Wow, so not only did you use a $ sign instead of a £ sign, you abbreviated “Great British Pound” to GPB!

    To type a £ sign on a US keyboard on Windows:
    alt+0163 (on numpad)
    and on Linux:
    ctl+shift+u00a3

  5. I don’t get it .. wth is funcube?!

    From what I understand this dongle receives the dvb-t signal from 51 MHz to 1.7 GHz (with some gap between 1.1 and 1.2 GHz ), and then what? It’s satellite radio? I don’t get it, what’s it used for? You take a dish, a $50 receiver and you have bunch of satellite radio stations? Is this dongle replacing this $50 satellite receiver? What else can you use it for?

    I get the technical part – you receive from 50M to 1G7, you have 80k bandwidth and then you demodulate the signal on your computer .. but what’s on the signal ?! music?!

    They are sending the satellite up there ?! what’s the point? what is the satellite going to be used for?

    I checked both http://www.funcubedongle.com and http://funcube.org.uk/ and I found no answers there…

    1. The linked video is about the FUNcube Dongle which main mission is to enable educational users to receive the FUNcube.
      The FUNcube Dongle Base will according to the video be quite cheap but its frequency coverage is restricted so it will only be used for receiving the FUNcube.
      It’s also available to the general public as the FUNcube Dongle Pro version which is not frequency restricted.

      “FUNcube is a UK Amateur Radio Satellite for science education in schools and for use by radio amateurs as a relay station (transponder)” (quote from one of the sub-pages on funcube.org.uk)
      That means everyone can receive telemetry information from the satellite – either with a FUNcube Dongle or any other 2 meter band receiver. Which is certainly a nice thing to show to students.
      Additionally radio amateur will be able to use the satellite as an intermediary station (a relay) to talk to each other.

    2. It is exactly that, you lock it to transponder (you can’t see a whole radiation of satellite but you see a whole transponder width) and it gets singnal strength for all frequencies on the transponder (so you can plot a nice graph and see channels there, different width and different powers for each channel on transponder). And when you select a band you want to “receive” it uses fast adc to read the fairly narrow band and send to computer as audio stream, then you get that audio stream and demodulate it in software.

      Basically obsolete technology that’s cheap enough so that radio amateurs can use it

  6. Squonk, I think you’re missing the point of SDR, doessn’t matter how wide the receiver as the demodulation is done in software. Could beSSB,FM or AM or any digital mode. Software Defined!

    1. No, you don’t understand what I meant, I know that because it is done in software, the demodulation can be whatever you want, SDR makes it very flexible!

      But my point was: it is very difficult to get a good AM demodulation with only a 7-bit amplitude resolution ;)

      In order to get something usable, it would require at least twice that resolution, unless you are only interested in OOK!

  7. Well I’ll soon find out as my dongle is “in the mail”, the youtube vids looked good and I ordered mine a week ago.

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